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Downloads:

37,234

Downloads of v 3.4.1:

2,627

Last Update:

18 Jul 2023

Package Maintainer(s):

Software Author(s):

  • IronPython Contributors
  • Microsoft

Tags:

ironpython python dynamic dlr

IronPython

  • 1
  • 2
  • 3

3.4.1 | Updated: 18 Jul 2023

Downloads:

37,234

Downloads of v 3.4.1:

2,627

Maintainer(s):

Software Author(s):

  • IronPython Contributors
  • Microsoft

IronPython 3.4.1

Legal Disclaimer: Neither this package nor Chocolatey Software, Inc. are affiliated with or endorsed by IronPython Contributors, Microsoft. The inclusion of IronPython Contributors, Microsoft trademark(s), if any, upon this webpage is solely to identify IronPython Contributors, Microsoft goods or services and not for commercial purposes.

  • 1
  • 2
  • 3

All Checks are Passing

3 Passing Tests


Validation Testing Passed


Verification Testing Passed

Details

Scan Testing Successful:

No detections found in any package files

Details
Learn More

Deployment Method: Individual Install, Upgrade, & Uninstall

To install IronPython, run the following command from the command line or from PowerShell:

>

To upgrade IronPython, run the following command from the command line or from PowerShell:

>

To uninstall IronPython, run the following command from the command line or from PowerShell:

>

Deployment Method:

NOTE

This applies to both open source and commercial editions of Chocolatey.

1. Enter Your Internal Repository Url

(this should look similar to https://community.chocolatey.org/api/v2/)


2. Setup Your Environment

1. Ensure you are set for organizational deployment

Please see the organizational deployment guide

2. Get the package into your environment

  • Open Source or Commercial:
    • Proxy Repository - Create a proxy nuget repository on Nexus, Artifactory Pro, or a proxy Chocolatey repository on ProGet. Point your upstream to https://community.chocolatey.org/api/v2/. Packages cache on first access automatically. Make sure your choco clients are using your proxy repository as a source and NOT the default community repository. See source command for more information.
    • You can also just download the package and push it to a repository Download

3. Copy Your Script

choco upgrade ironpython -y --source="'INTERNAL REPO URL'" [other options]

See options you can pass to upgrade.

See best practices for scripting.

Add this to a PowerShell script or use a Batch script with tools and in places where you are calling directly to Chocolatey. If you are integrating, keep in mind enhanced exit codes.

If you do use a PowerShell script, use the following to ensure bad exit codes are shown as failures:


choco upgrade ironpython -y --source="'INTERNAL REPO URL'" 
$exitCode = $LASTEXITCODE

Write-Verbose "Exit code was $exitCode"
$validExitCodes = @(0, 1605, 1614, 1641, 3010)
if ($validExitCodes -contains $exitCode) {
  Exit 0
}

Exit $exitCode

- name: Install ironpython
  win_chocolatey:
    name: ironpython
    version: '3.4.1'
    source: INTERNAL REPO URL
    state: present

See docs at https://docs.ansible.com/ansible/latest/modules/win_chocolatey_module.html.


chocolatey_package 'ironpython' do
  action    :install
  source   'INTERNAL REPO URL'
  version  '3.4.1'
end

See docs at https://docs.chef.io/resource_chocolatey_package.html.


cChocoPackageInstaller ironpython
{
    Name     = "ironpython"
    Version  = "3.4.1"
    Source   = "INTERNAL REPO URL"
}

Requires cChoco DSC Resource. See docs at https://github.com/chocolatey/cChoco.


package { 'ironpython':
  ensure   => '3.4.1',
  provider => 'chocolatey',
  source   => 'INTERNAL REPO URL',
}

Requires Puppet Chocolatey Provider module. See docs at https://forge.puppet.com/puppetlabs/chocolatey.


4. If applicable - Chocolatey configuration/installation

See infrastructure management matrix for Chocolatey configuration elements and examples.

Package Approved

This package was approved as a trusted package on 25 Oct 2024.

Description

IronPython is an open-source implementation of the Python programming language that is tightly integrated with the .NET Framework. IronPython can use the .NET Framework and Python libraries, and other .NET languages can use Python code just as easily.


IKVM.Reflection.dll
md5: 2EC8B6F478E732D34F6458B47CC83016 | sha1: 9D833125C1B4FCAE8B49C8DEB13D681D0BBC63F7 | sha256: 0718C32F2184FE2B177A9F1DFADFCFFCC2C1755DE84F659730BA237E13339AF7 | sha512: 6AD6A512471702967E67B76075EF7E458500A7EC6A3DA08841D8108ED287B1F9A20144420303EF95D12910F5318B3A7E8051E35F947732F3910CD281D2E366AA
IronPython.dll
md5: 0CEF60F8033247008F70D12457F52C6D | sha1: 69268B9C497635B85085284274431C56D455BE2B | sha256: FA31585F4EE4140EE4DC3E4130643EA21F514D142A8DBACBC12AFBA5ED7BB5A3 | sha512: D46D37B2AD9846E4AB524D7ABC342A06E046376B14242BD12009E70584F008F50CB63A29A2E616FEBBE533B65E9E93C65DAC9E6C95B62191FB6916609F524C62
IronPython.Modules.dll
md5: 81CB4E974BDD7BE3D2B6A517D5A6BE8A | sha1: BDEE2E351F189BCADB4DE623B634E4A674946619 | sha256: 42154D6CF9FC8C15571140F0656BD98A127814E40F8CEA1FB567D9D97CDE0AA5 | sha512: D75B778A748FDDCD571777DBC36CE1C399BF0E3620E51D079491E5231AAA78C4E47551B6F14D53CC23377253960D9F6ED7B716EF0A48C89CCE9A953E205AC4C9
Microsoft.Dynamic.dll
md5: E23F28491BF2FAA9B4FF0A5EA14F6104 | sha1: 0BCA66EF671E8C860E9F647278B084CAAEC721E4 | sha256: 237F9659526CB6C7F19837A6F2E13E368A19BD0A0731A4C9911038B146BDFF56 | sha512: F58D8396F210DABDFB3EAF011CE2503BF2DE4B005F37D8AE710745D84F81DD7E414C95E853D82DE6B1F48DFDD19FAA9A86DB4BA905B5409AA7CA4BDCC7650258
Microsoft.Scripting.dll
md5: 73DCF3954F7228B3290B6342B55A3D57 | sha1: 0AD74A838AD8AF7A766A99A24EDD822657E56114 | sha256: E5197479D47ADA36E395CBC9DA3381324A792D5D72C0F43916A45264EE97B0ED | sha512: 58763EF89E66C903887DD8B0EC60E8E243966496CBC6F8DEE49FD75F21D841162A4FB5C8EEA8C69C768A563827A73B30F2BBFB9B89B7F4C4B70462091DF50C70
System.Buffers.dll
md5: ECDFE8EDE869D2CCC6BF99981EA96400 | sha1: 2F410A0396BC148ED533AD49B6415FB58DD4D641 | sha256: ACCCCFBE45D9F08FFEED9916E37B33E98C65BE012CFFF6E7FA7B67210CE1FEFB | sha512: 5FC7FEE5C25CB2EEE19737068968E00A00961C257271B420F594E5A0DA0559502D04EE6BA2D8D2AAD77F3769622F6743A5EE8DAE23F8F993F33FB09ED8DB2741
System.Memory.dll
md5: F09441A1EE47FB3E6571A3A448E05BAF | sha1: 3C5C5DF5F8F8DB3F0A35C5ED8D357313A54E3CDE | sha256: BF3FB84664F4097F1A8A9BC71A51DCF8CF1A905D4080A4D290DA1730866E856F | sha512: 0199AE0633BCCFEAEFBB5AED20832A4379C7AD73461D41A9DA3D6DC044093CC319670E67C4EFBF830308CBD9A48FB40D4A6C7E472DCC42EB745C6BA813E8E7C6
System.Numerics.Vectors.dll
md5: AAA2CBF14E06E9D3586D8A4ED455DB33 | sha1: 3D216458740AD5CB05BC5F7C3491CDE44A1E5DF0 | sha256: 1D3EF8698281E7CF7371D1554AFEF5872B39F96C26DA772210A33DA041BA1183 | sha512: 0B14A039CA67982794A2BB69974EF04A7FBEE3686D7364F8F4DB70EA6259D29640CBB83D5B544D92FA1D3676C7619CD580FF45671A2BB4753ED8B383597C6DA8
System.Runtime.CompilerServices.Unsafe.dll
md5: DA04A75DDC22118ED24E0B53E474805A | sha1: 2D68C648A6A6371B6046E6C3AF09128230E0AD32 | sha256: 66409F670315AFE8610F17A4D3A1EE52D72B6A46C544CEC97544E8385F90AD74 | sha512: 26AF01CA25E921465F477A0E1499EDC9E0AC26C23908E5E9B97D3AFD60F3308BFBF2C8CA89EA21878454CD88A1CDDD2F2F0172A6E1E87EF33C56CD7A8D16E9C8
ipy.exe
md5: DA634C577CFE205A10D8D07789098565 | sha1: 1F0D5D2BD3A5331F3F3E2DB3803E500FC2153312 | sha256: E0D0ADA32DA47D7D72E0B1CD57A0146CF1BA456CD9BD7969D5753E5A79E50A1C | sha512: 8A147D5CB779C679B277689AE284BB6BB063A74B3932344DC46573E4C2A23BB221A7DFDA852EDBAD77F60AE8C3E2371E59B81F3DE1C1DC1D315993E37881DA74
ipy32.exe
md5: 7DF883A176DB40367A021870D5493984 | sha1: 94DA6B65FF390D7C26A3A44028D7021F85277376 | sha256: 9023CA3D1BB7DEBD58D74611B1F7A96F101B4192C6E146B6916060A78C170815 | sha512: 2C9C83449C90E5C30B36F193933B1D517EF1142E2EB9959A25EDAD7D64DED6AF4C277A1A471946F92A3654F7FA1ECBF673CC9AA1C90CB0FD7D1934D43E2F2F9A
ipyc.exe
md5: 1CBD3797464703E0F615CE6C305952DA | sha1: 482317A6B46E77B579B9E927B0057424D5A3A193 | sha256: D2E05B45DBD778448BAE830CB209431885463915205D01DB1AA88C76960D1C4C | sha512: CF18BB53E6917B18961806E5C1F81C87DF382ACD0BA5D7BF5D0BD6439F1305C455C8AC5C0929E97722B510E7DEC1BFF3EF181BE5034B184DECD0E4A397DB0204
ipyw.exe
md5: AB876538B68C21DAA09BD562321D088B | sha1: 98272EE4EB3DF1955632D57F450A5F7F8482CFB3 | sha256: 3D9987A384175801DF3B065EFAE6A3CF7C9ADA136E995F5DED9CB9F9F9998822 | sha512: B56CF32DA42A619EE0315FB68FD6C7E9783D30A870C73E407BC4E8EF2176C03C1E9DD2F32DB3B861C9E5CFFFD8E70A98A7D91401F74A5A7BC800DF9499714AFD
ipyw32.exe
md5: 6DC3877BBB2B7BB46EDD2590E94D335B | sha1: 1AA3A59FB5E392C1F8E0CF0C4D3A9A5687406344 | sha256: 19920DD81602A9CBB76F40268AC70D8897AC3B8BEA3EF0F7F1A1A27C9AD5674F | sha512: 3BD19444CEF28ACB741B9AABE675A2418865A2B6FE5DF9D8BD2050F68924DBE396A9011FDC14ACB2A085CDB51B8E37AD349C287F040A68E7F405EBD6E1EF763C
DLLs\IronPython.SQLite.dll
md5: 428C0BDEA54356A34218627970C3CFE7 | sha1: C4F0A7DBB18AD638E3E94E86E7042560B03B4F43 | sha256: 5C43C75D7D88DF61CF76C4739346A1F7947671019C08785457E61DC790ECB0A5 | sha512: B1A1FC669931D0D1D559E50D94C3E7E32C3478F7C52BA11441359FC9C8499193209AD1A931BAFCCF70D9ABD1B2F2ED2879397BBB06B6576418FB5357A8B62189
DLLs\IronPython.SQLite.pdb
 
DLLs\IronPython.Wpf.dll
md5: 248C5D53AA98789FEFBD8DA6DBA4156C | sha1: F80D766A9058765CA1BFD425D85C8677CD3A74A6 | sha256: 4E3C9E0D0EC9120DE35521EE3C3E7A5AD6709686EDC26E7B2B746973BA9C1A47 | sha512: 81EF2D3E12E249A7F26293B9DB981553AB7325A4AA2715573A7749716281B0080F08A0D3C8B6CDF7EBC10ABF353BF2A307646B5103CFD943F152CA0B67D2D21B
DLLs\IronPython.Wpf.pdb
 
lib\abc.py
# Copyright 2007 Google, Inc. All Rights Reserved.
# Licensed to PSF under a Contributor Agreement.

"""Abstract Base Classes (ABCs) according to PEP 3119."""

from _weakrefset import WeakSet


def abstractmethod(funcobj):
    """A decorator indicating abstract methods.

    Requires that the metaclass is ABCMeta or derived from it.  A
    class that has a metaclass derived from ABCMeta cannot be
    instantiated unless all of its abstract methods are overridden.
    The abstract methods can be called using any of the normal
    'super' call mechanisms.

    Usage:

        class C(metaclass=ABCMeta):
            @abstractmethod
            def my_abstract_method(self, ...):
                ...
    """
    funcobj.__isabstractmethod__ = True
    return funcobj


class abstractclassmethod(classmethod):
    """
    A decorator indicating abstract classmethods.

    Similar to abstractmethod.

    Usage:

        class C(metaclass=ABCMeta):
            @abstractclassmethod
            def my_abstract_classmethod(cls, ...):
                ...

    'abstractclassmethod' is deprecated. Use 'classmethod' with
    'abstractmethod' instead.
    """

    __isabstractmethod__ = True

    def __init__(self, callable):
        callable.__isabstractmethod__ = True
        super().__init__(callable)


class abstractstaticmethod(staticmethod):
    """
    A decorator indicating abstract staticmethods.

    Similar to abstractmethod.

    Usage:

        class C(metaclass=ABCMeta):
            @abstractstaticmethod
            def my_abstract_staticmethod(...):
                ...

    'abstractstaticmethod' is deprecated. Use 'staticmethod' with
    'abstractmethod' instead.
    """

    __isabstractmethod__ = True

    def __init__(self, callable):
        callable.__isabstractmethod__ = True
        super().__init__(callable)


class abstractproperty(property):
    """
    A decorator indicating abstract properties.

    Requires that the metaclass is ABCMeta or derived from it.  A
    class that has a metaclass derived from ABCMeta cannot be
    instantiated unless all of its abstract properties are overridden.
    The abstract properties can be called using any of the normal
    'super' call mechanisms.

    Usage:

        class C(metaclass=ABCMeta):
            @abstractproperty
            def my_abstract_property(self):
                ...

    This defines a read-only property; you can also define a read-write
    abstract property using the 'long' form of property declaration:

        class C(metaclass=ABCMeta):
            def getx(self): ...
            def setx(self, value): ...
            x = abstractproperty(getx, setx)

    'abstractproperty' is deprecated. Use 'property' with 'abstractmethod'
    instead.
    """

    __isabstractmethod__ = True


class ABCMeta(type):

    """Metaclass for defining Abstract Base Classes (ABCs).

    Use this metaclass to create an ABC.  An ABC can be subclassed
    directly, and then acts as a mix-in class.  You can also register
    unrelated concrete classes (even built-in classes) and unrelated
    ABCs as 'virtual subclasses' -- these and their descendants will
    be considered subclasses of the registering ABC by the built-in
    issubclass() function, but the registering ABC won't show up in
    their MRO (Method Resolution Order) nor will method
    implementations defined by the registering ABC be callable (not
    even via super()).

    """

    # A global counter that is incremented each time a class is
    # registered as a virtual subclass of anything.  It forces the
    # negative cache to be cleared before its next use.
    # Note: this counter is private. Use `abc.get_cache_token()` for
    #       external code.
    _abc_invalidation_counter = 0

    def __new__(mcls, name, bases, namespace):
        cls = super().__new__(mcls, name, bases, namespace)
        # Compute set of abstract method names
        abstracts = {name
                     for name, value in namespace.items()
                     if getattr(value, "__isabstractmethod__", False)}
        for base in bases:
            for name in getattr(base, "__abstractmethods__", set()):
                value = getattr(cls, name, None)
                if getattr(value, "__isabstractmethod__", False):
                    abstracts.add(name)
        cls.__abstractmethods__ = frozenset(abstracts)
        # Set up inheritance registry
        cls._abc_registry = WeakSet()
        cls._abc_cache = WeakSet()
        cls._abc_negative_cache = WeakSet()
        cls._abc_negative_cache_version = ABCMeta._abc_invalidation_counter
        return cls

    def register(cls, subclass):
        """Register a virtual subclass of an ABC.

        Returns the subclass, to allow usage as a class decorator.
        """
        if not isinstance(subclass, type):
            raise TypeError("Can only register classes")
        if issubclass(subclass, cls):
            return subclass  # Already a subclass
        # Subtle: test for cycles *after* testing for "already a subclass";
        # this means we allow X.register(X) and interpret it as a no-op.
        if issubclass(cls, subclass):
            # This would create a cycle, which is bad for the algorithm below
            raise RuntimeError("Refusing to create an inheritance cycle")
        cls._abc_registry.add(subclass)
        ABCMeta._abc_invalidation_counter += 1  # Invalidate negative cache
        return subclass

    def _dump_registry(cls, file=None):
        """Debug helper to print the ABC registry."""
        print("Class: %s.%s" % (cls.__module__, cls.__name__), file=file)
        print("Inv.counter: %s" % ABCMeta._abc_invalidation_counter, file=file)
        for name in sorted(cls.__dict__.keys()):
            if name.startswith("_abc_"):
                value = getattr(cls, name)
                print("%s: %r" % (name, value), file=file)

    def __instancecheck__(cls, instance):
        """Override for isinstance(instance, cls)."""
        # Inline the cache checking
        subclass = instance.__class__
        if subclass in cls._abc_cache:
            return True
        subtype = type(instance)
        if subtype is subclass:
            if (cls._abc_negative_cache_version ==
                ABCMeta._abc_invalidation_counter and
                subclass in cls._abc_negative_cache):
                return False
            # Fall back to the subclass check.
            return cls.__subclasscheck__(subclass)
        return any(cls.__subclasscheck__(c) for c in {subclass, subtype})

    def __subclasscheck__(cls, subclass):
        """Override for issubclass(subclass, cls)."""
        # Check cache
        if subclass in cls._abc_cache:
            return True
        # Check negative cache; may have to invalidate
        if cls._abc_negative_cache_version < ABCMeta._abc_invalidation_counter:
            # Invalidate the negative cache
            cls._abc_negative_cache = WeakSet()
            cls._abc_negative_cache_version = ABCMeta._abc_invalidation_counter
        elif subclass in cls._abc_negative_cache:
            return False
        # Check the subclass hook
        ok = cls.__subclasshook__(subclass)
        if ok is not NotImplemented:
            assert isinstance(ok, bool)
            if ok:
                cls._abc_cache.add(subclass)
            else:
                cls._abc_negative_cache.add(subclass)
            return ok
        # Check if it's a direct subclass
        if cls in getattr(subclass, '__mro__', ()):
            cls._abc_cache.add(subclass)
            return True
        # Check if it's a subclass of a registered class (recursive)
        for rcls in cls._abc_registry:
            if issubclass(subclass, rcls):
                cls._abc_cache.add(subclass)
                return True
        # Check if it's a subclass of a subclass (recursive)
        for scls in cls.__subclasses__():
            if issubclass(subclass, scls):
                cls._abc_cache.add(subclass)
                return True
        # No dice; update negative cache
        cls._abc_negative_cache.add(subclass)
        return False


class ABC(metaclass=ABCMeta):
    """Helper class that provides a standard way to create an ABC using
    inheritance.
    """
    pass


def get_cache_token():
    """Returns the current ABC cache token.

    The token is an opaque object (supporting equality testing) identifying the
    current version of the ABC cache for virtual subclasses. The token changes
    with every call to ``register()`` on any ABC.
    """
    return ABCMeta._abc_invalidation_counter
lib\aifc.py
"""Stuff to parse AIFF-C and AIFF files.

Unless explicitly stated otherwise, the description below is true
both for AIFF-C files and AIFF files.

An AIFF-C file has the following structure.

  +-----------------+
  | FORM            |
  +-----------------+
  | <size>          |
  +----+------------+
  |    | AIFC       |
  |    +------------+
  |    | <chunks>   |
  |    |    .       |
  |    |    .       |
  |    |    .       |
  +----+------------+

An AIFF file has the string "AIFF" instead of "AIFC".

A chunk consists of an identifier (4 bytes) followed by a size (4 bytes,
big endian order), followed by the data.  The size field does not include
the size of the 8 byte header.

The following chunk types are recognized.

  FVER
      <version number of AIFF-C defining document> (AIFF-C only).
  MARK
      <# of markers> (2 bytes)
      list of markers:
          <marker ID> (2 bytes, must be > 0)
          <position> (4 bytes)
          <marker name> ("pstring")
  COMM
      <# of channels> (2 bytes)
      <# of sound frames> (4 bytes)
      <size of the samples> (2 bytes)
      <sampling frequency> (10 bytes, IEEE 80-bit extended
          floating point)
      in AIFF-C files only:
      <compression type> (4 bytes)
      <human-readable version of compression type> ("pstring")
  SSND
      <offset> (4 bytes, not used by this program)
      <blocksize> (4 bytes, not used by this program)
      <sound data>

A pstring consists of 1 byte length, a string of characters, and 0 or 1
byte pad to make the total length even.

Usage.

Reading AIFF files:
  f = aifc.open(file, 'r')
where file is either the name of a file or an open file pointer.
The open file pointer must have methods read(), seek(), and close().
In some types of audio files, if the setpos() method is not used,
the seek() method is not necessary.

This returns an instance of a class with the following public methods:
  getnchannels()  -- returns number of audio channels (1 for
             mono, 2 for stereo)
  getsampwidth()  -- returns sample width in bytes
  getframerate()  -- returns sampling frequency
  getnframes()    -- returns number of audio frames
  getcomptype()   -- returns compression type ('NONE' for AIFF files)
  getcompname()   -- returns human-readable version of
             compression type ('not compressed' for AIFF files)
  getparams() -- returns a namedtuple consisting of all of the
             above in the above order
  getmarkers()    -- get the list of marks in the audio file or None
             if there are no marks
  getmark(id) -- get mark with the specified id (raises an error
             if the mark does not exist)
  readframes(n)   -- returns at most n frames of audio
  rewind()    -- rewind to the beginning of the audio stream
  setpos(pos) -- seek to the specified position
  tell()      -- return the current position
  close()     -- close the instance (make it unusable)
The position returned by tell(), the position given to setpos() and
the position of marks are all compatible and have nothing to do with
the actual position in the file.
The close() method is called automatically when the class instance
is destroyed.

Writing AIFF files:
  f = aifc.open(file, 'w')
where file is either the name of a file or an open file pointer.
The open file pointer must have methods write(), tell(), seek(), and
close().

This returns an instance of a class with the following public methods:
  aiff()      -- create an AIFF file (AIFF-C default)
  aifc()      -- create an AIFF-C file
  setnchannels(n) -- set the number of channels
  setsampwidth(n) -- set the sample width
  setframerate(n) -- set the frame rate
  setnframes(n)   -- set the number of frames
  setcomptype(type, name)
          -- set the compression type and the
             human-readable compression type
  setparams(tuple)
          -- set all parameters at once
  setmark(id, pos, name)
          -- add specified mark to the list of marks
  tell()      -- return current position in output file (useful
             in combination with setmark())
  writeframesraw(data)
          -- write audio frames without pathing up the
             file header
  writeframes(data)
          -- write audio frames and patch up the file header
  close()     -- patch up the file header and close the
             output file
You should set the parameters before the first writeframesraw or
writeframes.  The total number of frames does not need to be set,
but when it is set to the correct value, the header does not have to
be patched up.
It is best to first set all parameters, perhaps possibly the
compression type, and then write audio frames using writeframesraw.
When all frames have been written, either call writeframes(b'') or
close() to patch up the sizes in the header.
Marks can be added anytime.  If there are any marks, you must call
close() after all frames have been written.
The close() method is called automatically when the class instance
is destroyed.

When a file is opened with the extension '.aiff', an AIFF file is
written, otherwise an AIFF-C file is written.  This default can be
changed by calling aiff() or aifc() before the first writeframes or
writeframesraw.
"""

import struct
import builtins
import warnings

__all__ = ["Error", "open", "openfp"]

class Error(Exception):
    pass

_AIFC_version = 0xA2805140     # Version 1 of AIFF-C

def _read_long(file):
    try:
        return struct.unpack('>l', file.read(4))[0]
    except struct.error:
        raise EOFError

def _read_ulong(file):
    try:
        return struct.unpack('>L', file.read(4))[0]
    except struct.error:
        raise EOFError

def _read_short(file):
    try:
        return struct.unpack('>h', file.read(2))[0]
    except struct.error:
        raise EOFError

def _read_ushort(file):
    try:
        return struct.unpack('>H', file.read(2))[0]
    except struct.error:
        raise EOFError

def _read_string(file):
    length = ord(file.read(1))
    if length == 0:
        data = b''
    else:
        data = file.read(length)
    if length & 1 == 0:
        dummy = file.read(1)
    return data

_HUGE_VAL = 1.79769313486231e+308 # See <limits.h>

def _read_float(f): # 10 bytes
    expon = _read_short(f) # 2 bytes
    sign = 1
    if expon < 0:
        sign = -1
        expon = expon + 0x8000
    himant = _read_ulong(f) # 4 bytes
    lomant = _read_ulong(f) # 4 bytes
    if expon == himant == lomant == 0:
        f = 0.0
    elif expon == 0x7FFF:
        f = _HUGE_VAL
    else:
        expon = expon - 16383
        f = (himant * 0x100000000 + lomant) * pow(2.0, expon - 63)
    return sign * f

def _write_short(f, x):
    f.write(struct.pack('>h', x))

def _write_ushort(f, x):
    f.write(struct.pack('>H', x))

def _write_long(f, x):
    f.write(struct.pack('>l', x))

def _write_ulong(f, x):
    f.write(struct.pack('>L', x))

def _write_string(f, s):
    if len(s) > 255:
        raise ValueError("string exceeds maximum pstring length")
    f.write(struct.pack('B', len(s)))
    f.write(s)
    if len(s) & 1 == 0:
        f.write(b'\x00')

def _write_float(f, x):
    import math
    if x < 0:
        sign = 0x8000
        x = x * -1
    else:
        sign = 0
    if x == 0:
        expon = 0
        himant = 0
        lomant = 0
    else:
        fmant, expon = math.frexp(x)
        if expon > 16384 or fmant >= 1 or fmant != fmant: # Infinity or NaN
            expon = sign|0x7FFF
            himant = 0
            lomant = 0
        else:                   # Finite
            expon = expon + 16382
            if expon < 0:           # denormalized
                fmant = math.ldexp(fmant, expon)
                expon = 0
            expon = expon | sign
            fmant = math.ldexp(fmant, 32)
            fsmant = math.floor(fmant)
            himant = int(fsmant)
            fmant = math.ldexp(fmant - fsmant, 32)
            fsmant = math.floor(fmant)
            lomant = int(fsmant)
    _write_ushort(f, expon)
    _write_ulong(f, himant)
    _write_ulong(f, lomant)

from chunk import Chunk
from collections import namedtuple

_aifc_params = namedtuple('_aifc_params',
                          'nchannels sampwidth framerate nframes comptype compname')


class Aifc_read:
    # Variables used in this class:
    #
    # These variables are available to the user though appropriate
    # methods of this class:
    # _file -- the open file with methods read(), close(), and seek()
    #       set through the __init__() method
    # _nchannels -- the number of audio channels
    #       available through the getnchannels() method
    # _nframes -- the number of audio frames
    #       available through the getnframes() method
    # _sampwidth -- the number of bytes per audio sample
    #       available through the getsampwidth() method
    # _framerate -- the sampling frequency
    #       available through the getframerate() method
    # _comptype -- the AIFF-C compression type ('NONE' if AIFF)
    #       available through the getcomptype() method
    # _compname -- the human-readable AIFF-C compression type
    #       available through the getcomptype() method
    # _markers -- the marks in the audio file
    #       available through the getmarkers() and getmark()
    #       methods
    # _soundpos -- the position in the audio stream
    #       available through the tell() method, set through the
    #       setpos() method
    #
    # These variables are used internally only:
    # _version -- the AIFF-C version number
    # _decomp -- the decompressor from builtin module cl
    # _comm_chunk_read -- 1 iff the COMM chunk has been read
    # _aifc -- 1 iff reading an AIFF-C file
    # _ssnd_seek_needed -- 1 iff positioned correctly in audio
    #       file for readframes()
    # _ssnd_chunk -- instantiation of a chunk class for the SSND chunk
    # _framesize -- size of one frame in the file

    def initfp(self, file):
        self._version = 0
        self._convert = None
        self._markers = []
        self._soundpos = 0
        self._file = file
        chunk = Chunk(file)
        if chunk.getname() != b'FORM':
            raise Error('file does not start with FORM id')
        formdata = chunk.read(4)
        if formdata == b'AIFF':
            self._aifc = 0
        elif formdata == b'AIFC':
            self._aifc = 1
        else:
            raise Error('not an AIFF or AIFF-C file')
        self._comm_chunk_read = 0
        while 1:
            self._ssnd_seek_needed = 1
            try:
                chunk = Chunk(self._file)
            except EOFError:
                break
            chunkname = chunk.getname()
            if chunkname == b'COMM':
                self._read_comm_chunk(chunk)
                self._comm_chunk_read = 1
            elif chunkname == b'SSND':
                self._ssnd_chunk = chunk
                dummy = chunk.read(8)
                self._ssnd_seek_needed = 0
            elif chunkname == b'FVER':
                self._version = _read_ulong(chunk)
            elif chunkname == b'MARK':
                self._readmark(chunk)
            chunk.skip()
        if not self._comm_chunk_read or not self._ssnd_chunk:
            raise Error('COMM chunk and/or SSND chunk missing')

    def __init__(self, f):
        if isinstance(f, str):
            f = builtins.open(f, 'rb')
        # else, assume it is an open file object already
        self.initfp(f)

    def __enter__(self):
        return self

    def __exit__(self, *args):
        self.close()

    #
    # User visible methods.
    #
    def getfp(self):
        return self._file

    def rewind(self):
        self._ssnd_seek_needed = 1
        self._soundpos = 0

    def close(self):
        file = self._file
        if file is not None:
            self._file = None
            file.close()

    def tell(self):
        return self._soundpos

    def getnchannels(self):
        return self._nchannels

    def getnframes(self):
        return self._nframes

    def getsampwidth(self):
        return self._sampwidth

    def getframerate(self):
        return self._framerate

    def getcomptype(self):
        return self._comptype

    def getcompname(self):
        return self._compname

##  def getversion(self):
##      return self._version

    def getparams(self):
        return _aifc_params(self.getnchannels(), self.getsampwidth(),
                            self.getframerate(), self.getnframes(),
                            self.getcomptype(), self.getcompname())

    def getmarkers(self):
        if len(self._markers) == 0:
            return None
        return self._markers

    def getmark(self, id):
        for marker in self._markers:
            if id == marker[0]:
                return marker
        raise Error('marker {0!r} does not exist'.format(id))

    def setpos(self, pos):
        if pos < 0 or pos > self._nframes:
            raise Error('position not in range')
        self._soundpos = pos
        self._ssnd_seek_needed = 1

    def readframes(self, nframes):
        if self._ssnd_seek_needed:
            self._ssnd_chunk.seek(0)
            dummy = self._ssnd_chunk.read(8)
            pos = self._soundpos * self._framesize
            if pos:
                self._ssnd_chunk.seek(pos + 8)
            self._ssnd_seek_needed = 0
        if nframes == 0:
            return b''
        data = self._ssnd_chunk.read(nframes * self._framesize)
        if self._convert and data:
            data = self._convert(data)
        self._soundpos = self._soundpos + len(data) // (self._nchannels
                                                        * self._sampwidth)
        return data

    #
    # Internal methods.
    #

    def _alaw2lin(self, data):
        import audioop
        return audioop.alaw2lin(data, 2)

    def _ulaw2lin(self, data):
        import audioop
        return audioop.ulaw2lin(data, 2)

    def _adpcm2lin(self, data):
        import audioop
        if not hasattr(self, '_adpcmstate'):
            # first time
            self._adpcmstate = None
        data, self._adpcmstate = audioop.adpcm2lin(data, 2, self._adpcmstate)
        return data

    def _read_comm_chunk(self, chunk):
        self._nchannels = _read_short(chunk)
        self._nframes = _read_long(chunk)
        self._sampwidth = (_read_short(chunk) + 7) // 8
        self._framerate = int(_read_float(chunk))
        self._framesize = self._nchannels * self._sampwidth
        if self._aifc:
            #DEBUG: SGI's soundeditor produces a bad size :-(
            kludge = 0
            if chunk.chunksize == 18:
                kludge = 1
                warnings.warn('Warning: bad COMM chunk size')
                chunk.chunksize = 23
            #DEBUG end
            self._comptype = chunk.read(4)
            #DEBUG start
            if kludge:
                length = ord(chunk.file.read(1))
                if length & 1 == 0:
                    length = length + 1
                chunk.chunksize = chunk.chunksize + length
                chunk.file.seek(-1, 1)
            #DEBUG end
            self._compname = _read_string(chunk)
            if self._comptype != b'NONE':
                if self._comptype == b'G722':
                    self._convert = self._adpcm2lin
                elif self._comptype in (b'ulaw', b'ULAW'):
                    self._convert = self._ulaw2lin
                elif self._comptype in (b'alaw', b'ALAW'):
                    self._convert = self._alaw2lin
                else:
                    raise Error('unsupported compression type')
                self._sampwidth = 2
        else:
            self._comptype = b'NONE'
            self._compname = b'not compressed'

    def _readmark(self, chunk):
        nmarkers = _read_short(chunk)
        # Some files appear to contain invalid counts.
        # Cope with this by testing for EOF.
        try:
            for i in range(nmarkers):
                id = _read_short(chunk)
                pos = _read_long(chunk)
                name = _read_string(chunk)
                if pos or name:
                    # some files appear to have
                    # dummy markers consisting of
                    # a position 0 and name ''
                    self._markers.append((id, pos, name))
        except EOFError:
            w = ('Warning: MARK chunk contains only %s marker%s instead of %s' %
                 (len(self._markers), '' if len(self._markers) == 1 else 's',
                  nmarkers))
            warnings.warn(w)

class Aifc_write:
    # Variables used in this class:
    #
    # These variables are user settable through appropriate methods
    # of this class:
    # _file -- the open file with methods write(), close(), tell(), seek()
    #       set through the __init__() method
    # _comptype -- the AIFF-C compression type ('NONE' in AIFF)
    #       set through the setcomptype() or setparams() method
    # _compname -- the human-readable AIFF-C compression type
    #       set through the setcomptype() or setparams() method
    # _nchannels -- the number of audio channels
    #       set through the setnchannels() or setparams() method
    # _sampwidth -- the number of bytes per audio sample
    #       set through the setsampwidth() or setparams() method
    # _framerate -- the sampling frequency
    #       set through the setframerate() or setparams() method
    # _nframes -- the number of audio frames written to the header
    #       set through the setnframes() or setparams() method
    # _aifc -- whether we're writing an AIFF-C file or an AIFF file
    #       set through the aifc() method, reset through the
    #       aiff() method
    #
    # These variables are used internally only:
    # _version -- the AIFF-C version number
    # _comp -- the compressor from builtin module cl
    # _nframeswritten -- the number of audio frames actually written
    # _datalength -- the size of the audio samples written to the header
    # _datawritten -- the size of the audio samples actually written

    def __init__(self, f):
        if isinstance(f, str):
            filename = f
            f = builtins.open(f, 'wb')
        else:
            # else, assume it is an open file object already
            filename = '???'
        self.initfp(f)
        if filename[-5:] == '.aiff':
            self._aifc = 0
        else:
            self._aifc = 1

    def initfp(self, file):
        self._file = file
        self._version = _AIFC_version
        self._comptype = b'NONE'
        self._compname = b'not compressed'
        self._convert = None
        self._nchannels = 0
        self._sampwidth = 0
        self._framerate = 0
        self._nframes = 0
        self._nframeswritten = 0
        self._datawritten = 0
        self._datalength = 0
        self._markers = []
        self._marklength = 0
        self._aifc = 1      # AIFF-C is default

    def __del__(self):
        self.close()

    def __enter__(self):
        return self

    def __exit__(self, *args):
        self.close()

    #
    # User visible methods.
    #
    def aiff(self):
        if self._nframeswritten:
            raise Error('cannot change parameters after starting to write')
        self._aifc = 0

    def aifc(self):
        if self._nframeswritten:
            raise Error('cannot change parameters after starting to write')
        self._aifc = 1

    def setnchannels(self, nchannels):
        if self._nframeswritten:
            raise Error('cannot change parameters after starting to write')
        if nchannels < 1:
            raise Error('bad # of channels')
        self._nchannels = nchannels

    def getnchannels(self):
        if not self._nchannels:
            raise Error('number of channels not set')
        return self._nchannels

    def setsampwidth(self, sampwidth):
        if self._nframeswritten:
            raise Error('cannot change parameters after starting to write')
        if sampwidth < 1 or sampwidth > 4:
            raise Error('bad sample width')
        self._sampwidth = sampwidth

    def getsampwidth(self):
        if not self._sampwidth:
            raise Error('sample width not set')
        return self._sampwidth

    def setframerate(self, framerate):
        if self._nframeswritten:
            raise Error('cannot change parameters after starting to write')
        if framerate <= 0:
            raise Error('bad frame rate')
        self._framerate = framerate

    def getframerate(self):
        if not self._framerate:
            raise Error('frame rate not set')
        return self._framerate

    def setnframes(self, nframes):
        if self._nframeswritten:
            raise Error('cannot change parameters after starting to write')
        self._nframes = nframes

    def getnframes(self):
        return self._nframeswritten

    def setcomptype(self, comptype, compname):
        if self._nframeswritten:
            raise Error('cannot change parameters after starting to write')
        if comptype not in (b'NONE', b'ulaw', b'ULAW',
                            b'alaw', b'ALAW', b'G722'):
            raise Error('unsupported compression type')
        self._comptype = comptype
        self._compname = compname

    def getcomptype(self):
        return self._comptype

    def getcompname(self):
        return self._compname

##  def setversion(self, version):
##      if self._nframeswritten:
##          raise Error, 'cannot change parameters after starting to write'
##      self._version = version

    def setparams(self, params):
        nchannels, sampwidth, framerate, nframes, comptype, compname = params
        if self._nframeswritten:
            raise Error('cannot change parameters after starting to write')
        if comptype not in (b'NONE', b'ulaw', b'ULAW',
                            b'alaw', b'ALAW', b'G722'):
            raise Error('unsupported compression type')
        self.setnchannels(nchannels)
        self.setsampwidth(sampwidth)
        self.setframerate(framerate)
        self.setnframes(nframes)
        self.setcomptype(comptype, compname)

    def getparams(self):
        if not self._nchannels or not self._sampwidth or not self._framerate:
            raise Error('not all parameters set')
        return _aifc_params(self._nchannels, self._sampwidth, self._framerate,
                            self._nframes, self._comptype, self._compname)

    def setmark(self, id, pos, name):
        if id <= 0:
            raise Error('marker ID must be > 0')
        if pos < 0:
            raise Error('marker position must be >= 0')
        if not isinstance(name, bytes):
            raise Error('marker name must be bytes')
        for i in range(len(self._markers)):
            if id == self._markers[i][0]:
                self._markers[i] = id, pos, name
                return
        self._markers.append((id, pos, name))

    def getmark(self, id):
        for marker in self._markers:
            if id == marker[0]:
                return marker
        raise Error('marker {0!r} does not exist'.format(id))

    def getmarkers(self):
        if len(self._markers) == 0:
            return None
        return self._markers

    def tell(self):
        return self._nframeswritten

    def writeframesraw(self, data):
        if not isinstance(data, (bytes, bytearray)):
            data = memoryview(data).cast('B')
        self._ensure_header_written(len(data))
        nframes = len(data) // (self._sampwidth * self._nchannels)
        if self._convert:
            data = self._convert(data)
        self._file.write(data)
        self._nframeswritten = self._nframeswritten + nframes
        self._datawritten = self._datawritten + len(data)

    def writeframes(self, data):
        self.writeframesraw(data)
        if self._nframeswritten != self._nframes or \
              self._datalength != self._datawritten:
            self._patchheader()

    def close(self):
        if self._file is None:
            return
        try:
            self._ensure_header_written(0)
            if self._datawritten & 1:
                # quick pad to even size
                self._file.write(b'\x00')
                self._datawritten = self._datawritten + 1
            self._writemarkers()
            if self._nframeswritten != self._nframes or \
                  self._datalength != self._datawritten or \
                  self._marklength:
                self._patchheader()
        finally:
            # Prevent ref cycles
            self._convert = None
            f = self._file
            self._file = None
            f.close()

    #
    # Internal methods.
    #

    def _lin2alaw(self, data):
        import audioop
        return audioop.lin2alaw(data, 2)

    def _lin2ulaw(self, data):
        import audioop
        return audioop.lin2ulaw(data, 2)

    def _lin2adpcm(self, data):
        import audioop
        if not hasattr(self, '_adpcmstate'):
            self._adpcmstate = None
        data, self._adpcmstate = audioop.lin2adpcm(data, 2, self._adpcmstate)
        return data

    def _ensure_header_written(self, datasize):
        if not self._nframeswritten:
            if self._comptype in (b'ULAW', b'ulaw', b'ALAW', b'alaw', b'G722'):
                if not self._sampwidth:
                    self._sampwidth = 2
                if self._sampwidth != 2:
                    raise Error('sample width must be 2 when compressing '
                                'with ulaw/ULAW, alaw/ALAW or G7.22 (ADPCM)')
            if not self._nchannels:
                raise Error('# channels not specified')
            if not self._sampwidth:
                raise Error('sample width not specified')
            if not self._framerate:
                raise Error('sampling rate not specified')
            self._write_header(datasize)

    def _init_compression(self):
        if self._comptype == b'G722':
            self._convert = self._lin2adpcm
        elif self._comptype in (b'ulaw', b'ULAW'):
            self._convert = self._lin2ulaw
        elif self._comptype in (b'alaw', b'ALAW'):
            self._convert = self._lin2alaw

    def _write_header(self, initlength):
        if self._aifc and self._comptype != b'NONE':
            self._init_compression()
        self._file.write(b'FORM')
        if not self._nframes:
            self._nframes = initlength // (self._nchannels * self._sampwidth)
        self._datalength = self._nframes * self._nchannels * self._sampwidth
        if self._datalength & 1:
            self._datalength = self._datalength + 1
        if self._aifc:
            if self._comptype in (b'ulaw', b'ULAW', b'alaw', b'ALAW'):
                self._datalength = self._datalength // 2
                if self._datalength & 1:
                    self._datalength = self._datalength + 1
            elif self._comptype == b'G722':
                self._datalength = (self._datalength + 3) // 4
                if self._datalength & 1:
                    self._datalength = self._datalength + 1
        try:
            self._form_length_pos = self._file.tell()
        except (AttributeError, OSError):
            self._form_length_pos = None
        commlength = self._write_form_length(self._datalength)
        if self._aifc:
            self._file.write(b'AIFC')
            self._file.write(b'FVER')
            _write_ulong(self._file, 4)
            _write_ulong(self._file, self._version)
        else:
            self._file.write(b'AIFF')
        self._file.write(b'COMM')
        _write_ulong(self._file, commlength)
        _write_short(self._file, self._nchannels)
        if self._form_length_pos is not None:
            self._nframes_pos = self._file.tell()
        _write_ulong(self._file, self._nframes)
        if self._comptype in (b'ULAW', b'ulaw', b'ALAW', b'alaw', b'G722'):
            _write_short(self._file, 8)
        else:
            _write_short(self._file, self._sampwidth * 8)
        _write_float(self._file, self._framerate)
        if self._aifc:
            self._file.write(self._comptype)
            _write_string(self._file, self._compname)
        self._file.write(b'SSND')
        if self._form_length_pos is not None:
            self._ssnd_length_pos = self._file.tell()
        _write_ulong(self._file, self._datalength + 8)
        _write_ulong(self._file, 0)
        _write_ulong(self._file, 0)

    def _write_form_length(self, datalength):
        if self._aifc:
            commlength = 18 + 5 + len(self._compname)
            if commlength & 1:
                commlength = commlength + 1
            verslength = 12
        else:
            commlength = 18
            verslength = 0
        _write_ulong(self._file, 4 + verslength + self._marklength + \
                     8 + commlength + 16 + datalength)
        return commlength

    def _patchheader(self):
        curpos = self._file.tell()
        if self._datawritten & 1:
            datalength = self._datawritten + 1
            self._file.write(b'\x00')
        else:
            datalength = self._datawritten
        if datalength == self._datalength and \
              self._nframes == self._nframeswritten and \
              self._marklength == 0:
            self._file.seek(curpos, 0)
            return
        self._file.seek(self._form_length_pos, 0)
        dummy = self._write_form_length(datalength)
        self._file.seek(self._nframes_pos, 0)
        _write_ulong(self._file, self._nframeswritten)
        self._file.seek(self._ssnd_length_pos, 0)
        _write_ulong(self._file, datalength + 8)
        self._file.seek(curpos, 0)
        self._nframes = self._nframeswritten
        self._datalength = datalength

    def _writemarkers(self):
        if len(self._markers) == 0:
            return
        self._file.write(b'MARK')
        length = 2
        for marker in self._markers:
            id, pos, name = marker
            length = length + len(name) + 1 + 6
            if len(name) & 1 == 0:
                length = length + 1
        _write_ulong(self._file, length)
        self._marklength = length + 8
        _write_short(self._file, len(self._markers))
        for marker in self._markers:
            id, pos, name = marker
            _write_short(self._file, id)
            _write_ulong(self._file, pos)
            _write_string(self._file, name)

def open(f, mode=None):
    if mode is None:
        if hasattr(f, 'mode'):
            mode = f.mode
        else:
            mode = 'rb'
    if mode in ('r', 'rb'):
        return Aifc_read(f)
    elif mode in ('w', 'wb'):
        return Aifc_write(f)
    else:
        raise Error("mode must be 'r', 'rb', 'w', or 'wb'")

openfp = open # B/W compatibility

if __name__ == '__main__':
    import sys
    if not sys.argv[1:]:
        sys.argv.append('/usr/demos/data/audio/bach.aiff')
    fn = sys.argv[1]
    with open(fn, 'r') as f:
        print("Reading", fn)
        print("nchannels =", f.getnchannels())
        print("nframes   =", f.getnframes())
        print("sampwidth =", f.getsampwidth())
        print("framerate =", f.getframerate())
        print("comptype  =", f.getcomptype())
        print("compname  =", f.getcompname())
        if sys.argv[2:]:
            gn = sys.argv[2]
            print("Writing", gn)
            with open(gn, 'w') as g:
                g.setparams(f.getparams())
                while 1:
                    data = f.readframes(1024)
                    if not data:
                        break
                    g.writeframes(data)
            print("Done.")
lib\antigravity.py

import webbrowser
import hashlib

webbrowser.open("http://xkcd.com/353/")

def geohash(latitude, longitude, datedow):
    '''Compute geohash() using the Munroe algorithm.

    >>> geohash(37.421542, -122.085589, b'2005-05-26-10458.68')
    37.857713 -122.544543

    '''
    # http://xkcd.com/426/
    h = hashlib.md5(datedow).hexdigest()
    p, q = [('%f' % float.fromhex('0.' + x)) for x in (h[:16], h[16:32])]
    print('%d%s %d%s' % (latitude, p[1:], longitude, q[1:]))
lib\argparse.py
# Author: Steven J. Bethard <[email protected]>.

"""Command-line parsing library

This module is an optparse-inspired command-line parsing library that:

    - handles both optional and positional arguments
    - produces highly informative usage messages
    - supports parsers that dispatch to sub-parsers

The following is a simple usage example that sums integers from the
command-line and writes the result to a file::

    parser = argparse.ArgumentParser(
        description='sum the integers at the command line')
    parser.add_argument(
        'integers', metavar='int', nargs='+', type=int,
        help='an integer to be summed')
    parser.add_argument(
        '--log', default=sys.stdout, type=argparse.FileType('w'),
        help='the file where the sum should be written')
    args = parser.parse_args()
    args.log.write('%s' % sum(args.integers))
    args.log.close()

The module contains the following public classes:

    - ArgumentParser -- The main entry point for command-line parsing. As the
        example above shows, the add_argument() method is used to populate
        the parser with actions for optional and positional arguments. Then
        the parse_args() method is invoked to convert the args at the
        command-line into an object with attributes.

    - ArgumentError -- The exception raised by ArgumentParser objects when
        there are errors with the parser's actions. Errors raised while
        parsing the command-line are caught by ArgumentParser and emitted
        as command-line messages.

    - FileType -- A factory for defining types of files to be created. As the
        example above shows, instances of FileType are typically passed as
        the type= argument of add_argument() calls.

    - Action -- The base class for parser actions. Typically actions are
        selected by passing strings like 'store_true' or 'append_const' to
        the action= argument of add_argument(). However, for greater
        customization of ArgumentParser actions, subclasses of Action may
        be defined and passed as the action= argument.

    - HelpFormatter, RawDescriptionHelpFormatter, RawTextHelpFormatter,
        ArgumentDefaultsHelpFormatter -- Formatter classes which
        may be passed as the formatter_class= argument to the
        ArgumentParser constructor. HelpFormatter is the default,
        RawDescriptionHelpFormatter and RawTextHelpFormatter tell the parser
        not to change the formatting for help text, and
        ArgumentDefaultsHelpFormatter adds information about argument defaults
        to the help.

All other classes in this module are considered implementation details.
(Also note that HelpFormatter and RawDescriptionHelpFormatter are only
considered public as object names -- the API of the formatter objects is
still considered an implementation detail.)
"""

__version__ = '1.1'
__all__ = [
    'ArgumentParser',
    'ArgumentError',
    'ArgumentTypeError',
    'FileType',
    'HelpFormatter',
    'ArgumentDefaultsHelpFormatter',
    'RawDescriptionHelpFormatter',
    'RawTextHelpFormatter',
    'MetavarTypeHelpFormatter',
    'Namespace',
    'Action',
    'ONE_OR_MORE',
    'OPTIONAL',
    'PARSER',
    'REMAINDER',
    'SUPPRESS',
    'ZERO_OR_MORE',
]


import collections as _collections
import copy as _copy
import os as _os
import re as _re
import sys as _sys
import textwrap as _textwrap

from gettext import gettext as _, ngettext


SUPPRESS = '==SUPPRESS=='

OPTIONAL = '?'
ZERO_OR_MORE = '*'
ONE_OR_MORE = '+'
PARSER = 'A...'
REMAINDER = '...'
_UNRECOGNIZED_ARGS_ATTR = '_unrecognized_args'

# =============================
# Utility functions and classes
# =============================

class _AttributeHolder(object):
    """Abstract base class that provides __repr__.

    The __repr__ method returns a string in the format::
        ClassName(attr=name, attr=name, ...)
    The attributes are determined either by a class-level attribute,
    '_kwarg_names', or by inspecting the instance __dict__.
    """

    def __repr__(self):
        type_name = type(self).__name__
        arg_strings = []
        for arg in self._get_args():
            arg_strings.append(repr(arg))
        for name, value in self._get_kwargs():
            arg_strings.append('%s=%r' % (name, value))
        return '%s(%s)' % (type_name, ', '.join(arg_strings))

    def _get_kwargs(self):
        return sorted(self.__dict__.items())

    def _get_args(self):
        return []


def _ensure_value(namespace, name, value):
    if getattr(namespace, name, None) is None:
        setattr(namespace, name, value)
    return getattr(namespace, name)


# ===============
# Formatting Help
# ===============

class HelpFormatter(object):
    """Formatter for generating usage messages and argument help strings.

    Only the name of this class is considered a public API. All the methods
    provided by the class are considered an implementation detail.
    """

    def __init__(self,
                 prog,
                 indent_increment=2,
                 max_help_position=24,
                 width=None):

        # default setting for width
        if width is None:
            try:
                width = int(_os.environ['COLUMNS'])
            except (KeyError, ValueError):
                width = 80
            width -= 2

        self._prog = prog
        self._indent_increment = indent_increment
        self._max_help_position = max_help_position
        self._max_help_position = min(max_help_position,
                                      max(width - 20, indent_increment * 2))
        self._width = width

        self._current_indent = 0
        self._level = 0
        self._action_max_length = 0

        self._root_section = self._Section(self, None)
        self._current_section = self._root_section

        self._whitespace_matcher = _re.compile(r'\s+')
        self._long_break_matcher = _re.compile(r'\n\n\n+')

    # ===============================
    # Section and indentation methods
    # ===============================
    def _indent(self):
        self._current_indent += self._indent_increment
        self._level += 1

    def _dedent(self):
        self._current_indent -= self._indent_increment
        assert self._current_indent >= 0, 'Indent decreased below 0.'
        self._level -= 1

    class _Section(object):

        def __init__(self, formatter, parent, heading=None):
            self.formatter = formatter
            self.parent = parent
            self.heading = heading
            self.items = []

        def format_help(self):
            # format the indented section
            if self.parent is not None:
                self.formatter._indent()
            join = self.formatter._join_parts
            for func, args in self.items:
                func(*args)
            item_help = join([func(*args) for func, args in self.items])
            if self.parent is not None:
                self.formatter._dedent()

            # return nothing if the section was empty
            if not item_help:
                return ''

            # add the heading if the section was non-empty
            if self.heading is not SUPPRESS and self.heading is not None:
                current_indent = self.formatter._current_indent
                heading = '%*s%s:\n' % (current_indent, '', self.heading)
            else:
                heading = ''

            # join the section-initial newline, the heading and the help
            return join(['\n', heading, item_help, '\n'])

    def _add_item(self, func, args):
        self._current_section.items.append((func, args))

    # ========================
    # Message building methods
    # ========================
    def start_section(self, heading):
        self._indent()
        section = self._Section(self, self._current_section, heading)
        self._add_item(section.format_help, [])
        self._current_section = section

    def end_section(self):
        self._current_section = self._current_section.parent
        self._dedent()

    def add_text(self, text):
        if text is not SUPPRESS and text is not None:
            self._add_item(self._format_text, [text])

    def add_usage(self, usage, actions, groups, prefix=None):
        if usage is not SUPPRESS:
            args = usage, actions, groups, prefix
            self._add_item(self._format_usage, args)

    def add_argument(self, action):
        if action.help is not SUPPRESS:

            # find all invocations
            get_invocation = self._format_action_invocation
            invocations = [get_invocation(action)]
            for subaction in self._iter_indented_subactions(action):
                invocations.append(get_invocation(subaction))

            # update the maximum item length
            invocation_length = max([len(s) for s in invocations])
            action_length = invocation_length + self._current_indent
            self._action_max_length = max(self._action_max_length,
                                          action_length)

            # add the item to the list
            self._add_item(self._format_action, [action])

    def add_arguments(self, actions):
        for action in actions:
            self.add_argument(action)

    # =======================
    # Help-formatting methods
    # =======================
    def format_help(self):
        help = self._root_section.format_help()
        if help:
            help = self._long_break_matcher.sub('\n\n', help)
            help = help.strip('\n') + '\n'
        return help

    def _join_parts(self, part_strings):
        return ''.join([part
                        for part in part_strings
                        if part and part is not SUPPRESS])

    def _format_usage(self, usage, actions, groups, prefix):
        if prefix is None:
            prefix = _('usage: ')

        # if usage is specified, use that
        if usage is not None:
            usage = usage % dict(prog=self._prog)

        # if no optionals or positionals are available, usage is just prog
        elif usage is None and not actions:
            usage = '%(prog)s' % dict(prog=self._prog)

        # if optionals and positionals are available, calculate usage
        elif usage is None:
            prog = '%(prog)s' % dict(prog=self._prog)

            # split optionals from positionals
            optionals = []
            positionals = []
            for action in actions:
                if action.option_strings:
                    optionals.append(action)
                else:
                    positionals.append(action)

            # build full usage string
            format = self._format_actions_usage
            action_usage = format(optionals + positionals, groups)
            usage = ' '.join([s for s in [prog, action_usage] if s])

            # wrap the usage parts if it's too long
            text_width = self._width - self._current_indent
            if len(prefix) + len(usage) > text_width:

                # break usage into wrappable parts
                part_regexp = r'\(.*?\)+|\[.*?\]+|\S+'
                opt_usage = format(optionals, groups)
                pos_usage = format(positionals, groups)
                opt_parts = _re.findall(part_regexp, opt_usage)
                pos_parts = _re.findall(part_regexp, pos_usage)
                assert ' '.join(opt_parts) == opt_usage
                assert ' '.join(pos_parts) == pos_usage

                # helper for wrapping lines
                def get_lines(parts, indent, prefix=None):
                    lines = []
                    line = []
                    if prefix is not None:
                        line_len = len(prefix) - 1
                    else:
                        line_len = len(indent) - 1
                    for part in parts:
                        if line_len + 1 + len(part) > text_width and line:
                            lines.append(indent + ' '.join(line))
                            line = []
                            line_len = len(indent) - 1
                        line.append(part)
                        line_len += len(part) + 1
                    if line:
                        lines.append(indent + ' '.join(line))
                    if prefix is not None:
                        lines[0] = lines[0][len(indent):]
                    return lines

                # if prog is short, follow it with optionals or positionals
                if len(prefix) + len(prog) <= 0.75 * text_width:
                    indent = ' ' * (len(prefix) + len(prog) + 1)
                    if opt_parts:
                        lines = get_lines([prog] + opt_parts, indent, prefix)
                        lines.extend(get_lines(pos_parts, indent))
                    elif pos_parts:
                        lines = get_lines([prog] + pos_parts, indent, prefix)
                    else:
                        lines = [prog]

                # if prog is long, put it on its own line
                else:
                    indent = ' ' * len(prefix)
                    parts = opt_parts + pos_parts
                    lines = get_lines(parts, indent)
                    if len(lines) > 1:
                        lines = []
                        lines.extend(get_lines(opt_parts, indent))
                        lines.extend(get_lines(pos_parts, indent))
                    lines = [prog] + lines

                # join lines into usage
                usage = '\n'.join(lines)

        # prefix with 'usage:'
        return '%s%s\n\n' % (prefix, usage)

    def _format_actions_usage(self, actions, groups):
        # find group indices and identify actions in groups
        group_actions = set()
        inserts = {}
        for group in groups:
            try:
                start = actions.index(group._group_actions[0])
            except ValueError:
                continue
            else:
                end = start + len(group._group_actions)
                if actions[start:end] == group._group_actions:
                    for action in group._group_actions:
                        group_actions.add(action)
                    if not group.required:
                        if start in inserts:
                            inserts[start] += ' ['
                        else:
                            inserts[start] = '['
                        inserts[end] = ']'
                    else:
                        if start in inserts:
                            inserts[start] += ' ('
                        else:
                            inserts[start] = '('
                        inserts[end] = ')'
                    for i in range(start + 1, end):
                        inserts[i] = '|'

        # collect all actions format strings
        parts = []
        for i, action in enumerate(actions):

            # suppressed arguments are marked with None
            # remove | separators for suppressed arguments
            if action.help is SUPPRESS:
                parts.append(None)
                if inserts.get(i) == '|':
                    inserts.pop(i)
                elif inserts.get(i + 1) == '|':
                    inserts.pop(i + 1)

            # produce all arg strings
            elif not action.option_strings:
                default = self._get_default_metavar_for_positional(action)
                part = self._format_args(action, default)

                # if it's in a group, strip the outer []
                if action in group_actions:
                    if part[0] == '[' and part[-1] == ']':
                        part = part[1:-1]

                # add the action string to the list
                parts.append(part)

            # produce the first way to invoke the option in brackets
            else:
                option_string = action.option_strings[0]

                # if the Optional doesn't take a value, format is:
                #    -s or --long
                if action.nargs == 0:
                    part = '%s' % option_string

                # if the Optional takes a value, format is:
                #    -s ARGS or --long ARGS
                else:
                    default = self._get_default_metavar_for_optional(action)
                    args_string = self._format_args(action, default)
                    part = '%s %s' % (option_string, args_string)

                # make it look optional if it's not required or in a group
                if not action.required and action not in group_actions:
                    part = '[%s]' % part

                # add the action string to the list
                parts.append(part)

        # insert things at the necessary indices
        for i in sorted(inserts, reverse=True):
            parts[i:i] = [inserts[i]]

        # join all the action items with spaces
        text = ' '.join([item for item in parts if item is not None])

        # clean up separators for mutually exclusive groups
        open = r'[\[(]'
        close = r'[\])]'
        text = _re.sub(r'(%s) ' % open, r'\1', text)
        text = _re.sub(r' (%s)' % close, r'\1', text)
        text = _re.sub(r'%s *%s' % (open, close), r'', text)
        text = _re.sub(r'\(([^|]*)\)', r'\1', text)
        text = text.strip()

        # return the text
        return text

    def _format_text(self, text):
        if '%(prog)' in text:
            text = text % dict(prog=self._prog)
        text_width = max(self._width - self._current_indent, 11)
        indent = ' ' * self._current_indent
        return self._fill_text(text, text_width, indent) + '\n\n'

    def _format_action(self, action):
        # determine the required width and the entry label
        help_position = min(self._action_max_length + 2,
                            self._max_help_position)
        help_width = max(self._width - help_position, 11)
        action_width = help_position - self._current_indent - 2
        action_header = self._format_action_invocation(action)

        # no help; start on same line and add a final newline
        if not action.help:
            tup = self._current_indent, '', action_header
            action_header = '%*s%s\n' % tup

        # short action name; start on the same line and pad two spaces
        elif len(action_header) <= action_width:
            tup = self._current_indent, '', action_width, action_header
            action_header = '%*s%-*s  ' % tup
            indent_first = 0

        # long action name; start on the next line
        else:
            tup = self._current_indent, '', action_header
            action_header = '%*s%s\n' % tup
            indent_first = help_position

        # collect the pieces of the action help
        parts = [action_header]

        # if there was help for the action, add lines of help text
        if action.help:
            help_text = self._expand_help(action)
            help_lines = self._split_lines(help_text, help_width)
            parts.append('%*s%s\n' % (indent_first, '', help_lines[0]))
            for line in help_lines[1:]:
                parts.append('%*s%s\n' % (help_position, '', line))

        # or add a newline if the description doesn't end with one
        elif not action_header.endswith('\n'):
            parts.append('\n')

        # if there are any sub-actions, add their help as well
        for subaction in self._iter_indented_subactions(action):
            parts.append(self._format_action(subaction))

        # return a single string
        return self._join_parts(parts)

    def _format_action_invocation(self, action):
        if not action.option_strings:
            default = self._get_default_metavar_for_positional(action)
            metavar, = self._metavar_formatter(action, default)(1)
            return metavar

        else:
            parts = []

            # if the Optional doesn't take a value, format is:
            #    -s, --long
            if action.nargs == 0:
                parts.extend(action.option_strings)

            # if the Optional takes a value, format is:
            #    -s ARGS, --long ARGS
            else:
                default = self._get_default_metavar_for_optional(action)
                args_string = self._format_args(action, default)
                for option_string in action.option_strings:
                    parts.append('%s %s' % (option_string, args_string))

            return ', '.join(parts)

    def _metavar_formatter(self, action, default_metavar):
        if action.metavar is not None:
            result = action.metavar
        elif action.choices is not None:
            choice_strs = [str(choice) for choice in action.choices]
            result = '{%s}' % ','.join(choice_strs)
        else:
            result = default_metavar

        def format(tuple_size):
            if isinstance(result, tuple):
                return result
            else:
                return (result, ) * tuple_size
        return format

    def _format_args(self, action, default_metavar):
        get_metavar = self._metavar_formatter(action, default_metavar)
        if action.nargs is None:
            result = '%s' % get_metavar(1)
        elif action.nargs == OPTIONAL:
            result = '[%s]' % get_metavar(1)
        elif action.nargs == ZERO_OR_MORE:
            result = '[%s [%s ...]]' % get_metavar(2)
        elif action.nargs == ONE_OR_MORE:
            result = '%s [%s ...]' % get_metavar(2)
        elif action.nargs == REMAINDER:
            result = '...'
        elif action.nargs == PARSER:
            result = '%s ...' % get_metavar(1)
        else:
            formats = ['%s' for _ in range(action.nargs)]
            result = ' '.join(formats) % get_metavar(action.nargs)
        return result

    def _expand_help(self, action):
        params = dict(vars(action), prog=self._prog)
        for name in list(params):
            if params[name] is SUPPRESS:
                del params[name]
        for name in list(params):
            if hasattr(params[name], '__name__'):
                params[name] = params[name].__name__
        if params.get('choices') is not None:
            choices_str = ', '.join([str(c) for c in params['choices']])
            params['choices'] = choices_str
        return self._get_help_string(action) % params

    def _iter_indented_subactions(self, action):
        try:
            get_subactions = action._get_subactions
        except AttributeError:
            pass
        else:
            self._indent()
            yield from get_subactions()
            self._dedent()

    def _split_lines(self, text, width):
        text = self._whitespace_matcher.sub(' ', text).strip()
        return _textwrap.wrap(text, width)

    def _fill_text(self, text, width, indent):
        text = self._whitespace_matcher.sub(' ', text).strip()
        return _textwrap.fill(text, width, initial_indent=indent,
                                           subsequent_indent=indent)

    def _get_help_string(self, action):
        return action.help

    def _get_default_metavar_for_optional(self, action):
        return action.dest.upper()

    def _get_default_metavar_for_positional(self, action):
        return action.dest


class RawDescriptionHelpFormatter(HelpFormatter):
    """Help message formatter which retains any formatting in descriptions.

    Only the name of this class is considered a public API. All the methods
    provided by the class are considered an implementation detail.
    """

    def _fill_text(self, text, width, indent):
        return ''.join(indent + line for line in text.splitlines(keepends=True))


class RawTextHelpFormatter(RawDescriptionHelpFormatter):
    """Help message formatter which retains formatting of all help text.

    Only the name of this class is considered a public API. All the methods
    provided by the class are considered an implementation detail.
    """

    def _split_lines(self, text, width):
        return text.splitlines()


class ArgumentDefaultsHelpFormatter(HelpFormatter):
    """Help message formatter which adds default values to argument help.

    Only the name of this class is considered a public API. All the methods
    provided by the class are considered an implementation detail.
    """

    def _get_help_string(self, action):
        help = action.help
        if '%(default)' not in action.help:
            if action.default is not SUPPRESS:
                defaulting_nargs = [OPTIONAL, ZERO_OR_MORE]
                if action.option_strings or action.nargs in defaulting_nargs:
                    help += ' (default: %(default)s)'
        return help


class MetavarTypeHelpFormatter(HelpFormatter):
    """Help message formatter which uses the argument 'type' as the default
    metavar value (instead of the argument 'dest')

    Only the name of this class is considered a public API. All the methods
    provided by the class are considered an implementation detail.
    """

    def _get_default_metavar_for_optional(self, action):
        return action.type.__name__

    def _get_default_metavar_for_positional(self, action):
        return action.type.__name__



# =====================
# Options and Arguments
# =====================

def _get_action_name(argument):
    if argument is None:
        return None
    elif argument.option_strings:
        return  '/'.join(argument.option_strings)
    elif argument.metavar not in (None, SUPPRESS):
        return argument.metavar
    elif argument.dest not in (None, SUPPRESS):
        return argument.dest
    else:
        return None


class ArgumentError(Exception):
    """An error from creating or using an argument (optional or positional).

    The string value of this exception is the message, augmented with
    information about the argument that caused it.
    """

    def __init__(self, argument, message):
        self.argument_name = _get_action_name(argument)
        self.message = message

    def __str__(self):
        if self.argument_name is None:
            format = '%(message)s'
        else:
            format = 'argument %(argument_name)s: %(message)s'
        return format % dict(message=self.message,
                             argument_name=self.argument_name)


class ArgumentTypeError(Exception):
    """An error from trying to convert a command line string to a type."""
    pass


# ==============
# Action classes
# ==============

class Action(_AttributeHolder):
    """Information about how to convert command line strings to Python objects.

    Action objects are used by an ArgumentParser to represent the information
    needed to parse a single argument from one or more strings from the
    command line. The keyword arguments to the Action constructor are also
    all attributes of Action instances.

    Keyword Arguments:

        - option_strings -- A list of command-line option strings which
            should be associated with this action.

        - dest -- The name of the attribute to hold the created object(s)

        - nargs -- The number of command-line arguments that should be
            consumed. By default, one argument will be consumed and a single
            value will be produced.  Other values include:
                - N (an integer) consumes N arguments (and produces a list)
                - '?' consumes zero or one arguments
                - '*' consumes zero or more arguments (and produces a list)
                - '+' consumes one or more arguments (and produces a list)
            Note that the difference between the default and nargs=1 is that
            with the default, a single value will be produced, while with
            nargs=1, a list containing a single value will be produced.

        - const -- The value to be produced if the option is specified and the
            option uses an action that takes no values.

        - default -- The value to be produced if the option is not specified.

        - type -- A callable that accepts a single string argument, and
            returns the converted value.  The standard Python types str, int,
            float, and complex are useful examples of such callables.  If None,
            str is used.

        - choices -- A container of values that should be allowed. If not None,
            after a command-line argument has been converted to the appropriate
            type, an exception will be raised if it is not a member of this
            collection.

        - required -- True if the action must always be specified at the
            command line. This is only meaningful for optional command-line
            arguments.

        - help -- The help string describing the argument.

        - metavar -- The name to be used for the option's argument with the
            help string. If None, the 'dest' value will be used as the name.
    """

    def __init__(self,
                 option_strings,
                 dest,
                 nargs=None,
                 const=None,
                 default=None,
                 type=None,
                 choices=None,
                 required=False,
                 help=None,
                 metavar=None):
        self.option_strings = option_strings
        self.dest = dest
        self.nargs = nargs
        self.const = const
        self.default = default
        self.type = type
        self.choices = choices
        self.required = required
        self.help = help
        self.metavar = metavar

    def _get_kwargs(self):
        names = [
            'option_strings',
            'dest',
            'nargs',
            'const',
            'default',
            'type',
            'choices',
            'help',
            'metavar',
        ]
        return [(name, getattr(self, name)) for name in names]

    def __call__(self, parser, namespace, values, option_string=None):
        raise NotImplementedError(_('.__call__() not defined'))


class _StoreAction(Action):

    def __init__(self,
                 option_strings,
                 dest,
                 nargs=None,
                 const=None,
                 default=None,
                 type=None,
                 choices=None,
                 required=False,
                 help=None,
                 metavar=None):
        if nargs == 0:
            raise ValueError('nargs for store actions must be > 0; if you '
                             'have nothing to store, actions such as store '
                             'true or store const may be more appropriate')
        if const is not None and nargs != OPTIONAL:
            raise ValueError('nargs must be %r to supply const' % OPTIONAL)
        super(_StoreAction, self).__init__(
            option_strings=option_strings,
            dest=dest,
            nargs=nargs,
            const=const,
            default=default,
            type=type,
            choices=choices,
            required=required,
            help=help,
            metavar=metavar)

    def __call__(self, parser, namespace, values, option_string=None):
        setattr(namespace, self.dest, values)


class _StoreConstAction(Action):

    def __init__(self,
                 option_strings,
                 dest,
                 const,
                 default=None,
                 required=False,
                 help=None,
                 metavar=None):
        super(_StoreConstAction, self).__init__(
            option_strings=option_strings,
            dest=dest,
            nargs=0,
            const=const,
            default=default,
            required=required,
            help=help)

    def __call__(self, parser, namespace, values, option_string=None):
        setattr(namespace, self.dest, self.const)


class _StoreTrueAction(_StoreConstAction):

    def __init__(self,
                 option_strings,
                 dest,
                 default=False,
                 required=False,
                 help=None):
        super(_StoreTrueAction, self).__init__(
            option_strings=option_strings,
            dest=dest,
            const=True,
            default=default,
            required=required,
            help=help)


class _StoreFalseAction(_StoreConstAction):

    def __init__(self,
                 option_strings,
                 dest,
                 default=True,
                 required=False,
                 help=None):
        super(_StoreFalseAction, self).__init__(
            option_strings=option_strings,
            dest=dest,
            const=False,
            default=default,
            required=required,
            help=help)


class _AppendAction(Action):

    def __init__(self,
                 option_strings,
                 dest,
                 nargs=None,
                 const=None,
                 default=None,
                 type=None,
                 choices=None,
                 required=False,
                 help=None,
                 metavar=None):
        if nargs == 0:
            raise ValueError('nargs for append actions must be > 0; if arg '
                             'strings are not supplying the value to append, '
                             'the append const action may be more appropriate')
        if const is not None and nargs != OPTIONAL:
            raise ValueError('nargs must be %r to supply const' % OPTIONAL)
        super(_AppendAction, self).__init__(
            option_strings=option_strings,
            dest=dest,
            nargs=nargs,
            const=const,
            default=default,
            type=type,
            choices=choices,
            required=required,
            help=help,
            metavar=metavar)

    def __call__(self, parser, namespace, values, option_string=None):
        items = _copy.copy(_ensure_value(namespace, self.dest, []))
        items.append(values)
        setattr(namespace, self.dest, items)


class _AppendConstAction(Action):

    def __init__(self,
                 option_strings,
                 dest,
                 const,
                 default=None,
                 required=False,
                 help=None,
                 metavar=None):
        super(_AppendConstAction, self).__init__(
            option_strings=option_strings,
            dest=dest,
            nargs=0,
            const=const,
            default=default,
            required=required,
            help=help,
            metavar=metavar)

    def __call__(self, parser, namespace, values, option_string=None):
        items = _copy.copy(_ensure_value(namespace, self.dest, []))
        items.append(self.const)
        setattr(namespace, self.dest, items)


class _CountAction(Action):

    def __init__(self,
                 option_strings,
                 dest,
                 default=None,
                 required=False,
                 help=None):
        super(_CountAction, self).__init__(
            option_strings=option_strings,
            dest=dest,
            nargs=0,
            default=default,
            required=required,
            help=help)

    def __call__(self, parser, namespace, values, option_string=None):
        new_count = _ensure_value(namespace, self.dest, 0) + 1
        setattr(namespace, self.dest, new_count)


class _HelpAction(Action):

    def __init__(self,
                 option_strings,
                 dest=SUPPRESS,
                 default=SUPPRESS,
                 help=None):
        super(_HelpAction, self).__init__(
            option_strings=option_strings,
            dest=dest,
            default=default,
            nargs=0,
            help=help)

    def __call__(self, parser, namespace, values, option_string=None):
        parser.print_help()
        parser.exit()


class _VersionAction(Action):

    def __init__(self,
                 option_strings,
                 version=None,
                 dest=SUPPRESS,
                 default=SUPPRESS,
                 help="show program's version number and exit"):
        super(_VersionAction, self).__init__(
            option_strings=option_strings,
            dest=dest,
            default=default,
            nargs=0,
            help=help)
        self.version = version

    def __call__(self, parser, namespace, values, option_string=None):
        version = self.version
        if version is None:
            version = parser.version
        formatter = parser._get_formatter()
        formatter.add_text(version)
        parser._print_message(formatter.format_help(), _sys.stdout)
        parser.exit()


class _SubParsersAction(Action):

    class _ChoicesPseudoAction(Action):

        def __init__(self, name, aliases, help):
            metavar = dest = name
            if aliases:
                metavar += ' (%s)' % ', '.join(aliases)
            sup = super(_SubParsersAction._ChoicesPseudoAction, self)
            sup.__init__(option_strings=[], dest=dest, help=help,
                         metavar=metavar)

    def __init__(self,
                 option_strings,
                 prog,
                 parser_class,
                 dest=SUPPRESS,
                 help=None,
                 metavar=None):

        self._prog_prefix = prog
        self._parser_class = parser_class
        self._name_parser_map = _collections.OrderedDict()
        self._choices_actions = []

        super(_SubParsersAction, self).__init__(
            option_strings=option_strings,
            dest=dest,
            nargs=PARSER,
            choices=self._name_parser_map,
            help=help,
            metavar=metavar)

    def add_parser(self, name, **kwargs):
        # set prog from the existing prefix
        if kwargs.get('prog') is None:
            kwargs['prog'] = '%s %s' % (self._prog_prefix, name)

        aliases = kwargs.pop('aliases', ())

        # create a pseudo-action to hold the choice help
        if 'help' in kwargs:
            help = kwargs.pop('help')
            choice_action = self._ChoicesPseudoAction(name, aliases, help)
            self._choices_actions.append(choice_action)

        # create the parser and add it to the map
        parser = self._parser_class(**kwargs)
        self._name_parser_map[name] = parser

        # make parser available under aliases also
        for alias in aliases:
            self._name_parser_map[alias] = parser

        return parser

    def _get_subactions(self):
        return self._choices_actions

    def __call__(self, parser, namespace, values, option_string=None):
        parser_name = values[0]
        arg_strings = values[1:]

        # set the parser name if requested
        if self.dest is not SUPPRESS:
            setattr(namespace, self.dest, parser_name)

        # select the parser
        try:
            parser = self._name_parser_map[parser_name]
        except KeyError:
            args = {'parser_name': parser_name,
                    'choices': ', '.join(self._name_parser_map)}
            msg = _('unknown parser %(parser_name)r (choices: %(choices)s)') % args
            raise ArgumentError(self, msg)

        # parse all the remaining options into the namespace
        # store any unrecognized options on the object, so that the top
        # level parser can decide what to do with them

        # In case this subparser defines new defaults, we parse them
        # in a new namespace object and then update the original
        # namespace for the relevant parts.
        subnamespace, arg_strings = parser.parse_known_args(arg_strings, None)
        for key, value in vars(subnamespace).items():
            setattr(namespace, key, value)

        if arg_strings:
            vars(namespace).setdefault(_UNRECOGNIZED_ARGS_ATTR, [])
            getattr(namespace, _UNRECOGNIZED_ARGS_ATTR).extend(arg_strings)


# ==============
# Type classes
# ==============

class FileType(object):
    """Factory for creating file object types

    Instances of FileType are typically passed as type= arguments to the
    ArgumentParser add_argument() method.

    Keyword Arguments:
        - mode -- A string indicating how the file is to be opened. Accepts the
            same values as the builtin open() function.
        - bufsize -- The file's desired buffer size. Accepts the same values as
            the builtin open() function.
        - encoding -- The file's encoding. Accepts the same values as the
            builtin open() function.
        - errors -- A string indicating how encoding and decoding errors are to
            be handled. Accepts the same value as the builtin open() function.
    """

    def __init__(self, mode='r', bufsize=-1, encoding=None, errors=None):
        self._mode = mode
        self._bufsize = bufsize
        self._encoding = encoding
        self._errors = errors

    def __call__(self, string):
        # the special argument "-" means sys.std{in,out}
        if string == '-':
            if 'r' in self._mode:
                return _sys.stdin
            elif 'w' in self._mode:
                return _sys.stdout
            else:
                msg = _('argument "-" with mode %r') % self._mode
                raise ValueError(msg)

        # all other arguments are used as file names
        try:
            return open(string, self._mode, self._bufsize, self._encoding,
                        self._errors)
        except OSError as e:
            message = _("can't open '%s': %s")
            raise ArgumentTypeError(message % (string, e))

    def __repr__(self):
        args = self._mode, self._bufsize
        kwargs = [('encoding', self._encoding), ('errors', self._errors)]
        args_str = ', '.join([repr(arg) for arg in args if arg != -1] +
                             ['%s=%r' % (kw, arg) for kw, arg in kwargs
                              if arg is not None])
        return '%s(%s)' % (type(self).__name__, args_str)

# ===========================
# Optional and Positional Parsing
# ===========================

class Namespace(_AttributeHolder):
    """Simple object for storing attributes.

    Implements equality by attribute names and values, and provides a simple
    string representation.
    """

    def __init__(self, **kwargs):
        for name in kwargs:
            setattr(self, name, kwargs[name])

    def __eq__(self, other):
        if not isinstance(other, Namespace):
            return NotImplemented
        return vars(self) == vars(other)

    def __ne__(self, other):
        if not isinstance(other, Namespace):
            return NotImplemented
        return not (self == other)

    def __contains__(self, key):
        return key in self.__dict__


class _ActionsContainer(object):

    def __init__(self,
                 description,
                 prefix_chars,
                 argument_default,
                 conflict_handler):
        super(_ActionsContainer, self).__init__()

        self.description = description
        self.argument_default = argument_default
        self.prefix_chars = prefix_chars
        self.conflict_handler = conflict_handler

        # set up registries
        self._registries = {}

        # register actions
        self.register('action', None, _StoreAction)
        self.register('action', 'store', _StoreAction)
        self.register('action', 'store_const', _StoreConstAction)
        self.register('action', 'store_true', _StoreTrueAction)
        self.register('action', 'store_false', _StoreFalseAction)
        self.register('action', 'append', _AppendAction)
        self.register('action', 'append_const', _AppendConstAction)
        self.register('action', 'count', _CountAction)
        self.register('action', 'help', _HelpAction)
        self.register('action', 'version', _VersionAction)
        self.register('action', 'parsers', _SubParsersAction)

        # raise an exception if the conflict handler is invalid
        self._get_handler()

        # action storage
        self._actions = []
        self._option_string_actions = {}

        # groups
        self._action_groups = []
        self._mutually_exclusive_groups = []

        # defaults storage
        self._defaults = {}

        # determines whether an "option" looks like a negative number
        self._negative_number_matcher = _re.compile(r'^-\d+$|^-\d*\.\d+$')

        # whether or not there are any optionals that look like negative
        # numbers -- uses a list so it can be shared and edited
        self._has_negative_number_optionals = []

    # ====================
    # Registration methods
    # ====================
    def register(self, registry_name, value, object):
        registry = self._registries.setdefault(registry_name, {})
        registry[value] = object

    def _registry_get(self, registry_name, value, default=None):
        return self._registries[registry_name].get(value, default)

    # ==================================
    # Namespace default accessor methods
    # ==================================
    def set_defaults(self, **kwargs):
        self._defaults.update(kwargs)

        # if these defaults match any existing arguments, replace
        # the previous default on the object with the new one
        for action in self._actions:
            if action.dest in kwargs:
                action.default = kwargs[action.dest]

    def get_default(self, dest):
        for action in self._actions:
            if action.dest == dest and action.default is not None:
                return action.default
        return self._defaults.get(dest, None)


    # =======================
    # Adding argument actions
    # =======================
    def add_argument(self, *args, **kwargs):
        """
        add_argument(dest, ..., name=value, ...)
        add_argument(option_string, option_string, ..., name=value, ...)
        """

        # if no positional args are supplied or only one is supplied and
        # it doesn't look like an option string, parse a positional
        # argument
        chars = self.prefix_chars
        if not args or len(args) == 1 and args[0][0] not in chars:
            if args and 'dest' in kwargs:
                raise ValueError('dest supplied twice for positional argument')
            kwargs = self._get_positional_kwargs(*args, **kwargs)

        # otherwise, we're adding an optional argument
        else:
            kwargs = self._get_optional_kwargs(*args, **kwargs)

        # if no default was supplied, use the parser-level default
        if 'default' not in kwargs:
            dest = kwargs['dest']
            if dest in self._defaults:
                kwargs['default'] = self._defaults[dest]
            elif self.argument_default is not None:
                kwargs['default'] = self.argument_default

        # create the action object, and add it to the parser
        action_class = self._pop_action_class(kwargs)
        if not callable(action_class):
            raise ValueError('unknown action "%s"' % (action_class,))
        action = action_class(**kwargs)

        # raise an error if the action type is not callable
        type_func = self._registry_get('type', action.type, action.type)
        if not callable(type_func):
            raise ValueError('%r is not callable' % (type_func,))

        # raise an error if the metavar does not match the type
        if hasattr(self, "_get_formatter"):
            try:
                self._get_formatter()._format_args(action, None)
            except TypeError:
                raise ValueError("length of metavar tuple does not match nargs")

        return self._add_action(action)

    def add_argument_group(self, *args, **kwargs):
        group = _ArgumentGroup(self, *args, **kwargs)
        self._action_groups.append(group)
        return group

    def add_mutually_exclusive_group(self, **kwargs):
        group = _MutuallyExclusiveGroup(self, **kwargs)
        self._mutually_exclusive_groups.append(group)
        return group

    def _add_action(self, action):
        # resolve any conflicts
        self._check_conflict(action)

        # add to actions list
        self._actions.append(action)
        action.container = self

        # index the action by any option strings it has
        for option_string in action.option_strings:
            self._option_string_actions[option_string] = action

        # set the flag if any option strings look like negative numbers
        for option_string in action.option_strings:
            if self._negative_number_matcher.match(option_string):
                if not self._has_negative_number_optionals:
                    self._has_negative_number_optionals.append(True)

        # return the created action
        return action

    def _remove_action(self, action):
        self._actions.remove(action)

    def _add_container_actions(self, container):
        # collect groups by titles
        title_group_map = {}
        for group in self._action_groups:
            if group.title in title_group_map:
                msg = _('cannot merge actions - two groups are named %r')
                raise ValueError(msg % (group.title))
            title_group_map[group.title] = group

        # map each action to its group
        group_map = {}
        for group in container._action_groups:

            # if a group with the title exists, use that, otherwise
            # create a new group matching the container's group
            if group.title not in title_group_map:
                title_group_map[group.title] = self.add_argument_group(
                    title=group.title,
                    description=group.description,
                    conflict_handler=group.conflict_handler)

            # map the actions to their new group
            for action in group._group_actions:
                group_map[action] = title_group_map[group.title]

        # add container's mutually exclusive groups
        # NOTE: if add_mutually_exclusive_group ever gains title= and
        # description= then this code will need to be expanded as above
        for group in container._mutually_exclusive_groups:
            mutex_group = self.add_mutually_exclusive_group(
                required=group.required)

            # map the actions to their new mutex group
            for action in group._group_actions:
                group_map[action] = mutex_group

        # add all actions to this container or their group
        for action in container._actions:
            group_map.get(action, self)._add_action(action)

    def _get_positional_kwargs(self, dest, **kwargs):
        # make sure required is not specified
        if 'required' in kwargs:
            msg = _("'required' is an invalid argument for positionals")
            raise TypeError(msg)

        # mark positional arguments as required if at least one is
        # always required
        if kwargs.get('nargs') not in [OPTIONAL, ZERO_OR_MORE]:
            kwargs['required'] = True
        if kwargs.get('nargs') == ZERO_OR_MORE and 'default' not in kwargs:
            kwargs['required'] = True

        # return the keyword arguments with no option strings
        return dict(kwargs, dest=dest, option_strings=[])

    def _get_optional_kwargs(self, *args, **kwargs):
        # determine short and long option strings
        option_strings = []
        long_option_strings = []
        for option_string in args:
            # error on strings that don't start with an appropriate prefix
            if not option_string[0] in self.prefix_chars:
                args = {'option': option_string,
                        'prefix_chars': self.prefix_chars}
                msg = _('invalid option string %(option)r: '
                        'must start with a character %(prefix_chars)r')
                raise ValueError(msg % args)

            # strings starting with two prefix characters are long options
            option_strings.append(option_string)
            if option_string[0] in self.prefix_chars:
                if len(option_string) > 1:
                    if option_string[1] in self.prefix_chars:
                        long_option_strings.append(option_string)

        # infer destination, '--foo-bar' -> 'foo_bar' and '-x' -> 'x'
        dest = kwargs.pop('dest', None)
        if dest is None:
            if long_option_strings:
                dest_option_string = long_option_strings[0]
            else:
                dest_option_string = option_strings[0]
            dest = dest_option_string.lstrip(self.prefix_chars)
            if not dest:
                msg = _('dest= is required for options like %r')
                raise ValueError(msg % option_string)
            dest = dest.replace('-', '_')

        # return the updated keyword arguments
        return dict(kwargs, dest=dest, option_strings=option_strings)

    def _pop_action_class(self, kwargs, default=None):
        action = kwargs.pop('action', default)
        return self._registry_get('action', action, action)

    def _get_handler(self):
        # determine function from conflict handler string
        handler_func_name = '_handle_conflict_%s' % self.conflict_handler
        try:
            return getattr(self, handler_func_name)
        except AttributeError:
            msg = _('invalid conflict_resolution value: %r')
            raise ValueError(msg % self.conflict_handler)

    def _check_conflict(self, action):

        # find all options that conflict with this option
        confl_optionals = []
        for option_string in action.option_strings:
            if option_string in self._option_string_actions:
                confl_optional = self._option_string_actions[option_string]
                confl_optionals.append((option_string, confl_optional))

        # resolve any conflicts
        if confl_optionals:
            conflict_handler = self._get_handler()
            conflict_handler(action, confl_optionals)

    def _handle_conflict_error(self, action, conflicting_actions):
        message = ngettext('conflicting option string: %s',
                           'conflicting option strings: %s',
                           len(conflicting_actions))
        conflict_string = ', '.join([option_string
                                     for option_string, action
                                     in conflicting_actions])
        raise ArgumentError(action, message % conflict_string)

    def _handle_conflict_resolve(self, action, conflicting_actions):

        # remove all conflicting options
        for option_string, action in conflicting_actions:

            # remove the conflicting option
            action.option_strings.remove(option_string)
            self._option_string_actions.pop(option_string, None)

            # if the option now has no option string, remove it from the
            # container holding it
            if not action.option_strings:
                action.container._remove_action(action)


class _ArgumentGroup(_ActionsContainer):

    def __init__(self, container, title=None, description=None, **kwargs):
        # add any missing keyword arguments by checking the container
        update = kwargs.setdefault
        update('conflict_handler', container.conflict_handler)
        update('prefix_chars', container.prefix_chars)
        update('argument_default', container.argument_default)
        super_init = super(_ArgumentGroup, self).__init__
        super_init(description=description, **kwargs)

        # group attributes
        self.title = title
        self._group_actions = []

        # share most attributes with the container
        self._registries = container._registries
        self._actions = container._actions
        self._option_string_actions = container._option_string_actions
        self._defaults = container._defaults
        self._has_negative_number_optionals = \
            container._has_negative_number_optionals
        self._mutually_exclusive_groups = container._mutually_exclusive_groups

    def _add_action(self, action):
        action = super(_ArgumentGroup, self)._add_action(action)
        self._group_actions.append(action)
        return action

    def _remove_action(self, action):
        super(_ArgumentGroup, self)._remove_action(action)
        self._group_actions.remove(action)


class _MutuallyExclusiveGroup(_ArgumentGroup):

    def __init__(self, container, required=False):
        super(_MutuallyExclusiveGroup, self).__init__(container)
        self.required = required
        self._container = container

    def _add_action(self, action):
        if action.required:
            msg = _('mutually exclusive arguments must be optional')
            raise ValueError(msg)
        action = self._container._add_action(action)
        self._group_actions.append(action)
        return action

    def _remove_action(self, action):
        self._container._remove_action(action)
        self._group_actions.remove(action)


class ArgumentParser(_AttributeHolder, _ActionsContainer):
    """Object for parsing command line strings into Python objects.

    Keyword Arguments:
        - prog -- The name of the program (default: sys.argv[0])
        - usage -- A usage message (default: auto-generated from arguments)
        - description -- A description of what the program does
        - epilog -- Text following the argument descriptions
        - parents -- Parsers whose arguments should be copied into this one
        - formatter_class -- HelpFormatter class for printing help messages
        - prefix_chars -- Characters that prefix optional arguments
        - fromfile_prefix_chars -- Characters that prefix files containing
            additional arguments
        - argument_default -- The default value for all arguments
        - conflict_handler -- String indicating how to handle conflicts
        - add_help -- Add a -h/-help option
    """

    def __init__(self,
                 prog=None,
                 usage=None,
                 description=None,
                 epilog=None,
                 parents=[],
                 formatter_class=HelpFormatter,
                 prefix_chars='-',
                 fromfile_prefix_chars=None,
                 argument_default=None,
                 conflict_handler='error',
                 add_help=True):

        superinit = super(ArgumentParser, self).__init__
        superinit(description=description,
                  prefix_chars=prefix_chars,
                  argument_default=argument_default,
                  conflict_handler=conflict_handler)

        # default setting for prog
        if prog is None:
            prog = _os.path.basename(_sys.argv[0])

        self.prog = prog
        self.usage = usage
        self.epilog = epilog
        self.formatter_class = formatter_class
        self.fromfile_prefix_chars = fromfile_prefix_chars
        self.add_help = add_help

        add_group = self.add_argument_group
        self._positionals = add_group(_('positional arguments'))
        self._optionals = add_group(_('optional arguments'))
        self._subparsers = None

        # register types
        def identity(string):
            return string
        self.register('type', None, identity)

        # add help argument if necessary
        # (using explicit default to override global argument_default)
        default_prefix = '-' if '-' in prefix_chars else prefix_chars[0]
        if self.add_help:
            self.add_argument(
                default_prefix+'h', default_prefix*2+'help',
                action='help', default=SUPPRESS,
                help=_('show this help message and exit'))

        # add parent arguments and defaults
        for parent in parents:
            self._add_container_actions(parent)
            try:
                defaults = parent._defaults
            except AttributeError:
                pass
            else:
                self._defaults.update(defaults)

    # =======================
    # Pretty __repr__ methods
    # =======================
    def _get_kwargs(self):
        names = [
            'prog',
            'usage',
            'description',
            'formatter_class',
            'conflict_handler',
            'add_help',
        ]
        return [(name, getattr(self, name)) for name in names]

    # ==================================
    # Optional/Positional adding methods
    # ==================================
    def add_subparsers(self, **kwargs):
        if self._subparsers is not None:
            self.error(_('cannot have multiple subparser arguments'))

        # add the parser class to the arguments if it's not present
        kwargs.setdefault('parser_class', type(self))

        if 'title' in kwargs or 'description' in kwargs:
            title = _(kwargs.pop('title', 'subcommands'))
            description = _(kwargs.pop('description', None))
            self._subparsers = self.add_argument_group(title, description)
        else:
            self._subparsers = self._positionals

        # prog defaults to the usage message of this parser, skipping
        # optional arguments and with no "usage:" prefix
        if kwargs.get('prog') is None:
            formatter = self._get_formatter()
            positionals = self._get_positional_actions()
            groups = self._mutually_exclusive_groups
            formatter.add_usage(self.usage, positionals, groups, '')
            kwargs['prog'] = formatter.format_help().strip()

        # create the parsers action and add it to the positionals list
        parsers_class = self._pop_action_class(kwargs, 'parsers')
        action = parsers_class(option_strings=[], **kwargs)
        self._subparsers._add_action(action)

        # return the created parsers action
        return action

    def _add_action(self, action):
        if action.option_strings:
            self._optionals._add_action(action)
        else:
            self._positionals._add_action(action)
        return action

    def _get_optional_actions(self):
        return [action
                for action in self._actions
                if action.option_strings]

    def _get_positional_actions(self):
        return [action
                for action in self._actions
                if not action.option_strings]

    # =====================================
    # Command line argument parsing methods
    # =====================================
    def parse_args(self, args=None, namespace=None):
        args, argv = self.parse_known_args(args, namespace)
        if argv:
            msg = _('unrecognized arguments: %s')
            self.error(msg % ' '.join(argv))
        return args

    def parse_known_args(self, args=None, namespace=None):
        if args is None:
            # args default to the system args
            args = _sys.argv[1:]
        else:
            # make sure that args are mutable
            args = list(args)

        # default Namespace built from parser defaults
        if namespace is None:
            namespace = Namespace()

        # add any action defaults that aren't present
        for action in self._actions:
            if action.dest is not SUPPRESS:
                if not hasattr(namespace, action.dest):
                    if action.default is not SUPPRESS:
                        setattr(namespace, action.dest, action.default)

        # add any parser defaults that aren't present
        for dest in self._defaults:
            if not hasattr(namespace, dest):
                setattr(namespace, dest, self._defaults[dest])

        # parse the arguments and exit if there are any errors
        try:
            namespace, args = self._parse_known_args(args, namespace)
            if hasattr(namespace, _UNRECOGNIZED_ARGS_ATTR):
                args.extend(getattr(namespace, _UNRECOGNIZED_ARGS_ATTR))
                delattr(namespace, _UNRECOGNIZED_ARGS_ATTR)
            return namespace, args
        except ArgumentError:
            err = _sys.exc_info()[1]
            self.error(str(err))

    def _parse_known_args(self, arg_strings, namespace):
        # replace arg strings that are file references
        if self.fromfile_prefix_chars is not None:
            arg_strings = self._read_args_from_files(arg_strings)

        # map all mutually exclusive arguments to the other arguments
        # they can't occur with
        action_conflicts = {}
        for mutex_group in self._mutually_exclusive_groups:
            group_actions = mutex_group._group_actions
            for i, mutex_action in enumerate(mutex_group._group_actions):
                conflicts = action_conflicts.setdefault(mutex_action, [])
                conflicts.extend(group_actions[:i])
                conflicts.extend(group_actions[i + 1:])

        # find all option indices, and determine the arg_string_pattern
        # which has an 'O' if there is an option at an index,
        # an 'A' if there is an argument, or a '-' if there is a '--'
        option_string_indices = {}
        arg_string_pattern_parts = []
        arg_strings_iter = iter(arg_strings)
        for i, arg_string in enumerate(arg_strings_iter):

            # all args after -- are non-options
            if arg_string == '--':
                arg_string_pattern_parts.append('-')
                for arg_string in arg_strings_iter:
                    arg_string_pattern_parts.append('A')

            # otherwise, add the arg to the arg strings
            # and note the index if it was an option
            else:
                option_tuple = self._parse_optional(arg_string)
                if option_tuple is None:
                    pattern = 'A'
                else:
                    option_string_indices[i] = option_tuple
                    pattern = 'O'
                arg_string_pattern_parts.append(pattern)

        # join the pieces together to form the pattern
        arg_strings_pattern = ''.join(arg_string_pattern_parts)

        # converts arg strings to the appropriate and then takes the action
        seen_actions = set()
        seen_non_default_actions = set()

        def take_action(action, argument_strings, option_string=None):
            seen_actions.add(action)
            argument_values = self._get_values(action, argument_strings)

            # error if this argument is not allowed with other previously
            # seen arguments, assuming that actions that use the default
            # value don't really count as "present"
            if argument_values is not action.default:
                seen_non_default_actions.add(action)
                for conflict_action in action_conflicts.get(action, []):
                    if conflict_action in seen_non_default_actions:
                        msg = _('not allowed with argument %s')
                        action_name = _get_action_name(conflict_action)
                        raise ArgumentError(action, msg % action_name)

            # take the action if we didn't receive a SUPPRESS value
            # (e.g. from a default)
            if argument_values is not SUPPRESS:
                action(self, namespace, argument_values, option_string)

        # function to convert arg_strings into an optional action
        def consume_optional(start_index):

            # get the optional identified at this index
            option_tuple = option_string_indices[start_index]
            action, option_string, explicit_arg = option_tuple

            # identify additional optionals in the same arg string
            # (e.g. -xyz is the same as -x -y -z if no args are required)
            match_argument = self._match_argument
            action_tuples = []
            while True:

                # if we found no optional action, skip it
                if action is None:
                    extras.append(arg_strings[start_index])
                    return start_index + 1

                # if there is an explicit argument, try to match the
                # optional's string arguments to only this
                if explicit_arg is not None:
                    arg_count = match_argument(action, 'A')

                    # if the action is a single-dash option and takes no
                    # arguments, try to parse more single-dash options out
                    # of the tail of the option string
                    chars = self.prefix_chars
                    if arg_count == 0 and option_string[1] not in chars:
                        action_tuples.append((action, [], option_string))
                        char = option_string[0]
                        option_string = char + explicit_arg[0]
                        new_explicit_arg = explicit_arg[1:] or None
                        optionals_map = self._option_string_actions
                        if option_string in optionals_map:
                            action = optionals_map[option_string]
                            explicit_arg = new_explicit_arg
                        else:
                            msg = _('ignored explicit argument %r')
                            raise ArgumentError(action, msg % explicit_arg)

                    # if the action expect exactly one argument, we've
                    # successfully matched the option; exit the loop
                    elif arg_count == 1:
                        stop = start_index + 1
                        args = [explicit_arg]
                        action_tuples.append((action, args, option_string))
                        break

                    # error if a double-dash option did not use the
                    # explicit argument
                    else:
                        msg = _('ignored explicit argument %r')
                        raise ArgumentError(action, msg % explicit_arg)

                # if there is no explicit argument, try to match the
                # optional's string arguments with the following strings
                # if successful, exit the loop
                else:
                    start = start_index + 1
                    selected_patterns = arg_strings_pattern[start:]
                    arg_count = match_argument(action, selected_patterns)
                    stop = start + arg_count
                    args = arg_strings[start:stop]
                    action_tuples.append((action, args, option_string))
                    break

            # add the Optional to the list and return the index at which
            # the Optional's string args stopped
            assert action_tuples
            for action, args, option_string in action_tuples:
                take_action(action, args, option_string)
            return stop

        # the list of Positionals left to be parsed; this is modified
        # by consume_positionals()
        positionals = self._get_positional_actions()

        # function to convert arg_strings into positional actions
        def consume_positionals(start_index):
            # match as many Positionals as possible
            match_partial = self._match_arguments_partial
            selected_pattern = arg_strings_pattern[start_index:]
            arg_counts = match_partial(positionals, selected_pattern)

            # slice off the appropriate arg strings for each Positional
            # and add the Positional and its args to the list
            for action, arg_count in zip(positionals, arg_counts):
                args = arg_strings[start_index: start_index + arg_count]
                start_index += arg_count
                take_action(action, args)

            # slice off the Positionals that we just parsed and return the
            # index at which the Positionals' string args stopped
            positionals[:] = positionals[len(arg_counts):]
            return start_index

        # consume Positionals and Optionals alternately, until we have
        # passed the last option string
        extras = []
        start_index = 0
        if option_string_indices:
            max_option_string_index = max(option_string_indices)
        else:
            max_option_string_index = -1
        while start_index <= max_option_string_index:

            # consume any Positionals preceding the next option
            next_option_string_index = min([
                index
                for index in option_string_indices
                if index >= start_index])
            if start_index != next_option_string_index:
                positionals_end_index = consume_positionals(start_index)

                # only try to parse the next optional if we didn't consume
                # the option string during the positionals parsing
                if positionals_end_index > start_index:
                    start_index = positionals_end_index
                    continue
                else:
                    start_index = positionals_end_index

            # if we consumed all the positionals we could and we're not
            # at the index of an option string, there were extra arguments
            if start_index not in option_string_indices:
                strings = arg_strings[start_index:next_option_string_index]
                extras.extend(strings)
                start_index = next_option_string_index

            # consume the next optional and any arguments for it
            start_index = consume_optional(start_index)

        # consume any positionals following the last Optional
        stop_index = consume_positionals(start_index)

        # if we didn't consume all the argument strings, there were extras
        extras.extend(arg_strings[stop_index:])

        # make sure all required actions were present and also convert
        # action defaults which were not given as arguments
        required_actions = []
        for action in self._actions:
            if action not in seen_actions:
                if action.required:
                    required_actions.append(_get_action_name(action))
                else:
                    # Convert action default now instead of doing it before
                    # parsing arguments to avoid calling convert functions
                    # twice (which may fail) if the argument was given, but
                    # only if it was defined already in the namespace
                    if (action.default is not None and
                        isinstance(action.default, str) and
                        hasattr(namespace, action.dest) and
                        action.default is getattr(namespace, action.dest)):
                        setattr(namespace, action.dest,
                                self._get_value(action, action.default))

        if required_actions:
            self.error(_('the following arguments are required: %s') %
                       ', '.join(required_actions))

        # make sure all required groups had one option present
        for group in self._mutually_exclusive_groups:
            if group.required:
                for action in group._group_actions:
                    if action in seen_non_default_actions:
                        break

                # if no actions were used, report the error
                else:
                    names = [_get_action_name(action)
                             for action in group._group_actions
                             if action.help is not SUPPRESS]
                    msg = _('one of the arguments %s is required')
                    self.error(msg % ' '.join(names))

        # return the updated namespace and the extra arguments
        return namespace, extras

    def _read_args_from_files(self, arg_strings):
        # expand arguments referencing files
        new_arg_strings = []
        for arg_string in arg_strings:

            # for regular arguments, just add them back into the list
            if not arg_string or arg_string[0] not in self.fromfile_prefix_chars:
                new_arg_strings.append(arg_string)

            # replace arguments referencing files with the file content
            else:
                try:
                    with open(arg_string[1:]) as args_file:
                        arg_strings = []
                        for arg_line in args_file.read().splitlines():
                            for arg in self.convert_arg_line_to_args(arg_line):
                                arg_strings.append(arg)
                        arg_strings = self._read_args_from_files(arg_strings)
                        new_arg_strings.extend(arg_strings)
                except OSError:
                    err = _sys.exc_info()[1]
                    self.error(str(err))

        # return the modified argument list
        return new_arg_strings

    def convert_arg_line_to_args(self, arg_line):
        return [arg_line]

    def _match_argument(self, action, arg_strings_pattern):
        # match the pattern for this action to the arg strings
        nargs_pattern = self._get_nargs_pattern(action)
        match = _re.match(nargs_pattern, arg_strings_pattern)

        # raise an exception if we weren't able to find a match
        if match is None:
            nargs_errors = {
                None: _('expected one argument'),
                OPTIONAL: _('expected at most one argument'),
                ONE_OR_MORE: _('expected at least one argument'),
            }
            default = ngettext('expected %s argument',
                               'expected %s arguments',
                               action.nargs) % action.nargs
            msg = nargs_errors.get(action.nargs, default)
            raise ArgumentError(action, msg)

        # return the number of arguments matched
        return len(match.group(1))

    def _match_arguments_partial(self, actions, arg_strings_pattern):
        # progressively shorten the actions list by slicing off the
        # final actions until we find a match
        result = []
        for i in range(len(actions), 0, -1):
            actions_slice = actions[:i]
            pattern = ''.join([self._get_nargs_pattern(action)
                               for action in actions_slice])
            match = _re.match(pattern, arg_strings_pattern)
            if match is not None:
                result.extend([len(string) for string in match.groups()])
                break

        # return the list of arg string counts
        return result

    def _parse_optional(self, arg_string):
        # if it's an empty string, it was meant to be a positional
        if not arg_string:
            return None

        # if it doesn't start with a prefix, it was meant to be positional
        if not arg_string[0] in self.prefix_chars:
            return None

        # if the option string is present in the parser, return the action
        if arg_string in self._option_string_actions:
            action = self._option_string_actions[arg_string]
            return action, arg_string, None

        # if it's just a single character, it was meant to be positional
        if len(arg_string) == 1:
            return None

        # if the option string before the "=" is present, return the action
        if '=' in arg_string:
            option_string, explicit_arg = arg_string.split('=', 1)
            if option_string in self._option_string_actions:
                action = self._option_string_actions[option_string]
                return action, option_string, explicit_arg

        # search through all possible prefixes of the option string
        # and all actions in the parser for possible interpretations
        option_tuples = self._get_option_tuples(arg_string)

        # if multiple actions match, the option string was ambiguous
        if len(option_tuples) > 1:
            options = ', '.join([option_string
                for action, option_string, explicit_arg in option_tuples])
            args = {'option': arg_string, 'matches': options}
            msg = _('ambiguous option: %(option)s could match %(matches)s')
            self.error(msg % args)

        # if exactly one action matched, this segmentation is good,
        # so return the parsed action
        elif len(option_tuples) == 1:
            option_tuple, = option_tuples
            return option_tuple

        # if it was not found as an option, but it looks like a negative
        # number, it was meant to be positional
        # unless there are negative-number-like options
        if self._negative_number_matcher.match(arg_string):
            if not self._has_negative_number_optionals:
                return None

        # if it contains a space, it was meant to be a positional
        if ' ' in arg_string:
            return None

        # it was meant to be an optional but there is no such option
        # in this parser (though it might be a valid option in a subparser)
        return None, arg_string, None

    def _get_option_tuples(self, option_string):
        result = []

        # option strings starting with two prefix characters are only
        # split at the '='
        chars = self.prefix_chars
        if option_string[0] in chars and option_string[1] in chars:
            if '=' in option_string:
                option_prefix, explicit_arg = option_string.split('=', 1)
            else:
                option_prefix = option_string
                explicit_arg = None
            for option_string in self._option_string_actions:
                if option_string.startswith(option_prefix):
                    action = self._option_string_actions[option_string]
                    tup = action, option_string, explicit_arg
                    result.append(tup)

        # single character options can be concatenated with their arguments
        # but multiple character options always have to have their argument
        # separate
        elif option_string[0] in chars and option_string[1] not in chars:
            option_prefix = option_string
            explicit_arg = None
            short_option_prefix = option_string[:2]
            short_explicit_arg = option_string[2:]

            for option_string in self._option_string_actions:
                if option_string == short_option_prefix:
                    action = self._option_string_actions[option_string]
                    tup = action, option_string, short_explicit_arg
                    result.append(tup)
                elif option_string.startswith(option_prefix):
                    action = self._option_string_actions[option_string]
                    tup = action, option_string, explicit_arg
                    result.append(tup)

        # shouldn't ever get here
        else:
            self.error(_('unexpected option string: %s') % option_string)

        # return the collected option tuples
        return result

    def _get_nargs_pattern(self, action):
        # in all examples below, we have to allow for '--' args
        # which are represented as '-' in the pattern
        nargs = action.nargs

        # the default (None) is assumed to be a single argument
        if nargs is None:
            nargs_pattern = '(-*A-*)'

        # allow zero or one arguments
        elif nargs == OPTIONAL:
            nargs_pattern = '(-*A?-*)'

        # allow zero or more arguments
        elif nargs == ZERO_OR_MORE:
            nargs_pattern = '(-*[A-]*)'

        # allow one or more arguments
        elif nargs == ONE_OR_MORE:
            nargs_pattern = '(-*A[A-]*)'

        # allow any number of options or arguments
        elif nargs == REMAINDER:
            nargs_pattern = '([-AO]*)'

        # allow one argument followed by any number of options or arguments
        elif nargs == PARSER:
            nargs_pattern = '(-*A[-AO]*)'

        # all others should be integers
        else:
            nargs_pattern = '(-*%s-*)' % '-*'.join('A' * nargs)

        # if this is an optional action, -- is not allowed
        if action.option_strings:
            nargs_pattern = nargs_pattern.replace('-*', '')
            nargs_pattern = nargs_pattern.replace('-', '')

        # return the pattern
        return nargs_pattern

    # ========================
    # Value conversion methods
    # ========================
    def _get_values(self, action, arg_strings):
        # for everything but PARSER, REMAINDER args, strip out first '--'
        if action.nargs not in [PARSER, REMAINDER]:
            try:
                arg_strings.remove('--')
            except ValueError:
                pass

        # optional argument produces a default when not present
        if not arg_strings and action.nargs == OPTIONAL:
            if action.option_strings:
                value = action.const
            else:
                value = action.default
            if isinstance(value, str):
                value = self._get_value(action, value)
                self._check_value(action, value)

        # when nargs='*' on a positional, if there were no command-line
        # args, use the default if it is anything other than None
        elif (not arg_strings and action.nargs == ZERO_OR_MORE and
              not action.option_strings):
            if action.default is not None:
                value = action.default
            else:
                value = arg_strings
            self._check_value(action, value)

        # single argument or optional argument produces a single value
        elif len(arg_strings) == 1 and action.nargs in [None, OPTIONAL]:
            arg_string, = arg_strings
            value = self._get_value(action, arg_string)
            self._check_value(action, value)

        # REMAINDER arguments convert all values, checking none
        elif action.nargs == REMAINDER:
            value = [self._get_value(action, v) for v in arg_strings]

        # PARSER arguments convert all values, but check only the first
        elif action.nargs == PARSER:
            value = [self._get_value(action, v) for v in arg_strings]
            self._check_value(action, value[0])

        # all other types of nargs produce a list
        else:
            value = [self._get_value(action, v) for v in arg_strings]
            for v in value:
                self._check_value(action, v)

        # return the converted value
        return value

    def _get_value(self, action, arg_string):
        type_func = self._registry_get('type', action.type, action.type)
        if not callable(type_func):
            msg = _('%r is not callable')
            raise ArgumentError(action, msg % type_func)

        # convert the value to the appropriate type
        try:
            result = type_func(arg_string)

        # ArgumentTypeErrors indicate errors
        except ArgumentTypeError:
            name = getattr(action.type, '__name__', repr(action.type))
            msg = str(_sys.exc_info()[1])
            raise ArgumentError(action, msg)

        # TypeErrors or ValueErrors also indicate errors
        except (TypeError, ValueError):
            name = getattr(action.type, '__name__', repr(action.type))
            args = {'type': name, 'value': arg_string}
            msg = _('invalid %(type)s value: %(value)r')
            raise ArgumentError(action, msg % args)

        # return the converted value
        return result

    def _check_value(self, action, value):
        # converted value must be one of the choices (if specified)
        if action.choices is not None and value not in action.choices:
            args = {'value': value,
                    'choices': ', '.join(map(repr, action.choices))}
            msg = _('invalid choice: %(value)r (choose from %(choices)s)')
            raise ArgumentError(action, msg % args)

    # =======================
    # Help-formatting methods
    # =======================
    def format_usage(self):
        formatter = self._get_formatter()
        formatter.add_usage(self.usage, self._actions,
                            self._mutually_exclusive_groups)
        return formatter.format_help()

    def format_help(self):
        formatter = self._get_formatter()

        # usage
        formatter.add_usage(self.usage, self._actions,
                            self._mutually_exclusive_groups)

        # description
        formatter.add_text(self.description)

        # positionals, optionals and user-defined groups
        for action_group in self._action_groups:
            formatter.start_section(action_group.title)
            formatter.add_text(action_group.description)
            formatter.add_arguments(action_group._group_actions)
            formatter.end_section()

        # epilog
        formatter.add_text(self.epilog)

        # determine help from format above
        return formatter.format_help()

    def _get_formatter(self):
        return self.formatter_class(prog=self.prog)

    # =====================
    # Help-printing methods
    # =====================
    def print_usage(self, file=None):
        if file is None:
            file = _sys.stdout
        self._print_message(self.format_usage(), file)

    def print_help(self, file=None):
        if file is None:
            file = _sys.stdout
        self._print_message(self.format_help(), file)

    def _print_message(self, message, file=None):
        if message:
            if file is None:
                file = _sys.stderr
            file.write(message)

    # ===============
    # Exiting methods
    # ===============
    def exit(self, status=0, message=None):
        if message:
            self._print_message(message, _sys.stderr)
        _sys.exit(status)

    def error(self, message):
        """error(message: string)

        Prints a usage message incorporating the message to stderr and
        exits.

        If you override this in a subclass, it should not return -- it
        should either exit or raise an exception.
        """
        self.print_usage(_sys.stderr)
        args = {'prog': self.prog, 'message': message}
        self.exit(2, _('%(prog)s: error: %(message)s\n') % args)
lib\ast.py
"""
    ast
    ~~~

    The `ast` module helps Python applications to process trees of the Python
    abstract syntax grammar.  The abstract syntax itself might change with
    each Python release; this module helps to find out programmatically what
    the current grammar looks like and allows modifications of it.

    An abstract syntax tree can be generated by passing `ast.PyCF_ONLY_AST` as
    a flag to the `compile()` builtin function or by using the `parse()`
    function from this module.  The result will be a tree of objects whose
    classes all inherit from `ast.AST`.

    A modified abstract syntax tree can be compiled into a Python code object
    using the built-in `compile()` function.

    Additionally various helper functions are provided that make working with
    the trees simpler.  The main intention of the helper functions and this
    module in general is to provide an easy to use interface for libraries
    that work tightly with the python syntax (template engines for example).


    :copyright: Copyright 2008 by Armin Ronacher.
    :license: Python License.
"""
from _ast import *


def parse(source, filename='<unknown>', mode='exec'):
    """
    Parse the source into an AST node.
    Equivalent to compile(source, filename, mode, PyCF_ONLY_AST).
    """
    return compile(source, filename, mode, PyCF_ONLY_AST)


def literal_eval(node_or_string):
    """
    Safely evaluate an expression node or a string containing a Python
    expression.  The string or node provided may only consist of the following
    Python literal structures: strings, bytes, numbers, tuples, lists, dicts,
    sets, booleans, and None.
    """
    if isinstance(node_or_string, str):
        node_or_string = parse(node_or_string, mode='eval')
    if isinstance(node_or_string, Expression):
        node_or_string = node_or_string.body
    def _convert(node):
        if isinstance(node, (Str, Bytes)):
            return node.s
        elif isinstance(node, Num):
            return node.n
        elif isinstance(node, Tuple):
            return tuple(map(_convert, node.elts))
        elif isinstance(node, List):
            return list(map(_convert, node.elts))
        elif isinstance(node, Set):
            return set(map(_convert, node.elts))
        elif isinstance(node, Dict):
            return dict((_convert(k), _convert(v)) for k, v
                        in zip(node.keys, node.values))
        elif isinstance(node, NameConstant):
            return node.value
        elif isinstance(node, UnaryOp) and \
             isinstance(node.op, (UAdd, USub)) and \
             isinstance(node.operand, (Num, UnaryOp, BinOp)):
            operand = _convert(node.operand)
            if isinstance(node.op, UAdd):
                return + operand
            else:
                return - operand
        elif isinstance(node, BinOp) and \
             isinstance(node.op, (Add, Sub)) and \
             isinstance(node.right, (Num, UnaryOp, BinOp)) and \
             isinstance(node.left, (Num, UnaryOp, BinOp)):
            left = _convert(node.left)
            right = _convert(node.right)
            if isinstance(node.op, Add):
                return left + right
            else:
                return left - right
        raise ValueError('malformed node or string: ' + repr(node))
    return _convert(node_or_string)


def dump(node, annotate_fields=True, include_attributes=False):
    """
    Return a formatted dump of the tree in *node*.  This is mainly useful for
    debugging purposes.  The returned string will show the names and the values
    for fields.  This makes the code impossible to evaluate, so if evaluation is
    wanted *annotate_fields* must be set to False.  Attributes such as line
    numbers and column offsets are not dumped by default.  If this is wanted,
    *include_attributes* can be set to True.
    """
    def _format(node):
        if isinstance(node, AST):
            fields = [(a, _format(b)) for a, b in iter_fields(node)]
            rv = '%s(%s' % (node.__class__.__name__, ', '.join(
                ('%s=%s' % field for field in fields)
                if annotate_fields else
                (b for a, b in fields)
            ))
            if include_attributes and node._attributes:
                rv += fields and ', ' or ' '
                rv += ', '.join('%s=%s' % (a, _format(getattr(node, a)))
                                for a in node._attributes)
            return rv + ')'
        elif isinstance(node, list):
            return '[%s]' % ', '.join(_format(x) for x in node)
        return repr(node)
    if not isinstance(node, AST):
        raise TypeError('expected AST, got %r' % node.__class__.__name__)
    return _format(node)


def copy_location(new_node, old_node):
    """
    Copy source location (`lineno` and `col_offset` attributes) from
    *old_node* to *new_node* if possible, and return *new_node*.
    """
    for attr in 'lineno', 'col_offset':
        if attr in old_node._attributes and attr in new_node._attributes \
           and hasattr(old_node, attr):
            setattr(new_node, attr, getattr(old_node, attr))
    return new_node


def fix_missing_locations(node):
    """
    When you compile a node tree with compile(), the compiler expects lineno and
    col_offset attributes for every node that supports them.  This is rather
    tedious to fill in for generated nodes, so this helper adds these attributes
    recursively where not already set, by setting them to the values of the
    parent node.  It works recursively starting at *node*.
    """
    def _fix(node, lineno, col_offset):
        if 'lineno' in node._attributes:
            if not hasattr(node, 'lineno'):
                node.lineno = lineno
            else:
                lineno = node.lineno
        if 'col_offset' in node._attributes:
            if not hasattr(node, 'col_offset'):
                node.col_offset = col_offset
            else:
                col_offset = node.col_offset
        for child in iter_child_nodes(node):
            _fix(child, lineno, col_offset)
    _fix(node, 1, 0)
    return node


def increment_lineno(node, n=1):
    """
    Increment the line number of each node in the tree starting at *node* by *n*.
    This is useful to "move code" to a different location in a file.
    """
    for child in walk(node):
        if 'lineno' in child._attributes:
            child.lineno = getattr(child, 'lineno', 0) + n
    return node


def iter_fields(node):
    """
    Yield a tuple of ``(fieldname, value)`` for each field in ``node._fields``
    that is present on *node*.
    """
    for field in node._fields:
        try:
            yield field, getattr(node, field)
        except AttributeError:
            pass


def iter_child_nodes(node):
    """
    Yield all direct child nodes of *node*, that is, all fields that are nodes
    and all items of fields that are lists of nodes.
    """
    for name, field in iter_fields(node):
        if isinstance(field, AST):
            yield field
        elif isinstance(field, list):
            for item in field:
                if isinstance(item, AST):
                    yield item


def get_docstring(node, clean=True):
    """
    Return the docstring for the given node or None if no docstring can
    be found.  If the node provided does not have docstrings a TypeError
    will be raised.
    """
    if not isinstance(node, (FunctionDef, ClassDef, Module)):
        raise TypeError("%r can't have docstrings" % node.__class__.__name__)
    if node.body and isinstance(node.body[0], Expr) and \
       isinstance(node.body[0].value, Str):
        if clean:
            import inspect
            return inspect.cleandoc(node.body[0].value.s)
        return node.body[0].value.s


def walk(node):
    """
    Recursively yield all descendant nodes in the tree starting at *node*
    (including *node* itself), in no specified order.  This is useful if you
    only want to modify nodes in place and don't care about the context.
    """
    from collections import deque
    todo = deque([node])
    while todo:
        node = todo.popleft()
        todo.extend(iter_child_nodes(node))
        yield node


class NodeVisitor(object):
    """
    A node visitor base class that walks the abstract syntax tree and calls a
    visitor function for every node found.  This function may return a value
    which is forwarded by the `visit` method.

    This class is meant to be subclassed, with the subclass adding visitor
    methods.

    Per default the visitor functions for the nodes are ``'visit_'`` +
    class name of the node.  So a `TryFinally` node visit function would
    be `visit_TryFinally`.  This behavior can be changed by overriding
    the `visit` method.  If no visitor function exists for a node
    (return value `None`) the `generic_visit` visitor is used instead.

    Don't use the `NodeVisitor` if you want to apply changes to nodes during
    traversing.  For this a special visitor exists (`NodeTransformer`) that
    allows modifications.
    """

    def visit(self, node):
        """Visit a node."""
        method = 'visit_' + node.__class__.__name__
        visitor = getattr(self, method, self.generic_visit)
        return visitor(node)

    def generic_visit(self, node):
        """Called if no explicit visitor function exists for a node."""
        for field, value in iter_fields(node):
            if isinstance(value, list):
                for item in value:
                    if isinstance(item, AST):
                        self.visit(item)
            elif isinstance(value, AST):
                self.visit(value)


class NodeTransformer(NodeVisitor):
    """
    A :class:`NodeVisitor` subclass that walks the abstract syntax tree and
    allows modification of nodes.

    The `NodeTransformer` will walk the AST and use the return value of the
    visitor methods to replace or remove the old node.  If the return value of
    the visitor method is ``None``, the node will be removed from its location,
    otherwise it is replaced with the return value.  The return value may be the
    original node in which case no replacement takes place.

    Here is an example transformer that rewrites all occurrences of name lookups
    (``foo``) to ``data['foo']``::

       class RewriteName(NodeTransformer):

           def visit_Name(self, node):
               return copy_location(Subscript(
                   value=Name(id='data', ctx=Load()),
                   slice=Index(value=Str(s=node.id)),
                   ctx=node.ctx
               ), node)

    Keep in mind that if the node you're operating on has child nodes you must
    either transform the child nodes yourself or call the :meth:`generic_visit`
    method for the node first.

    For nodes that were part of a collection of statements (that applies to all
    statement nodes), the visitor may also return a list of nodes rather than
    just a single node.

    Usually you use the transformer like this::

       node = YourTransformer().visit(node)
    """

    def generic_visit(self, node):
        for field, old_value in iter_fields(node):
            old_value = getattr(node, field, None)
            if isinstance(old_value, list):
                new_values = []
                for value in old_value:
                    if isinstance(value, AST):
                        value = self.visit(value)
                        if value is None:
                            continue
                        elif not isinstance(value, AST):
                            new_values.extend(value)
                            continue
                    new_values.append(value)
                old_value[:] = new_values
            elif isinstance(old_value, AST):
                new_node = self.visit(old_value)
                if new_node is None:
                    delattr(node, field)
                else:
                    setattr(node, field, new_node)
        return node
lib\asynchat.py
# -*- Mode: Python; tab-width: 4 -*-
#       Id: asynchat.py,v 2.26 2000/09/07 22:29:26 rushing Exp
#       Author: Sam Rushing <[email protected]>

# ======================================================================
# Copyright 1996 by Sam Rushing
#
#                         All Rights Reserved
#
# Permission to use, copy, modify, and distribute this software and
# its documentation for any purpose and without fee is hereby
# granted, provided that the above copyright notice appear in all
# copies and that both that copyright notice and this permission
# notice appear in supporting documentation, and that the name of Sam
# Rushing not be used in advertising or publicity pertaining to
# distribution of the software without specific, written prior
# permission.
#
# SAM RUSHING DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
# INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN
# NO EVENT SHALL SAM RUSHING BE LIABLE FOR ANY SPECIAL, INDIRECT OR
# CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
# OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
# NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
# CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
# ======================================================================

r"""A class supporting chat-style (command/response) protocols.

This class adds support for 'chat' style protocols - where one side
sends a 'command', and the other sends a response (examples would be
the common internet protocols - smtp, nntp, ftp, etc..).

The handle_read() method looks at the input stream for the current
'terminator' (usually '\r\n' for single-line responses, '\r\n.\r\n'
for multi-line output), calling self.found_terminator() on its
receipt.

for example:
Say you build an async nntp client using this class.  At the start
of the connection, you'll have self.terminator set to '\r\n', in
order to process the single-line greeting.  Just before issuing a
'LIST' command you'll set it to '\r\n.\r\n'.  The output of the LIST
command will be accumulated (using your own 'collect_incoming_data'
method) up to the terminator, and then control will be returned to
you - by calling your self.found_terminator() method.
"""
import asyncore
from collections import deque


class async_chat(asyncore.dispatcher):
    """This is an abstract class.  You must derive from this class, and add
    the two methods collect_incoming_data() and found_terminator()"""

    # these are overridable defaults

    ac_in_buffer_size = 65536
    ac_out_buffer_size = 65536

    # we don't want to enable the use of encoding by default, because that is a
    # sign of an application bug that we don't want to pass silently

    use_encoding = 0
    encoding = 'latin-1'

    def __init__(self, sock=None, map=None):
        # for string terminator matching
        self.ac_in_buffer = b''

        # we use a list here rather than io.BytesIO for a few reasons...
        # del lst[:] is faster than bio.truncate(0)
        # lst = [] is faster than bio.truncate(0)
        self.incoming = []

        # we toss the use of the "simple producer" and replace it with
        # a pure deque, which the original fifo was a wrapping of
        self.producer_fifo = deque()
        asyncore.dispatcher.__init__(self, sock, map)

    def collect_incoming_data(self, data):
        raise NotImplementedError("must be implemented in subclass")

    def _collect_incoming_data(self, data):
        self.incoming.append(data)

    def _get_data(self):
        d = b''.join(self.incoming)
        del self.incoming[:]
        return d

    def found_terminator(self):
        raise NotImplementedError("must be implemented in subclass")

    def set_terminator(self, term):
        """Set the input delimiter.

        Can be a fixed string of any length, an integer, or None.
        """
        if isinstance(term, str) and self.use_encoding:
            term = bytes(term, self.encoding)
        elif isinstance(term, int) and term < 0:
            raise ValueError('the number of received bytes must be positive')
        self.terminator = term

    def get_terminator(self):
        return self.terminator

    # grab some more data from the socket,
    # throw it to the collector method,
    # check for the terminator,
    # if found, transition to the next state.

    def handle_read(self):

        try:
            data = self.recv(self.ac_in_buffer_size)
        except BlockingIOError:
            return
        except OSError as why:
            self.handle_error()
            return

        if isinstance(data, str) and self.use_encoding:
            data = bytes(str, self.encoding)
        self.ac_in_buffer = self.ac_in_buffer + data

        # Continue to search for self.terminator in self.ac_in_buffer,
        # while calling self.collect_incoming_data.  The while loop
        # is necessary because we might read several data+terminator
        # combos with a single recv(4096).

        while self.ac_in_buffer:
            lb = len(self.ac_in_buffer)
            terminator = self.get_terminator()
            if not terminator:
                # no terminator, collect it all
                self.collect_incoming_data(self.ac_in_buffer)
                self.ac_in_buffer = b''
            elif isinstance(terminator, int):
                # numeric terminator
                n = terminator
                if lb < n:
                    self.collect_incoming_data(self.ac_in_buffer)
                    self.ac_in_buffer = b''
                    self.terminator = self.terminator - lb
                else:
                    self.collect_incoming_data(self.ac_in_buffer[:n])
                    self.ac_in_buffer = self.ac_in_buffer[n:]
                    self.terminator = 0
                    self.found_terminator()
            else:
                # 3 cases:
                # 1) end of buffer matches terminator exactly:
                #    collect data, transition
                # 2) end of buffer matches some prefix:
                #    collect data to the prefix
                # 3) end of buffer does not match any prefix:
                #    collect data
                terminator_len = len(terminator)
                index = self.ac_in_buffer.find(terminator)
                if index != -1:
                    # we found the terminator
                    if index > 0:
                        # don't bother reporting the empty string
                        # (source of subtle bugs)
                        self.collect_incoming_data(self.ac_in_buffer[:index])
                    self.ac_in_buffer = self.ac_in_buffer[index+terminator_len:]
                    # This does the Right Thing if the terminator
                    # is changed here.
                    self.found_terminator()
                else:
                    # check for a prefix of the terminator
                    index = find_prefix_at_end(self.ac_in_buffer, terminator)
                    if index:
                        if index != lb:
                            # we found a prefix, collect up to the prefix
                            self.collect_incoming_data(self.ac_in_buffer[:-index])
                            self.ac_in_buffer = self.ac_in_buffer[-index:]
                        break
                    else:
                        # no prefix, collect it all
                        self.collect_incoming_data(self.ac_in_buffer)
                        self.ac_in_buffer = b''

    def handle_write(self):
        self.initiate_send()

    def handle_close(self):
        self.close()

    def push(self, data):
        if not isinstance(data, (bytes, bytearray, memoryview)):
            raise TypeError('data argument must be byte-ish (%r)',
                            type(data))
        sabs = self.ac_out_buffer_size
        if len(data) > sabs:
            for i in range(0, len(data), sabs):
                self.producer_fifo.append(data[i:i+sabs])
        else:
            self.producer_fifo.append(data)
        self.initiate_send()

    def push_with_producer(self, producer):
        self.producer_fifo.append(producer)
        self.initiate_send()

    def readable(self):
        "predicate for inclusion in the readable for select()"
        # cannot use the old predicate, it violates the claim of the
        # set_terminator method.

        # return (len(self.ac_in_buffer) <= self.ac_in_buffer_size)
        return 1

    def writable(self):
        "predicate for inclusion in the writable for select()"
        return self.producer_fifo or (not self.connected)

    def close_when_done(self):
        "automatically close this channel once the outgoing queue is empty"
        self.producer_fifo.append(None)

    def initiate_send(self):
        while self.producer_fifo and self.connected:
            first = self.producer_fifo[0]
            # handle empty string/buffer or None entry
            if not first:
                del self.producer_fifo[0]
                if first is None:
                    self.handle_close()
                    return

            # handle classic producer behavior
            obs = self.ac_out_buffer_size
            try:
                data = first[:obs]
            except TypeError:
                data = first.more()
                if data:
                    self.producer_fifo.appendleft(data)
                else:
                    del self.producer_fifo[0]
                continue

            if isinstance(data, str) and self.use_encoding:
                data = bytes(data, self.encoding)

            # send the data
            try:
                num_sent = self.send(data)
            except OSError:
                self.handle_error()
                return

            if num_sent:
                if num_sent < len(data) or obs < len(first):
                    self.producer_fifo[0] = first[num_sent:]
                else:
                    del self.producer_fifo[0]
            # we tried to send some actual data
            return

    def discard_buffers(self):
        # Emergencies only!
        self.ac_in_buffer = b''
        del self.incoming[:]
        self.producer_fifo.clear()


class simple_producer:

    def __init__(self, data, buffer_size=512):
        self.data = data
        self.buffer_size = buffer_size

    def more(self):
        if len(self.data) > self.buffer_size:
            result = self.data[:self.buffer_size]
            self.data = self.data[self.buffer_size:]
            return result
        else:
            result = self.data
            self.data = b''
            return result


class fifo:
    def __init__(self, list=None):
        if not list:
            self.list = deque()
        else:
            self.list = deque(list)

    def __len__(self):
        return len(self.list)

    def is_empty(self):
        return not self.list

    def first(self):
        return self.list[0]

    def push(self, data):
        self.list.append(data)

    def pop(self):
        if self.list:
            return (1, self.list.popleft())
        else:
            return (0, None)


# Given 'haystack', see if any prefix of 'needle' is at its end.  This
# assumes an exact match has already been checked.  Return the number of
# characters matched.
# for example:
# f_p_a_e("qwerty\r", "\r\n") => 1
# f_p_a_e("qwertydkjf", "\r\n") => 0
# f_p_a_e("qwerty\r\n", "\r\n") => <undefined>

# this could maybe be made faster with a computed regex?
# [answer: no; circa Python-2.0, Jan 2001]
# new python:   28961/s
# old python:   18307/s
# re:        12820/s
# regex:     14035/s

def find_prefix_at_end(haystack, needle):
    l = len(needle) - 1
    while l and not haystack.endswith(needle[:l]):
        l -= 1
    return l
lib\asyncore.py
# -*- Mode: Python -*-
#   Id: asyncore.py,v 2.51 2000/09/07 22:29:26 rushing Exp
#   Author: Sam Rushing <[email protected]>

# ======================================================================
# Copyright 1996 by Sam Rushing
#
#                         All Rights Reserved
#
# Permission to use, copy, modify, and distribute this software and
# its documentation for any purpose and without fee is hereby
# granted, provided that the above copyright notice appear in all
# copies and that both that copyright notice and this permission
# notice appear in supporting documentation, and that the name of Sam
# Rushing not be used in advertising or publicity pertaining to
# distribution of the software without specific, written prior
# permission.
#
# SAM RUSHING DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
# INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN
# NO EVENT SHALL SAM RUSHING BE LIABLE FOR ANY SPECIAL, INDIRECT OR
# CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
# OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
# NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
# CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
# ======================================================================

"""Basic infrastructure for asynchronous socket service clients and servers.

There are only two ways to have a program on a single processor do "more
than one thing at a time".  Multi-threaded programming is the simplest and
most popular way to do it, but there is another very different technique,
that lets you have nearly all the advantages of multi-threading, without
actually using multiple threads. it's really only practical if your program
is largely I/O bound. If your program is CPU bound, then pre-emptive
scheduled threads are probably what you really need. Network servers are
rarely CPU-bound, however.

If your operating system supports the select() system call in its I/O
library (and nearly all do), then you can use it to juggle multiple
communication channels at once; doing other work while your I/O is taking
place in the "background."  Although this strategy can seem strange and
complex, especially at first, it is in many ways easier to understand and
control than multi-threaded programming. The module documented here solves
many of the difficult problems for you, making the task of building
sophisticated high-performance network servers and clients a snap.
"""

import select
import socket
import sys
import time
import warnings

import os
from errno import EALREADY, EINPROGRESS, EWOULDBLOCK, ECONNRESET, EINVAL, \
     ENOTCONN, ESHUTDOWN, EISCONN, EBADF, ECONNABORTED, EPIPE, EAGAIN, \
     errorcode

_DISCONNECTED = frozenset((ECONNRESET, ENOTCONN, ESHUTDOWN, ECONNABORTED, EPIPE,
                           EBADF))

try:
    socket_map
except NameError:
    socket_map = {}

def _strerror(err):
    try:
        return os.strerror(err)
    except (ValueError, OverflowError, NameError):
        if err in errorcode:
            return errorcode[err]
        return "Unknown error %s" %err

class ExitNow(Exception):
    pass

_reraised_exceptions = (ExitNow, KeyboardInterrupt, SystemExit)

def read(obj):
    try:
        obj.handle_read_event()
    except _reraised_exceptions:
        raise
    except:
        obj.handle_error()

def write(obj):
    try:
        obj.handle_write_event()
    except _reraised_exceptions:
        raise
    except:
        obj.handle_error()

def _exception(obj):
    try:
        obj.handle_expt_event()
    except _reraised_exceptions:
        raise
    except:
        obj.handle_error()

def readwrite(obj, flags):
    try:
        if flags & select.POLLIN:
            obj.handle_read_event()
        if flags & select.POLLOUT:
            obj.handle_write_event()
        if flags & select.POLLPRI:
            obj.handle_expt_event()
        if flags & (select.POLLHUP | select.POLLERR | select.POLLNVAL):
            obj.handle_close()
    except OSError as e:
        if e.args[0] not in _DISCONNECTED:
            obj.handle_error()
        else:
            obj.handle_close()
    except _reraised_exceptions:
        raise
    except:
        obj.handle_error()

def poll(timeout=0.0, map=None):
    if map is None:
        map = socket_map
    if map:
        r = []; w = []; e = []
        for fd, obj in list(map.items()):
            is_r = obj.readable()
            is_w = obj.writable()
            if is_r:
                r.append(fd)
            # accepting sockets should not be writable
            if is_w and not obj.accepting:
                w.append(fd)
            if is_r or is_w:
                e.append(fd)
        if [] == r == w == e:
            time.sleep(timeout)
            return

        try:
            r, w, e = select.select(r, w, e, timeout)
        except InterruptedError:
            return

        for fd in r:
            obj = map.get(fd)
            if obj is None:
                continue
            read(obj)

        for fd in w:
            obj = map.get(fd)
            if obj is None:
                continue
            write(obj)

        for fd in e:
            obj = map.get(fd)
            if obj is None:
                continue
            _exception(obj)

def poll2(timeout=0.0, map=None):
    # Use the poll() support added to the select module in Python 2.0
    if map is None:
        map = socket_map
    if timeout is not None:
        # timeout is in milliseconds
        timeout = int(timeout*1000)
    pollster = select.poll()
    if map:
        for fd, obj in list(map.items()):
            flags = 0
            if obj.readable():
                flags |= select.POLLIN | select.POLLPRI
            # accepting sockets should not be writable
            if obj.writable() and not obj.accepting:
                flags |= select.POLLOUT
            if flags:
                pollster.register(fd, flags)
        try:
            r = pollster.poll(timeout)
        except InterruptedError:
            r = []
        for fd, flags in r:
            obj = map.get(fd)
            if obj is None:
                continue
            readwrite(obj, flags)

poll3 = poll2                           # Alias for backward compatibility

def loop(timeout=30.0, use_poll=False, map=None, count=None):
    if map is None:
        map = socket_map

    if use_poll and hasattr(select, 'poll'):
        poll_fun = poll2
    else:
        poll_fun = poll

    if count is None:
        while map:
            poll_fun(timeout, map)

    else:
        while map and count > 0:
            poll_fun(timeout, map)
            count = count - 1

class dispatcher:

    debug = False
    connected = False
    accepting = False
    connecting = False
    closing = False
    addr = None
    ignore_log_types = frozenset(['warning'])

    def __init__(self, sock=None, map=None):
        if map is None:
            self._map = socket_map
        else:
            self._map = map

        self._fileno = None

        if sock:
            # Set to nonblocking just to make sure for cases where we
            # get a socket from a blocking source.
            sock.setblocking(0)
            self.set_socket(sock, map)
            self.connected = True
            # The constructor no longer requires that the socket
            # passed be connected.
            try:
                self.addr = sock.getpeername()
            except OSError as err:
                if err.args[0] in (ENOTCONN, EINVAL):
                    # To handle the case where we got an unconnected
                    # socket.
                    self.connected = False
                else:
                    # The socket is broken in some unknown way, alert
                    # the user and remove it from the map (to prevent
                    # polling of broken sockets).
                    self.del_channel(map)
                    raise
        else:
            self.socket = None

    def __repr__(self):
        status = [self.__class__.__module__+"."+self.__class__.__name__]
        if self.accepting and self.addr:
            status.append('listening')
        elif self.connected:
            status.append('connected')
        if self.addr is not None:
            try:
                status.append('%s:%d' % self.addr)
            except TypeError:
                status.append(repr(self.addr))
        return '<%s at %#x>' % (' '.join(status), id(self))

    __str__ = __repr__

    def add_channel(self, map=None):
        #self.log_info('adding channel %s' % self)
        if map is None:
            map = self._map
        map[self._fileno] = self

    def del_channel(self, map=None):
        fd = self._fileno
        if map is None:
            map = self._map
        if fd in map:
            #self.log_info('closing channel %d:%s' % (fd, self))
            del map[fd]
        self._fileno = None

    def create_socket(self, family=socket.AF_INET, type=socket.SOCK_STREAM):
        self.family_and_type = family, type
        sock = socket.socket(family, type)
        sock.setblocking(0)
        self.set_socket(sock)

    def set_socket(self, sock, map=None):
        self.socket = sock
##        self.__dict__['socket'] = sock
        self._fileno = sock.fileno()
        self.add_channel(map)

    def set_reuse_addr(self):
        # try to re-use a server port if possible
        try:
            self.socket.setsockopt(
                socket.SOL_SOCKET, socket.SO_REUSEADDR,
                self.socket.getsockopt(socket.SOL_SOCKET,
                                       socket.SO_REUSEADDR) | 1
                )
        except OSError:
            pass

    # ==================================================
    # predicates for select()
    # these are used as filters for the lists of sockets
    # to pass to select().
    # ==================================================

    def readable(self):
        return True

    def writable(self):
        return True

    # ==================================================
    # socket object methods.
    # ==================================================

    def listen(self, num):
        self.accepting = True
        if os.name == 'nt' and num > 5:
            num = 5
        return self.socket.listen(num)

    def bind(self, addr):
        self.addr = addr
        return self.socket.bind(addr)

    def connect(self, address):
        self.connected = False
        self.connecting = True
        err = self.socket.connect_ex(address)
        if err in (EINPROGRESS, EALREADY, EWOULDBLOCK) \
        or err == EINVAL and os.name in ('nt', 'ce'):
            self.addr = address
            return
        if err in (0, EISCONN):
            self.addr = address
            self.handle_connect_event()
        else:
            raise OSError(err, errorcode[err])

    def accept(self):
        # XXX can return either an address pair or None
        try:
            conn, addr = self.socket.accept()
        except TypeError:
            return None
        except OSError as why:
            if why.args[0] in (EWOULDBLOCK, ECONNABORTED, EAGAIN):
                return None
            else:
                raise
        else:
            return conn, addr

    def send(self, data):
        try:
            result = self.socket.send(data)
            return result
        except OSError as why:
            if why.args[0] == EWOULDBLOCK:
                return 0
            elif why.args[0] in _DISCONNECTED:
                self.handle_close()
                return 0
            else:
                raise

    def recv(self, buffer_size):
        try:
            data = self.socket.recv(buffer_size)
            if not data:
                # a closed connection is indicated by signaling
                # a read condition, and having recv() return 0.
                self.handle_close()
                return b''
            else:
                return data
        except OSError as why:
            # winsock sometimes raises ENOTCONN
            if why.args[0] in _DISCONNECTED:
                self.handle_close()
                return b''
            else:
                raise

    def close(self):
        self.connected = False
        self.accepting = False
        self.connecting = False
        self.del_channel()
        if self.socket is not None:
            try:
                self.socket.close()
            except OSError as why:
                if why.args[0] not in (ENOTCONN, EBADF):
                    raise

    # cheap inheritance, used to pass all other attribute
    # references to the underlying socket object.
    def __getattr__(self, attr):
        try:
            retattr = getattr(self.socket, attr)
        except AttributeError:
            raise AttributeError("%s instance has no attribute '%s'"
                                 %(self.__class__.__name__, attr))
        else:
            msg = "%(me)s.%(attr)s is deprecated; use %(me)s.socket.%(attr)s " \
                  "instead" % {'me' : self.__class__.__name__, 'attr' : attr}
            warnings.warn(msg, DeprecationWarning, stacklevel=2)
            return retattr

    # log and log_info may be overridden to provide more sophisticated
    # logging and warning methods. In general, log is for 'hit' logging
    # and 'log_info' is for informational, warning and error logging.

    def log(self, message):
        sys.stderr.write('log: %s\n' % str(message))

    def log_info(self, message, type='info'):
        if type not in self.ignore_log_types:
            print('%s: %s' % (type, message))

    def handle_read_event(self):
        if self.accepting:
            # accepting sockets are never connected, they "spawn" new
            # sockets that are connected
            self.handle_accept()
        elif not self.connected:
            if self.connecting:
                self.handle_connect_event()
            self.handle_read()
        else:
            self.handle_read()

    def handle_connect_event(self):
        err = self.socket.getsockopt(socket.SOL_SOCKET, socket.SO_ERROR)
        if err != 0:
            raise OSError(err, _strerror(err))
        self.handle_connect()
        self.connected = True
        self.connecting = False

    def handle_write_event(self):
        if self.accepting:
            # Accepting sockets shouldn't get a write event.
            # We will pretend it didn't happen.
            return

        if not self.connected:
            if self.connecting:
                self.handle_connect_event()
        self.handle_write()

    def handle_expt_event(self):
        # handle_expt_event() is called if there might be an error on the
        # socket, or if there is OOB data
        # check for the error condition first
        err = self.socket.getsockopt(socket.SOL_SOCKET, socket.SO_ERROR)
        if err != 0:
            # we can get here when select.select() says that there is an
            # exceptional condition on the socket
            # since there is an error, we'll go ahead and close the socket
            # like we would in a subclassed handle_read() that received no
            # data
            self.handle_close()
        else:
            self.handle_expt()

    def handle_error(self):
        nil, t, v, tbinfo = compact_traceback()

        # sometimes a user repr method will crash.
        try:
            self_repr = repr(self)
        except:
            self_repr = '<__repr__(self) failed for object at %0x>' % id(self)

        self.log_info(
            'uncaptured python exception, closing channel %s (%s:%s %s)' % (
                self_repr,
                t,
                v,
                tbinfo
                ),
            'error'
            )
        self.handle_close()

    def handle_expt(self):
        self.log_info('unhandled incoming priority event', 'warning')

    def handle_read(self):
        self.log_info('unhandled read event', 'warning')

    def handle_write(self):
        self.log_info('unhandled write event', 'warning')

    def handle_connect(self):
        self.log_info('unhandled connect event', 'warning')

    def handle_accept(self):
        pair = self.accept()
        if pair is not None:
            self.handle_accepted(*pair)

    def handle_accepted(self, sock, addr):
        sock.close()
        self.log_info('unhandled accepted event', 'warning')

    def handle_close(self):
        self.log_info('unhandled close event', 'warning')
        self.close()

# ---------------------------------------------------------------------------
# adds simple buffered output capability, useful for simple clients.
# [for more sophisticated usage use asynchat.async_chat]
# ---------------------------------------------------------------------------

class dispatcher_with_send(dispatcher):

    def __init__(self, sock=None, map=None):
        dispatcher.__init__(self, sock, map)
        self.out_buffer = b''

    def initiate_send(self):
        num_sent = 0
        num_sent = dispatcher.send(self, self.out_buffer[:65536])
        self.out_buffer = self.out_buffer[num_sent:]

    def handle_write(self):
        self.initiate_send()

    def writable(self):
        return (not self.connected) or len(self.out_buffer)

    def send(self, data):
        if self.debug:
            self.log_info('sending %s' % repr(data))
        self.out_buffer = self.out_buffer + data
        self.initiate_send()

# ---------------------------------------------------------------------------
# used for debugging.
# ---------------------------------------------------------------------------

def compact_traceback():
    t, v, tb = sys.exc_info()
    tbinfo = []
    if not tb: # Must have a traceback
        raise AssertionError("traceback does not exist")
    while tb:
        tbinfo.append((
            tb.tb_frame.f_code.co_filename,
            tb.tb_frame.f_code.co_name,
            str(tb.tb_lineno)
            ))
        tb = tb.tb_next

    # just to be safe
    del tb

    file, function, line = tbinfo[-1]
    info = ' '.join(['[%s|%s|%s]' % x for x in tbinfo])
    return (file, function, line), t, v, info

def close_all(map=None, ignore_all=False):
    if map is None:
        map = socket_map
    for x in list(map.values()):
        try:
            x.close()
        except OSError as x:
            if x.args[0] == EBADF:
                pass
            elif not ignore_all:
                raise
        except _reraised_exceptions:
            raise
        except:
            if not ignore_all:
                raise
    map.clear()

# Asynchronous File I/O:
#
# After a little research (reading man pages on various unixen, and
# digging through the linux kernel), I've determined that select()
# isn't meant for doing asynchronous file i/o.
# Heartening, though - reading linux/mm/filemap.c shows that linux
# supports asynchronous read-ahead.  So _MOST_ of the time, the data
# will be sitting in memory for us already when we go to read it.
#
# What other OS's (besides NT) support async file i/o?  [VMS?]
#
# Regardless, this is useful for pipes, and stdin/stdout...

if os.name == 'posix':
    import fcntl

    class file_wrapper:
        # Here we override just enough to make a file
        # look like a socket for the purposes of asyncore.
        # The passed fd is automatically os.dup()'d

        def __init__(self, fd):
            self.fd = os.dup(fd)

        def __del__(self):
            if self.fd >= 0:
                warnings.warn("unclosed file %r" % self, ResourceWarning)
            self.close()

        def recv(self, *args):
            return os.read(self.fd, *args)

        def send(self, *args):
            return os.write(self.fd, *args)

        def getsockopt(self, level, optname, buflen=None):
            if (level == socket.SOL_SOCKET and
                optname == socket.SO_ERROR and
                not buflen):
                return 0
            raise NotImplementedError("Only asyncore specific behaviour "
                                      "implemented.")

        read = recv
        write = send

        def close(self):
            if self.fd < 0:
                return
            os.close(self.fd)
            self.fd = -1

        def fileno(self):
            return self.fd

    class file_dispatcher(dispatcher):

        def __init__(self, fd, map=None):
            dispatcher.__init__(self, None, map)
            self.connected = True
            try:
                fd = fd.fileno()
            except AttributeError:
                pass
            self.set_file(fd)
            # set it to non-blocking mode
            flags = fcntl.fcntl(fd, fcntl.F_GETFL, 0)
            flags = flags | os.O_NONBLOCK
            fcntl.fcntl(fd, fcntl.F_SETFL, flags)

        def set_file(self, fd):
            self.socket = file_wrapper(fd)
            self._fileno = self.socket.fileno()
            self.add_channel()
lib\base64.py
#! /usr/bin/env python3

"""Base16, Base32, Base64 (RFC 3548), Base85 and Ascii85 data encodings"""

# Modified 04-Oct-1995 by Jack Jansen to use binascii module
# Modified 30-Dec-2003 by Barry Warsaw to add full RFC 3548 support
# Modified 22-May-2007 by Guido van Rossum to use bytes everywhere

import re
import struct
import binascii


__all__ = [
    # Legacy interface exports traditional RFC 1521 Base64 encodings
    'encode', 'decode', 'encodebytes', 'decodebytes',
    # Generalized interface for other encodings
    'b64encode', 'b64decode', 'b32encode', 'b32decode',
    'b16encode', 'b16decode',
    # Base85 and Ascii85 encodings
    'b85encode', 'b85decode', 'a85encode', 'a85decode',
    # Standard Base64 encoding
    'standard_b64encode', 'standard_b64decode',
    # Some common Base64 alternatives.  As referenced by RFC 3458, see thread
    # starting at:
    #
    # http://zgp.org/pipermail/p2p-hackers/2001-September/000316.html
    'urlsafe_b64encode', 'urlsafe_b64decode',
    ]


bytes_types = (bytes, bytearray)  # Types acceptable as binary data

def _bytes_from_decode_data(s):
    if isinstance(s, str):
        try:
            return s.encode('ascii')
        except UnicodeEncodeError:
            raise ValueError('string argument should contain only ASCII characters')
    if isinstance(s, bytes_types):
        return s
    try:
        return memoryview(s).tobytes()
    except TypeError:
        raise TypeError("argument should be a bytes-like object or ASCII "
                        "string, not %r" % s.__class__.__name__) from None


# Base64 encoding/decoding uses binascii

def b64encode(s, altchars=None):
    """Encode a byte string using Base64.

    s is the byte string to encode.  Optional altchars must be a byte
    string of length 2 which specifies an alternative alphabet for the
    '+' and '/' characters.  This allows an application to
    e.g. generate url or filesystem safe Base64 strings.

    The encoded byte string is returned.
    """
    # Strip off the trailing newline
    encoded = binascii.b2a_base64(s)[:-1]
    if altchars is not None:
        assert len(altchars) == 2, repr(altchars)
        return encoded.translate(bytes.maketrans(b'+/', altchars))
    return encoded


def b64decode(s, altchars=None, validate=False):
    """Decode a Base64 encoded byte string.

    s is the byte string to decode.  Optional altchars must be a
    string of length 2 which specifies the alternative alphabet used
    instead of the '+' and '/' characters.

    The decoded string is returned.  A binascii.Error is raised if s is
    incorrectly padded.

    If validate is False (the default), non-base64-alphabet characters are
    discarded prior to the padding check.  If validate is True,
    non-base64-alphabet characters in the input result in a binascii.Error.
    """
    s = _bytes_from_decode_data(s)
    if altchars is not None:
        altchars = _bytes_from_decode_data(altchars)
        assert len(altchars) == 2, repr(altchars)
        s = s.translate(bytes.maketrans(altchars, b'+/'))
    if validate and not re.match(b'^[A-Za-z0-9+/]*={0,2}$', s):
        raise binascii.Error('Non-base64 digit found')
    return binascii.a2b_base64(s)


def standard_b64encode(s):
    """Encode a byte string using the standard Base64 alphabet.

    s is the byte string to encode.  The encoded byte string is returned.
    """
    return b64encode(s)

def standard_b64decode(s):
    """Decode a byte string encoded with the standard Base64 alphabet.

    s is the byte string to decode.  The decoded byte string is
    returned.  binascii.Error is raised if the input is incorrectly
    padded or if there are non-alphabet characters present in the
    input.
    """
    return b64decode(s)


_urlsafe_encode_translation = bytes.maketrans(b'+/', b'-_')
_urlsafe_decode_translation = bytes.maketrans(b'-_', b'+/')

def urlsafe_b64encode(s):
    """Encode a byte string using a url-safe Base64 alphabet.

    s is the byte string to encode.  The encoded byte string is
    returned.  The alphabet uses '-' instead of '+' and '_' instead of
    '/'.
    """
    return b64encode(s).translate(_urlsafe_encode_translation)

def urlsafe_b64decode(s):
    """Decode a byte string encoded with the standard Base64 alphabet.

    s is the byte string to decode.  The decoded byte string is
    returned.  binascii.Error is raised if the input is incorrectly
    padded or if there are non-alphabet characters present in the
    input.

    The alphabet uses '-' instead of '+' and '_' instead of '/'.
    """
    s = _bytes_from_decode_data(s)
    s = s.translate(_urlsafe_decode_translation)
    return b64decode(s)



# Base32 encoding/decoding must be done in Python
_b32alphabet = b'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567'
_b32tab2 = None
_b32rev = None

def b32encode(s):
    """Encode a byte string using Base32.

    s is the byte string to encode.  The encoded byte string is returned.
    """
    global _b32tab2
    # Delay the initialization of the table to not waste memory
    # if the function is never called
    if _b32tab2 is None:
        b32tab = [bytes((i,)) for i in _b32alphabet]
        _b32tab2 = [a + b for a in b32tab for b in b32tab]
        b32tab = None

    if not isinstance(s, bytes_types):
        s = memoryview(s).tobytes()
    leftover = len(s) % 5
    # Pad the last quantum with zero bits if necessary
    if leftover:
        s = s + bytes(5 - leftover)  # Don't use += !
    encoded = bytearray()
    from_bytes = int.from_bytes
    b32tab2 = _b32tab2
    for i in range(0, len(s), 5):
        c = from_bytes(s[i: i + 5], 'big')
        encoded += (b32tab2[c >> 30] +           # bits 1 - 10
                    b32tab2[(c >> 20) & 0x3ff] + # bits 11 - 20
                    b32tab2[(c >> 10) & 0x3ff] + # bits 21 - 30
                    b32tab2[c & 0x3ff]           # bits 31 - 40
                   )
    # Adjust for any leftover partial quanta
    if leftover == 1:
        encoded[-6:] = b'======'
    elif leftover == 2:
        encoded[-4:] = b'===='
    elif leftover == 3:
        encoded[-3:] = b'==='
    elif leftover == 4:
        encoded[-1:] = b'='
    return bytes(encoded)

def b32decode(s, casefold=False, map01=None):
    """Decode a Base32 encoded byte string.

    s is the byte string to decode.  Optional casefold is a flag
    specifying whether a lowercase alphabet is acceptable as input.
    For security purposes, the default is False.

    RFC 3548 allows for optional mapping of the digit 0 (zero) to the
    letter O (oh), and for optional mapping of the digit 1 (one) to
    either the letter I (eye) or letter L (el).  The optional argument
    map01 when not None, specifies which letter the digit 1 should be
    mapped to (when map01 is not None, the digit 0 is always mapped to
    the letter O).  For security purposes the default is None, so that
    0 and 1 are not allowed in the input.

    The decoded byte string is returned.  binascii.Error is raised if
    the input is incorrectly padded or if there are non-alphabet
    characters present in the input.
    """
    global _b32rev
    # Delay the initialization of the table to not waste memory
    # if the function is never called
    if _b32rev is None:
        _b32rev = {v: k for k, v in enumerate(_b32alphabet)}
    s = _bytes_from_decode_data(s)
    if len(s) % 8:
        raise binascii.Error('Incorrect padding')
    # Handle section 2.4 zero and one mapping.  The flag map01 will be either
    # False, or the character to map the digit 1 (one) to.  It should be
    # either L (el) or I (eye).
    if map01 is not None:
        map01 = _bytes_from_decode_data(map01)
        assert len(map01) == 1, repr(map01)
        s = s.translate(bytes.maketrans(b'01', b'O' + map01))
    if casefold:
        s = s.upper()
    # Strip off pad characters from the right.  We need to count the pad
    # characters because this will tell us how many null bytes to remove from
    # the end of the decoded string.
    l = len(s)
    s = s.rstrip(b'=')
    padchars = l - len(s)
    # Now decode the full quanta
    decoded = bytearray()
    b32rev = _b32rev
    for i in range(0, len(s), 8):
        quanta = s[i: i + 8]
        acc = 0
        try:
            for c in quanta:
                acc = (acc << 5) + b32rev[c]
        except KeyError:
            raise binascii.Error('Non-base32 digit found') from None
        decoded += acc.to_bytes(5, 'big')
    # Process the last, partial quanta
    if padchars:
        acc <<= 5 * padchars
        last = acc.to_bytes(5, 'big')
        if padchars == 1:
            decoded[-5:] = last[:-1]
        elif padchars == 3:
            decoded[-5:] = last[:-2]
        elif padchars == 4:
            decoded[-5:] = last[:-3]
        elif padchars == 6:
            decoded[-5:] = last[:-4]
        else:
            raise binascii.Error('Incorrect padding')
    return bytes(decoded)



# RFC 3548, Base 16 Alphabet specifies uppercase, but hexlify() returns
# lowercase.  The RFC also recommends against accepting input case
# insensitively.
def b16encode(s):
    """Encode a byte string using Base16.

    s is the byte string to encode.  The encoded byte string is returned.
    """
    return binascii.hexlify(s).upper()


def b16decode(s, casefold=False):
    """Decode a Base16 encoded byte string.

    s is the byte string to decode.  Optional casefold is a flag
    specifying whether a lowercase alphabet is acceptable as input.
    For security purposes, the default is False.

    The decoded byte string is returned.  binascii.Error is raised if
    s were incorrectly padded or if there are non-alphabet characters
    present in the string.
    """
    s = _bytes_from_decode_data(s)
    if casefold:
        s = s.upper()
    if re.search(b'[^0-9A-F]', s):
        raise binascii.Error('Non-base16 digit found')
    return binascii.unhexlify(s)

#
# Ascii85 encoding/decoding
#

_a85chars = None
_a85chars2 = None
_A85START = b"<~"
_A85END = b"~>"

def _85encode(b, chars, chars2, pad=False, foldnuls=False, foldspaces=False):
    # Helper function for a85encode and b85encode
    if not isinstance(b, bytes_types):
        b = memoryview(b).tobytes()

    padding = (-len(b)) % 4
    if padding:
        b = b + b'\0' * padding
    words = struct.Struct('!%dI' % (len(b) // 4)).unpack(b)

    chunks = [b'z' if foldnuls and not word else
              b'y' if foldspaces and word == 0x20202020 else
              (chars2[word // 614125] +
               chars2[word // 85 % 7225] +
               chars[word % 85])
              for word in words]

    if padding and not pad:
        if chunks[-1] == b'z':
            chunks[-1] = chars[0] * 5
        chunks[-1] = chunks[-1][:-padding]

    return b''.join(chunks)

def a85encode(b, *, foldspaces=False, wrapcol=0, pad=False, adobe=False):
    """Encode a byte string using Ascii85.

    b is the byte string to encode. The encoded byte string is returned.

    foldspaces is an optional flag that uses the special short sequence 'y'
    instead of 4 consecutive spaces (ASCII 0x20) as supported by 'btoa'. This
    feature is not supported by the "standard" Adobe encoding.

    wrapcol controls whether the output should have newline ('\\n') characters
    added to it. If this is non-zero, each output line will be at most this
    many characters long.

    pad controls whether the input string is padded to a multiple of 4 before
    encoding. Note that the btoa implementation always pads.

    adobe controls whether the encoded byte sequence is framed with <~ and ~>,
    which is used by the Adobe implementation.
    """
    global _a85chars, _a85chars2
    # Delay the initialization of tables to not waste memory
    # if the function is never called
    if _a85chars is None:
        _a85chars = [bytes((i,)) for i in range(33, 118)]
        _a85chars2 = [(a + b) for a in _a85chars for b in _a85chars]

    result = _85encode(b, _a85chars, _a85chars2, pad, True, foldspaces)

    if adobe:
        result = _A85START + result
    if wrapcol:
        wrapcol = max(2 if adobe else 1, wrapcol)
        chunks = [result[i: i + wrapcol]
                  for i in range(0, len(result), wrapcol)]
        if adobe:
            if len(chunks[-1]) + 2 > wrapcol:
                chunks.append(b'')
        result = b'\n'.join(chunks)
    if adobe:
        result += _A85END

    return result

def a85decode(b, *, foldspaces=False, adobe=False, ignorechars=b' \t\n\r\v'):
    """Decode an Ascii85 encoded byte string.

    s is the byte string to decode.

    foldspaces is a flag that specifies whether the 'y' short sequence should be
    accepted as shorthand for 4 consecutive spaces (ASCII 0x20). This feature is
    not supported by the "standard" Adobe encoding.

    adobe controls whether the input sequence is in Adobe Ascii85 format (i.e.
    is framed with <~ and ~>).

    ignorechars should be a byte string containing characters to ignore from the
    input. This should only contain whitespace characters, and by default
    contains all whitespace characters in ASCII.
    """
    b = _bytes_from_decode_data(b)
    if adobe:
        if not (b.startswith(_A85START) and b.endswith(_A85END)):
            raise ValueError("Ascii85 encoded byte sequences must be bracketed "
                             "by {!r} and {!r}".format(_A85START, _A85END))
        b = b[2:-2] # Strip off start/end markers
    #
    # We have to go through this stepwise, so as to ignore spaces and handle
    # special short sequences
    #
    packI = struct.Struct('!I').pack
    decoded = []
    decoded_append = decoded.append
    curr = []
    curr_append = curr.append
    curr_clear = curr.clear
    for x in b + b'u' * 4:
        if b'!'[0] <= x <= b'u'[0]:
            curr_append(x)
            if len(curr) == 5:
                acc = 0
                for x in curr:
                    acc = 85 * acc + (x - 33)
                try:
                    decoded_append(packI(acc))
                except struct.error:
                    raise ValueError('Ascii85 overflow') from None
                curr_clear()
        elif x == b'z'[0]:
            if curr:
                raise ValueError('z inside Ascii85 5-tuple')
            decoded_append(b'\0\0\0\0')
        elif foldspaces and x == b'y'[0]:
            if curr:
                raise ValueError('y inside Ascii85 5-tuple')
            decoded_append(b'\x20\x20\x20\x20')
        elif x in ignorechars:
            # Skip whitespace
            continue
        else:
            raise ValueError('Non-Ascii85 digit found: %c' % x)

    result = b''.join(decoded)
    padding = 4 - len(curr)
    if padding:
        # Throw away the extra padding
        result = result[:-padding]
    return result

# The following code is originally taken (with permission) from Mercurial

_b85alphabet = (b"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
                b"abcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~")
_b85chars = None
_b85chars2 = None
_b85dec = None

def b85encode(b, pad=False):
    """Encode an ASCII-encoded byte array in base85 format.

    If pad is true, the input is padded with "\\0" so its length is a multiple of
    4 characters before encoding.
    """
    global _b85chars, _b85chars2
    # Delay the initialization of tables to not waste memory
    # if the function is never called
    if _b85chars is None:
        _b85chars = [bytes((i,)) for i in _b85alphabet]
        _b85chars2 = [(a + b) for a in _b85chars for b in _b85chars]
    return _85encode(b, _b85chars, _b85chars2, pad)

def b85decode(b):
    """Decode base85-encoded byte array"""
    global _b85dec
    # Delay the initialization of tables to not waste memory
    # if the function is never called
    if _b85dec is None:
        _b85dec = [None] * 256
        for i, c in enumerate(_b85alphabet):
            _b85dec[c] = i

    b = _bytes_from_decode_data(b)
    padding = (-len(b)) % 5
    b = b + b'~' * padding
    out = []
    packI = struct.Struct('!I').pack
    for i in range(0, len(b), 5):
        chunk = b[i:i + 5]
        acc = 0
        try:
            for c in chunk:
                acc = acc * 85 + _b85dec[c]
        except TypeError:
            for j, c in enumerate(chunk):
                if _b85dec[c] is None:
                    raise ValueError('bad base85 character at position %d'
                                    % (i + j)) from None
            raise
        try:
            out.append(packI(acc))
        except struct.error:
            raise ValueError('base85 overflow in hunk starting at byte %d'
                             % i) from None

    result = b''.join(out)
    if padding:
        result = result[:-padding]
    return result

# Legacy interface.  This code could be cleaned up since I don't believe
# binascii has any line length limitations.  It just doesn't seem worth it
# though.  The files should be opened in binary mode.

MAXLINESIZE = 76 # Excluding the CRLF
MAXBINSIZE = (MAXLINESIZE//4)*3

def encode(input, output):
    """Encode a file; input and output are binary files."""
    while True:
        s = input.read(MAXBINSIZE)
        if not s:
            break
        while len(s) < MAXBINSIZE:
            ns = input.read(MAXBINSIZE-len(s))
            if not ns:
                break
            s += ns
        line = binascii.b2a_base64(s)
        output.write(line)


def decode(input, output):
    """Decode a file; input and output are binary files."""
    while True:
        line = input.readline()
        if not line:
            break
        s = binascii.a2b_base64(line)
        output.write(s)

def _input_type_check(s):
    try:
        m = memoryview(s)
    except TypeError as err:
        msg = "expected bytes-like object, not %s" % s.__class__.__name__
        raise TypeError(msg) from err
    if m.format not in ('c', 'b', 'B'):
        msg = ("expected single byte elements, not %r from %s" %
                                          (m.format, s.__class__.__name__))
        raise TypeError(msg)
    if m.ndim != 1:
        msg = ("expected 1-D data, not %d-D data from %s" %
                                          (m.ndim, s.__class__.__name__))
        raise TypeError(msg)


def encodebytes(s):
    """Encode a bytestring into a bytestring containing multiple lines
    of base-64 data."""
    _input_type_check(s)
    pieces = []
    for i in range(0, len(s), MAXBINSIZE):
        chunk = s[i : i + MAXBINSIZE]
        pieces.append(binascii.b2a_base64(chunk))
    return b"".join(pieces)

def encodestring(s):
    """Legacy alias of encodebytes()."""
    import warnings
    warnings.warn("encodestring() is a deprecated alias, use encodebytes()",
                  DeprecationWarning, 2)
    return encodebytes(s)


def decodebytes(s):
    """Decode a bytestring of base-64 data into a bytestring."""
    _input_type_check(s)
    return binascii.a2b_base64(s)

def decodestring(s):
    """Legacy alias of decodebytes()."""
    import warnings
    warnings.warn("decodestring() is a deprecated alias, use decodebytes()",
                  DeprecationWarning, 2)
    return decodebytes(s)


# Usable as a script...
def main():
    """Small main program"""
    import sys, getopt
    try:
        opts, args = getopt.getopt(sys.argv[1:], 'deut')
    except getopt.error as msg:
        sys.stdout = sys.stderr
        print(msg)
        print("""usage: %s [-d|-e|-u|-t] [file|-]
        -d, -u: decode
        -e: encode (default)
        -t: encode and decode string 'Aladdin:open sesame'"""%sys.argv[0])
        sys.exit(2)
    func = encode
    for o, a in opts:
        if o == '-e': func = encode
        if o == '-d': func = decode
        if o == '-u': func = decode
        if o == '-t': test(); return
    if args and args[0] != '-':
        with open(args[0], 'rb') as f:
            func(f, sys.stdout.buffer)
    else:
        func(sys.stdin.buffer, sys.stdout.buffer)

def test():
    s0 = b"Aladdin:open sesame"
    print(repr(s0))
    s1 = encodebytes(s0)
    print(repr(s1))
    s2 = decodebytes(s1)
    print(repr(s2))
    assert s0 == s2


if __name__ == '__main__':
    main()
lib\bdb.py
"""Debugger basics"""

import fnmatch
import sys
import os
from inspect import CO_GENERATOR

__all__ = ["BdbQuit", "Bdb", "Breakpoint"]

class BdbQuit(Exception):
    """Exception to give up completely."""


class Bdb:
    """Generic Python debugger base class.

    This class takes care of details of the trace facility;
    a derived class should implement user interaction.
    The standard debugger class (pdb.Pdb) is an example.
    """

    def __init__(self, skip=None):
        self.skip = set(skip) if skip else None
        self.breaks = {}
        self.fncache = {}
        self.frame_returning = None

    def canonic(self, filename):
        if filename == "<" + filename[1:-1] + ">":
            return filename
        canonic = self.fncache.get(filename)
        if not canonic:
            canonic = os.path.abspath(filename)
            canonic = os.path.normcase(canonic)
            self.fncache[filename] = canonic
        return canonic

    def reset(self):
        import linecache
        linecache.checkcache()
        self.botframe = None
        self._set_stopinfo(None, None)

    def trace_dispatch(self, frame, event, arg):
        if self.quitting:
            return # None
        if event == 'line':
            return self.dispatch_line(frame)
        if event == 'call':
            return self.dispatch_call(frame, arg)
        if event == 'return':
            return self.dispatch_return(frame, arg)
        if event == 'exception':
            return self.dispatch_exception(frame, arg)
        if event == 'c_call':
            return self.trace_dispatch
        if event == 'c_exception':
            return self.trace_dispatch
        if event == 'c_return':
            return self.trace_dispatch
        print('bdb.Bdb.dispatch: unknown debugging event:', repr(event))
        return self.trace_dispatch

    def dispatch_line(self, frame):
        if self.stop_here(frame) or self.break_here(frame):
            self.user_line(frame)
            if self.quitting: raise BdbQuit
        return self.trace_dispatch

    def dispatch_call(self, frame, arg):
        # XXX 'arg' is no longer used
        if self.botframe is None:
            # First call of dispatch since reset()
            self.botframe = frame.f_back # (CT) Note that this may also be None!
            return self.trace_dispatch
        if not (self.stop_here(frame) or self.break_anywhere(frame)):
            # No need to trace this function
            return # None
        # Ignore call events in generator except when stepping.
        if self.stopframe and frame.f_code.co_flags & CO_GENERATOR:
            return self.trace_dispatch
        self.user_call(frame, arg)
        if self.quitting: raise BdbQuit
        return self.trace_dispatch

    def dispatch_return(self, frame, arg):
        if self.stop_here(frame) or frame == self.returnframe:
            # Ignore return events in generator except when stepping.
            if self.stopframe and frame.f_code.co_flags & CO_GENERATOR:
                return self.trace_dispatch
            try:
                self.frame_returning = frame
                self.user_return(frame, arg)
            finally:
                self.frame_returning = None
            if self.quitting: raise BdbQuit
            # The user issued a 'next' or 'until' command.
            if self.stopframe is frame and self.stoplineno != -1:
                self._set_stopinfo(None, None)
        return self.trace_dispatch

    def dispatch_exception(self, frame, arg):
        if self.stop_here(frame):
            # When stepping with next/until/return in a generator frame, skip
            # the internal StopIteration exception (with no traceback)
            # triggered by a subiterator run with the 'yield from' statement.
            if not (frame.f_code.co_flags & CO_GENERATOR
                    and arg[0] is StopIteration and arg[2] is None):
                self.user_exception(frame, arg)
                if self.quitting: raise BdbQuit
        # Stop at the StopIteration or GeneratorExit exception when the user
        # has set stopframe in a generator by issuing a return command, or a
        # next/until command at the last statement in the generator before the
        # exception.
        elif (self.stopframe and frame is not self.stopframe
                and self.stopframe.f_code.co_flags & CO_GENERATOR
                and arg[0] in (StopIteration, GeneratorExit)):
            self.user_exception(frame, arg)
            if self.quitting: raise BdbQuit

        return self.trace_dispatch

    # Normally derived classes don't override the following
    # methods, but they may if they want to redefine the
    # definition of stopping and breakpoints.

    def is_skipped_module(self, module_name):
        for pattern in self.skip:
            if fnmatch.fnmatch(module_name, pattern):
                return True
        return False

    def stop_here(self, frame):
        # (CT) stopframe may now also be None, see dispatch_call.
        # (CT) the former test for None is therefore removed from here.
        if self.skip and \
               self.is_skipped_module(frame.f_globals.get('__name__')):
            return False
        if frame is self.stopframe:
            if self.stoplineno == -1:
                return False
            return frame.f_lineno >= self.stoplineno
        if not self.stopframe:
            return True
        return False

    def break_here(self, frame):
        filename = self.canonic(frame.f_code.co_filename)
        if filename not in self.breaks:
            return False
        lineno = frame.f_lineno
        if lineno not in self.breaks[filename]:
            # The line itself has no breakpoint, but maybe the line is the
            # first line of a function with breakpoint set by function name.
            lineno = frame.f_code.co_firstlineno
            if lineno not in self.breaks[filename]:
                return False

        # flag says ok to delete temp. bp
        (bp, flag) = effective(filename, lineno, frame)
        if bp:
            self.currentbp = bp.number
            if (flag and bp.temporary):
                self.do_clear(str(bp.number))
            return True
        else:
            return False

    def do_clear(self, arg):
        raise NotImplementedError("subclass of bdb must implement do_clear()")

    def break_anywhere(self, frame):
        return self.canonic(frame.f_code.co_filename) in self.breaks

    # Derived classes should override the user_* methods
    # to gain control.

    def user_call(self, frame, argument_list):
        """This method is called when there is the remote possibility
        that we ever need to stop in this function."""
        pass

    def user_line(self, frame):
        """This method is called when we stop or break at this line."""
        pass

    def user_return(self, frame, return_value):
        """This method is called when a return trap is set here."""
        pass

    def user_exception(self, frame, exc_info):
        """This method is called if an exception occurs,
        but only if we are to stop at or just below this level."""
        pass

    def _set_stopinfo(self, stopframe, returnframe, stoplineno=0):
        self.stopframe = stopframe
        self.returnframe = returnframe
        self.quitting = False
        # stoplineno >= 0 means: stop at line >= the stoplineno
        # stoplineno -1 means: don't stop at all
        self.stoplineno = stoplineno

    # Derived classes and clients can call the following methods
    # to affect the stepping state.

    def set_until(self, frame, lineno=None):
        """Stop when the line with the line no greater than the current one is
        reached or when returning from current frame"""
        # the name "until" is borrowed from gdb
        if lineno is None:
            lineno = frame.f_lineno + 1
        self._set_stopinfo(frame, frame, lineno)

    def set_step(self):
        """Stop after one line of code."""
        # Issue #13183: pdb skips frames after hitting a breakpoint and running
        # step commands.
        # Restore the trace function in the caller (that may not have been set
        # for performance reasons) when returning from the current frame.
        if self.frame_returning:
            caller_frame = self.frame_returning.f_back
            if caller_frame and not caller_frame.f_trace:
                caller_frame.f_trace = self.trace_dispatch
        self._set_stopinfo(None, None)

    def set_next(self, frame):
        """Stop on the next line in or below the given frame."""
        self._set_stopinfo(frame, None)

    def set_return(self, frame):
        """Stop when returning from the given frame."""
        if frame.f_code.co_flags & CO_GENERATOR:
            self._set_stopinfo(frame, None, -1)
        else:
            self._set_stopinfo(frame.f_back, frame)

    def set_trace(self, frame=None):
        """Start debugging from `frame`.

        If frame is not specified, debugging starts from caller's frame.
        """
        if frame is None:
            frame = sys._getframe().f_back
        self.reset()
        while frame:
            frame.f_trace = self.trace_dispatch
            self.botframe = frame
            frame = frame.f_back
        self.set_step()
        sys.settrace(self.trace_dispatch)

    def set_continue(self):
        # Don't stop except at breakpoints or when finished
        self._set_stopinfo(self.botframe, None, -1)
        if not self.breaks:
            # no breakpoints; run without debugger overhead
            sys.settrace(None)
            frame = sys._getframe().f_back
            while frame and frame is not self.botframe:
                del frame.f_trace
                frame = frame.f_back

    def set_quit(self):
        self.stopframe = self.botframe
        self.returnframe = None
        self.quitting = True
        sys.settrace(None)

    # Derived classes and clients can call the following methods
    # to manipulate breakpoints.  These methods return an
    # error message is something went wrong, None if all is well.
    # Set_break prints out the breakpoint line and file:lineno.
    # Call self.get_*break*() to see the breakpoints or better
    # for bp in Breakpoint.bpbynumber: if bp: bp.bpprint().

    def set_break(self, filename, lineno, temporary=False, cond=None,
                  funcname=None):
        filename = self.canonic(filename)
        import linecache # Import as late as possible
        line = linecache.getline(filename, lineno)
        if not line:
            return 'Line %s:%d does not exist' % (filename, lineno)
        list = self.breaks.setdefault(filename, [])
        if lineno not in list:
            list.append(lineno)
        bp = Breakpoint(filename, lineno, temporary, cond, funcname)

    def _prune_breaks(self, filename, lineno):
        if (filename, lineno) not in Breakpoint.bplist:
            self.breaks[filename].remove(lineno)
        if not self.breaks[filename]:
            del self.breaks[filename]

    def clear_break(self, filename, lineno):
        filename = self.canonic(filename)
        if filename not in self.breaks:
            return 'There are no breakpoints in %s' % filename
        if lineno not in self.breaks[filename]:
            return 'There is no breakpoint at %s:%d' % (filename, lineno)
        # If there's only one bp in the list for that file,line
        # pair, then remove the breaks entry
        for bp in Breakpoint.bplist[filename, lineno][:]:
            bp.deleteMe()
        self._prune_breaks(filename, lineno)

    def clear_bpbynumber(self, arg):
        try:
            bp = self.get_bpbynumber(arg)
        except ValueError as err:
            return str(err)
        bp.deleteMe()
        self._prune_breaks(bp.file, bp.line)

    def clear_all_file_breaks(self, filename):
        filename = self.canonic(filename)
        if filename not in self.breaks:
            return 'There are no breakpoints in %s' % filename
        for line in self.breaks[filename]:
            blist = Breakpoint.bplist[filename, line]
            for bp in blist:
                bp.deleteMe()
        del self.breaks[filename]

    def clear_all_breaks(self):
        if not self.breaks:
            return 'There are no breakpoints'
        for bp in Breakpoint.bpbynumber:
            if bp:
                bp.deleteMe()
        self.breaks = {}

    def get_bpbynumber(self, arg):
        if not arg:
            raise ValueError('Breakpoint number expected')
        try:
            number = int(arg)
        except ValueError:
            raise ValueError('Non-numeric breakpoint number %s' % arg)
        try:
            bp = Breakpoint.bpbynumber[number]
        except IndexError:
            raise ValueError('Breakpoint number %d out of range' % number)
        if bp is None:
            raise ValueError('Breakpoint %d already deleted' % number)
        return bp

    def get_break(self, filename, lineno):
        filename = self.canonic(filename)
        return filename in self.breaks and \
            lineno in self.breaks[filename]

    def get_breaks(self, filename, lineno):
        filename = self.canonic(filename)
        return filename in self.breaks and \
            lineno in self.breaks[filename] and \
            Breakpoint.bplist[filename, lineno] or []

    def get_file_breaks(self, filename):
        filename = self.canonic(filename)
        if filename in self.breaks:
            return self.breaks[filename]
        else:
            return []

    def get_all_breaks(self):
        return self.breaks

    # Derived classes and clients can call the following method
    # to get a data structure representing a stack trace.

    def get_stack(self, f, t):
        stack = []
        if t and t.tb_frame is f:
            t = t.tb_next
        while f is not None:
            stack.append((f, f.f_lineno))
            if f is self.botframe:
                break
            f = f.f_back
        stack.reverse()
        i = max(0, len(stack) - 1)
        while t is not None:
            stack.append((t.tb_frame, t.tb_lineno))
            t = t.tb_next
        if f is None:
            i = max(0, len(stack) - 1)
        return stack, i

    def format_stack_entry(self, frame_lineno, lprefix=': '):
        import linecache, reprlib
        frame, lineno = frame_lineno
        filename = self.canonic(frame.f_code.co_filename)
        s = '%s(%r)' % (filename, lineno)
        if frame.f_code.co_name:
            s += frame.f_code.co_name
        else:
            s += "<lambda>"
        if '__args__' in frame.f_locals:
            args = frame.f_locals['__args__']
        else:
            args = None
        if args:
            s += reprlib.repr(args)
        else:
            s += '()'
        if '__return__' in frame.f_locals:
            rv = frame.f_locals['__return__']
            s += '->'
            s += reprlib.repr(rv)
        line = linecache.getline(filename, lineno, frame.f_globals)
        if line:
            s += lprefix + line.strip()
        return s

    # The following methods can be called by clients to use
    # a debugger to debug a statement or an expression.
    # Both can be given as a string, or a code object.

    def run(self, cmd, globals=None, locals=None):
        if globals is None:
            import __main__
            globals = __main__.__dict__
        if locals is None:
            locals = globals
        self.reset()
        if isinstance(cmd, str):
            cmd = compile(cmd, "<string>", "exec")
        sys.settrace(self.trace_dispatch)
        try:
            exec(cmd, globals, locals)
        except BdbQuit:
            pass
        finally:
            self.quitting = True
            sys.settrace(None)

    def runeval(self, expr, globals=None, locals=None):
        if globals is None:
            import __main__
            globals = __main__.__dict__
        if locals is None:
            locals = globals
        self.reset()
        sys.settrace(self.trace_dispatch)
        try:
            return eval(expr, globals, locals)
        except BdbQuit:
            pass
        finally:
            self.quitting = True
            sys.settrace(None)

    def runctx(self, cmd, globals, locals):
        # B/W compatibility
        self.run(cmd, globals, locals)

    # This method is more useful to debug a single function call.

    def runcall(self, func, *args, **kwds):
        self.reset()
        sys.settrace(self.trace_dispatch)
        res = None
        try:
            res = func(*args, **kwds)
        except BdbQuit:
            pass
        finally:
            self.quitting = True
            sys.settrace(None)
        return res


def set_trace():
    Bdb().set_trace()


class Breakpoint:
    """Breakpoint class.

    Implements temporary breakpoints, ignore counts, disabling and
    (re)-enabling, and conditionals.

    Breakpoints are indexed by number through bpbynumber and by
    the file,line tuple using bplist.  The former points to a
    single instance of class Breakpoint.  The latter points to a
    list of such instances since there may be more than one
    breakpoint per line.

    """

    # XXX Keeping state in the class is a mistake -- this means
    # you cannot have more than one active Bdb instance.

    next = 1        # Next bp to be assigned
    bplist = {}     # indexed by (file, lineno) tuple
    bpbynumber = [None] # Each entry is None or an instance of Bpt
                # index 0 is unused, except for marking an
                # effective break .... see effective()

    def __init__(self, file, line, temporary=False, cond=None, funcname=None):
        self.funcname = funcname
        # Needed if funcname is not None.
        self.func_first_executable_line = None
        self.file = file    # This better be in canonical form!
        self.line = line
        self.temporary = temporary
        self.cond = cond
        self.enabled = True
        self.ignore = 0
        self.hits = 0
        self.number = Breakpoint.next
        Breakpoint.next += 1
        # Build the two lists
        self.bpbynumber.append(self)
        if (file, line) in self.bplist:
            self.bplist[file, line].append(self)
        else:
            self.bplist[file, line] = [self]

    def deleteMe(self):
        index = (self.file, self.line)
        self.bpbynumber[self.number] = None   # No longer in list
        self.bplist[index].remove(self)
        if not self.bplist[index]:
            # No more bp for this f:l combo
            del self.bplist[index]

    def enable(self):
        self.enabled = True

    def disable(self):
        self.enabled = False

    def bpprint(self, out=None):
        if out is None:
            out = sys.stdout
        print(self.bpformat(), file=out)

    def bpformat(self):
        if self.temporary:
            disp = 'del  '
        else:
            disp = 'keep '
        if self.enabled:
            disp = disp + 'yes  '
        else:
            disp = disp + 'no   '
        ret = '%-4dbreakpoint   %s at %s:%d' % (self.number, disp,
                                                self.file, self.line)
        if self.cond:
            ret += '\n\tstop only if %s' % (self.cond,)
        if self.ignore:
            ret += '\n\tignore next %d hits' % (self.ignore,)
        if self.hits:
            if self.hits > 1:
                ss = 's'
            else:
                ss = ''
            ret += '\n\tbreakpoint already hit %d time%s' % (self.hits, ss)
        return ret

    def __str__(self):
        return 'breakpoint %s at %s:%s' % (self.number, self.file, self.line)

# -----------end of Breakpoint class----------

def checkfuncname(b, frame):
    """Check whether we should break here because of `b.funcname`."""
    if not b.funcname:
        # Breakpoint was set via line number.
        if b.line != frame.f_lineno:
            # Breakpoint was set at a line with a def statement and the function
            # defined is called: don't break.
            return False
        return True

    # Breakpoint set via function name.

    if frame.f_code.co_name != b.funcname:
        # It's not a function call, but rather execution of def statement.
        return False

    # We are in the right frame.
    if not b.func_first_executable_line:
        # The function is entered for the 1st time.
        b.func_first_executable_line = frame.f_lineno

    if  b.func_first_executable_line != frame.f_lineno:
        # But we are not at the first line number: don't break.
        return False
    return True

# Determines if there is an effective (active) breakpoint at this
# line of code.  Returns breakpoint number or 0 if none
def effective(file, line, frame):
    """Determine which breakpoint for this file:line is to be acted upon.

    Called only if we know there is a bpt at this
    location.  Returns breakpoint that was triggered and a flag
    that indicates if it is ok to delete a temporary bp.

    """
    possibles = Breakpoint.bplist[file, line]
    for b in possibles:
        if not b.enabled:
            continue
        if not checkfuncname(b, frame):
            continue
        # Count every hit when bp is enabled
        b.hits += 1
        if not b.cond:
            # If unconditional, and ignoring go on to next, else break
            if b.ignore > 0:
                b.ignore -= 1
                continue
            else:
                # breakpoint and marker that it's ok to delete if temporary
                return (b, True)
        else:
            # Conditional bp.
            # Ignore count applies only to those bpt hits where the
            # condition evaluates to true.
            try:
                val = eval(b.cond, frame.f_globals, frame.f_locals)
                if val:
                    if b.ignore > 0:
                        b.ignore -= 1
                        # continue
                    else:
                        return (b, True)
                # else:
                #   continue
            except:
                # if eval fails, most conservative thing is to stop on
                # breakpoint regardless of ignore count.  Don't delete
                # temporary, as another hint to user.
                return (b, False)
    return (None, None)


# -------------------- testing --------------------

class Tdb(Bdb):
    def user_call(self, frame, args):
        name = frame.f_code.co_name
        if not name: name = '???'
        print('+++ call', name, args)
    def user_line(self, frame):
        import linecache
        name = frame.f_code.co_name
        if not name: name = '???'
        fn = self.canonic(frame.f_code.co_filename)
        line = linecache.getline(fn, frame.f_lineno, frame.f_globals)
        print('+++', fn, frame.f_lineno, name, ':', line.strip())
    def user_return(self, frame, retval):
        print('+++ return', retval)
    def user_exception(self, frame, exc_stuff):
        print('+++ exception', exc_stuff)
        self.set_continue()

def foo(n):
    print('foo(', n, ')')
    x = bar(n*10)
    print('bar returned', x)

def bar(a):
    print('bar(', a, ')')
    return a/2

def test():
    t = Tdb()
    t.run('import bdb; bdb.foo(10)')
lib\binhex.py
"""Macintosh binhex compression/decompression.

easy interface:
binhex(inputfilename, outputfilename)
hexbin(inputfilename, outputfilename)
"""

#
# Jack Jansen, CWI, August 1995.
#
# The module is supposed to be as compatible as possible. Especially the
# easy interface should work "as expected" on any platform.
# XXXX Note: currently, textfiles appear in mac-form on all platforms.
# We seem to lack a simple character-translate in python.
# (we should probably use ISO-Latin-1 on all but the mac platform).
# XXXX The simple routines are too simple: they expect to hold the complete
# files in-core. Should be fixed.
# XXXX It would be nice to handle AppleDouble format on unix
# (for servers serving macs).
# XXXX I don't understand what happens when you get 0x90 times the same byte on
# input. The resulting code (xx 90 90) would appear to be interpreted as an
# escaped *value* of 0x90. All coders I've seen appear to ignore this nicety...
#
import io
import os
import struct
import binascii

__all__ = ["binhex","hexbin","Error"]

class Error(Exception):
    pass

# States (what have we written)
_DID_HEADER = 0
_DID_DATA = 1

# Various constants
REASONABLY_LARGE = 32768  # Minimal amount we pass the rle-coder
LINELEN = 64
RUNCHAR = b"\x90"

#
# This code is no longer byte-order dependent


class FInfo:
    def __init__(self):
        self.Type = '????'
        self.Creator = '????'
        self.Flags = 0

def getfileinfo(name):
    finfo = FInfo()
    with io.open(name, 'rb') as fp:
        # Quick check for textfile
        data = fp.read(512)
        if 0 not in data:
            finfo.Type = 'TEXT'
        fp.seek(0, 2)
        dsize = fp.tell()
    dir, file = os.path.split(name)
    file = file.replace(':', '-', 1)
    return file, finfo, dsize, 0

class openrsrc:
    def __init__(self, *args):
        pass

    def read(self, *args):
        return b''

    def write(self, *args):
        pass

    def close(self):
        pass

class _Hqxcoderengine:
    """Write data to the coder in 3-byte chunks"""

    def __init__(self, ofp):
        self.ofp = ofp
        self.data = b''
        self.hqxdata = b''
        self.linelen = LINELEN - 1

    def write(self, data):
        self.data = self.data + data
        datalen = len(self.data)
        todo = (datalen // 3) * 3
        data = self.data[:todo]
        self.data = self.data[todo:]
        if not data:
            return
        self.hqxdata = self.hqxdata + binascii.b2a_hqx(data)
        self._flush(0)

    def _flush(self, force):
        first = 0
        while first <= len(self.hqxdata) - self.linelen:
            last = first + self.linelen
            self.ofp.write(self.hqxdata[first:last] + b'\n')
            self.linelen = LINELEN
            first = last
        self.hqxdata = self.hqxdata[first:]
        if force:
            self.ofp.write(self.hqxdata + b':\n')

    def close(self):
        if self.data:
            self.hqxdata = self.hqxdata + binascii.b2a_hqx(self.data)
        self._flush(1)
        self.ofp.close()
        del self.ofp

class _Rlecoderengine:
    """Write data to the RLE-coder in suitably large chunks"""

    def __init__(self, ofp):
        self.ofp = ofp
        self.data = b''

    def write(self, data):
        self.data = self.data + data
        if len(self.data) < REASONABLY_LARGE:
            return
        rledata = binascii.rlecode_hqx(self.data)
        self.ofp.write(rledata)
        self.data = b''

    def close(self):
        if self.data:
            rledata = binascii.rlecode_hqx(self.data)
            self.ofp.write(rledata)
        self.ofp.close()
        del self.ofp

class BinHex:
    def __init__(self, name_finfo_dlen_rlen, ofp):
        name, finfo, dlen, rlen = name_finfo_dlen_rlen
        close_on_error = False
        if isinstance(ofp, str):
            ofname = ofp
            ofp = io.open(ofname, 'wb')
            close_on_error = True
        try:
            ofp.write(b'(This file must be converted with BinHex 4.0)\r\r:')
            hqxer = _Hqxcoderengine(ofp)
            self.ofp = _Rlecoderengine(hqxer)
            self.crc = 0
            if finfo is None:
                finfo = FInfo()
            self.dlen = dlen
            self.rlen = rlen
            self._writeinfo(name, finfo)
            self.state = _DID_HEADER
        except:
            if close_on_error:
                ofp.close()
            raise

    def _writeinfo(self, name, finfo):
        nl = len(name)
        if nl > 63:
            raise Error('Filename too long')
        d = bytes([nl]) + name.encode("latin-1") + b'\0'
        tp, cr = finfo.Type, finfo.Creator
        if isinstance(tp, str):
            tp = tp.encode("latin-1")
        if isinstance(cr, str):
            cr = cr.encode("latin-1")
        d2 = tp + cr

        # Force all structs to be packed with big-endian
        d3 = struct.pack('>h', finfo.Flags)
        d4 = struct.pack('>ii', self.dlen, self.rlen)
        info = d + d2 + d3 + d4
        self._write(info)
        self._writecrc()

    def _write(self, data):
        self.crc = binascii.crc_hqx(data, self.crc)
        self.ofp.write(data)

    def _writecrc(self):
        # XXXX Should this be here??
        # self.crc = binascii.crc_hqx('\0\0', self.crc)
        if self.crc < 0:
            fmt = '>h'
        else:
            fmt = '>H'
        self.ofp.write(struct.pack(fmt, self.crc))
        self.crc = 0

    def write(self, data):
        if self.state != _DID_HEADER:
            raise Error('Writing data at the wrong time')
        self.dlen = self.dlen - len(data)
        self._write(data)

    def close_data(self):
        if self.dlen != 0:
            raise Error('Incorrect data size, diff=%r' % (self.rlen,))
        self._writecrc()
        self.state = _DID_DATA

    def write_rsrc(self, data):
        if self.state < _DID_DATA:
            self.close_data()
        if self.state != _DID_DATA:
            raise Error('Writing resource data at the wrong time')
        self.rlen = self.rlen - len(data)
        self._write(data)

    def close(self):
        if self.state is None:
            return
        try:
            if self.state < _DID_DATA:
                self.close_data()
            if self.state != _DID_DATA:
                raise Error('Close at the wrong time')
            if self.rlen != 0:
                raise Error("Incorrect resource-datasize, diff=%r" % (self.rlen,))
            self._writecrc()
        finally:
            self.state = None
            ofp = self.ofp
            del self.ofp
            ofp.close()

def binhex(inp, out):
    """binhex(infilename, outfilename): create binhex-encoded copy of a file"""
    finfo = getfileinfo(inp)
    ofp = BinHex(finfo, out)

    ifp = io.open(inp, 'rb')
    # XXXX Do textfile translation on non-mac systems
    while True:
        d = ifp.read(128000)
        if not d: break
        ofp.write(d)
    ofp.close_data()
    ifp.close()

    ifp = openrsrc(inp, 'rb')
    while True:
        d = ifp.read(128000)
        if not d: break
        ofp.write_rsrc(d)
    ofp.close()
    ifp.close()

class _Hqxdecoderengine:
    """Read data via the decoder in 4-byte chunks"""

    def __init__(self, ifp):
        self.ifp = ifp
        self.eof = 0

    def read(self, totalwtd):
        """Read at least wtd bytes (or until EOF)"""
        decdata = b''
        wtd = totalwtd
        #
        # The loop here is convoluted, since we don't really now how
        # much to decode: there may be newlines in the incoming data.
        while wtd > 0:
            if self.eof: return decdata
            wtd = ((wtd + 2) // 3) * 4
            data = self.ifp.read(wtd)
            #
            # Next problem: there may not be a complete number of
            # bytes in what we pass to a2b. Solve by yet another
            # loop.
            #
            while True:
                try:
                    decdatacur, self.eof = binascii.a2b_hqx(data)
                    break
                except binascii.Incomplete:
                    pass
                newdata = self.ifp.read(1)
                if not newdata:
                    raise Error('Premature EOF on binhex file')
                data = data + newdata
            decdata = decdata + decdatacur
            wtd = totalwtd - len(decdata)
            if not decdata and not self.eof:
                raise Error('Premature EOF on binhex file')
        return decdata

    def close(self):
        self.ifp.close()

class _Rledecoderengine:
    """Read data via the RLE-coder"""

    def __init__(self, ifp):
        self.ifp = ifp
        self.pre_buffer = b''
        self.post_buffer = b''
        self.eof = 0

    def read(self, wtd):
        if wtd > len(self.post_buffer):
            self._fill(wtd - len(self.post_buffer))
        rv = self.post_buffer[:wtd]
        self.post_buffer = self.post_buffer[wtd:]
        return rv

    def _fill(self, wtd):
        self.pre_buffer = self.pre_buffer + self.ifp.read(wtd + 4)
        if self.ifp.eof:
            self.post_buffer = self.post_buffer + \
                binascii.rledecode_hqx(self.pre_buffer)
            self.pre_buffer = b''
            return

        #
        # Obfuscated code ahead. We have to take care that we don't
        # end up with an orphaned RUNCHAR later on. So, we keep a couple
        # of bytes in the buffer, depending on what the end of
        # the buffer looks like:
        # '\220\0\220' - Keep 3 bytes: repeated \220 (escaped as \220\0)
        # '?\220' - Keep 2 bytes: repeated something-else
        # '\220\0' - Escaped \220: Keep 2 bytes.
        # '?\220?' - Complete repeat sequence: decode all
        # otherwise: keep 1 byte.
        #
        mark = len(self.pre_buffer)
        if self.pre_buffer[-3:] == RUNCHAR + b'\0' + RUNCHAR:
            mark = mark - 3
        elif self.pre_buffer[-1:] == RUNCHAR:
            mark = mark - 2
        elif self.pre_buffer[-2:] == RUNCHAR + b'\0':
            mark = mark - 2
        elif self.pre_buffer[-2:-1] == RUNCHAR:
            pass # Decode all
        else:
            mark = mark - 1

        self.post_buffer = self.post_buffer + \
            binascii.rledecode_hqx(self.pre_buffer[:mark])
        self.pre_buffer = self.pre_buffer[mark:]

    def close(self):
        self.ifp.close()

class HexBin:
    def __init__(self, ifp):
        if isinstance(ifp, str):
            ifp = io.open(ifp, 'rb')
        #
        # Find initial colon.
        #
        while True:
            ch = ifp.read(1)
            if not ch:
                raise Error("No binhex data found")
            # Cater for \r\n terminated lines (which show up as \n\r, hence
            # all lines start with \r)
            if ch == b'\r':
                continue
            if ch == b':':
                break

        hqxifp = _Hqxdecoderengine(ifp)
        self.ifp = _Rledecoderengine(hqxifp)
        self.crc = 0
        self._readheader()

    def _read(self, len):
        data = self.ifp.read(len)
        self.crc = binascii.crc_hqx(data, self.crc)
        return data

    def _checkcrc(self):
        filecrc = struct.unpack('>h', self.ifp.read(2))[0] & 0xffff
        #self.crc = binascii.crc_hqx('\0\0', self.crc)
        # XXXX Is this needed??
        self.crc = self.crc & 0xffff
        if filecrc != self.crc:
            raise Error('CRC error, computed %x, read %x'
                        % (self.crc, filecrc))
        self.crc = 0

    def _readheader(self):
        len = self._read(1)
        fname = self._read(ord(len))
        rest = self._read(1 + 4 + 4 + 2 + 4 + 4)
        self._checkcrc()

        type = rest[1:5]
        creator = rest[5:9]
        flags = struct.unpack('>h', rest[9:11])[0]
        self.dlen = struct.unpack('>l', rest[11:15])[0]
        self.rlen = struct.unpack('>l', rest[15:19])[0]

        self.FName = fname
        self.FInfo = FInfo()
        self.FInfo.Creator = creator
        self.FInfo.Type = type
        self.FInfo.Flags = flags

        self.state = _DID_HEADER

    def read(self, *n):
        if self.state != _DID_HEADER:
            raise Error('Read data at wrong time')
        if n:
            n = n[0]
            n = min(n, self.dlen)
        else:
            n = self.dlen
        rv = b''
        while len(rv) < n:
            rv = rv + self._read(n-len(rv))
        self.dlen = self.dlen - n
        return rv

    def close_data(self):
        if self.state != _DID_HEADER:
            raise Error('close_data at wrong time')
        if self.dlen:
            dummy = self._read(self.dlen)
        self._checkcrc()
        self.state = _DID_DATA

    def read_rsrc(self, *n):
        if self.state == _DID_HEADER:
            self.close_data()
        if self.state != _DID_DATA:
            raise Error('Read resource data at wrong time')
        if n:
            n = n[0]
            n = min(n, self.rlen)
        else:
            n = self.rlen
        self.rlen = self.rlen - n
        return self._read(n)

    def close(self):
        if self.state is None:
            return
        try:
            if self.rlen:
                dummy = self.read_rsrc(self.rlen)
            self._checkcrc()
        finally:
            self.state = None
            self.ifp.close()

def hexbin(inp, out):
    """hexbin(infilename, outfilename) - Decode binhexed file"""
    ifp = HexBin(inp)
    finfo = ifp.FInfo
    if not out:
        out = ifp.FName

    ofp = io.open(out, 'wb')
    # XXXX Do translation on non-mac systems
    while True:
        d = ifp.read(128000)
        if not d: break
        ofp.write(d)
    ofp.close()
    ifp.close_data()

    d = ifp.read_rsrc(128000)
    if d:
        ofp = openrsrc(out, 'wb')
        ofp.write(d)
        while True:
            d = ifp.read_rsrc(128000)
            if not d: break
            ofp.write(d)
        ofp.close()

    ifp.close()
lib\bisect.py
"""Bisection algorithms."""

def insort_right(a, x, lo=0, hi=None):
    """Insert item x in list a, and keep it sorted assuming a is sorted.

    If x is already in a, insert it to the right of the rightmost x.

    Optional args lo (default 0) and hi (default len(a)) bound the
    slice of a to be searched.
    """

    if lo < 0:
        raise ValueError('lo must be non-negative')
    if hi is None:
        hi = len(a)
    while lo < hi:
        mid = (lo+hi)//2
        if x < a[mid]: hi = mid
        else: lo = mid+1
    a.insert(lo, x)

insort = insort_right   # backward compatibility

def bisect_right(a, x, lo=0, hi=None):
    """Return the index where to insert item x in list a, assuming a is sorted.

    The return value i is such that all e in a[:i] have e <= x, and all e in
    a[i:] have e > x.  So if x already appears in the list, a.insert(x) will
    insert just after the rightmost x already there.

    Optional args lo (default 0) and hi (default len(a)) bound the
    slice of a to be searched.
    """

    if lo < 0:
        raise ValueError('lo must be non-negative')
    if hi is None:
        hi = len(a)
    while lo < hi:
        mid = (lo+hi)//2
        if x < a[mid]: hi = mid
        else: lo = mid+1
    return lo

bisect = bisect_right   # backward compatibility

def insort_left(a, x, lo=0, hi=None):
    """Insert item x in list a, and keep it sorted assuming a is sorted.

    If x is already in a, insert it to the left of the leftmost x.

    Optional args lo (default 0) and hi (default len(a)) bound the
    slice of a to be searched.
    """

    if lo < 0:
        raise ValueError('lo must be non-negative')
    if hi is None:
        hi = len(a)
    while lo < hi:
        mid = (lo+hi)//2
        if a[mid] < x: lo = mid+1
        else: hi = mid
    a.insert(lo, x)


def bisect_left(a, x, lo=0, hi=None):
    """Return the index where to insert item x in list a, assuming a is sorted.

    The return value i is such that all e in a[:i] have e < x, and all e in
    a[i:] have e >= x.  So if x already appears in the list, a.insert(x) will
    insert just before the leftmost x already there.

    Optional args lo (default 0) and hi (default len(a)) bound the
    slice of a to be searched.
    """

    if lo < 0:
        raise ValueError('lo must be non-negative')
    if hi is None:
        hi = len(a)
    while lo < hi:
        mid = (lo+hi)//2
        if a[mid] < x: lo = mid+1
        else: hi = mid
    return lo

# Overwrite above definitions with a fast C implementation
try:
    from _bisect import *
except ImportError:
    pass
lib\bz2.py
"""Interface to the libbzip2 compression library.

This module provides a file interface, classes for incremental
(de)compression, and functions for one-shot (de)compression.
"""

__all__ = ["BZ2File", "BZ2Compressor", "BZ2Decompressor",
           "open", "compress", "decompress"]

__author__ = "Nadeem Vawda <[email protected]>"

from builtins import open as _builtin_open
import io
import warnings

try:
    from threading import RLock
except ImportError:
    from dummy_threading import RLock

from _bz2 import BZ2Compressor, BZ2Decompressor


_MODE_CLOSED   = 0
_MODE_READ     = 1
_MODE_READ_EOF = 2
_MODE_WRITE    = 3

_BUFFER_SIZE = 8192


class BZ2File(io.BufferedIOBase):

    """A file object providing transparent bzip2 (de)compression.

    A BZ2File can act as a wrapper for an existing file object, or refer
    directly to a named file on disk.

    Note that BZ2File provides a *binary* file interface - data read is
    returned as bytes, and data to be written should be given as bytes.
    """

    def __init__(self, filename, mode="r", buffering=None, compresslevel=9):
        """Open a bzip2-compressed file.

        If filename is a str or bytes object, it gives the name
        of the file to be opened. Otherwise, it should be a file object,
        which will be used to read or write the compressed data.

        mode can be 'r' for reading (default), 'w' for (over)writing,
        'x' for creating exclusively, or 'a' for appending. These can
        equivalently be given as 'rb', 'wb', 'xb', and 'ab'.

        buffering is ignored. Its use is deprecated.

        If mode is 'w', 'x' or 'a', compresslevel can be a number between 1
        and 9 specifying the level of compression: 1 produces the least
        compression, and 9 (default) produces the most compression.

        If mode is 'r', the input file may be the concatenation of
        multiple compressed streams.
        """
        # This lock must be recursive, so that BufferedIOBase's
        # readline(), readlines() and writelines() don't deadlock.
        self._lock = RLock()
        self._fp = None
        self._closefp = False
        self._mode = _MODE_CLOSED
        self._pos = 0
        self._size = -1

        if buffering is not None:
            warnings.warn("Use of 'buffering' argument is deprecated",
                          DeprecationWarning)

        if not (1 <= compresslevel <= 9):
            raise ValueError("compresslevel must be between 1 and 9")

        if mode in ("", "r", "rb"):
            mode = "rb"
            mode_code = _MODE_READ
            self._decompressor = BZ2Decompressor()
            self._buffer = b""
            self._buffer_offset = 0
        elif mode in ("w", "wb"):
            mode = "wb"
            mode_code = _MODE_WRITE
            self._compressor = BZ2Compressor(compresslevel)
        elif mode in ("x", "xb"):
            mode = "xb"
            mode_code = _MODE_WRITE
            self._compressor = BZ2Compressor(compresslevel)
        elif mode in ("a", "ab"):
            mode = "ab"
            mode_code = _MODE_WRITE
            self._compressor = BZ2Compressor(compresslevel)
        else:
            raise ValueError("Invalid mode: %r" % (mode,))

        if isinstance(filename, (str, bytes)):
            self._fp = _builtin_open(filename, mode)
            self._closefp = True
            self._mode = mode_code
        elif hasattr(filename, "read") or hasattr(filename, "write"):
            self._fp = filename
            self._mode = mode_code
        else:
            raise TypeError("filename must be a str or bytes object, or a file")

    def close(self):
        """Flush and close the file.

        May be called more than once without error. Once the file is
        closed, any other operation on it will raise a ValueError.
        """
        with self._lock:
            if self._mode == _MODE_CLOSED:
                return
            try:
                if self._mode in (_MODE_READ, _MODE_READ_EOF):
                    self._decompressor = None
                elif self._mode == _MODE_WRITE:
                    self._fp.write(self._compressor.flush())
                    self._compressor = None
            finally:
                try:
                    if self._closefp:
                        self._fp.close()
                finally:
                    self._fp = None
                    self._closefp = False
                    self._mode = _MODE_CLOSED
                    self._buffer = b""
                    self._buffer_offset = 0

    @property
    def closed(self):
        """True if this file is closed."""
        return self._mode == _MODE_CLOSED

    def fileno(self):
        """Return the file descriptor for the underlying file."""
        self._check_not_closed()
        return self._fp.fileno()

    def seekable(self):
        """Return whether the file supports seeking."""
        return self.readable() and self._fp.seekable()

    def readable(self):
        """Return whether the file was opened for reading."""
        self._check_not_closed()
        return self._mode in (_MODE_READ, _MODE_READ_EOF)

    def writable(self):
        """Return whether the file was opened for writing."""
        self._check_not_closed()
        return self._mode == _MODE_WRITE

    # Mode-checking helper functions.

    def _check_not_closed(self):
        if self.closed:
            raise ValueError("I/O operation on closed file")

    def _check_can_read(self):
        if self._mode not in (_MODE_READ, _MODE_READ_EOF):
            self._check_not_closed()
            raise io.UnsupportedOperation("File not open for reading")

    def _check_can_write(self):
        if self._mode != _MODE_WRITE:
            self._check_not_closed()
            raise io.UnsupportedOperation("File not open for writing")

    def _check_can_seek(self):
        if self._mode not in (_MODE_READ, _MODE_READ_EOF):
            self._check_not_closed()
            raise io.UnsupportedOperation("Seeking is only supported "
                                          "on files open for reading")
        if not self._fp.seekable():
            raise io.UnsupportedOperation("The underlying file object "
                                          "does not support seeking")

    # Fill the readahead buffer if it is empty. Returns False on EOF.
    def _fill_buffer(self):
        if self._mode == _MODE_READ_EOF:
            return False
        # Depending on the input data, our call to the decompressor may not
        # return any data. In this case, try again after reading another block.
        while self._buffer_offset == len(self._buffer):
            rawblock = (self._decompressor.unused_data or
                        self._fp.read(_BUFFER_SIZE))

            if not rawblock:
                if self._decompressor.eof:
                    # End-of-stream marker and end of file. We're good.
                    self._mode = _MODE_READ_EOF
                    self._size = self._pos
                    return False
                else:
                    # Problem - we were expecting more compressed data.
                    raise EOFError("Compressed file ended before the "
                                   "end-of-stream marker was reached")

            if self._decompressor.eof:
                # Continue to next stream.
                self._decompressor = BZ2Decompressor()
                try:
                    self._buffer = self._decompressor.decompress(rawblock)
                except OSError:
                    # Trailing data isn't a valid bzip2 stream. We're done here.
                    self._mode = _MODE_READ_EOF
                    self._size = self._pos
                    return False
            else:
                self._buffer = self._decompressor.decompress(rawblock)
            self._buffer_offset = 0
        return True

    # Read data until EOF.
    # If return_data is false, consume the data without returning it.
    def _read_all(self, return_data=True):
        # The loop assumes that _buffer_offset is 0. Ensure that this is true.
        self._buffer = self._buffer[self._buffer_offset:]
        self._buffer_offset = 0

        blocks = []
        while self._fill_buffer():
            if return_data:
                blocks.append(self._buffer)
            self._pos += len(self._buffer)
            self._buffer = b""
        if return_data:
            return b"".join(blocks)

    # Read a block of up to n bytes.
    # If return_data is false, consume the data without returning it.
    def _read_block(self, n, return_data=True):
        # If we have enough data buffered, return immediately.
        end = self._buffer_offset + n
        if end <= len(self._buffer):
            data = self._buffer[self._buffer_offset : end]
            self._buffer_offset = end
            self._pos += len(data)
            return data if return_data else None

        # The loop assumes that _buffer_offset is 0. Ensure that this is true.
        self._buffer = self._buffer[self._buffer_offset:]
        self._buffer_offset = 0

        blocks = []
        while n > 0 and self._fill_buffer():
            if n < len(self._buffer):
                data = self._buffer[:n]
                self._buffer_offset = n
            else:
                data = self._buffer
                self._buffer = b""
            if return_data:
                blocks.append(data)
            self._pos += len(data)
            n -= len(data)
        if return_data:
            return b"".join(blocks)

    def peek(self, n=0):
        """Return buffered data without advancing the file position.

        Always returns at least one byte of data, unless at EOF.
        The exact number of bytes returned is unspecified.
        """
        with self._lock:
            self._check_can_read()
            if not self._fill_buffer():
                return b""
            return self._buffer[self._buffer_offset:]

    def read(self, size=-1):
        """Read up to size uncompressed bytes from the file.

        If size is negative or omitted, read until EOF is reached.
        Returns b'' if the file is already at EOF.
        """
        with self._lock:
            self._check_can_read()
            if size == 0:
                return b""
            elif size < 0:
                return self._read_all()
            else:
                return self._read_block(size)

    def read1(self, size=-1):
        """Read up to size uncompressed bytes, while trying to avoid
        making multiple reads from the underlying stream.

        Returns b'' if the file is at EOF.
        """
        # Usually, read1() calls _fp.read() at most once. However, sometimes
        # this does not give enough data for the decompressor to make progress.
        # In this case we make multiple reads, to avoid returning b"".
        with self._lock:
            self._check_can_read()
            if (size == 0 or
                # Only call _fill_buffer() if the buffer is actually empty.
                # This gives a significant speedup if *size* is small.
                (self._buffer_offset == len(self._buffer) and not self._fill_buffer())):
                return b""
            if size > 0:
                data = self._buffer[self._buffer_offset :
                                    self._buffer_offset + size]
                self._buffer_offset += len(data)
            else:
                data = self._buffer[self._buffer_offset:]
                self._buffer = b""
                self._buffer_offset = 0
            self._pos += len(data)
            return data

    def readinto(self, b):
        """Read up to len(b) bytes into b.

        Returns the number of bytes read (0 for EOF).
        """
        with self._lock:
            return io.BufferedIOBase.readinto(self, b)

    def readline(self, size=-1):
        """Read a line of uncompressed bytes from the file.

        The terminating newline (if present) is retained. If size is
        non-negative, no more than size bytes will be read (in which
        case the line may be incomplete). Returns b'' if already at EOF.
        """
        if not isinstance(size, int):
            if not hasattr(size, "__index__"):
                raise TypeError("Integer argument expected")
            size = size.__index__()
        with self._lock:
            self._check_can_read()
            # Shortcut for the common case - the whole line is in the buffer.
            if size < 0:
                end = self._buffer.find(b"\n", self._buffer_offset) + 1
                if end > 0:
                    line = self._buffer[self._buffer_offset : end]
                    self._buffer_offset = end
                    self._pos += len(line)
                    return line
            return io.BufferedIOBase.readline(self, size)

    def readlines(self, size=-1):
        """Read a list of lines of uncompressed bytes from the file.

        size can be specified to control the number of lines read: no
        further lines will be read once the total size of the lines read
        so far equals or exceeds size.
        """
        if not isinstance(size, int):
            if not hasattr(size, "__index__"):
                raise TypeError("Integer argument expected")
            size = size.__index__()
        with self._lock:
            return io.BufferedIOBase.readlines(self, size)

    def write(self, data):
        """Write a byte string to the file.

        Returns the number of uncompressed bytes written, which is
        always len(data). Note that due to buffering, the file on disk
        may not reflect the data written until close() is called.
        """
        with self._lock:
            self._check_can_write()
            compressed = self._compressor.compress(data)
            self._fp.write(compressed)
            self._pos += len(data)
            return len(data)

    def writelines(self, seq):
        """Write a sequence of byte strings to the file.

        Returns the number of uncompressed bytes written.
        seq can be any iterable yielding byte strings.

        Line separators are not added between the written byte strings.
        """
        with self._lock:
            return io.BufferedIOBase.writelines(self, seq)

    # Rewind the file to the beginning of the data stream.
    def _rewind(self):
        self._fp.seek(0, 0)
        self._mode = _MODE_READ
        self._pos = 0
        self._decompressor = BZ2Decompressor()
        self._buffer = b""
        self._buffer_offset = 0

    def seek(self, offset, whence=0):
        """Change the file position.

        The new position is specified by offset, relative to the
        position indicated by whence. Values for whence are:

            0: start of stream (default); offset must not be negative
            1: current stream position
            2: end of stream; offset must not be positive

        Returns the new file position.

        Note that seeking is emulated, so depending on the parameters,
        this operation may be extremely slow.
        """
        with self._lock:
            self._check_can_seek()

            # Recalculate offset as an absolute file position.
            if whence == 0:
                pass
            elif whence == 1:
                offset = self._pos + offset
            elif whence == 2:
                # Seeking relative to EOF - we need to know the file's size.
                if self._size < 0:
                    self._read_all(return_data=False)
                offset = self._size + offset
            else:
                raise ValueError("Invalid value for whence: %s" % (whence,))

            # Make it so that offset is the number of bytes to skip forward.
            if offset < self._pos:
                self._rewind()
            else:
                offset -= self._pos

            # Read and discard data until we reach the desired position.
            self._read_block(offset, return_data=False)

            return self._pos

    def tell(self):
        """Return the current file position."""
        with self._lock:
            self._check_not_closed()
            return self._pos


def open(filename, mode="rb", compresslevel=9,
         encoding=None, errors=None, newline=None):
    """Open a bzip2-compressed file in binary or text mode.

    The filename argument can be an actual filename (a str or bytes
    object), or an existing file object to read from or write to.

    The mode argument can be "r", "rb", "w", "wb", "x", "xb", "a" or
    "ab" for binary mode, or "rt", "wt", "xt" or "at" for text mode.
    The default mode is "rb", and the default compresslevel is 9.

    For binary mode, this function is equivalent to the BZ2File
    constructor: BZ2File(filename, mode, compresslevel). In this case,
    the encoding, errors and newline arguments must not be provided.

    For text mode, a BZ2File object is created, and wrapped in an
    io.TextIOWrapper instance with the specified encoding, error
    handling behavior, and line ending(s).

    """
    if "t" in mode:
        if "b" in mode:
            raise ValueError("Invalid mode: %r" % (mode,))
    else:
        if encoding is not None:
            raise ValueError("Argument 'encoding' not supported in binary mode")
        if errors is not None:
            raise ValueError("Argument 'errors' not supported in binary mode")
        if newline is not None:
            raise ValueError("Argument 'newline' not supported in binary mode")

    bz_mode = mode.replace("t", "")
    binary_file = BZ2File(filename, bz_mode, compresslevel=compresslevel)

    if "t" in mode:
        return io.TextIOWrapper(binary_file, encoding, errors, newline)
    else:
        return binary_file


def compress(data, compresslevel=9):
    """Compress a block of data.

    compresslevel, if given, must be a number between 1 and 9.

    For incremental compression, use a BZ2Compressor object instead.
    """
    comp = BZ2Compressor(compresslevel)
    return comp.compress(data) + comp.flush()


def decompress(data):
    """Decompress a block of data.

    For incremental decompression, use a BZ2Decompressor object instead.
    """
    results = []
    while data:
        decomp = BZ2Decompressor()
        try:
            res = decomp.decompress(data)
        except OSError:
            if results:
                break  # Leftover data is not a valid bzip2 stream; ignore it.
            else:
                raise  # Error on the first iteration; bail out.
        results.append(res)
        if not decomp.eof:
            raise ValueError("Compressed data ended before the "
                             "end-of-stream marker was reached")
        data = decomp.unused_data
    return b"".join(results)
lib\calendar.py
"""Calendar printing functions

Note when comparing these calendars to the ones printed by cal(1): By
default, these calendars have Monday as the first day of the week, and
Sunday as the last (the European convention). Use setfirstweekday() to
set the first day of the week (0=Monday, 6=Sunday)."""

import sys
import datetime
import locale as _locale

__all__ = ["IllegalMonthError", "IllegalWeekdayError", "setfirstweekday",
           "firstweekday", "isleap", "leapdays", "weekday", "monthrange",
           "monthcalendar", "prmonth", "month", "prcal", "calendar",
           "timegm", "month_name", "month_abbr", "day_name", "day_abbr"]

# Exception raised for bad input (with string parameter for details)
error = ValueError

# Exceptions raised for bad input
class IllegalMonthError(ValueError):
    def __init__(self, month):
        self.month = month
    def __str__(self):
        return "bad month number %r; must be 1-12" % self.month


class IllegalWeekdayError(ValueError):
    def __init__(self, weekday):
        self.weekday = weekday
    def __str__(self):
        return "bad weekday number %r; must be 0 (Monday) to 6 (Sunday)" % self.weekday


# Constants for months referenced later
January = 1
February = 2

# Number of days per month (except for February in leap years)
mdays = [0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]

# This module used to have hard-coded lists of day and month names, as
# English strings.  The classes following emulate a read-only version of
# that, but supply localized names.  Note that the values are computed
# fresh on each call, in case the user changes locale between calls.

class _localized_month:

    _months = [datetime.date(2001, i+1, 1).strftime for i in range(12)]
    _months.insert(0, lambda x: "")

    def __init__(self, format):
        self.format = format

    def __getitem__(self, i):
        funcs = self._months[i]
        if isinstance(i, slice):
            return [f(self.format) for f in funcs]
        else:
            return funcs(self.format)

    def __len__(self):
        return 13


class _localized_day:

    # January 1, 2001, was a Monday.
    _days = [datetime.date(2001, 1, i+1).strftime for i in range(7)]

    def __init__(self, format):
        self.format = format

    def __getitem__(self, i):
        funcs = self._days[i]
        if isinstance(i, slice):
            return [f(self.format) for f in funcs]
        else:
            return funcs(self.format)

    def __len__(self):
        return 7


# Full and abbreviated names of weekdays
day_name = _localized_day('%A')
day_abbr = _localized_day('%a')

# Full and abbreviated names of months (1-based arrays!!!)
month_name = _localized_month('%B')
month_abbr = _localized_month('%b')

# Constants for weekdays
(MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY, SUNDAY) = range(7)


def isleap(year):
    """Return True for leap years, False for non-leap years."""
    return year % 4 == 0 and (year % 100 != 0 or year % 400 == 0)


def leapdays(y1, y2):
    """Return number of leap years in range [y1, y2).
       Assume y1 <= y2."""
    y1 -= 1
    y2 -= 1
    return (y2//4 - y1//4) - (y2//100 - y1//100) + (y2//400 - y1//400)


def weekday(year, month, day):
    """Return weekday (0-6 ~ Mon-Sun) for year (1970-...), month (1-12),
       day (1-31)."""
    return datetime.date(year, month, day).weekday()


def monthrange(year, month):
    """Return weekday (0-6 ~ Mon-Sun) and number of days (28-31) for
       year, month."""
    if not 1 <= month <= 12:
        raise IllegalMonthError(month)
    day1 = weekday(year, month, 1)
    ndays = mdays[month] + (month == February and isleap(year))
    return day1, ndays


class Calendar(object):
    """
    Base calendar class. This class doesn't do any formatting. It simply
    provides data to subclasses.
    """

    def __init__(self, firstweekday=0):
        self.firstweekday = firstweekday # 0 = Monday, 6 = Sunday

    def getfirstweekday(self):
        return self._firstweekday % 7

    def setfirstweekday(self, firstweekday):
        self._firstweekday = firstweekday

    firstweekday = property(getfirstweekday, setfirstweekday)

    def iterweekdays(self):
        """
        Return an iterator for one week of weekday numbers starting with the
        configured first one.
        """
        for i in range(self.firstweekday, self.firstweekday + 7):
            yield i%7

    def itermonthdates(self, year, month):
        """
        Return an iterator for one month. The iterator will yield datetime.date
        values and will always iterate through complete weeks, so it will yield
        dates outside the specified month.
        """
        date = datetime.date(year, month, 1)
        # Go back to the beginning of the week
        days = (date.weekday() - self.firstweekday) % 7
        date -= datetime.timedelta(days=days)
        oneday = datetime.timedelta(days=1)
        while True:
            yield date
            try:
                date += oneday
            except OverflowError:
                # Adding one day could fail after datetime.MAXYEAR
                break
            if date.month != month and date.weekday() == self.firstweekday:
                break

    def itermonthdays2(self, year, month):
        """
        Like itermonthdates(), but will yield (day number, weekday number)
        tuples. For days outside the specified month the day number is 0.
        """
        for date in self.itermonthdates(year, month):
            if date.month != month:
                yield (0, date.weekday())
            else:
                yield (date.day, date.weekday())

    def itermonthdays(self, year, month):
        """
        Like itermonthdates(), but will yield day numbers. For days outside
        the specified month the day number is 0.
        """
        for date in self.itermonthdates(year, month):
            if date.month != month:
                yield 0
            else:
                yield date.day

    def monthdatescalendar(self, year, month):
        """
        Return a matrix (list of lists) representing a month's calendar.
        Each row represents a week; week entries are datetime.date values.
        """
        dates = list(self.itermonthdates(year, month))
        return [ dates[i:i+7] for i in range(0, len(dates), 7) ]

    def monthdays2calendar(self, year, month):
        """
        Return a matrix representing a month's calendar.
        Each row represents a week; week entries are
        (day number, weekday number) tuples. Day numbers outside this month
        are zero.
        """
        days = list(self.itermonthdays2(year, month))
        return [ days[i:i+7] for i in range(0, len(days), 7) ]

    def monthdayscalendar(self, year, month):
        """
        Return a matrix representing a month's calendar.
        Each row represents a week; days outside this month are zero.
        """
        days = list(self.itermonthdays(year, month))
        return [ days[i:i+7] for i in range(0, len(days), 7) ]

    def yeardatescalendar(self, year, width=3):
        """
        Return the data for the specified year ready for formatting. The return
        value is a list of month rows. Each month row contains up to width months.
        Each month contains between 4 and 6 weeks and each week contains 1-7
        days. Days are datetime.date objects.
        """
        months = [
            self.monthdatescalendar(year, i)
            for i in range(January, January+12)
        ]
        return [months[i:i+width] for i in range(0, len(months), width) ]

    def yeardays2calendar(self, year, width=3):
        """
        Return the data for the specified year ready for formatting (similar to
        yeardatescalendar()). Entries in the week lists are
        (day number, weekday number) tuples. Day numbers outside this month are
        zero.
        """
        months = [
            self.monthdays2calendar(year, i)
            for i in range(January, January+12)
        ]
        return [months[i:i+width] for i in range(0, len(months), width) ]

    def yeardayscalendar(self, year, width=3):
        """
        Return the data for the specified year ready for formatting (similar to
        yeardatescalendar()). Entries in the week lists are day numbers.
        Day numbers outside this month are zero.
        """
        months = [
            self.monthdayscalendar(year, i)
            for i in range(January, January+12)
        ]
        return [months[i:i+width] for i in range(0, len(months), width) ]


class TextCalendar(Calendar):
    """
    Subclass of Calendar that outputs a calendar as a simple plain text
    similar to the UNIX program cal.
    """

    def prweek(self, theweek, width):
        """
        Print a single week (no newline).
        """
        print(self.formatweek(theweek, width), end=' ')

    def formatday(self, day, weekday, width):
        """
        Returns a formatted day.
        """
        if day == 0:
            s = ''
        else:
            s = '%2i' % day             # right-align single-digit days
        return s.center(width)

    def formatweek(self, theweek, width):
        """
        Returns a single week in a string (no newline).
        """
        return ' '.join(self.formatday(d, wd, width) for (d, wd) in theweek)

    def formatweekday(self, day, width):
        """
        Returns a formatted week day name.
        """
        if width >= 9:
            names = day_name
        else:
            names = day_abbr
        return names[day][:width].center(width)

    def formatweekheader(self, width):
        """
        Return a header for a week.
        """
        return ' '.join(self.formatweekday(i, width) for i in self.iterweekdays())

    def formatmonthname(self, theyear, themonth, width, withyear=True):
        """
        Return a formatted month name.
        """
        s = month_name[themonth]
        if withyear:
            s = "%s %r" % (s, theyear)
        return s.center(width)

    def prmonth(self, theyear, themonth, w=0, l=0):
        """
        Print a month's calendar.
        """
        print(self.formatmonth(theyear, themonth, w, l), end=' ')

    def formatmonth(self, theyear, themonth, w=0, l=0):
        """
        Return a month's calendar string (multi-line).
        """
        w = max(2, w)
        l = max(1, l)
        s = self.formatmonthname(theyear, themonth, 7 * (w + 1) - 1)
        s = s.rstrip()
        s += '\n' * l
        s += self.formatweekheader(w).rstrip()
        s += '\n' * l
        for week in self.monthdays2calendar(theyear, themonth):
            s += self.formatweek(week, w).rstrip()
            s += '\n' * l
        return s

    def formatyear(self, theyear, w=2, l=1, c=6, m=3):
        """
        Returns a year's calendar as a multi-line string.
        """
        w = max(2, w)
        l = max(1, l)
        c = max(2, c)
        colwidth = (w + 1) * 7 - 1
        v = []
        a = v.append
        a(repr(theyear).center(colwidth*m+c*(m-1)).rstrip())
        a('\n'*l)
        header = self.formatweekheader(w)
        for (i, row) in enumerate(self.yeardays2calendar(theyear, m)):
            # months in this row
            months = range(m*i+1, min(m*(i+1)+1, 13))
            a('\n'*l)
            names = (self.formatmonthname(theyear, k, colwidth, False)
                     for k in months)
            a(formatstring(names, colwidth, c).rstrip())
            a('\n'*l)
            headers = (header for k in months)
            a(formatstring(headers, colwidth, c).rstrip())
            a('\n'*l)
            # max number of weeks for this row
            height = max(len(cal) for cal in row)
            for j in range(height):
                weeks = []
                for cal in row:
                    if j >= len(cal):
                        weeks.append('')
                    else:
                        weeks.append(self.formatweek(cal[j], w))
                a(formatstring(weeks, colwidth, c).rstrip())
                a('\n' * l)
        return ''.join(v)

    def pryear(self, theyear, w=0, l=0, c=6, m=3):
        """Print a year's calendar."""
        print(self.formatyear(theyear, w, l, c, m))


class HTMLCalendar(Calendar):
    """
    This calendar returns complete HTML pages.
    """

    # CSS classes for the day <td>s
    cssclasses = ["mon", "tue", "wed", "thu", "fri", "sat", "sun"]

    def formatday(self, day, weekday):
        """
        Return a day as a table cell.
        """
        if day == 0:
            return '<td class="noday">&nbsp;</td>' # day outside month
        else:
            return '<td class="%s">%d</td>' % (self.cssclasses[weekday], day)

    def formatweek(self, theweek):
        """
        Return a complete week as a table row.
        """
        s = ''.join(self.formatday(d, wd) for (d, wd) in theweek)
        return '<tr>%s</tr>' % s

    def formatweekday(self, day):
        """
        Return a weekday name as a table header.
        """
        return '<th class="%s">%s</th>' % (self.cssclasses[day], day_abbr[day])

    def formatweekheader(self):
        """
        Return a header for a week as a table row.
        """
        s = ''.join(self.formatweekday(i) for i in self.iterweekdays())
        return '<tr>%s</tr>' % s

    def formatmonthname(self, theyear, themonth, withyear=True):
        """
        Return a month name as a table row.
        """
        if withyear:
            s = '%s %s' % (month_name[themonth], theyear)
        else:
            s = '%s' % month_name[themonth]
        return '<tr><th colspan="7" class="month">%s</th></tr>' % s

    def formatmonth(self, theyear, themonth, withyear=True):
        """
        Return a formatted month as a table.
        """
        v = []
        a = v.append
        a('<table border="0" cellpadding="0" cellspacing="0" class="month">')
        a('\n')
        a(self.formatmonthname(theyear, themonth, withyear=withyear))
        a('\n')
        a(self.formatweekheader())
        a('\n')
        for week in self.monthdays2calendar(theyear, themonth):
            a(self.formatweek(week))
            a('\n')
        a('</table>')
        a('\n')
        return ''.join(v)

    def formatyear(self, theyear, width=3):
        """
        Return a formatted year as a table of tables.
        """
        v = []
        a = v.append
        width = max(width, 1)
        a('<table border="0" cellpadding="0" cellspacing="0" class="year">')
        a('\n')
        a('<tr><th colspan="%d" class="year">%s</th></tr>' % (width, theyear))
        for i in range(January, January+12, width):
            # months in this row
            months = range(i, min(i+width, 13))
            a('<tr>')
            for m in months:
                a('<td>')
                a(self.formatmonth(theyear, m, withyear=False))
                a('</td>')
            a('</tr>')
        a('</table>')
        return ''.join(v)

    def formatyearpage(self, theyear, width=3, css='calendar.css', encoding=None):
        """
        Return a formatted year as a complete HTML page.
        """
        if encoding is None:
            encoding = sys.getdefaultencoding()
        v = []
        a = v.append
        a('<?xml version="1.0" encoding="%s"?>\n' % encoding)
        a('<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">\n')
        a('<html>\n')
        a('<head>\n')
        a('<meta http-equiv="Content-Type" content="text/html; charset=%s" />\n' % encoding)
        if css is not None:
            a('<link rel="stylesheet" type="text/css" href="%s" />\n' % css)
        a('<title>Calendar for %d</title>\n' % theyear)
        a('</head>\n')
        a('<body>\n')
        a(self.formatyear(theyear, width))
        a('</body>\n')
        a('</html>\n')
        return ''.join(v).encode(encoding, "xmlcharrefreplace")


class different_locale:
    def __init__(self, locale):
        self.locale = locale

    def __enter__(self):
        self.oldlocale = _locale.getlocale(_locale.LC_TIME)
        _locale.setlocale(_locale.LC_TIME, self.locale)

    def __exit__(self, *args):
        _locale.setlocale(_locale.LC_TIME, self.oldlocale)


class LocaleTextCalendar(TextCalendar):
    """
    This class can be passed a locale name in the constructor and will return
    month and weekday names in the specified locale. If this locale includes
    an encoding all strings containing month and weekday names will be returned
    as unicode.
    """

    def __init__(self, firstweekday=0, locale=None):
        TextCalendar.__init__(self, firstweekday)
        if locale is None:
            locale = _locale.getdefaultlocale()
        self.locale = locale

    def formatweekday(self, day, width):
        with different_locale(self.locale):
            if width >= 9:
                names = day_name
            else:
                names = day_abbr
            name = names[day]
            return name[:width].center(width)

    def formatmonthname(self, theyear, themonth, width, withyear=True):
        with different_locale(self.locale):
            s = month_name[themonth]
            if withyear:
                s = "%s %r" % (s, theyear)
            return s.center(width)


class LocaleHTMLCalendar(HTMLCalendar):
    """
    This class can be passed a locale name in the constructor and will return
    month and weekday names in the specified locale. If this locale includes
    an encoding all strings containing month and weekday names will be returned
    as unicode.
    """
    def __init__(self, firstweekday=0, locale=None):
        HTMLCalendar.__init__(self, firstweekday)
        if locale is None:
            locale = _locale.getdefaultlocale()
        self.locale = locale

    def formatweekday(self, day):
        with different_locale(self.locale):
            s = day_abbr[day]
            return '<th class="%s">%s</th>' % (self.cssclasses[day], s)

    def formatmonthname(self, theyear, themonth, withyear=True):
        with different_locale(self.locale):
            s = month_name[themonth]
            if withyear:
                s = '%s %s' % (s, theyear)
            return '<tr><th colspan="7" class="month">%s</th></tr>' % s


# Support for old module level interface
c = TextCalendar()

firstweekday = c.getfirstweekday

def setfirstweekday(firstweekday):
    if not MONDAY <= firstweekday <= SUNDAY:
        raise IllegalWeekdayError(firstweekday)
    c.firstweekday = firstweekday

monthcalendar = c.monthdayscalendar
prweek = c.prweek
week = c.formatweek
weekheader = c.formatweekheader
prmonth = c.prmonth
month = c.formatmonth
calendar = c.formatyear
prcal = c.pryear


# Spacing of month columns for multi-column year calendar
_colwidth = 7*3 - 1         # Amount printed by prweek()
_spacing = 6                # Number of spaces between columns


def format(cols, colwidth=_colwidth, spacing=_spacing):
    """Prints multi-column formatting for year calendars"""
    print(formatstring(cols, colwidth, spacing))


def formatstring(cols, colwidth=_colwidth, spacing=_spacing):
    """Returns a string formatted from n strings, centered within n columns."""
    spacing *= ' '
    return spacing.join(c.center(colwidth) for c in cols)


EPOCH = 1970
_EPOCH_ORD = datetime.date(EPOCH, 1, 1).toordinal()


def timegm(tuple):
    """Unrelated but handy function to calculate Unix timestamp from GMT."""
    year, month, day, hour, minute, second = tuple[:6]
    days = datetime.date(year, month, 1).toordinal() - _EPOCH_ORD + day - 1
    hours = days*24 + hour
    minutes = hours*60 + minute
    seconds = minutes*60 + second
    return seconds


def main(args):
    import optparse
    parser = optparse.OptionParser(usage="usage: %prog [options] [year [month]]")
    parser.add_option(
        "-w", "--width",
        dest="width", type="int", default=2,
        help="width of date column (default 2, text only)"
    )
    parser.add_option(
        "-l", "--lines",
        dest="lines", type="int", default=1,
        help="number of lines for each week (default 1, text only)"
    )
    parser.add_option(
        "-s", "--spacing",
        dest="spacing", type="int", default=6,
        help="spacing between months (default 6, text only)"
    )
    parser.add_option(
        "-m", "--months",
        dest="months", type="int", default=3,
        help="months per row (default 3, text only)"
    )
    parser.add_option(
        "-c", "--css",
        dest="css", default="calendar.css",
        help="CSS to use for page (html only)"
    )
    parser.add_option(
        "-L", "--locale",
        dest="locale", default=None,
        help="locale to be used from month and weekday names"
    )
    parser.add_option(
        "-e", "--encoding",
        dest="encoding", default=None,
        help="Encoding to use for output."
    )
    parser.add_option(
        "-t", "--type",
        dest="type", default="text",
        choices=("text", "html"),
        help="output type (text or html)"
    )

    (options, args) = parser.parse_args(args)

    if options.locale and not options.encoding:
        parser.error("if --locale is specified --encoding is required")
        sys.exit(1)

    locale = options.locale, options.encoding

    if options.type == "html":
        if options.locale:
            cal = LocaleHTMLCalendar(locale=locale)
        else:
            cal = HTMLCalendar()
        encoding = options.encoding
        if encoding is None:
            encoding = sys.getdefaultencoding()
        optdict = dict(encoding=encoding, css=options.css)
        write = sys.stdout.buffer.write
        if len(args) == 1:
            write(cal.formatyearpage(datetime.date.today().year, **optdict))
        elif len(args) == 2:
            write(cal.formatyearpage(int(args[1]), **optdict))
        else:
            parser.error("incorrect number of arguments")
            sys.exit(1)
    else:
        if options.locale:
            cal = LocaleTextCalendar(locale=locale)
        else:
            cal = TextCalendar()
        optdict = dict(w=options.width, l=options.lines)
        if len(args) != 3:
            optdict["c"] = options.spacing
            optdict["m"] = options.months
        if len(args) == 1:
            result = cal.formatyear(datetime.date.today().year, **optdict)
        elif len(args) == 2:
            result = cal.formatyear(int(args[1]), **optdict)
        elif len(args) == 3:
            result = cal.formatmonth(int(args[1]), int(args[2]), **optdict)
        else:
            parser.error("incorrect number of arguments")
            sys.exit(1)
        write = sys.stdout.write
        if options.encoding:
            result = result.encode(options.encoding)
            write = sys.stdout.buffer.write
        write(result)


if __name__ == "__main__":
    main(sys.argv)
lib\cgi.py
#! /usr/local/bin/python

# NOTE: the above "/usr/local/bin/python" is NOT a mistake.  It is
# intentionally NOT "/usr/bin/env python".  On many systems
# (e.g. Solaris), /usr/local/bin is not in $PATH as passed to CGI
# scripts, and /usr/local/bin is the default directory where Python is
# installed, so /usr/bin/env would be unable to find python.  Granted,
# binary installations by Linux vendors often install Python in
# /usr/bin.  So let those vendors patch cgi.py to match their choice
# of installation.

"""Support module for CGI (Common Gateway Interface) scripts.

This module defines a number of utilities for use by CGI scripts
written in Python.
"""

# History
# -------
#
# Michael McLay started this module.  Steve Majewski changed the
# interface to SvFormContentDict and FormContentDict.  The multipart
# parsing was inspired by code submitted by Andreas Paepcke.  Guido van
# Rossum rewrote, reformatted and documented the module and is currently
# responsible for its maintenance.
#

__version__ = "2.6"


# Imports
# =======

from io import StringIO, BytesIO, TextIOWrapper
from collections import Mapping
import sys
import os
import urllib.parse
from email.parser import FeedParser
from email.message import Message
from warnings import warn
import html
import locale
import tempfile

__all__ = ["MiniFieldStorage", "FieldStorage",
           "parse", "parse_qs", "parse_qsl", "parse_multipart",
           "parse_header", "print_exception", "print_environ",
           "print_form", "print_directory", "print_arguments",
           "print_environ_usage", "escape"]

# Logging support
# ===============

logfile = ""            # Filename to log to, if not empty
logfp = None            # File object to log to, if not None

def initlog(*allargs):
    """Write a log message, if there is a log file.

    Even though this function is called initlog(), you should always
    use log(); log is a variable that is set either to initlog
    (initially), to dolog (once the log file has been opened), or to
    nolog (when logging is disabled).

    The first argument is a format string; the remaining arguments (if
    any) are arguments to the % operator, so e.g.
        log("%s: %s", "a", "b")
    will write "a: b" to the log file, followed by a newline.

    If the global logfp is not None, it should be a file object to
    which log data is written.

    If the global logfp is None, the global logfile may be a string
    giving a filename to open, in append mode.  This file should be
    world writable!!!  If the file can't be opened, logging is
    silently disabled (since there is no safe place where we could
    send an error message).

    """
    global log, logfile, logfp
    if logfile and not logfp:
        try:
            logfp = open(logfile, "a")
        except OSError:
            pass
    if not logfp:
        log = nolog
    else:
        log = dolog
    log(*allargs)

def dolog(fmt, *args):
    """Write a log message to the log file.  See initlog() for docs."""
    logfp.write(fmt%args + "\n")

def nolog(*allargs):
    """Dummy function, assigned to log when logging is disabled."""
    pass

def closelog():
    """Close the log file."""
    global log, logfile, logfp
    logfile = ''
    if logfp:
        logfp.close()
        logfp = None
    log = initlog

log = initlog           # The current logging function


# Parsing functions
# =================

# Maximum input we will accept when REQUEST_METHOD is POST
# 0 ==> unlimited input
maxlen = 0

def parse(fp=None, environ=os.environ, keep_blank_values=0, strict_parsing=0):
    """Parse a query in the environment or from a file (default stdin)

        Arguments, all optional:

        fp              : file pointer; default: sys.stdin.buffer

        environ         : environment dictionary; default: os.environ

        keep_blank_values: flag indicating whether blank values in
            percent-encoded forms should be treated as blank strings.
            A true value indicates that blanks should be retained as
            blank strings.  The default false value indicates that
            blank values are to be ignored and treated as if they were
            not included.

        strict_parsing: flag indicating what to do with parsing errors.
            If false (the default), errors are silently ignored.
            If true, errors raise a ValueError exception.
    """
    if fp is None:
        fp = sys.stdin

    # field keys and values (except for files) are returned as strings
    # an encoding is required to decode the bytes read from self.fp
    if hasattr(fp,'encoding'):
        encoding = fp.encoding
    else:
        encoding = 'latin-1'

    # fp.read() must return bytes
    if isinstance(fp, TextIOWrapper):
        fp = fp.buffer

    if not 'REQUEST_METHOD' in environ:
        environ['REQUEST_METHOD'] = 'GET'       # For testing stand-alone
    if environ['REQUEST_METHOD'] == 'POST':
        ctype, pdict = parse_header(environ['CONTENT_TYPE'])
        if ctype == 'multipart/form-data':
            return parse_multipart(fp, pdict)
        elif ctype == 'application/x-www-form-urlencoded':
            clength = int(environ['CONTENT_LENGTH'])
            if maxlen and clength > maxlen:
                raise ValueError('Maximum content length exceeded')
            qs = fp.read(clength).decode(encoding)
        else:
            qs = ''                     # Unknown content-type
        if 'QUERY_STRING' in environ:
            if qs: qs = qs + '&'
            qs = qs + environ['QUERY_STRING']
        elif sys.argv[1:]:
            if qs: qs = qs + '&'
            qs = qs + sys.argv[1]
        environ['QUERY_STRING'] = qs    # XXX Shouldn't, really
    elif 'QUERY_STRING' in environ:
        qs = environ['QUERY_STRING']
    else:
        if sys.argv[1:]:
            qs = sys.argv[1]
        else:
            qs = ""
        environ['QUERY_STRING'] = qs    # XXX Shouldn't, really
    return urllib.parse.parse_qs(qs, keep_blank_values, strict_parsing,
                                 encoding=encoding)


# parse query string function called from urlparse,
# this is done in order to maintain backward compatiblity.

def parse_qs(qs, keep_blank_values=0, strict_parsing=0):
    """Parse a query given as a string argument."""
    warn("cgi.parse_qs is deprecated, use urllib.parse.parse_qs instead",
         DeprecationWarning, 2)
    return urllib.parse.parse_qs(qs, keep_blank_values, strict_parsing)

def parse_qsl(qs, keep_blank_values=0, strict_parsing=0):
    """Parse a query given as a string argument."""
    warn("cgi.parse_qsl is deprecated, use urllib.parse.parse_qsl instead",
         DeprecationWarning, 2)
    return urllib.parse.parse_qsl(qs, keep_blank_values, strict_parsing)

def parse_multipart(fp, pdict):
    """Parse multipart input.

    Arguments:
    fp   : input file
    pdict: dictionary containing other parameters of content-type header

    Returns a dictionary just like parse_qs(): keys are the field names, each
    value is a list of values for that field.  This is easy to use but not
    much good if you are expecting megabytes to be uploaded -- in that case,
    use the FieldStorage class instead which is much more flexible.  Note
    that content-type is the raw, unparsed contents of the content-type
    header.

    XXX This does not parse nested multipart parts -- use FieldStorage for
    that.

    XXX This should really be subsumed by FieldStorage altogether -- no
    point in having two implementations of the same parsing algorithm.
    Also, FieldStorage protects itself better against certain DoS attacks
    by limiting the size of the data read in one chunk.  The API here
    does not support that kind of protection.  This also affects parse()
    since it can call parse_multipart().

    """
    import http.client

    boundary = b""
    if 'boundary' in pdict:
        boundary = pdict['boundary']
    if not valid_boundary(boundary):
        raise ValueError('Invalid boundary in multipart form: %r'
                            % (boundary,))

    nextpart = b"--" + boundary
    lastpart = b"--" + boundary + b"--"
    partdict = {}
    terminator = b""

    while terminator != lastpart:
        bytes = -1
        data = None
        if terminator:
            # At start of next part.  Read headers first.
            headers = http.client.parse_headers(fp)
            clength = headers.get('content-length')
            if clength:
                try:
                    bytes = int(clength)
                except ValueError:
                    pass
            if bytes > 0:
                if maxlen and bytes > maxlen:
                    raise ValueError('Maximum content length exceeded')
                data = fp.read(bytes)
            else:
                data = b""
        # Read lines until end of part.
        lines = []
        while 1:
            line = fp.readline()
            if not line:
                terminator = lastpart # End outer loop
                break
            if line.startswith(b"--"):
                terminator = line.rstrip()
                if terminator in (nextpart, lastpart):
                    break
            lines.append(line)
        # Done with part.
        if data is None:
            continue
        if bytes < 0:
            if lines:
                # Strip final line terminator
                line = lines[-1]
                if line[-2:] == b"\r\n":
                    line = line[:-2]
                elif line[-1:] == b"\n":
                    line = line[:-1]
                lines[-1] = line
                data = b"".join(lines)
        line = headers['content-disposition']
        if not line:
            continue
        key, params = parse_header(line)
        if key != 'form-data':
            continue
        if 'name' in params:
            name = params['name']
        else:
            continue
        if name in partdict:
            partdict[name].append(data)
        else:
            partdict[name] = [data]

    return partdict


def _parseparam(s):
    while s[:1] == ';':
        s = s[1:]
        end = s.find(';')
        while end > 0 and (s.count('"', 0, end) - s.count('\\"', 0, end)) % 2:
            end = s.find(';', end + 1)
        if end < 0:
            end = len(s)
        f = s[:end]
        yield f.strip()
        s = s[end:]

def parse_header(line):
    """Parse a Content-type like header.

    Return the main content-type and a dictionary of options.

    """
    parts = _parseparam(';' + line)
    key = parts.__next__()
    pdict = {}
    for p in parts:
        i = p.find('=')
        if i >= 0:
            name = p[:i].strip().lower()
            value = p[i+1:].strip()
            if len(value) >= 2 and value[0] == value[-1] == '"':
                value = value[1:-1]
                value = value.replace('\\\\', '\\').replace('\\"', '"')
            pdict[name] = value
    return key, pdict


# Classes for field storage
# =========================

class MiniFieldStorage:

    """Like FieldStorage, for use when no file uploads are possible."""

    # Dummy attributes
    filename = None
    list = None
    type = None
    file = None
    type_options = {}
    disposition = None
    disposition_options = {}
    headers = {}

    def __init__(self, name, value):
        """Constructor from field name and value."""
        self.name = name
        self.value = value
        # self.file = StringIO(value)

    def __repr__(self):
        """Return printable representation."""
        return "MiniFieldStorage(%r, %r)" % (self.name, self.value)


class FieldStorage:

    """Store a sequence of fields, reading multipart/form-data.

    This class provides naming, typing, files stored on disk, and
    more.  At the top level, it is accessible like a dictionary, whose
    keys are the field names.  (Note: None can occur as a field name.)
    The items are either a Python list (if there's multiple values) or
    another FieldStorage or MiniFieldStorage object.  If it's a single
    object, it has the following attributes:

    name: the field name, if specified; otherwise None

    filename: the filename, if specified; otherwise None; this is the
        client side filename, *not* the file name on which it is
        stored (that's a temporary file you don't deal with)

    value: the value as a *string*; for file uploads, this
        transparently reads the file every time you request the value
        and returns *bytes*

    file: the file(-like) object from which you can read the data *as
        bytes* ; None if the data is stored a simple string

    type: the content-type, or None if not specified

    type_options: dictionary of options specified on the content-type
        line

    disposition: content-disposition, or None if not specified

    disposition_options: dictionary of corresponding options

    headers: a dictionary(-like) object (sometimes email.message.Message or a
        subclass thereof) containing *all* headers

    The class is subclassable, mostly for the purpose of overriding
    the make_file() method, which is called internally to come up with
    a file open for reading and writing.  This makes it possible to
    override the default choice of storing all files in a temporary
    directory and unlinking them as soon as they have been opened.

    """
    def __init__(self, fp=None, headers=None, outerboundary=b'',
                 environ=os.environ, keep_blank_values=0, strict_parsing=0,
                 limit=None, encoding='utf-8', errors='replace'):
        """Constructor.  Read multipart/* until last part.

        Arguments, all optional:

        fp              : file pointer; default: sys.stdin.buffer
            (not used when the request method is GET)
            Can be :
            1. a TextIOWrapper object
            2. an object whose read() and readline() methods return bytes

        headers         : header dictionary-like object; default:
            taken from environ as per CGI spec

        outerboundary   : terminating multipart boundary
            (for internal use only)

        environ         : environment dictionary; default: os.environ

        keep_blank_values: flag indicating whether blank values in
            percent-encoded forms should be treated as blank strings.
            A true value indicates that blanks should be retained as
            blank strings.  The default false value indicates that
            blank values are to be ignored and treated as if they were
            not included.

        strict_parsing: flag indicating what to do with parsing errors.
            If false (the default), errors are silently ignored.
            If true, errors raise a ValueError exception.

        limit : used internally to read parts of multipart/form-data forms,
            to exit from the reading loop when reached. It is the difference
            between the form content-length and the number of bytes already
            read

        encoding, errors : the encoding and error handler used to decode the
            binary stream to strings. Must be the same as the charset defined
            for the page sending the form (content-type : meta http-equiv or
            header)

        """
        method = 'GET'
        self.keep_blank_values = keep_blank_values
        self.strict_parsing = strict_parsing
        if 'REQUEST_METHOD' in environ:
            method = environ['REQUEST_METHOD'].upper()
        self.qs_on_post = None
        if method == 'GET' or method == 'HEAD':
            if 'QUERY_STRING' in environ:
                qs = environ['QUERY_STRING']
            elif sys.argv[1:]:
                qs = sys.argv[1]
            else:
                qs = ""
            qs = qs.encode(locale.getpreferredencoding(), 'surrogateescape')
            fp = BytesIO(qs)
            if headers is None:
                headers = {'content-type':
                           "application/x-www-form-urlencoded"}
        if headers is None:
            headers = {}
            if method == 'POST':
                # Set default content-type for POST to what's traditional
                headers['content-type'] = "application/x-www-form-urlencoded"
            if 'CONTENT_TYPE' in environ:
                headers['content-type'] = environ['CONTENT_TYPE']
            if 'QUERY_STRING' in environ:
                self.qs_on_post = environ['QUERY_STRING']
            if 'CONTENT_LENGTH' in environ:
                headers['content-length'] = environ['CONTENT_LENGTH']
        else:
            if not (isinstance(headers, (Mapping, Message))):
                raise TypeError("headers must be mapping or an instance of "
                                "email.message.Message")
        self.headers = headers
        if fp is None:
            self.fp = sys.stdin.buffer
        # self.fp.read() must return bytes
        elif isinstance(fp, TextIOWrapper):
            self.fp = fp.buffer
        else:
            if not (hasattr(fp, 'read') and hasattr(fp, 'readline')):
                raise TypeError("fp must be file pointer")
            self.fp = fp

        self.encoding = encoding
        self.errors = errors

        if not isinstance(outerboundary, bytes):
            raise TypeError('outerboundary must be bytes, not %s'
                            % type(outerboundary).__name__)
        self.outerboundary = outerboundary

        self.bytes_read = 0
        self.limit = limit

        # Process content-disposition header
        cdisp, pdict = "", {}
        if 'content-disposition' in self.headers:
            cdisp, pdict = parse_header(self.headers['content-disposition'])
        self.disposition = cdisp
        self.disposition_options = pdict
        self.name = None
        if 'name' in pdict:
            self.name = pdict['name']
        self.filename = None
        if 'filename' in pdict:
            self.filename = pdict['filename']
        self._binary_file = self.filename is not None

        # Process content-type header
        #
        # Honor any existing content-type header.  But if there is no
        # content-type header, use some sensible defaults.  Assume
        # outerboundary is "" at the outer level, but something non-false
        # inside a multi-part.  The default for an inner part is text/plain,
        # but for an outer part it should be urlencoded.  This should catch
        # bogus clients which erroneously forget to include a content-type
        # header.
        #
        # See below for what we do if there does exist a content-type header,
        # but it happens to be something we don't understand.
        if 'content-type' in self.headers:
            ctype, pdict = parse_header(self.headers['content-type'])
        elif self.outerboundary or method != 'POST':
            ctype, pdict = "text/plain", {}
        else:
            ctype, pdict = 'application/x-www-form-urlencoded', {}
        self.type = ctype
        self.type_options = pdict
        if 'boundary' in pdict:
            self.innerboundary = pdict['boundary'].encode(self.encoding)
        else:
            self.innerboundary = b""

        clen = -1
        if 'content-length' in self.headers:
            try:
                clen = int(self.headers['content-length'])
            except ValueError:
                pass
            if maxlen and clen > maxlen:
                raise ValueError('Maximum content length exceeded')
        self.length = clen
        if self.limit is None and clen:
            self.limit = clen

        self.list = self.file = None
        self.done = 0
        if ctype == 'application/x-www-form-urlencoded':
            self.read_urlencoded()
        elif ctype[:10] == 'multipart/':
            self.read_multi(environ, keep_blank_values, strict_parsing)
        else:
            self.read_single()

    def __del__(self):
        try:
            self.file.close()
        except AttributeError:
            pass

    def __repr__(self):
        """Return a printable representation."""
        return "FieldStorage(%r, %r, %r)" % (
                self.name, self.filename, self.value)

    def __iter__(self):
        return iter(self.keys())

    def __getattr__(self, name):
        if name != 'value':
            raise AttributeError(name)
        if self.file:
            self.file.seek(0)
            value = self.file.read()
            self.file.seek(0)
        elif self.list is not None:
            value = self.list
        else:
            value = None
        return value

    def __getitem__(self, key):
        """Dictionary style indexing."""
        if self.list is None:
            raise TypeError("not indexable")
        found = []
        for item in self.list:
            if item.name == key: found.append(item)
        if not found:
            raise KeyError(key)
        if len(found) == 1:
            return found[0]
        else:
            return found

    def getvalue(self, key, default=None):
        """Dictionary style get() method, including 'value' lookup."""
        if key in self:
            value = self[key]
            if isinstance(value, list):
                return [x.value for x in value]
            else:
                return value.value
        else:
            return default

    def getfirst(self, key, default=None):
        """ Return the first value received."""
        if key in self:
            value = self[key]
            if isinstance(value, list):
                return value[0].value
            else:
                return value.value
        else:
            return default

    def getlist(self, key):
        """ Return list of received values."""
        if key in self:
            value = self[key]
            if isinstance(value, list):
                return [x.value for x in value]
            else:
                return [value.value]
        else:
            return []

    def keys(self):
        """Dictionary style keys() method."""
        if self.list is None:
            raise TypeError("not indexable")
        return list(set(item.name for item in self.list))

    def __contains__(self, key):
        """Dictionary style __contains__ method."""
        if self.list is None:
            raise TypeError("not indexable")
        return any(item.name == key for item in self.list)

    def __len__(self):
        """Dictionary style len(x) support."""
        return len(self.keys())

    def __bool__(self):
        if self.list is None:
            raise TypeError("Cannot be converted to bool.")
        return bool(self.list)

    def read_urlencoded(self):
        """Internal: read data in query string format."""
        qs = self.fp.read(self.length)
        if not isinstance(qs, bytes):
            raise ValueError("%s should return bytes, got %s" \
                             % (self.fp, type(qs).__name__))
        qs = qs.decode(self.encoding, self.errors)
        if self.qs_on_post:
            qs += '&' + self.qs_on_post
        self.list = []
        query = urllib.parse.parse_qsl(
            qs, self.keep_blank_values, self.strict_parsing,
            encoding=self.encoding, errors=self.errors)
        for key, value in query:
            self.list.append(MiniFieldStorage(key, value))
        self.skip_lines()

    FieldStorageClass = None

    def read_multi(self, environ, keep_blank_values, strict_parsing):
        """Internal: read a part that is itself multipart."""
        ib = self.innerboundary
        if not valid_boundary(ib):
            raise ValueError('Invalid boundary in multipart form: %r' % (ib,))
        self.list = []
        if self.qs_on_post:
            query = urllib.parse.parse_qsl(
                self.qs_on_post, self.keep_blank_values, self.strict_parsing,
                encoding=self.encoding, errors=self.errors)
            for key, value in query:
                self.list.append(MiniFieldStorage(key, value))

        klass = self.FieldStorageClass or self.__class__
        first_line = self.fp.readline() # bytes
        if not isinstance(first_line, bytes):
            raise ValueError("%s should return bytes, got %s" \
                             % (self.fp, type(first_line).__name__))
        self.bytes_read += len(first_line)

        # Ensure that we consume the file until we've hit our inner boundary
        while (first_line.strip() != (b"--" + self.innerboundary) and
                first_line):
            first_line = self.fp.readline()
            self.bytes_read += len(first_line)

        while True:
            parser = FeedParser()
            hdr_text = b""
            while True:
                data = self.fp.readline()
                hdr_text += data
                if not data.strip():
                    break
            if not hdr_text:
                break
            # parser takes strings, not bytes
            self.bytes_read += len(hdr_text)
            parser.feed(hdr_text.decode(self.encoding, self.errors))
            headers = parser.close()

            # Some clients add Content-Length for part headers, ignore them
            if 'content-length' in headers:
                del headers['content-length']

            part = klass(self.fp, headers, ib, environ, keep_blank_values,
                         strict_parsing,self.limit-self.bytes_read,
                         self.encoding, self.errors)
            self.bytes_read += part.bytes_read
            self.list.append(part)
            if part.done or self.bytes_read >= self.length > 0:
                break
        self.skip_lines()

    def read_single(self):
        """Internal: read an atomic part."""
        if self.length >= 0:
            self.read_binary()
            self.skip_lines()
        else:
            self.read_lines()
        self.file.seek(0)

    bufsize = 8*1024            # I/O buffering size for copy to file

    def read_binary(self):
        """Internal: read binary data."""
        self.file = self.make_file()
        todo = self.length
        if todo >= 0:
            while todo > 0:
                data = self.fp.read(min(todo, self.bufsize)) # bytes
                if not isinstance(data, bytes):
                    raise ValueError("%s should return bytes, got %s"
                                     % (self.fp, type(data).__name__))
                self.bytes_read += len(data)
                if not data:
                    self.done = -1
                    break
                self.file.write(data)
                todo = todo - len(data)

    def read_lines(self):
        """Internal: read lines until EOF or outerboundary."""
        if self._binary_file:
            self.file = self.__file = BytesIO() # store data as bytes for files
        else:
            self.file = self.__file = StringIO() # as strings for other fields
        if self.outerboundary:
            self.read_lines_to_outerboundary()
        else:
            self.read_lines_to_eof()

    def __write(self, line):
        """line is always bytes, not string"""
        if self.__file is not None:
            if self.__file.tell() + len(line) > 1000:
                self.file = self.make_file()
                data = self.__file.getvalue()
                self.file.write(data)
                self.__file = None
        if self._binary_file:
            # keep bytes
            self.file.write(line)
        else:
            # decode to string
            self.file.write(line.decode(self.encoding, self.errors))

    def read_lines_to_eof(self):
        """Internal: read lines until EOF."""
        while 1:
            line = self.fp.readline(1<<16) # bytes
            self.bytes_read += len(line)
            if not line:
                self.done = -1
                break
            self.__write(line)

    def read_lines_to_outerboundary(self):
        """Internal: read lines until outerboundary.
        Data is read as bytes: boundaries and line ends must be converted
        to bytes for comparisons.
        """
        next_boundary = b"--" + self.outerboundary
        last_boundary = next_boundary + b"--"
        delim = b""
        last_line_lfend = True
        _read = 0
        while 1:
            if _read >= self.limit:
                break
            line = self.fp.readline(1<<16) # bytes
            self.bytes_read += len(line)
            _read += len(line)
            if not line:
                self.done = -1
                break
            if delim == b"\r":
                line = delim + line
                delim = b""
            if line.startswith(b"--") and last_line_lfend:
                strippedline = line.rstrip()
                if strippedline == next_boundary:
                    break
                if strippedline == last_boundary:
                    self.done = 1
                    break
            odelim = delim
            if line.endswith(b"\r\n"):
                delim = b"\r\n"
                line = line[:-2]
                last_line_lfend = True
            elif line.endswith(b"\n"):
                delim = b"\n"
                line = line[:-1]
                last_line_lfend = True
            elif line.endswith(b"\r"):
                # We may interrupt \r\n sequences if they span the 2**16
                # byte boundary
                delim = b"\r"
                line = line[:-1]
                last_line_lfend = False
            else:
                delim = b""
                last_line_lfend = False
            self.__write(odelim + line)

    def skip_lines(self):
        """Internal: skip lines until outer boundary if defined."""
        if not self.outerboundary or self.done:
            return
        next_boundary = b"--" + self.outerboundary
        last_boundary = next_boundary + b"--"
        last_line_lfend = True
        while True:
            line = self.fp.readline(1<<16)
            self.bytes_read += len(line)
            if not line:
                self.done = -1
                break
            if line.endswith(b"--") and last_line_lfend:
                strippedline = line.strip()
                if strippedline == next_boundary:
                    break
                if strippedline == last_boundary:
                    self.done = 1
                    break
            last_line_lfend = line.endswith(b'\n')

    def make_file(self):
        """Overridable: return a readable & writable file.

        The file will be used as follows:
        - data is written to it
        - seek(0)
        - data is read from it

        The file is opened in binary mode for files, in text mode
        for other fields

        This version opens a temporary file for reading and writing,
        and immediately deletes (unlinks) it.  The trick (on Unix!) is
        that the file can still be used, but it can't be opened by
        another process, and it will automatically be deleted when it
        is closed or when the current process terminates.

        If you want a more permanent file, you derive a class which
        overrides this method.  If you want a visible temporary file
        that is nevertheless automatically deleted when the script
        terminates, try defining a __del__ method in a derived class
        which unlinks the temporary files you have created.

        """
        if self._binary_file:
            return tempfile.TemporaryFile("wb+")
        else:
            return tempfile.TemporaryFile("w+",
                encoding=self.encoding, newline = '\n')


# Test/debug code
# ===============

def test(environ=os.environ):
    """Robust test CGI script, usable as main program.

    Write minimal HTTP headers and dump all information provided to
    the script in HTML form.

    """
    print("Content-type: text/html")
    print()
    sys.stderr = sys.stdout
    try:
        form = FieldStorage()   # Replace with other classes to test those
        print_directory()
        print_arguments()
        print_form(form)
        print_environ(environ)
        print_environ_usage()
        def f():
            exec("testing print_exception() -- <I>italics?</I>")
        def g(f=f):
            f()
        print("<H3>What follows is a test, not an actual exception:</H3>")
        g()
    except:
        print_exception()

    print("<H1>Second try with a small maxlen...</H1>")

    global maxlen
    maxlen = 50
    try:
        form = FieldStorage()   # Replace with other classes to test those
        print_directory()
        print_arguments()
        print_form(form)
        print_environ(environ)
    except:
        print_exception()

def print_exception(type=None, value=None, tb=None, limit=None):
    if type is None:
        type, value, tb = sys.exc_info()
    import traceback
    print()
    print("<H3>Traceback (most recent call last):</H3>")
    list = traceback.format_tb(tb, limit) + \
           traceback.format_exception_only(type, value)
    print("<PRE>%s<B>%s</B></PRE>" % (
        html.escape("".join(list[:-1])),
        html.escape(list[-1]),
        ))
    del tb

def print_environ(environ=os.environ):
    """Dump the shell environment as HTML."""
    keys = sorted(environ.keys())
    print()
    print("<H3>Shell Environment:</H3>")
    print("<DL>")
    for key in keys:
        print("<DT>", html.escape(key), "<DD>", html.escape(environ[key]))
    print("</DL>")
    print()

def print_form(form):
    """Dump the contents of a form as HTML."""
    keys = sorted(form.keys())
    print()
    print("<H3>Form Contents:</H3>")
    if not keys:
        print("<P>No form fields.")
    print("<DL>")
    for key in keys:
        print("<DT>" + html.escape(key) + ":", end=' ')
        value = form[key]
        print("<i>" + html.escape(repr(type(value))) + "</i>")
        print("<DD>" + html.escape(repr(value)))
    print("</DL>")
    print()

def print_directory():
    """Dump the current directory as HTML."""
    print()
    print("<H3>Current Working Directory:</H3>")
    try:
        pwd = os.getcwd()
    except OSError as msg:
        print("OSError:", html.escape(str(msg)))
    else:
        print(html.escape(pwd))
    print()

def print_arguments():
    print()
    print("<H3>Command Line Arguments:</H3>")
    print()
    print(sys.argv)
    print()

def print_environ_usage():
    """Dump a list of environment variables used by CGI as HTML."""
    print("""
<H3>These environment variables could have been set:</H3>
<UL>
<LI>AUTH_TYPE
<LI>CONTENT_LENGTH
<LI>CONTENT_TYPE
<LI>DATE_GMT
<LI>DATE_LOCAL
<LI>DOCUMENT_NAME
<LI>DOCUMENT_ROOT
<LI>DOCUMENT_URI
<LI>GATEWAY_INTERFACE
<LI>LAST_MODIFIED
<LI>PATH
<LI>PATH_INFO
<LI>PATH_TRANSLATED
<LI>QUERY_STRING
<LI>REMOTE_ADDR
<LI>REMOTE_HOST
<LI>REMOTE_IDENT
<LI>REMOTE_USER
<LI>REQUEST_METHOD
<LI>SCRIPT_NAME
<LI>SERVER_NAME
<LI>SERVER_PORT
<LI>SERVER_PROTOCOL
<LI>SERVER_ROOT
<LI>SERVER_SOFTWARE
</UL>
In addition, HTTP headers sent by the server may be passed in the
environment as well.  Here are some common variable names:
<UL>
<LI>HTTP_ACCEPT
<LI>HTTP_CONNECTION
<LI>HTTP_HOST
<LI>HTTP_PRAGMA
<LI>HTTP_REFERER
<LI>HTTP_USER_AGENT
</UL>
""")


# Utilities
# =========

def escape(s, quote=None):
    """Deprecated API."""
    warn("cgi.escape is deprecated, use html.escape instead",
         DeprecationWarning, stacklevel=2)
    s = s.replace("&", "&amp;") # Must be done first!
    s = s.replace("<", "&lt;")
    s = s.replace(">", "&gt;")
    if quote:
        s = s.replace('"', "&quot;")
    return s


def valid_boundary(s):
    import re
    if isinstance(s, bytes):
        _vb_pattern = b"^[ -~]{0,200}[!-~]$"
    else:
        _vb_pattern = "^[ -~]{0,200}[!-~]$"
    return re.match(_vb_pattern, s)

# Invoke mainline
# ===============

# Call test() when this file is run as a script (not imported as a module)
if __name__ == '__main__':
    test()
lib\cgitb.py
"""More comprehensive traceback formatting for Python scripts.

To enable this module, do:

    import cgitb; cgitb.enable()

at the top of your script.  The optional arguments to enable() are:

    display     - if true, tracebacks are displayed in the web browser
    logdir      - if set, tracebacks are written to files in this directory
    context     - number of lines of source code to show for each stack frame
    format      - 'text' or 'html' controls the output format

By default, tracebacks are displayed but not saved, the context is 5 lines
and the output format is 'html' (for backwards compatibility with the
original use of this module)

Alternatively, if you have caught an exception and want cgitb to display it
for you, call cgitb.handler().  The optional argument to handler() is a
3-item tuple (etype, evalue, etb) just like the value of sys.exc_info().
The default handler displays output as HTML.

"""
import inspect
import keyword
import linecache
import os
import pydoc
import sys
import tempfile
import time
import tokenize
import traceback

def reset():
    """Return a string that resets the CGI and browser to a known state."""
    return '''<!--: spam
Content-Type: text/html

<body bgcolor="#f0f0f8"><font color="#f0f0f8" size="-5"> -->
<body bgcolor="#f0f0f8"><font color="#f0f0f8" size="-5"> --> -->
</font> </font> </font> </script> </object> </blockquote> </pre>
</table> </table> </table> </table> </table> </font> </font> </font>'''

__UNDEF__ = []                          # a special sentinel object
def small(text):
    if text:
        return '<small>' + text + '</small>'
    else:
        return ''

def strong(text):
    if text:
        return '<strong>' + text + '</strong>'
    else:
        return ''

def grey(text):
    if text:
        return '<font color="#909090">' + text + '</font>'
    else:
        return ''

def lookup(name, frame, locals):
    """Find the value for a given name in the given environment."""
    if name in locals:
        return 'local', locals[name]
    if name in frame.f_globals:
        return 'global', frame.f_globals[name]
    if '__builtins__' in frame.f_globals:
        builtins = frame.f_globals['__builtins__']
        if type(builtins) is type({}):
            if name in builtins:
                return 'builtin', builtins[name]
        else:
            if hasattr(builtins, name):
                return 'builtin', getattr(builtins, name)
    return None, __UNDEF__

def scanvars(reader, frame, locals):
    """Scan one logical line of Python and look up values of variables used."""
    vars, lasttoken, parent, prefix, value = [], None, None, '', __UNDEF__
    for ttype, token, start, end, line in tokenize.generate_tokens(reader):
        if ttype == tokenize.NEWLINE: break
        if ttype == tokenize.NAME and token not in keyword.kwlist:
            if lasttoken == '.':
                if parent is not __UNDEF__:
                    value = getattr(parent, token, __UNDEF__)
                    vars.append((prefix + token, prefix, value))
            else:
                where, value = lookup(token, frame, locals)
                vars.append((token, where, value))
        elif token == '.':
            prefix += lasttoken + '.'
            parent = value
        else:
            parent, prefix = None, ''
        lasttoken = token
    return vars

def html(einfo, context=5):
    """Return a nice HTML document describing a given traceback."""
    etype, evalue, etb = einfo
    if isinstance(etype, type):
        etype = etype.__name__
    pyver = 'Python ' + sys.version.split()[0] + ': ' + sys.executable
    date = time.ctime(time.time())
    head = '<body bgcolor="#f0f0f8">' + pydoc.html.heading(
        '<big><big>%s</big></big>' %
        strong(pydoc.html.escape(str(etype))),
        '#ffffff', '#6622aa', pyver + '<br>' + date) + '''
<p>A problem occurred in a Python script.  Here is the sequence of
function calls leading up to the error, in the order they occurred.</p>'''

    indent = '<tt>' + small('&nbsp;' * 5) + '&nbsp;</tt>'
    frames = []
    records = inspect.getinnerframes(etb, context)
    for frame, file, lnum, func, lines, index in records:
        if file:
            file = os.path.abspath(file)
            link = '<a href="file://%s">%s</a>' % (file, pydoc.html.escape(file))
        else:
            file = link = '?'
        args, varargs, varkw, locals = inspect.getargvalues(frame)
        call = ''
        if func != '?':
            call = 'in ' + strong(func) + \
                inspect.formatargvalues(args, varargs, varkw, locals,
                    formatvalue=lambda value: '=' + pydoc.html.repr(value))

        highlight = {}
        def reader(lnum=[lnum]):
            highlight[lnum[0]] = 1
            try: return linecache.getline(file, lnum[0])
            finally: lnum[0] += 1
        vars = scanvars(reader, frame, locals)

        rows = ['<tr><td bgcolor="#d8bbff">%s%s %s</td></tr>' %
                ('<big>&nbsp;</big>', link, call)]
        if index is not None:
            i = lnum - index
            for line in lines:
                num = small('&nbsp;' * (5-len(str(i))) + str(i)) + '&nbsp;'
                if i in highlight:
                    line = '<tt>=&gt;%s%s</tt>' % (num, pydoc.html.preformat(line))
                    rows.append('<tr><td bgcolor="#ffccee">%s</td></tr>' % line)
                else:
                    line = '<tt>&nbsp;&nbsp;%s%s</tt>' % (num, pydoc.html.preformat(line))
                    rows.append('<tr><td>%s</td></tr>' % grey(line))
                i += 1

        done, dump = {}, []
        for name, where, value in vars:
            if name in done: continue
            done[name] = 1
            if value is not __UNDEF__:
                if where in ('global', 'builtin'):
                    name = ('<em>%s</em> ' % where) + strong(name)
                elif where == 'local':
                    name = strong(name)
                else:
                    name = where + strong(name.split('.')[-1])
                dump.append('%s&nbsp;= %s' % (name, pydoc.html.repr(value)))
            else:
                dump.append(name + ' <em>undefined</em>')

        rows.append('<tr><td>%s</td></tr>' % small(grey(', '.join(dump))))
        frames.append('''
<table width="100%%" cellspacing=0 cellpadding=0 border=0>
%s</table>''' % '\n'.join(rows))

    exception = ['<p>%s: %s' % (strong(pydoc.html.escape(str(etype))),
                                pydoc.html.escape(str(evalue)))]
    for name in dir(evalue):
        if name[:1] == '_': continue
        value = pydoc.html.repr(getattr(evalue, name))
        exception.append('\n<br>%s%s&nbsp;=\n%s' % (indent, name, value))

    return head + ''.join(frames) + ''.join(exception) + '''


<!-- The above is a description of an error in a Python program, formatted
     for a Web browser because the 'cgitb' module was enabled.  In case you
     are not reading this in a Web browser, here is the original traceback:

%s
-->
''' % pydoc.html.escape(
          ''.join(traceback.format_exception(etype, evalue, etb)))

def text(einfo, context=5):
    """Return a plain text document describing a given traceback."""
    etype, evalue, etb = einfo
    if isinstance(etype, type):
        etype = etype.__name__
    pyver = 'Python ' + sys.version.split()[0] + ': ' + sys.executable
    date = time.ctime(time.time())
    head = "%s\n%s\n%s\n" % (str(etype), pyver, date) + '''
A problem occurred in a Python script.  Here is the sequence of
function calls leading up to the error, in the order they occurred.
'''

    frames = []
    records = inspect.getinnerframes(etb, context)
    for frame, file, lnum, func, lines, index in records:
        file = file and os.path.abspath(file) or '?'
        args, varargs, varkw, locals = inspect.getargvalues(frame)
        call = ''
        if func != '?':
            call = 'in ' + func + \
                inspect.formatargvalues(args, varargs, varkw, locals,
                    formatvalue=lambda value: '=' + pydoc.text.repr(value))

        highlight = {}
        def reader(lnum=[lnum]):
            highlight[lnum[0]] = 1
            try: return linecache.getline(file, lnum[0])
            finally: lnum[0] += 1
        vars = scanvars(reader, frame, locals)

        rows = [' %s %s' % (file, call)]
        if index is not None:
            i = lnum - index
            for line in lines:
                num = '%5d ' % i
                rows.append(num+line.rstrip())
                i += 1

        done, dump = {}, []
        for name, where, value in vars:
            if name in done: continue
            done[name] = 1
            if value is not __UNDEF__:
                if where == 'global': name = 'global ' + name
                elif where != 'local': name = where + name.split('.')[-1]
                dump.append('%s = %s' % (name, pydoc.text.repr(value)))
            else:
                dump.append(name + ' undefined')

        rows.append('\n'.join(dump))
        frames.append('\n%s\n' % '\n'.join(rows))

    exception = ['%s: %s' % (str(etype), str(evalue))]
    for name in dir(evalue):
        value = pydoc.text.repr(getattr(evalue, name))
        exception.append('\n%s%s = %s' % (" "*4, name, value))

    return head + ''.join(frames) + ''.join(exception) + '''

The above is a description of an error in a Python program.  Here is
the original traceback:

%s
''' % ''.join(traceback.format_exception(etype, evalue, etb))

class Hook:
    """A hook to replace sys.excepthook that shows tracebacks in HTML."""

    def __init__(self, display=1, logdir=None, context=5, file=None,
                 format="html"):
        self.display = display          # send tracebacks to browser if true
        self.logdir = logdir            # log tracebacks to files if not None
        self.context = context          # number of source code lines per frame
        self.file = file or sys.stdout  # place to send the output
        self.format = format

    def __call__(self, etype, evalue, etb):
        self.handle((etype, evalue, etb))

    def handle(self, info=None):
        info = info or sys.exc_info()
        if self.format == "html":
            self.file.write(reset())

        formatter = (self.format=="html") and html or text
        plain = False
        try:
            doc = formatter(info, self.context)
        except:                         # just in case something goes wrong
            doc = ''.join(traceback.format_exception(*info))
            plain = True

        if self.display:
            if plain:
                doc = doc.replace('&', '&amp;').replace('<', '&lt;')
                self.file.write('<pre>' + doc + '</pre>\n')
            else:
                self.file.write(doc + '\n')
        else:
            self.file.write('<p>A problem occurred in a Python script.\n')

        if self.logdir is not None:
            suffix = ['.txt', '.html'][self.format=="html"]
            (fd, path) = tempfile.mkstemp(suffix=suffix, dir=self.logdir)

            try:
                file = os.fdopen(fd, 'w')
                file.write(doc)
                file.close()
                msg = '%s contains the description of this error.' % path
            except:
                msg = 'Tried to save traceback to %s, but failed.' % path

            if self.format == 'html':
                self.file.write('<p>%s</p>\n' % msg)
            else:
                self.file.write(msg + '\n')
        try:
            self.file.flush()
        except: pass

handler = Hook().handle
def enable(display=1, logdir=None, context=5, format="html"):
    """Install an exception handler that formats tracebacks as HTML.

    The optional argument 'display' can be set to 0 to suppress sending the
    traceback to the browser, and 'logdir' can be set to a directory to cause
    tracebacks to be written to files there."""
    sys.excepthook = Hook(display=display, logdir=logdir,
                          context=context, format=format)
lib\chunk.py
"""Simple class to read IFF chunks.

An IFF chunk (used in formats such as AIFF, TIFF, RMFF (RealMedia File
Format)) has the following structure:

+----------------+
| ID (4 bytes)   |
+----------------+
| size (4 bytes) |
+----------------+
| data           |
| ...            |
+----------------+

The ID is a 4-byte string which identifies the type of chunk.

The size field (a 32-bit value, encoded using big-endian byte order)
gives the size of the whole chunk, including the 8-byte header.

Usually an IFF-type file consists of one or more chunks.  The proposed
usage of the Chunk class defined here is to instantiate an instance at
the start of each chunk and read from the instance until it reaches
the end, after which a new instance can be instantiated.  At the end
of the file, creating a new instance will fail with an EOFError
exception.

Usage:
while True:
    try:
        chunk = Chunk(file)
    except EOFError:
        break
    chunktype = chunk.getname()
    while True:
        data = chunk.read(nbytes)
        if not data:
            pass
        # do something with data

The interface is file-like.  The implemented methods are:
read, close, seek, tell, isatty.
Extra methods are: skip() (called by close, skips to the end of the chunk),
getname() (returns the name (ID) of the chunk)

The __init__ method has one required argument, a file-like object
(including a chunk instance), and one optional argument, a flag which
specifies whether or not chunks are aligned on 2-byte boundaries.  The
default is 1, i.e. aligned.
"""

class Chunk:
    def __init__(self, file, align=True, bigendian=True, inclheader=False):
        import struct
        self.closed = False
        self.align = align      # whether to align to word (2-byte) boundaries
        if bigendian:
            strflag = '>'
        else:
            strflag = '<'
        self.file = file
        self.chunkname = file.read(4)
        if len(self.chunkname) < 4:
            raise EOFError
        try:
            self.chunksize = struct.unpack_from(strflag+'L', file.read(4))[0]
        except struct.error:
            raise EOFError
        if inclheader:
            self.chunksize = self.chunksize - 8 # subtract header
        self.size_read = 0
        try:
            self.offset = self.file.tell()
        except (AttributeError, OSError):
            self.seekable = False
        else:
            self.seekable = True

    def getname(self):
        """Return the name (ID) of the current chunk."""
        return self.chunkname

    def getsize(self):
        """Return the size of the current chunk."""
        return self.chunksize

    def close(self):
        if not self.closed:
            try:
                self.skip()
            finally:
                self.closed = True

    def isatty(self):
        if self.closed:
            raise ValueError("I/O operation on closed file")
        return False

    def seek(self, pos, whence=0):
        """Seek to specified position into the chunk.
        Default position is 0 (start of chunk).
        If the file is not seekable, this will result in an error.
        """

        if self.closed:
            raise ValueError("I/O operation on closed file")
        if not self.seekable:
            raise OSError("cannot seek")
        if whence == 1:
            pos = pos + self.size_read
        elif whence == 2:
            pos = pos + self.chunksize
        if pos < 0 or pos > self.chunksize:
            raise RuntimeError
        self.file.seek(self.offset + pos, 0)
        self.size_read = pos

    def tell(self):
        if self.closed:
            raise ValueError("I/O operation on closed file")
        return self.size_read

    def read(self, size=-1):
        """Read at most size bytes from the chunk.
        If size is omitted or negative, read until the end
        of the chunk.
        """

        if self.closed:
            raise ValueError("I/O operation on closed file")
        if self.size_read >= self.chunksize:
            return b''
        if size < 0:
            size = self.chunksize - self.size_read
        if size > self.chunksize - self.size_read:
            size = self.chunksize - self.size_read
        data = self.file.read(size)
        self.size_read = self.size_read + len(data)
        if self.size_read == self.chunksize and \
           self.align and \
           (self.chunksize & 1):
            dummy = self.file.read(1)
            self.size_read = self.size_read + len(dummy)
        return data

    def skip(self):
        """Skip the rest of the chunk.
        If you are not interested in the contents of the chunk,
        this method should be called so that the file points to
        the start of the next chunk.
        """

        if self.closed:
            raise ValueError("I/O operation on closed file")
        if self.seekable:
            try:
                n = self.chunksize - self.size_read
                # maybe fix alignment
                if self.align and (self.chunksize & 1):
                    n = n + 1
                self.file.seek(n, 1)
                self.size_read = self.size_read + n
                return
            except OSError:
                pass
        while self.size_read < self.chunksize:
            n = min(8192, self.chunksize - self.size_read)
            dummy = self.read(n)
            if not dummy:
                raise EOFError
lib\clrtype.py
# Licensed to the .NET Foundation under one or more agreements.
# The .NET Foundation licenses this file to you under the Apache 2.0 License.
# See the LICENSE file in the project root for more information.

__all__ = ["ClrClass", "ClrInterface", "accepts", "returns", "attribute", "propagate_attributes"]

import clr
clr.AddReference("Microsoft.Dynamic")
clr.AddReference("Microsoft.Scripting")
clr.AddReference("IronPython")

if clr.IsNetCoreApp:
    clr.AddReference("System.Reflection.Emit")

import System
from System import Char, Void, Boolean, Array, Type, AppDomain
from System.Reflection import FieldAttributes, MethodAttributes, PropertyAttributes, ParameterAttributes
from System.Reflection import CallingConventions, TypeAttributes, AssemblyName
from System.Reflection.Emit import OpCodes, CustomAttributeBuilder, AssemblyBuilder, AssemblyBuilderAccess
from System.Runtime.InteropServices import DllImportAttribute, CallingConvention, CharSet
from Microsoft.Scripting.Generation import Snippets
from Microsoft.Scripting.Runtime import DynamicOperations
from Microsoft.Scripting.Utils import ReflectionUtils
from IronPython.Runtime import NameType, PythonContext
from IronPython.Runtime.Types import PythonType, ReflectedField, ReflectedProperty

PropertyAttributes_None = getattr(PropertyAttributes, "None")
ParameterAttributes_None = getattr(ParameterAttributes, "None")

def validate_clr_types(signature_types, var_signature = False):
    if not isinstance(signature_types, tuple):
        signature_types = (signature_types,)
    for t in signature_types:
        if type(t) is type(System.IComparable): # type overloaded on generic arity, eg IComparable and IComparable[T]
            t = t[()] # select non-generic version
        clr_type = clr.GetClrType(t)
        if t == Void:
            raise TypeError("Void cannot be used in signature")
        is_typed = clr.GetPythonType(clr_type) == t
        # is_typed needs to be weakened until the generated type
        # gets explicitly published as the underlying CLR type
        is_typed = is_typed or (hasattr(t, "__metaclass__") and t.__metaclass__ in [ClrInterface, ClrClass])
        if not is_typed:
            raise Exception("Invalid CLR type %s" % str(t))
        if not var_signature:
            if clr_type.IsByRef:
                raise TypeError("Byref can only be used as arguments and locals")
            # ArgIterator is not present in Silverlight
            if hasattr(System, "ArgIterator") and t == System.ArgIterator:
                raise TypeError("Stack-referencing types can only be used as arguments and locals")

class TypedFunction(object):
    """
    A strongly-typed function can get wrapped up as a staticmethod, a property, etc.
    This class represents the raw function, but with the type information
    it is decorated with.
    Other information is stored as attributes on the function. See propagate_attributes
    """
    def __init__(self, function, is_static = False, prop_name_if_prop_get = None, prop_name_if_prop_set = None):
        self.function = function
        self.is_static = is_static
        self.prop_name_if_prop_get = prop_name_if_prop_get
        self.prop_name_if_prop_set = prop_name_if_prop_set

class ClrType(type):
    """
    Base metaclass for creating strongly-typed CLR types
    """

    def is_typed_method(self, function):
        if hasattr(function, "arg_types") != hasattr(function, "return_type"):
            raise TypeError("One of @accepts and @returns is missing for %s" % function.__name__)

        return hasattr(function, "arg_types")

    def get_typed_properties(self):
        for item_name, item in self.__dict__.items():
            if isinstance(item, property):
                if item.fget:
                    if not self.is_typed_method(item.fget): continue
                    prop_type = item.fget.return_type
                else:
                    if not self.is_typed_method(item.fset): continue
                    prop_type = item.fset.arg_types[0]
                validate_clr_types(prop_type)
                clr_prop_type = clr.GetClrType(prop_type)
                yield item, item_name, clr_prop_type

    def emit_properties(self, typebld):
        for prop, prop_name, clr_prop_type in self.get_typed_properties():
            self.emit_property(typebld, prop, prop_name, clr_prop_type)

    def emit_property(self, typebld, prop, name, clrtype):
        prpbld = typebld.DefineProperty(name, PropertyAttributes_None, clrtype, None)
        if prop.fget:
            getter = self.emitted_methods[(prop.fget.__name__, prop.fget.arg_types)]
            prpbld.SetGetMethod(getter)
        if prop.fset:
            setter = self.emitted_methods[(prop.fset.__name__, prop.fset.arg_types)]
            prpbld.SetSetMethod(setter)

    def dummy_function(self): raise RuntimeError("this should not get called")

    def get_typed_methods(self):
        """
        Get all the methods with @accepts (and @returns) decorators
        Functions are assumed to be instance methods, unless decorated with @staticmethod
        """

        # We avoid using the "types" library as it is not a builtin
        FunctionType = type(ClrType.__dict__["dummy_function"])

        for item_name, item in self.__dict__.items():
            function = None
            is_static = False
            if isinstance(item, FunctionType):
                function, is_static = item, False
            elif isinstance(item, staticmethod):
                function, is_static = getattr(self, item_name), True
            elif isinstance(item, property):
                if item.fget and self.is_typed_method(item.fget):
                    if item.fget.__name__ == item_name:
                        # The property hides the getter. So yield the getter
                        yield TypedFunction(item.fget, False, item_name, None)
                if item.fset and self.is_typed_method(item.fset):
                    if item.fset.__name__ == item_name:
                        # The property hides the setter. So yield the setter
                        yield TypedFunction(item.fset, False, None, item_name)
                continue
            else:
                continue
            if self.is_typed_method(function):
                yield TypedFunction(function, is_static)

    def emit_methods(self, typebld):
        # We need to track the generated methods so that we can emit properties
        # referring these methods.
        # Also, the hash is indexed by name *and signature*. Even though Python does
        # not have method overloading, property getter and setter functions can have
        # the same __name__ attribute
        self.emitted_methods = {}
        for function_info in self.get_typed_methods():
            method_builder = self.emit_method(typebld, function_info)
            function = function_info.function
            if (function.__name__, function.arg_types) in self.emitted_methods:
                raise TypeError("methods with clashing names")
            self.emitted_methods[(function.__name__, function.arg_types)] = method_builder

    def emit_classattribs(self, typebld):
        if hasattr(self, '_clrclassattribs'):
            for attrib_info in self._clrclassattribs:
                if isinstance(attrib_info, type):
                    ci = clr.GetClrType(attrib_info).GetConstructor(())
                    cab = CustomAttributeBuilder(ci, ())
                elif isinstance(attrib_info, CustomAttributeDecorator):
                    cab = attrib_info.GetBuilder()
                else:
                    make_decorator = attrib_info()
                    cab = make_decorator.GetBuilder()
                typebld.SetCustomAttribute(cab)

    def get_clr_type_name(self):
        if hasattr(self, "_clrnamespace"):
            return self._clrnamespace + "." + self.__name__
        else:
            return self.__name__

    def create_type(self, typebld):
        self.emit_members(typebld)
        new_type = typebld.CreateType()
        self.map_members(new_type)
        return new_type

class ClrInterface(ClrType):
    """
    Set __metaclass__ in a Python class declaration to declare a
    CLR interface type.
    You need to specify object as the base-type if you do not specify any other
    interfaces as the base interfaces
    """

    def __init__(self, *args):
        return super(ClrInterface, self).__init__(*args)

    def emit_method(self, typebld, function_info):
        assert(not function_info.is_static)
        function = function_info.function
        attributes = MethodAttributes.Public | MethodAttributes.Virtual | MethodAttributes.Abstract
        method_builder = typebld.DefineMethod(
            function.__name__,
            attributes,
            function.return_type,
            function.arg_types)

        instance_offset = 0 if function_info.is_static else 1
        arg_names = function.__code__.co_varnames
        for i in range(len(function.arg_types)):
            # TODO - set non-trivial ParameterAttributes, default value and custom attributes
            p = method_builder.DefineParameter(i + 1, ParameterAttributes_None, arg_names[i + instance_offset])

        if hasattr(function, "CustomAttributeBuilders"):
            for cab in function.CustomAttributeBuilders:
                method_builder.SetCustomAttribute(cab)

        return method_builder

    def emit_members(self, typebld):
        self.emit_methods(typebld)
        self.emit_properties(typebld)
        self.emit_classattribs(typebld)

    def map_members(self, new_type): pass

    interface_module_builder = None

    @staticmethod
    def define_interface(typename, bases):
        for b in bases:
            validate_clr_types(b)
        if not ClrInterface.interface_module_builder:
            name = AssemblyName("interfaces")
            access = AssemblyBuilderAccess.Run
            assembly_builder = ReflectionUtils.DefineDynamicAssembly(name, access)
            ClrInterface.interface_module_builder = assembly_builder.DefineDynamicModule("interfaces")
        attrs = TypeAttributes.Public | TypeAttributes.Interface | TypeAttributes.Abstract
        return ClrInterface.interface_module_builder.DefineType(typename, attrs, None, bases)

    def map_clr_type(self, clr_type):
        """
        TODO - Currently "t = clr.GetPythonType(clr.GetClrType(C)); t == C" will be False
        for C where C.__metaclass__ is ClrInterface, even though both t and C
        represent the same CLR type. This can be fixed by publishing a mapping
        between t and C in the IronPython runtime.
        """
        pass

    def __clrtype__(self):
        # CFoo below will use ClrInterface as its metaclass, but the user will not expect CFoo
        # to be an interface in this case:
        #
        #   class IFoo(object):
        #     __metaclass__ = ClrInterface
        #   class CFoo(IFoo): pass
        if not "__metaclass__" in self.__dict__:
            return super(ClrInterface, self).__clrtype__()

        bases = list(self.__bases__)
        bases.remove(object)
        bases = tuple(bases)
        if False: # Snippets currently does not support creating interfaces
            typegen = Snippets.Shared.DefineType(self.get_clr_type_name(), bases, True, False)
            typebld = typegen.TypeBuilder
        else:
            typebld = ClrInterface.define_interface(self.get_clr_type_name(), bases)
        clr_type = self.create_type(typebld)
        self.map_clr_type(clr_type)
        return clr_type

# Note that ClrClass inherits from ClrInterface to satisfy Python requirements of metaclasses.
# A metaclass of a subtype has to be subtype of the metaclass of a base type. As a result,
# if you define a type hierarchy as shown below, it requires ClrClass to be a subtype
# of ClrInterface:
#
#   class IFoo(object):
#     __metaclass__ = ClrInterface
#   class CFoo(IFoo):
#     __metaclass__ = ClrClass
class ClrClass(ClrInterface):
    """
    Set __metaclass__ in a Python class declaration to specify strong-type
    information for the class or its attributes. The Python class
    retains its Python attributes, like being able to add or remove methods.
    """

    # Holds the FieldInfo for a static CLR field which points to a
    # Microsoft.Scripting.Runtime.DynamicOperations corresponding to the current ScriptEngine
    dynamic_operations_field = None

    def emit_fields(self, typebld):
        if hasattr(self, "_clrfields"):
            for fldname in self._clrfields:
                field_type = self._clrfields[fldname]
                validate_clr_types(field_type)
                typebld.DefineField(
                    fldname,
                    clr.GetClrType(field_type),
                    FieldAttributes.Public)

    def map_fields(self, new_type):
        if hasattr(self, "_clrfields"):
            for fldname in self._clrfields:
                fldinfo = new_type.GetField(fldname)
                setattr(self, fldname, ReflectedField(fldinfo))

    @staticmethod
    def get_dynamic_operations_field():
        if ClrClass.dynamic_operations_field:
            return ClrClass.dynamic_operations_field
        python_context = clr.GetCurrentRuntime().GetLanguage(PythonContext)
        dynamic_operations = DynamicOperations(python_context)

        typegen = Snippets.Shared.DefineType(
            "DynamicOperationsHolder" + str(hash(python_context)),
            object,
            True,
            False)
        typebld = typegen.TypeBuilder
        typebld.DefineField(
            "DynamicOperations",
            DynamicOperations,
            FieldAttributes.Public | FieldAttributes.Static)
        new_type = typebld.CreateType()
        ClrClass.dynamic_operations_field = new_type.GetField("DynamicOperations")

        ClrClass.dynamic_operations_field.SetValue(None, dynamic_operations)

        return ClrClass.dynamic_operations_field

    def emit_typed_stub_to_python_method(self, typebld, function_info):
        function = function_info.function
        """
        Generate a stub method that repushes all the arguments and
        dispatches to DynamicOperations.InvokeMember
        """
        invoke_member = clr.GetClrType(DynamicOperations).GetMethod(
            "InvokeMember",
            Array[Type]((object, str, Array[object])))

        # Type.GetMethod raises an AmbiguousMatchException if there is a generic and a non-generic method
        # (like DynamicOperations.GetMember) with the same name and signature. So we have to do things
        # the hard way
        get_member_search = [m for m in clr.GetClrType(DynamicOperations).GetMethods() if m.Name == "GetMember" and not m.IsGenericMethod and m.GetParameters().Length == 2]
        assert(len(get_member_search) == 1)
        get_member = get_member_search[0]

        set_member_search = [m for m in clr.GetClrType(DynamicOperations).GetMethods() if m.Name == "SetMember" and not m.IsGenericMethod and m.GetParameters().Length == 3]
        assert(len(set_member_search) == 1)
        set_member = set_member_search[0]

        convert_to = clr.GetClrType(DynamicOperations).GetMethod(
            "ConvertTo",
            Array[Type]((object, Type)))
        get_type_from_handle = clr.GetClrType(Type).GetMethod("GetTypeFromHandle")

        attributes = MethodAttributes.Public
        if function_info.is_static: attributes |= MethodAttributes.Static
        if function.__name__ == "__new__":
            if function_info.is_static: raise TypeError
            method_builder = typebld.DefineConstructor(
                attributes,
                CallingConventions.HasThis,
                function.arg_types)
            raise NotImplementedError("Need to call self.baseType ctor passing in self.get_python_type_field()")
        else:
            method_builder = typebld.DefineMethod(
                function.__name__,
                attributes,
                function.return_type,
                function.arg_types)

        instance_offset = 0 if function_info.is_static else 1
        arg_names = function.__code__.co_varnames
        for i in range(len(function.arg_types)):
            # TODO - set non-trivial ParameterAttributes, default value and custom attributes
            p = method_builder.DefineParameter(i + 1, ParameterAttributes_None, arg_names[i + instance_offset])

        ilgen = method_builder.GetILGenerator()

        args_array = ilgen.DeclareLocal(Array[object])
        args_count = len(function.arg_types)
        ilgen.Emit(OpCodes.Ldc_I4, args_count)
        ilgen.Emit(OpCodes.Newarr, object)
        ilgen.Emit(OpCodes.Stloc, args_array)
        for i in range(args_count):
            arg_type = function.arg_types[i]
            if clr.GetClrType(arg_type).IsByRef:
                raise NotImplementedError("byref params not supported")
            ilgen.Emit(OpCodes.Ldloc, args_array)
            ilgen.Emit(OpCodes.Ldc_I4, i)
            ilgen.Emit(OpCodes.Ldarg, i + int(not function_info.is_static))
            ilgen.Emit(OpCodes.Box, arg_type)
            ilgen.Emit(OpCodes.Stelem_Ref)

        has_return_value = True
        if function_info.prop_name_if_prop_get:
            ilgen.Emit(OpCodes.Ldsfld, ClrClass.get_dynamic_operations_field())
            ilgen.Emit(OpCodes.Ldarg, 0)
            ilgen.Emit(OpCodes.Ldstr, function_info.prop_name_if_prop_get)
            ilgen.Emit(OpCodes.Callvirt, get_member)
        elif function_info.prop_name_if_prop_set:
            ilgen.Emit(OpCodes.Ldsfld, ClrClass.get_dynamic_operations_field())
            ilgen.Emit(OpCodes.Ldarg, 0)
            ilgen.Emit(OpCodes.Ldstr, function_info.prop_name_if_prop_set)
            ilgen.Emit(OpCodes.Ldarg, 1)
            ilgen.Emit(OpCodes.Callvirt, set_member)
            has_return_value = False
        else:
            ilgen.Emit(OpCodes.Ldsfld, ClrClass.get_dynamic_operations_field())
            if function_info.is_static:
                raise NotImplementedError("need to load Python class object from a CLR static field")
                # ilgen.Emit(OpCodes.Ldsfld, class_object)
            else:
                ilgen.Emit(OpCodes.Ldarg, 0)

            ilgen.Emit(OpCodes.Ldstr, function.__name__)
            ilgen.Emit(OpCodes.Ldloc, args_array)
            ilgen.Emit(OpCodes.Callvirt, invoke_member)

        if has_return_value:
            if function.return_type == Void:
                ilgen.Emit(OpCodes.Pop)
            else:
                ret_val = ilgen.DeclareLocal(object)
                ilgen.Emit(OpCodes.Stloc, ret_val)
                ilgen.Emit(OpCodes.Ldsfld, ClrClass.get_dynamic_operations_field())
                ilgen.Emit(OpCodes.Ldloc, ret_val)
                ilgen.Emit(OpCodes.Ldtoken, clr.GetClrType(function.return_type))
                ilgen.Emit(OpCodes.Call, get_type_from_handle)
                ilgen.Emit(OpCodes.Callvirt, convert_to)
                ilgen.Emit(OpCodes.Unbox_Any, function.return_type)
        ilgen.Emit(OpCodes.Ret)
        return method_builder

    def emit_method(self, typebld, function_info):
        function = function_info.function
        if hasattr(function, "DllImportAttributeDecorator"):
            dllImportAttributeDecorator = function.DllImportAttributeDecorator
            name = function.__name__
            dllName = dllImportAttributeDecorator.args[0]
            entryName = function.__name__
            attributes = MethodAttributes.Public | MethodAttributes.Static | MethodAttributes.PinvokeImpl
            callingConvention = CallingConventions.Standard
            returnType = function.return_type
            returnTypeRequiredCustomModifiers = ()
            returnTypeOptionalCustomModifiers = ()
            parameterTypes = function.arg_types
            parameterTypeRequiredCustomModifiers = None
            parameterTypeOptionalCustomModifiers = None
            nativeCallConv = CallingConvention.Winapi
            nativeCharSet = CharSet.Auto
            method_builder = typebld.DefinePInvokeMethod(
                name,
                dllName,
                entryName,
                attributes,
                callingConvention,
                returnType,
                returnTypeRequiredCustomModifiers,
                returnTypeOptionalCustomModifiers,
                parameterTypes,
                parameterTypeRequiredCustomModifiers,
                parameterTypeOptionalCustomModifiers,
                nativeCallConv,
                nativeCharSet)
        else:
            method_builder = self.emit_typed_stub_to_python_method(typebld, function_info)

        if hasattr(function, "CustomAttributeBuilders"):
            for cab in function.CustomAttributeBuilders:
                method_builder.SetCustomAttribute(cab)

        return method_builder

    def map_pinvoke_methods(self, new_type):
        pythonType = clr.GetPythonType(new_type)
        for function_info in self.get_typed_methods():
            function = function_info.function
            if hasattr(function, "DllImportAttributeDecorator"):
                # Overwrite the Python function with the pinvoke_method
                pinvoke_method = getattr(pythonType, function.__name__)
                setattr(self, function.__name__, pinvoke_method)

    def emit_python_type_field(self, typebld):
        return typebld.DefineField(
            "PythonType",
            PythonType,
            FieldAttributes.Public | FieldAttributes.Static)

    def set_python_type_field(self, new_type):
        self.PythonType = new_type.GetField("PythonType")
        self.PythonType.SetValue(None, self)

    def add_wrapper_ctors(self, baseType, typebld):
        python_type_field = self.emit_python_type_field(typebld)
        for ctor in baseType.GetConstructors():
            ctorparams = ctor.GetParameters()

            # leave out the PythonType argument
            assert(ctorparams[0].ParameterType == clr.GetClrType(PythonType))
            ctorparams = ctorparams[1:]

            ctorbld = typebld.DefineConstructor(
                        ctor.Attributes,
                        ctor.CallingConvention,
                        tuple([p.ParameterType for p in ctorparams]))
            ilgen = ctorbld.GetILGenerator()
            ilgen.Emit(OpCodes.Ldarg, 0)
            ilgen.Emit(OpCodes.Ldsfld, python_type_field)
            for index in range(len(ctorparams)):
                ilgen.Emit(OpCodes.Ldarg, index + 1)
            ilgen.Emit(OpCodes.Call, ctor)
            ilgen.Emit(OpCodes.Ret)

    def emit_members(self, typebld):
        self.emit_fields(typebld)
        self.add_wrapper_ctors(self.baseType, typebld)
        super(ClrClass, self).emit_members(typebld)

    def map_members(self, new_type):
        self.map_fields(new_type)
        self.map_pinvoke_methods(new_type)
        self.set_python_type_field(new_type)
        super(ClrClass, self).map_members(new_type)

    def __clrtype__(self):
        # CDerived below will use ClrClass as its metaclass, but the user may not expect CDerived
        # to be a typed .NET class in this case:
        #
        #   class CBase(object):
        #     __metaclass__ = ClrClass
        #   class CDerived(CBase): pass
        if not "__metaclass__" in self.__dict__:
            return super(ClrClass, self).__clrtype__()

        # Create a simple Python type first.
        self.baseType = super(ClrType, self).__clrtype__()
        # We will now subtype it to create a customized class with the
        # CLR attributes as defined by the user
        typegen = Snippets.Shared.DefineType(self.get_clr_type_name(), self.baseType, True, False)
        typebld = typegen.TypeBuilder
        return self.create_type(typebld)

def make_cab(attrib_type, *args, **kwds):
    clrtype = clr.GetClrType(attrib_type)
    argtypes = tuple(map(lambda x:clr.GetClrType(type(x)), args))
    ci = clrtype.GetConstructor(argtypes)

    props = ([],[])
    fields = ([],[])

    for kwd in kwds:
        pi = clrtype.GetProperty(kwd)
        if pi is not None:
            props[0].append(pi)
            props[1].append(kwds[kwd])
        else:
            fi = clrtype.GetField(kwd)
            if fi is not None:
                fields[0].append(fi)
                fields[1].append(kwds[kwd])
            else:
                raise TypeError("No %s Member found on %s" % (kwd, clrtype.Name))

    return CustomAttributeBuilder(ci, args,
        tuple(props[0]), tuple(props[1]),
        tuple(fields[0]), tuple(fields[1]))

def accepts(*args):
    """
    TODO - needs to be merged with clr.accepts
    """
    validate_clr_types(args, True)
    def decorator(function):
        function.arg_types = args
        return function
    return decorator

def returns(return_type = Void):
    """
    TODO - needs to be merged with clr.returns
    """
    if return_type != Void:
        validate_clr_types(return_type)
    def decorator(function):
        function.return_type = return_type
        return function
    return decorator

class CustomAttributeDecorator(object):
    """
    This represents information about a custom-attribute applied to a type or a method
    Note that we cannot use an instance of System.Attribute to capture this information
    as it is not possible to go from an instance of System.Attribute to an instance
    of System.Reflection.Emit.CustomAttributeBuilder as the latter needs to know
    how to represent information in metadata to later *recreate* a similar instance of
    System.Attribute.

    Also note that once a CustomAttributeBuilder is created, it is not possible to
    query it. Hence, we need to store the arguments required to store the
    CustomAttributeBuilder so that pseudo-custom-attributes can get to the information.
    """
    def __init__(self, attrib_type, *args, **kwargs):
        self.attrib_type = attrib_type
        self.args = args
        self.kwargs = kwargs

    def __call__(self, function):
        if self.attrib_type == DllImportAttribute:
            function.DllImportAttributeDecorator = self
        else:
            if not hasattr(function, "CustomAttributeBuilders"):
                function.CustomAttributeBuilders = []
            function.CustomAttributeBuilders.append(self.GetBuilder())
        return function

    def GetBuilder(self):
        assert not self.attrib_type in [DllImportAttribute]
        return make_cab(self.attrib_type, *self.args, **self.kwargs)

def attribute(attrib_type):
    """
    This decorator is used to specify a CustomAttribute for a type or method.
    """
    def make_decorator(*args, **kwargs):
        return CustomAttributeDecorator(attrib_type, *args, **kwargs)
    return make_decorator

def propagate_attributes(old_function, new_function):
    """
    Use this if you replace a function in a type with ClrInterface or ClrClass as the metaclass.
    This will typically be needed if you are defining a decorator which wraps functions with
    new functions, and want it to work in conjunction with clrtype
    """
    if hasattr(old_function, "return_type"):
        new_function.__name__ = old_function.__name__
        new_function.return_type = old_function.return_type
        new_function.arg_types = old_function.arg_types
    if hasattr(old_function, "CustomAttributeBuilders"):
        new_function.CustomAttributeBuilders = old_function.CustomAttributeBuilders
    if hasattr(old_function, "CustomAttributeBuilders"):
        new_function.DllImportAttributeDecorator = old_function.DllImportAttributeDecorator
lib\cmd.py
"""A generic class to build line-oriented command interpreters.

Interpreters constructed with this class obey the following conventions:

1. End of file on input is processed as the command 'EOF'.
2. A command is parsed out of each line by collecting the prefix composed
   of characters in the identchars member.
3. A command `foo' is dispatched to a method 'do_foo()'; the do_ method
   is passed a single argument consisting of the remainder of the line.
4. Typing an empty line repeats the last command.  (Actually, it calls the
   method `emptyline', which may be overridden in a subclass.)
5. There is a predefined `help' method.  Given an argument `topic', it
   calls the command `help_topic'.  With no arguments, it lists all topics
   with defined help_ functions, broken into up to three topics; documented
   commands, miscellaneous help topics, and undocumented commands.
6. The command '?' is a synonym for `help'.  The command '!' is a synonym
   for `shell', if a do_shell method exists.
7. If completion is enabled, completing commands will be done automatically,
   and completing of commands args is done by calling complete_foo() with
   arguments text, line, begidx, endidx.  text is string we are matching
   against, all returned matches must begin with it.  line is the current
   input line (lstripped), begidx and endidx are the beginning and end
   indexes of the text being matched, which could be used to provide
   different completion depending upon which position the argument is in.

The `default' method may be overridden to intercept commands for which there
is no do_ method.

The `completedefault' method may be overridden to intercept completions for
commands that have no complete_ method.

The data member `self.ruler' sets the character used to draw separator lines
in the help messages.  If empty, no ruler line is drawn.  It defaults to "=".

If the value of `self.intro' is nonempty when the cmdloop method is called,
it is printed out on interpreter startup.  This value may be overridden
via an optional argument to the cmdloop() method.

The data members `self.doc_header', `self.misc_header', and
`self.undoc_header' set the headers used for the help function's
listings of documented functions, miscellaneous topics, and undocumented
functions respectively.
"""

import string, sys

__all__ = ["Cmd"]

PROMPT = '(Cmd) '
IDENTCHARS = string.ascii_letters + string.digits + '_'

class Cmd:
    """A simple framework for writing line-oriented command interpreters.

    These are often useful for test harnesses, administrative tools, and
    prototypes that will later be wrapped in a more sophisticated interface.

    A Cmd instance or subclass instance is a line-oriented interpreter
    framework.  There is no good reason to instantiate Cmd itself; rather,
    it's useful as a superclass of an interpreter class you define yourself
    in order to inherit Cmd's methods and encapsulate action methods.

    """
    prompt = PROMPT
    identchars = IDENTCHARS
    ruler = '='
    lastcmd = ''
    intro = None
    doc_leader = ""
    doc_header = "Documented commands (type help <topic>):"
    misc_header = "Miscellaneous help topics:"
    undoc_header = "Undocumented commands:"
    nohelp = "*** No help on %s"
    use_rawinput = 1

    def __init__(self, completekey='tab', stdin=None, stdout=None):
        """Instantiate a line-oriented interpreter framework.

        The optional argument 'completekey' is the readline name of a
        completion key; it defaults to the Tab key. If completekey is
        not None and the readline module is available, command completion
        is done automatically. The optional arguments stdin and stdout
        specify alternate input and output file objects; if not specified,
        sys.stdin and sys.stdout are used.

        """
        if stdin is not None:
            self.stdin = stdin
        else:
            self.stdin = sys.stdin
        if stdout is not None:
            self.stdout = stdout
        else:
            self.stdout = sys.stdout
        self.cmdqueue = []
        self.completekey = completekey

    def cmdloop(self, intro=None):
        """Repeatedly issue a prompt, accept input, parse an initial prefix
        off the received input, and dispatch to action methods, passing them
        the remainder of the line as argument.

        """

        self.preloop()
        if self.use_rawinput and self.completekey:
            try:
                import readline
                self.old_completer = readline.get_completer()
                readline.set_completer(self.complete)
                readline.parse_and_bind(self.completekey+": complete")
            except ImportError:
                pass
        try:
            if intro is not None:
                self.intro = intro
            if self.intro:
                self.stdout.write(str(self.intro)+"\n")
            stop = None
            while not stop:
                if self.cmdqueue:
                    line = self.cmdqueue.pop(0)
                else:
                    if self.use_rawinput:
                        try:
                            line = input(self.prompt)
                        except EOFError:
                            line = 'EOF'
                    else:
                        self.stdout.write(self.prompt)
                        self.stdout.flush()
                        line = self.stdin.readline()
                        if not len(line):
                            line = 'EOF'
                        else:
                            line = line.rstrip('\r\n')
                line = self.precmd(line)
                stop = self.onecmd(line)
                stop = self.postcmd(stop, line)
            self.postloop()
        finally:
            if self.use_rawinput and self.completekey:
                try:
                    import readline
                    readline.set_completer(self.old_completer)
                except ImportError:
                    pass


    def precmd(self, line):
        """Hook method executed just before the command line is
        interpreted, but after the input prompt is generated and issued.

        """
        return line

    def postcmd(self, stop, line):
        """Hook method executed just after a command dispatch is finished."""
        return stop

    def preloop(self):
        """Hook method executed once when the cmdloop() method is called."""
        pass

    def postloop(self):
        """Hook method executed once when the cmdloop() method is about to
        return.

        """
        pass

    def parseline(self, line):
        """Parse the line into a command name and a string containing
        the arguments.  Returns a tuple containing (command, args, line).
        'command' and 'args' may be None if the line couldn't be parsed.
        """
        line = line.strip()
        if not line:
            return None, None, line
        elif line[0] == '?':
            line = 'help ' + line[1:]
        elif line[0] == '!':
            if hasattr(self, 'do_shell'):
                line = 'shell ' + line[1:]
            else:
                return None, None, line
        i, n = 0, len(line)
        while i < n and line[i] in self.identchars: i = i+1
        cmd, arg = line[:i], line[i:].strip()
        return cmd, arg, line

    def onecmd(self, line):
        """Interpret the argument as though it had been typed in response
        to the prompt.

        This may be overridden, but should not normally need to be;
        see the precmd() and postcmd() methods for useful execution hooks.
        The return value is a flag indicating whether interpretation of
        commands by the interpreter should stop.

        """
        cmd, arg, line = self.parseline(line)
        if not line:
            return self.emptyline()
        if cmd is None:
            return self.default(line)
        self.lastcmd = line
        if line == 'EOF' :
            self.lastcmd = ''
        if cmd == '':
            return self.default(line)
        else:
            try:
                func = getattr(self, 'do_' + cmd)
            except AttributeError:
                return self.default(line)
            return func(arg)

    def emptyline(self):
        """Called when an empty line is entered in response to the prompt.

        If this method is not overridden, it repeats the last nonempty
        command entered.

        """
        if self.lastcmd:
            return self.onecmd(self.lastcmd)

    def default(self, line):
        """Called on an input line when the command prefix is not recognized.

        If this method is not overridden, it prints an error message and
        returns.

        """
        self.stdout.write('*** Unknown syntax: %s\n'%line)

    def completedefault(self, *ignored):
        """Method called to complete an input line when no command-specific
        complete_*() method is available.

        By default, it returns an empty list.

        """
        return []

    def completenames(self, text, *ignored):
        dotext = 'do_'+text
        return [a[3:] for a in self.get_names() if a.startswith(dotext)]

    def complete(self, text, state):
        """Return the next possible completion for 'text'.

        If a command has not been entered, then complete against command list.
        Otherwise try to call complete_<command> to get list of completions.
        """
        if state == 0:
            import readline
            origline = readline.get_line_buffer()
            line = origline.lstrip()
            stripped = len(origline) - len(line)
            begidx = readline.get_begidx() - stripped
            endidx = readline.get_endidx() - stripped
            if begidx>0:
                cmd, args, foo = self.parseline(line)
                if cmd == '':
                    compfunc = self.completedefault
                else:
                    try:
                        compfunc = getattr(self, 'complete_' + cmd)
                    except AttributeError:
                        compfunc = self.completedefault
            else:
                compfunc = self.completenames
            self.completion_matches = compfunc(text, line, begidx, endidx)
        try:
            return self.completion_matches[state]
        except IndexError:
            return None

    def get_names(self):
        # This method used to pull in base class attributes
        # at a time dir() didn't do it yet.
        return dir(self.__class__)

    def complete_help(self, *args):
        commands = set(self.completenames(*args))
        topics = set(a[5:] for a in self.get_names()
                     if a.startswith('help_' + args[0]))
        return list(commands | topics)

    def do_help(self, arg):
        'List available commands with "help" or detailed help with "help cmd".'
        if arg:
            # XXX check arg syntax
            try:
                func = getattr(self, 'help_' + arg)
            except AttributeError:
                try:
                    doc=getattr(self, 'do_' + arg).__doc__
                    if doc:
                        self.stdout.write("%s\n"%str(doc))
                        return
                except AttributeError:
                    pass
                self.stdout.write("%s\n"%str(self.nohelp % (arg,)))
                return
            func()
        else:
            names = self.get_names()
            cmds_doc = []
            cmds_undoc = []
            help = {}
            for name in names:
                if name[:5] == 'help_':
                    help[name[5:]]=1
            names.sort()
            # There can be duplicates if routines overridden
            prevname = ''
            for name in names:
                if name[:3] == 'do_':
                    if name == prevname:
                        continue
                    prevname = name
                    cmd=name[3:]
                    if cmd in help:
                        cmds_doc.append(cmd)
                        del help[cmd]
                    elif getattr(self, name).__doc__:
                        cmds_doc.append(cmd)
                    else:
                        cmds_undoc.append(cmd)
            self.stdout.write("%s\n"%str(self.doc_leader))
            self.print_topics(self.doc_header,   cmds_doc,   15,80)
            self.print_topics(self.misc_header,  list(help.keys()),15,80)
            self.print_topics(self.undoc_header, cmds_undoc, 15,80)

    def print_topics(self, header, cmds, cmdlen, maxcol):
        if cmds:
            self.stdout.write("%s\n"%str(header))
            if self.ruler:
                self.stdout.write("%s\n"%str(self.ruler * len(header)))
            self.columnize(cmds, maxcol-1)
            self.stdout.write("\n")

    def columnize(self, list, displaywidth=80):
        """Display a list of strings as a compact set of columns.

        Each column is only as wide as necessary.
        Columns are separated by two spaces (one was not legible enough).
        """
        if not list:
            self.stdout.write("<empty>\n")
            return

        nonstrings = [i for i in range(len(list))
                        if not isinstance(list[i], str)]
        if nonstrings:
            raise TypeError("list[i] not a string for i in %s"
                            % ", ".join(map(str, nonstrings)))
        size = len(list)
        if size == 1:
            self.stdout.write('%s\n'%str(list[0]))
            return
        # Try every row count from 1 upwards
        for nrows in range(1, len(list)):
            ncols = (size+nrows-1) // nrows
            colwidths = []
            totwidth = -2
            for col in range(ncols):
                colwidth = 0
                for row in range(nrows):
                    i = row + nrows*col
                    if i >= size:
                        break
                    x = list[i]
                    colwidth = max(colwidth, len(x))
                colwidths.append(colwidth)
                totwidth += colwidth + 2
                if totwidth > displaywidth:
                    break
            if totwidth <= displaywidth:
                break
        else:
            nrows = len(list)
            ncols = 1
            colwidths = [0]
        for row in range(nrows):
            texts = []
            for col in range(ncols):
                i = row + nrows*col
                if i >= size:
                    x = ""
                else:
                    x = list[i]
                texts.append(x)
            while texts and not texts[-1]:
                del texts[-1]
            for col in range(len(texts)):
                texts[col] = texts[col].ljust(colwidths[col])
            self.stdout.write("%s\n"%str("  ".join(texts)))
lib\code.py
"""Utilities needed to emulate Python's interactive interpreter.

"""

# Inspired by similar code by Jeff Epler and Fredrik Lundh.


import sys
import traceback
from codeop import CommandCompiler, compile_command

__all__ = ["InteractiveInterpreter", "InteractiveConsole", "interact",
           "compile_command"]

class InteractiveInterpreter:
    """Base class for InteractiveConsole.

    This class deals with parsing and interpreter state (the user's
    namespace); it doesn't deal with input buffering or prompting or
    input file naming (the filename is always passed in explicitly).

    """

    def __init__(self, locals=None):
        """Constructor.

        The optional 'locals' argument specifies the dictionary in
        which code will be executed; it defaults to a newly created
        dictionary with key "__name__" set to "__console__" and key
        "__doc__" set to None.

        """
        if locals is None:
            locals = {"__name__": "__console__", "__doc__": None}
        self.locals = locals
        self.compile = CommandCompiler()

    def runsource(self, source, filename="<input>", symbol="single"):
        """Compile and run some source in the interpreter.

        Arguments are as for compile_command().

        One several things can happen:

        1) The input is incorrect; compile_command() raised an
        exception (SyntaxError or OverflowError).  A syntax traceback
        will be printed by calling the showsyntaxerror() method.

        2) The input is incomplete, and more input is required;
        compile_command() returned None.  Nothing happens.

        3) The input is complete; compile_command() returned a code
        object.  The code is executed by calling self.runcode() (which
        also handles run-time exceptions, except for SystemExit).

        The return value is True in case 2, False in the other cases (unless
        an exception is raised).  The return value can be used to
        decide whether to use sys.ps1 or sys.ps2 to prompt the next
        line.

        """
        try:
            code = self.compile(source, filename, symbol)
        except (OverflowError, SyntaxError, ValueError):
            # Case 1
            self.showsyntaxerror(filename)
            return False

        if code is None:
            # Case 2
            return True

        # Case 3
        self.runcode(code)
        return False

    def runcode(self, code):
        """Execute a code object.

        When an exception occurs, self.showtraceback() is called to
        display a traceback.  All exceptions are caught except
        SystemExit, which is reraised.

        A note about KeyboardInterrupt: this exception may occur
        elsewhere in this code, and may not always be caught.  The
        caller should be prepared to deal with it.

        """
        try:
            exec(code, self.locals)
        except SystemExit:
            raise
        except:
            self.showtraceback()

    def showsyntaxerror(self, filename=None):
        """Display the syntax error that just occurred.

        This doesn't display a stack trace because there isn't one.

        If a filename is given, it is stuffed in the exception instead
        of what was there before (because Python's parser always uses
        "<string>" when reading from a string).

        The output is written by self.write(), below.

        """
        type, value, tb = sys.exc_info()
        sys.last_type = type
        sys.last_value = value
        sys.last_traceback = tb
        if filename and type is SyntaxError:
            # Work hard to stuff the correct filename in the exception
            try:
                msg, (dummy_filename, lineno, offset, line) = value.args
            except ValueError:
                # Not the format we expect; leave it alone
                pass
            else:
                # Stuff in the right filename
                value = SyntaxError(msg, (filename, lineno, offset, line))
                sys.last_value = value
        if sys.excepthook is sys.__excepthook__:
            lines = traceback.format_exception_only(type, value)
            self.write(''.join(lines))
        else:
            # If someone has set sys.excepthook, we let that take precedence
            # over self.write
            sys.excepthook(type, value, tb)

    def showtraceback(self):
        """Display the exception that just occurred.

        We remove the first stack item because it is our own code.

        The output is written by self.write(), below.

        """
        try:
            type, value, tb = sys.exc_info()
            sys.last_type = type
            sys.last_value = value
            sys.last_traceback = tb
            tblist = traceback.extract_tb(tb)
            del tblist[:1]
            lines = traceback.format_list(tblist)
            if lines:
                lines.insert(0, "Traceback (most recent call last):\n")
            lines.extend(traceback.format_exception_only(type, value))
        finally:
            tblist = tb = None
        if sys.excepthook is sys.__excepthook__:
            self.write(''.join(lines))
        else:
            # If someone has set sys.excepthook, we let that take precedence
            # over self.write
            sys.excepthook(type, value, tb)

    def write(self, data):
        """Write a string.

        The base implementation writes to sys.stderr; a subclass may
        replace this with a different implementation.

        """
        sys.stderr.write(data)


class InteractiveConsole(InteractiveInterpreter):
    """Closely emulate the behavior of the interactive Python interpreter.

    This class builds on InteractiveInterpreter and adds prompting
    using the familiar sys.ps1 and sys.ps2, and input buffering.

    """

    def __init__(self, locals=None, filename="<console>"):
        """Constructor.

        The optional locals argument will be passed to the
        InteractiveInterpreter base class.

        The optional filename argument should specify the (file)name
        of the input stream; it will show up in tracebacks.

        """
        InteractiveInterpreter.__init__(self, locals)
        self.filename = filename
        self.resetbuffer()

    def resetbuffer(self):
        """Reset the input buffer."""
        self.buffer = []

    def interact(self, banner=None):
        """Closely emulate the interactive Python console.

        The optional banner argument specifies the banner to print
        before the first interaction; by default it prints a banner
        similar to the one printed by the real Python interpreter,
        followed by the current class name in parentheses (so as not
        to confuse this with the real interpreter -- since it's so
        close!).

        """
        try:
            sys.ps1
        except AttributeError:
            sys.ps1 = ">>> "
        try:
            sys.ps2
        except AttributeError:
            sys.ps2 = "... "
        cprt = 'Type "help", "copyright", "credits" or "license" for more information.'
        if banner is None:
            self.write("Python %s on %s\n%s\n(%s)\n" %
                       (sys.version, sys.platform, cprt,
                        self.__class__.__name__))
        elif banner:
            self.write("%s\n" % str(banner))
        more = 0
        while 1:
            try:
                if more:
                    prompt = sys.ps2
                else:
                    prompt = sys.ps1
                try:
                    line = self.raw_input(prompt)
                except EOFError:
                    self.write("\n")
                    break
                else:
                    more = self.push(line)
            except KeyboardInterrupt:
                self.write("\nKeyboardInterrupt\n")
                self.resetbuffer()
                more = 0

    def push(self, line):
        """Push a line to the interpreter.

        The line should not have a trailing newline; it may have
        internal newlines.  The line is appended to a buffer and the
        interpreter's runsource() method is called with the
        concatenated contents of the buffer as source.  If this
        indicates that the command was executed or invalid, the buffer
        is reset; otherwise, the command is incomplete, and the buffer
        is left as it was after the line was appended.  The return
        value is 1 if more input is required, 0 if the line was dealt
        with in some way (this is the same as runsource()).

        """
        self.buffer.append(line)
        source = "\n".join(self.buffer)
        more = self.runsource(source, self.filename)
        if not more:
            self.resetbuffer()
        return more

    def raw_input(self, prompt=""):
        """Write a prompt and read a line.

        The returned line does not include the trailing newline.
        When the user enters the EOF key sequence, EOFError is raised.

        The base implementation uses the built-in function
        input(); a subclass may replace this with a different
        implementation.

        """
        return input(prompt)



def interact(banner=None, readfunc=None, local=None):
    """Closely emulate the interactive Python interpreter.

    This is a backwards compatible interface to the InteractiveConsole
    class.  When readfunc is not specified, it attempts to import the
    readline module to enable GNU readline if it is available.

    Arguments (all optional, all default to None):

    banner -- passed to InteractiveConsole.interact()
    readfunc -- if not None, replaces InteractiveConsole.raw_input()
    local -- passed to InteractiveInterpreter.__init__()

    """
    console = InteractiveConsole(local)
    if readfunc is not None:
        console.raw_input = readfunc
    else:
        try:
            import readline
        except ImportError:
            pass
    console.interact(banner)


if __name__ == "__main__":
    interact()
lib\codecs.py
""" codecs -- Python Codec Registry, API and helpers.


Written by Marc-Andre Lemburg ([email protected]).

(c) Copyright CNRI, All Rights Reserved. NO WARRANTY.

"""#"

import builtins, sys

### Registry and builtin stateless codec functions

try:
    from _codecs import *
except ImportError as why:
    raise SystemError('Failed to load the builtin codecs: %s' % why)

__all__ = ["register", "lookup", "open", "EncodedFile", "BOM", "BOM_BE",
           "BOM_LE", "BOM32_BE", "BOM32_LE", "BOM64_BE", "BOM64_LE",
           "BOM_UTF8", "BOM_UTF16", "BOM_UTF16_LE", "BOM_UTF16_BE",
           "BOM_UTF32", "BOM_UTF32_LE", "BOM_UTF32_BE",
           "CodecInfo", "Codec", "IncrementalEncoder", "IncrementalDecoder",
           "StreamReader", "StreamWriter",
           "StreamReaderWriter", "StreamRecoder",
           "getencoder", "getdecoder", "getincrementalencoder",
           "getincrementaldecoder", "getreader", "getwriter",
           "encode", "decode", "iterencode", "iterdecode",
           "strict_errors", "ignore_errors", "replace_errors",
           "xmlcharrefreplace_errors", "backslashreplace_errors",
           "register_error", "lookup_error"]

### Constants

#
# Byte Order Mark (BOM = ZERO WIDTH NO-BREAK SPACE = U+FEFF)
# and its possible byte string values
# for UTF8/UTF16/UTF32 output and little/big endian machines
#

# UTF-8
BOM_UTF8 = b'\xef\xbb\xbf'

# UTF-16, little endian
BOM_LE = BOM_UTF16_LE = b'\xff\xfe'

# UTF-16, big endian
BOM_BE = BOM_UTF16_BE = b'\xfe\xff'

# UTF-32, little endian
BOM_UTF32_LE = b'\xff\xfe\x00\x00'

# UTF-32, big endian
BOM_UTF32_BE = b'\x00\x00\xfe\xff'

if sys.byteorder == 'little':

    # UTF-16, native endianness
    BOM = BOM_UTF16 = BOM_UTF16_LE

    # UTF-32, native endianness
    BOM_UTF32 = BOM_UTF32_LE

else:

    # UTF-16, native endianness
    BOM = BOM_UTF16 = BOM_UTF16_BE

    # UTF-32, native endianness
    BOM_UTF32 = BOM_UTF32_BE

# Old broken names (don't use in new code)
BOM32_LE = BOM_UTF16_LE
BOM32_BE = BOM_UTF16_BE
BOM64_LE = BOM_UTF32_LE
BOM64_BE = BOM_UTF32_BE


### Codec base classes (defining the API)

class CodecInfo(tuple):
    """Codec details when looking up the codec registry"""

    # Private API to allow Python 3.4 to blacklist the known non-Unicode
    # codecs in the standard library. A more general mechanism to
    # reliably distinguish test encodings from other codecs will hopefully
    # be defined for Python 3.5
    #
    # See http://bugs.python.org/issue19619
    _is_text_encoding = True # Assume codecs are text encodings by default

    def __new__(cls, encode, decode, streamreader=None, streamwriter=None,
        incrementalencoder=None, incrementaldecoder=None, name=None,
        *, _is_text_encoding=None):
        self = tuple.__new__(cls, (encode, decode, streamreader, streamwriter))
        self.name = name
        self.encode = encode
        self.decode = decode
        self.incrementalencoder = incrementalencoder
        self.incrementaldecoder = incrementaldecoder
        self.streamwriter = streamwriter
        self.streamreader = streamreader
        if _is_text_encoding is not None:
            self._is_text_encoding = _is_text_encoding
        return self

    def __repr__(self):
        return "<%s.%s object for encoding %s at 0x%x>" % \
                (self.__class__.__module__, self.__class__.__name__,
                 self.name, id(self))

class Codec:

    """ Defines the interface for stateless encoders/decoders.

        The .encode()/.decode() methods may use different error
        handling schemes by providing the errors argument. These
        string values are predefined:

         'strict' - raise a ValueError error (or a subclass)
         'ignore' - ignore the character and continue with the next
         'replace' - replace with a suitable replacement character;
                    Python will use the official U+FFFD REPLACEMENT
                    CHARACTER for the builtin Unicode codecs on
                    decoding and '?' on encoding.
         'surrogateescape' - replace with private code points U+DCnn.
         'xmlcharrefreplace' - Replace with the appropriate XML
                               character reference (only for encoding).
         'backslashreplace'  - Replace with backslashed escape sequences
                               (only for encoding).

        The set of allowed values can be extended via register_error.

    """
    def encode(self, input, errors='strict'):

        """ Encodes the object input and returns a tuple (output
            object, length consumed).

            errors defines the error handling to apply. It defaults to
            'strict' handling.

            The method may not store state in the Codec instance. Use
            StreamWriter for codecs which have to keep state in order to
            make encoding efficient.

            The encoder must be able to handle zero length input and
            return an empty object of the output object type in this
            situation.

        """
        raise NotImplementedError

    def decode(self, input, errors='strict'):

        """ Decodes the object input and returns a tuple (output
            object, length consumed).

            input must be an object which provides the bf_getreadbuf
            buffer slot. Python strings, buffer objects and memory
            mapped files are examples of objects providing this slot.

            errors defines the error handling to apply. It defaults to
            'strict' handling.

            The method may not store state in the Codec instance. Use
            StreamReader for codecs which have to keep state in order to
            make decoding efficient.

            The decoder must be able to handle zero length input and
            return an empty object of the output object type in this
            situation.

        """
        raise NotImplementedError

class IncrementalEncoder(object):
    """
    An IncrementalEncoder encodes an input in multiple steps. The input can
    be passed piece by piece to the encode() method. The IncrementalEncoder
    remembers the state of the encoding process between calls to encode().
    """
    def __init__(self, errors='strict'):
        """
        Creates an IncrementalEncoder instance.

        The IncrementalEncoder may use different error handling schemes by
        providing the errors keyword argument. See the module docstring
        for a list of possible values.
        """
        self.errors = errors
        self.buffer = ""

    def encode(self, input, final=False):
        """
        Encodes input and returns the resulting object.
        """
        raise NotImplementedError

    def reset(self):
        """
        Resets the encoder to the initial state.
        """

    def getstate(self):
        """
        Return the current state of the encoder.
        """
        return 0

    def setstate(self, state):
        """
        Set the current state of the encoder. state must have been
        returned by getstate().
        """

class BufferedIncrementalEncoder(IncrementalEncoder):
    """
    This subclass of IncrementalEncoder can be used as the baseclass for an
    incremental encoder if the encoder must keep some of the output in a
    buffer between calls to encode().
    """
    def __init__(self, errors='strict'):
        IncrementalEncoder.__init__(self, errors)
        # unencoded input that is kept between calls to encode()
        self.buffer = ""

    def _buffer_encode(self, input, errors, final):
        # Overwrite this method in subclasses: It must encode input
        # and return an (output, length consumed) tuple
        raise NotImplementedError

    def encode(self, input, final=False):
        # encode input (taking the buffer into account)
        data = self.buffer + input
        (result, consumed) = self._buffer_encode(data, self.errors, final)
        # keep unencoded input until the next call
        self.buffer = data[consumed:]
        return result

    def reset(self):
        IncrementalEncoder.reset(self)
        self.buffer = ""

    def getstate(self):
        return self.buffer or 0

    def setstate(self, state):
        self.buffer = state or ""

class IncrementalDecoder(object):
    """
    An IncrementalDecoder decodes an input in multiple steps. The input can
    be passed piece by piece to the decode() method. The IncrementalDecoder
    remembers the state of the decoding process between calls to decode().
    """
    def __init__(self, errors='strict'):
        """
        Create an IncrementalDecoder instance.

        The IncrementalDecoder may use different error handling schemes by
        providing the errors keyword argument. See the module docstring
        for a list of possible values.
        """
        self.errors = errors

    def decode(self, input, final=False):
        """
        Decode input and returns the resulting object.
        """
        raise NotImplementedError

    def reset(self):
        """
        Reset the decoder to the initial state.
        """

    def getstate(self):
        """
        Return the current state of the decoder.

        This must be a (buffered_input, additional_state_info) tuple.
        buffered_input must be a bytes object containing bytes that
        were passed to decode() that have not yet been converted.
        additional_state_info must be a non-negative integer
        representing the state of the decoder WITHOUT yet having
        processed the contents of buffered_input.  In the initial state
        and after reset(), getstate() must return (b"", 0).
        """
        return (b"", 0)

    def setstate(self, state):
        """
        Set the current state of the decoder.

        state must have been returned by getstate().  The effect of
        setstate((b"", 0)) must be equivalent to reset().
        """

class BufferedIncrementalDecoder(IncrementalDecoder):
    """
    This subclass of IncrementalDecoder can be used as the baseclass for an
    incremental decoder if the decoder must be able to handle incomplete
    byte sequences.
    """
    def __init__(self, errors='strict'):
        IncrementalDecoder.__init__(self, errors)
        # undecoded input that is kept between calls to decode()
        self.buffer = b""

    def _buffer_decode(self, input, errors, final):
        # Overwrite this method in subclasses: It must decode input
        # and return an (output, length consumed) tuple
        raise NotImplementedError

    def decode(self, input, final=False):
        # decode input (taking the buffer into account)
        data = self.buffer + input
        (result, consumed) = self._buffer_decode(data, self.errors, final)
        # keep undecoded input until the next call
        self.buffer = data[consumed:]
        return result

    def reset(self):
        IncrementalDecoder.reset(self)
        self.buffer = b""

    def getstate(self):
        # additional state info is always 0
        return (self.buffer, 0)

    def setstate(self, state):
        # ignore additional state info
        self.buffer = state[0]

#
# The StreamWriter and StreamReader class provide generic working
# interfaces which can be used to implement new encoding submodules
# very easily. See encodings/utf_8.py for an example on how this is
# done.
#

class StreamWriter(Codec):

    def __init__(self, stream, errors='strict'):

        """ Creates a StreamWriter instance.

            stream must be a file-like object open for writing.

            The StreamWriter may use different error handling
            schemes by providing the errors keyword argument. These
            parameters are predefined:

             'strict' - raise a ValueError (or a subclass)
             'ignore' - ignore the character and continue with the next
             'replace'- replace with a suitable replacement character
             'xmlcharrefreplace' - Replace with the appropriate XML
                                   character reference.
             'backslashreplace'  - Replace with backslashed escape
                                   sequences (only for encoding).

            The set of allowed parameter values can be extended via
            register_error.
        """
        self.stream = stream
        self.errors = errors

    def write(self, object):

        """ Writes the object's contents encoded to self.stream.
        """
        data, consumed = self.encode(object, self.errors)
        self.stream.write(data)

    def writelines(self, list):

        """ Writes the concatenated list of strings to the stream
            using .write().
        """
        self.write(''.join(list))

    def reset(self):

        """ Flushes and resets the codec buffers used for keeping state.

            Calling this method should ensure that the data on the
            output is put into a clean state, that allows appending
            of new fresh data without having to rescan the whole
            stream to recover state.

        """
        pass

    def seek(self, offset, whence=0):
        self.stream.seek(offset, whence)
        if whence == 0 and offset == 0:
            self.reset()

    def __getattr__(self, name,
                    getattr=getattr):

        """ Inherit all other methods from the underlying stream.
        """
        return getattr(self.stream, name)

    def __enter__(self):
        return self

    def __exit__(self, type, value, tb):
        self.stream.close()

###

class StreamReader(Codec):

    charbuffertype = str

    def __init__(self, stream, errors='strict'):

        """ Creates a StreamReader instance.

            stream must be a file-like object open for reading.

            The StreamReader may use different error handling
            schemes by providing the errors keyword argument. These
            parameters are predefined:

             'strict' - raise a ValueError (or a subclass)
             'ignore' - ignore the character and continue with the next
             'replace'- replace with a suitable replacement character;

            The set of allowed parameter values can be extended via
            register_error.
        """
        self.stream = stream
        self.errors = errors
        self.bytebuffer = b""
        self._empty_charbuffer = self.charbuffertype()
        self.charbuffer = self._empty_charbuffer
        self.linebuffer = None

    def decode(self, input, errors='strict'):
        raise NotImplementedError

    def read(self, size=-1, chars=-1, firstline=False):

        """ Decodes data from the stream self.stream and returns the
            resulting object.

            chars indicates the number of decoded code points or bytes to
            return. read() will never return more data than requested,
            but it might return less, if there is not enough available.

            size indicates the approximate maximum number of decoded
            bytes or code points to read for decoding. The decoder
            can modify this setting as appropriate. The default value
            -1 indicates to read and decode as much as possible.  size
            is intended to prevent having to decode huge files in one
            step.

            If firstline is true, and a UnicodeDecodeError happens
            after the first line terminator in the input only the first line
            will be returned, the rest of the input will be kept until the
            next call to read().

            The method should use a greedy read strategy, meaning that
            it should read as much data as is allowed within the
            definition of the encoding and the given size, e.g.  if
            optional encoding endings or state markers are available
            on the stream, these should be read too.
        """
        # If we have lines cached, first merge them back into characters
        if self.linebuffer:
            self.charbuffer = self._empty_charbuffer.join(self.linebuffer)
            self.linebuffer = None

        # read until we get the required number of characters (if available)
        while True:
            # can the request be satisfied from the character buffer?
            if chars >= 0:
                if len(self.charbuffer) >= chars:
                    break
            elif size >= 0:
                if len(self.charbuffer) >= size:
                    break
            # we need more data
            if size < 0:
                newdata = self.stream.read()
            else:
                newdata = self.stream.read(size)
            # decode bytes (those remaining from the last call included)
            data = self.bytebuffer + newdata
            if not data:
                break
            try:
                newchars, decodedbytes = self.decode(data, self.errors)
            except UnicodeDecodeError as exc:
                if firstline:
                    newchars, decodedbytes = \
                        self.decode(data[:exc.start], self.errors)
                    lines = newchars.splitlines(keepends=True)
                    if len(lines)<=1:
                        raise
                else:
                    raise
            # keep undecoded bytes until the next call
            self.bytebuffer = data[decodedbytes:]
            # put new characters in the character buffer
            self.charbuffer += newchars
            # there was no data available
            if not newdata:
                break
        if chars < 0:
            # Return everything we've got
            result = self.charbuffer
            self.charbuffer = self._empty_charbuffer
        else:
            # Return the first chars characters
            result = self.charbuffer[:chars]
            self.charbuffer = self.charbuffer[chars:]
        return result

    def readline(self, size=None, keepends=True):

        """ Read one line from the input stream and return the
            decoded data.

            size, if given, is passed as size argument to the
            read() method.

        """
        # If we have lines cached from an earlier read, return
        # them unconditionally
        if self.linebuffer:
            line = self.linebuffer[0]
            del self.linebuffer[0]
            if len(self.linebuffer) == 1:
                # revert to charbuffer mode; we might need more data
                # next time
                self.charbuffer = self.linebuffer[0]
                self.linebuffer = None
            if not keepends:
                line = line.splitlines(keepends=False)[0]
            return line

        readsize = size or 72
        line = self._empty_charbuffer
        # If size is given, we call read() only once
        while True:
            data = self.read(readsize, firstline=True)
            if data:
                # If we're at a "\r" read one extra character (which might
                # be a "\n") to get a proper line ending. If the stream is
                # temporarily exhausted we return the wrong line ending.
                if (isinstance(data, str) and data.endswith("\r")) or \
                   (isinstance(data, bytes) and data.endswith(b"\r")):
                    data += self.read(size=1, chars=1)

            line += data
            lines = line.splitlines(keepends=True)
            if lines:
                if len(lines) > 1:
                    # More than one line result; the first line is a full line
                    # to return
                    line = lines[0]
                    del lines[0]
                    if len(lines) > 1:
                        # cache the remaining lines
                        lines[-1] += self.charbuffer
                        self.linebuffer = lines
                        self.charbuffer = None
                    else:
                        # only one remaining line, put it back into charbuffer
                        self.charbuffer = lines[0] + self.charbuffer
                    if not keepends:
                        line = line.splitlines(keepends=False)[0]
                    break
                line0withend = lines[0]
                line0withoutend = lines[0].splitlines(keepends=False)[0]
                if line0withend != line0withoutend: # We really have a line end
                    # Put the rest back together and keep it until the next call
                    self.charbuffer = self._empty_charbuffer.join(lines[1:]) + \
                                      self.charbuffer
                    if keepends:
                        line = line0withend
                    else:
                        line = line0withoutend
                    break
            # we didn't get anything or this was our only try
            if not data or size is not None:
                if line and not keepends:
                    line = line.splitlines(keepends=False)[0]
                break
            if readsize < 8000:
                readsize *= 2
        return line

    def readlines(self, sizehint=None, keepends=True):

        """ Read all lines available on the input stream
            and return them as a list.

            Line breaks are implemented using the codec's decoder
            method and are included in the list entries.

            sizehint, if given, is ignored since there is no efficient
            way to finding the true end-of-line.

        """
        data = self.read()
        return data.splitlines(keepends)

    def reset(self):

        """ Resets the codec buffers used for keeping state.

            Note that no stream repositioning should take place.
            This method is primarily intended to be able to recover
            from decoding errors.

        """
        self.bytebuffer = b""
        self.charbuffer = self._empty_charbuffer
        self.linebuffer = None

    def seek(self, offset, whence=0):
        """ Set the input stream's current position.

            Resets the codec buffers used for keeping state.
        """
        self.stream.seek(offset, whence)
        self.reset()

    def __next__(self):

        """ Return the next decoded line from the input stream."""
        line = self.readline()
        if line:
            return line
        raise StopIteration

    def __iter__(self):
        return self

    def __getattr__(self, name,
                    getattr=getattr):

        """ Inherit all other methods from the underlying stream.
        """
        return getattr(self.stream, name)

    def __enter__(self):
        return self

    def __exit__(self, type, value, tb):
        self.stream.close()

###

class StreamReaderWriter:

    """ StreamReaderWriter instances allow wrapping streams which
        work in both read and write modes.

        The design is such that one can use the factory functions
        returned by the codec.lookup() function to construct the
        instance.

    """
    # Optional attributes set by the file wrappers below
    encoding = 'unknown'

    def __init__(self, stream, Reader, Writer, errors='strict'):

        """ Creates a StreamReaderWriter instance.

            stream must be a Stream-like object.

            Reader, Writer must be factory functions or classes
            providing the StreamReader, StreamWriter interface resp.

            Error handling is done in the same way as defined for the
            StreamWriter/Readers.

        """
        self.stream = stream
        self.reader = Reader(stream, errors)
        self.writer = Writer(stream, errors)
        self.errors = errors

    def read(self, size=-1):

        return self.reader.read(size)

    def readline(self, size=None):

        return self.reader.readline(size)

    def readlines(self, sizehint=None):

        return self.reader.readlines(sizehint)

    def __next__(self):

        """ Return the next decoded line from the input stream."""
        return next(self.reader)

    def __iter__(self):
        return self

    def write(self, data):

        return self.writer.write(data)

    def writelines(self, list):

        return self.writer.writelines(list)

    def reset(self):

        self.reader.reset()
        self.writer.reset()

    def seek(self, offset, whence=0):
        self.stream.seek(offset, whence)
        self.reader.reset()
        if whence == 0 and offset == 0:
            self.writer.reset()

    def __getattr__(self, name,
                    getattr=getattr):

        """ Inherit all other methods from the underlying stream.
        """
        return getattr(self.stream, name)

    # these are needed to make "with codecs.open(...)" work properly

    def __enter__(self):
        return self

    def __exit__(self, type, value, tb):
        self.stream.close()

###

class StreamRecoder:

    """ StreamRecoder instances translate data from one encoding to another.

        They use the complete set of APIs returned by the
        codecs.lookup() function to implement their task.

        Data written to the StreamRecoder is first decoded into an
        intermediate format (depending on the "decode" codec) and then
        written to the underlying stream using an instance of the provided
        Writer class.

        In the other direction, data is read from the underlying stream using
        a Reader instance and then encoded and returned to the caller.

    """
    # Optional attributes set by the file wrappers below
    data_encoding = 'unknown'
    file_encoding = 'unknown'

    def __init__(self, stream, encode, decode, Reader, Writer,
                 errors='strict'):

        """ Creates a StreamRecoder instance which implements a two-way
            conversion: encode and decode work on the frontend (the
            data visible to .read() and .write()) while Reader and Writer
            work on the backend (the data in stream).

            You can use these objects to do transparent
            transcodings from e.g. latin-1 to utf-8 and back.

            stream must be a file-like object.

            encode and decode must adhere to the Codec interface; Reader and
            Writer must be factory functions or classes providing the
            StreamReader and StreamWriter interfaces resp.

            Error handling is done in the same way as defined for the
            StreamWriter/Readers.

        """
        self.stream = stream
        self.encode = encode
        self.decode = decode
        self.reader = Reader(stream, errors)
        self.writer = Writer(stream, errors)
        self.errors = errors

    def read(self, size=-1):

        data = self.reader.read(size)
        data, bytesencoded = self.encode(data, self.errors)
        return data

    def readline(self, size=None):

        if size is None:
            data = self.reader.readline()
        else:
            data = self.reader.readline(size)
        data, bytesencoded = self.encode(data, self.errors)
        return data

    def readlines(self, sizehint=None):

        data = self.reader.read()
        data, bytesencoded = self.encode(data, self.errors)
        return data.splitlines(keepends=True)

    def __next__(self):

        """ Return the next decoded line from the input stream."""
        data = next(self.reader)
        data, bytesencoded = self.encode(data, self.errors)
        return data

    def __iter__(self):
        return self

    def write(self, data):

        data, bytesdecoded = self.decode(data, self.errors)
        return self.writer.write(data)

    def writelines(self, list):

        data = ''.join(list)
        data, bytesdecoded = self.decode(data, self.errors)
        return self.writer.write(data)

    def reset(self):

        self.reader.reset()
        self.writer.reset()

    def __getattr__(self, name,
                    getattr=getattr):

        """ Inherit all other methods from the underlying stream.
        """
        return getattr(self.stream, name)

    def __enter__(self):
        return self

    def __exit__(self, type, value, tb):
        self.stream.close()

### Shortcuts

def open(filename, mode='r', encoding=None, errors='strict', buffering=1):

    """ Open an encoded file using the given mode and return
        a wrapped version providing transparent encoding/decoding.

        Note: The wrapped version will only accept the object format
        defined by the codecs, i.e. Unicode objects for most builtin
        codecs. Output is also codec dependent and will usually be
        Unicode as well.

        Underlying encoded files are always opened in binary mode.
        The default file mode is 'r', meaning to open the file in read mode.

        encoding specifies the encoding which is to be used for the
        file.

        errors may be given to define the error handling. It defaults
        to 'strict' which causes ValueErrors to be raised in case an
        encoding error occurs.

        buffering has the same meaning as for the builtin open() API.
        It defaults to line buffered.

        The returned wrapped file object provides an extra attribute
        .encoding which allows querying the used encoding. This
        attribute is only available if an encoding was specified as
        parameter.

    """
    if encoding is not None and \
       'b' not in mode:
        # Force opening of the file in binary mode
        mode = mode + 'b'
    file = builtins.open(filename, mode, buffering)
    if encoding is None:
        return file
    info = lookup(encoding)
    srw = StreamReaderWriter(file, info.streamreader, info.streamwriter, errors)
    # Add attributes to simplify introspection
    srw.encoding = encoding
    return srw

def EncodedFile(file, data_encoding, file_encoding=None, errors='strict'):

    """ Return a wrapped version of file which provides transparent
        encoding translation.

        Data written to the wrapped file is decoded according
        to the given data_encoding and then encoded to the underlying
        file using file_encoding. The intermediate data type
        will usually be Unicode but depends on the specified codecs.

        Bytes read from the file are decoded using file_encoding and then
        passed back to the caller encoded using data_encoding.

        If file_encoding is not given, it defaults to data_encoding.

        errors may be given to define the error handling. It defaults
        to 'strict' which causes ValueErrors to be raised in case an
        encoding error occurs.

        The returned wrapped file object provides two extra attributes
        .data_encoding and .file_encoding which reflect the given
        parameters of the same name. The attributes can be used for
        introspection by Python programs.

    """
    if file_encoding is None:
        file_encoding = data_encoding
    data_info = lookup(data_encoding)
    file_info = lookup(file_encoding)
    sr = StreamRecoder(file, data_info.encode, data_info.decode,
                       file_info.streamreader, file_info.streamwriter, errors)
    # Add attributes to simplify introspection
    sr.data_encoding = data_encoding
    sr.file_encoding = file_encoding
    return sr

### Helpers for codec lookup

def getencoder(encoding):

    """ Lookup up the codec for the given encoding and return
        its encoder function.

        Raises a LookupError in case the encoding cannot be found.

    """
    return lookup(encoding).encode

def getdecoder(encoding):

    """ Lookup up the codec for the given encoding and return
        its decoder function.

        Raises a LookupError in case the encoding cannot be found.

    """
    return lookup(encoding).decode

def getincrementalencoder(encoding):

    """ Lookup up the codec for the given encoding and return
        its IncrementalEncoder class or factory function.

        Raises a LookupError in case the encoding cannot be found
        or the codecs doesn't provide an incremental encoder.

    """
    encoder = lookup(encoding).incrementalencoder
    if encoder is None:
        raise LookupError(encoding)
    return encoder

def getincrementaldecoder(encoding):

    """ Lookup up the codec for the given encoding and return
        its IncrementalDecoder class or factory function.

        Raises a LookupError in case the encoding cannot be found
        or the codecs doesn't provide an incremental decoder.

    """
    decoder = lookup(encoding).incrementaldecoder
    if decoder is None:
        raise LookupError(encoding)
    return decoder

def getreader(encoding):

    """ Lookup up the codec for the given encoding and return
        its StreamReader class or factory function.

        Raises a LookupError in case the encoding cannot be found.

    """
    return lookup(encoding).streamreader

def getwriter(encoding):

    """ Lookup up the codec for the given encoding and return
        its StreamWriter class or factory function.

        Raises a LookupError in case the encoding cannot be found.

    """
    return lookup(encoding).streamwriter

def iterencode(iterator, encoding, errors='strict', **kwargs):
    """
    Encoding iterator.

    Encodes the input strings from the iterator using an IncrementalEncoder.

    errors and kwargs are passed through to the IncrementalEncoder
    constructor.
    """
    encoder = getincrementalencoder(encoding)(errors, **kwargs)
    for input in iterator:
        output = encoder.encode(input)
        if output:
            yield output
    output = encoder.encode("", True)
    if output:
        yield output

def iterdecode(iterator, encoding, errors='strict', **kwargs):
    """
    Decoding iterator.

    Decodes the input strings from the iterator using an IncrementalDecoder.

    errors and kwargs are passed through to the IncrementalDecoder
    constructor.
    """
    decoder = getincrementaldecoder(encoding)(errors, **kwargs)
    for input in iterator:
        output = decoder.decode(input)
        if output:
            yield output
    output = decoder.decode(b"", True)
    if output:
        yield output

### Helpers for charmap-based codecs

def make_identity_dict(rng):

    """ make_identity_dict(rng) -> dict

        Return a dictionary where elements of the rng sequence are
        mapped to themselves.

    """
    return {i:i for i in rng}

def make_encoding_map(decoding_map):

    """ Creates an encoding map from a decoding map.

        If a target mapping in the decoding map occurs multiple
        times, then that target is mapped to None (undefined mapping),
        causing an exception when encountered by the charmap codec
        during translation.

        One example where this happens is cp875.py which decodes
        multiple character to \\u001a.

    """
    m = {}
    for k,v in decoding_map.items():
        if not v in m:
            m[v] = k
        else:
            m[v] = None
    return m

### error handlers

try:
    strict_errors = lookup_error("strict")
    ignore_errors = lookup_error("ignore")
    replace_errors = lookup_error("replace")
    xmlcharrefreplace_errors = lookup_error("xmlcharrefreplace")
    backslashreplace_errors = lookup_error("backslashreplace")
except LookupError:
    # In --disable-unicode builds, these error handler are missing
    strict_errors = None
    ignore_errors = None
    replace_errors = None
    xmlcharrefreplace_errors = None
    backslashreplace_errors = None

# Tell modulefinder that using codecs probably needs the encodings
# package
_false = 0
if _false:
    import encodings

### Tests

if __name__ == '__main__':

    # Make stdout translate Latin-1 output into UTF-8 output
    sys.stdout = EncodedFile(sys.stdout, 'latin-1', 'utf-8')

    # Have stdin translate Latin-1 input into UTF-8 input
    sys.stdin = EncodedFile(sys.stdin, 'utf-8', 'latin-1')
lib\codeop.py
r"""Utilities to compile possibly incomplete Python source code.

This module provides two interfaces, broadly similar to the builtin
function compile(), which take program text, a filename and a 'mode'
and:

- Return code object if the command is complete and valid
- Return None if the command is incomplete
- Raise SyntaxError, ValueError or OverflowError if the command is a
  syntax error (OverflowError and ValueError can be produced by
  malformed literals).

Approach:

First, check if the source consists entirely of blank lines and
comments; if so, replace it with 'pass', because the built-in
parser doesn't always do the right thing for these.

Compile three times: as is, with \n, and with \n\n appended.  If it
compiles as is, it's complete.  If it compiles with one \n appended,
we expect more.  If it doesn't compile either way, we compare the
error we get when compiling with \n or \n\n appended.  If the errors
are the same, the code is broken.  But if the errors are different, we
expect more.  Not intuitive; not even guaranteed to hold in future
releases; but this matches the compiler's behavior from Python 1.4
through 2.2, at least.

Caveat:

It is possible (but not likely) that the parser stops parsing with a
successful outcome before reaching the end of the source; in this
case, trailing symbols may be ignored instead of causing an error.
For example, a backslash followed by two newlines may be followed by
arbitrary garbage.  This will be fixed once the API for the parser is
better.

The two interfaces are:

compile_command(source, filename, symbol):

    Compiles a single command in the manner described above.

CommandCompiler():

    Instances of this class have __call__ methods identical in
    signature to compile_command; the difference is that if the
    instance compiles program text containing a __future__ statement,
    the instance 'remembers' and compiles all subsequent program texts
    with the statement in force.

The module also provides another class:

Compile():

    Instances of this class act like the built-in function compile,
    but with 'memory' in the sense described above.
"""

import __future__

_features = [getattr(__future__, fname)
             for fname in __future__.all_feature_names]

__all__ = ["compile_command", "Compile", "CommandCompiler"]

PyCF_DONT_IMPLY_DEDENT = 0x200          # Matches pythonrun.h

def _maybe_compile(compiler, source, filename, symbol):
    # Check for source consisting of only blank lines and comments
    for line in source.split("\n"):
        line = line.strip()
        if line and line[0] != '#':
            break               # Leave it alone
    else:
        if symbol != "eval":
            source = "pass"     # Replace it with a 'pass' statement

    err = err1 = err2 = None
    code = code1 = code2 = None

    try:
        code = compiler(source, filename, symbol)
    except SyntaxError as err:
        pass

    try:
        code1 = compiler(source + "\n", filename, symbol)
    except SyntaxError as e:
        err1 = e

    try:
        code2 = compiler(source + "\n\n", filename, symbol)
    except SyntaxError as e:
        err2 = e

    if code:
        return code
    if not code1 and repr(err1) == repr(err2):
        raise err1

def _compile(source, filename, symbol):
    return compile(source, filename, symbol, PyCF_DONT_IMPLY_DEDENT)

def compile_command(source, filename="<input>", symbol="single"):
    r"""Compile a command and determine whether it is incomplete.

    Arguments:

    source -- the source string; may contain \n characters
    filename -- optional filename from which source was read; default
                "<input>"
    symbol -- optional grammar start symbol; "single" (default) or "eval"

    Return value / exceptions raised:

    - Return a code object if the command is complete and valid
    - Return None if the command is incomplete
    - Raise SyntaxError, ValueError or OverflowError if the command is a
      syntax error (OverflowError and ValueError can be produced by
      malformed literals).
    """
    return _maybe_compile(_compile, source, filename, symbol)

class Compile:
    """Instances of this class behave much like the built-in compile
    function, but if one is used to compile text containing a future
    statement, it "remembers" and compiles all subsequent program texts
    with the statement in force."""
    def __init__(self):
        self.flags = PyCF_DONT_IMPLY_DEDENT

    def __call__(self, source, filename, symbol):
        codeob = compile(source, filename, symbol, self.flags, 1)
        for feature in _features:
            if codeob.co_flags & feature.compiler_flag:
                self.flags |= feature.compiler_flag
        return codeob

class CommandCompiler:
    """Instances of this class have __call__ methods identical in
    signature to compile_command; the difference is that if the
    instance compiles program text containing a __future__ statement,
    the instance 'remembers' and compiles all subsequent program texts
    with the statement in force."""

    def __init__(self,):
        self.compiler = Compile()

    def __call__(self, source, filename="<input>", symbol="single"):
        r"""Compile a command and determine whether it is incomplete.

        Arguments:

        source -- the source string; may contain \n characters
        filename -- optional filename from which source was read;
                    default "<input>"
        symbol -- optional grammar start symbol; "single" (default) or
                  "eval"

        Return value / exceptions raised:

        - Return a code object if the command is complete and valid
        - Return None if the command is incomplete
        - Raise SyntaxError, ValueError or OverflowError if the command is a
          syntax error (OverflowError and ValueError can be produced by
          malformed literals).
        """
        return _maybe_compile(self.compiler, source, filename, symbol)
lib\colorsys.py
"""Conversion functions between RGB and other color systems.

This modules provides two functions for each color system ABC:

  rgb_to_abc(r, g, b) --> a, b, c
  abc_to_rgb(a, b, c) --> r, g, b

All inputs and outputs are triples of floats in the range [0.0...1.0]
(with the exception of I and Q, which covers a slightly larger range).
Inputs outside the valid range may cause exceptions or invalid outputs.

Supported color systems:
RGB: Red, Green, Blue components
YIQ: Luminance, Chrominance (used by composite video signals)
HLS: Hue, Luminance, Saturation
HSV: Hue, Saturation, Value
"""

# References:
# http://en.wikipedia.org/wiki/YIQ
# http://en.wikipedia.org/wiki/HLS_color_space
# http://en.wikipedia.org/wiki/HSV_color_space

__all__ = ["rgb_to_yiq","yiq_to_rgb","rgb_to_hls","hls_to_rgb",
           "rgb_to_hsv","hsv_to_rgb"]

# Some floating point constants

ONE_THIRD = 1.0/3.0
ONE_SIXTH = 1.0/6.0
TWO_THIRD = 2.0/3.0

# YIQ: used by composite video signals (linear combinations of RGB)
# Y: perceived grey level (0.0 == black, 1.0 == white)
# I, Q: color components
#
# There are a great many versions of the constants used in these formulae.
# The ones in this library uses constants from the FCC version of NTSC.

def rgb_to_yiq(r, g, b):
    y = 0.30*r + 0.59*g + 0.11*b
    i = 0.74*(r-y) - 0.27*(b-y)
    q = 0.48*(r-y) + 0.41*(b-y)
    return (y, i, q)

def yiq_to_rgb(y, i, q):
    # r = y + (0.27*q + 0.41*i) / (0.74*0.41 + 0.27*0.48)
    # b = y + (0.74*q - 0.48*i) / (0.74*0.41 + 0.27*0.48)
    # g = y - (0.30*(r-y) + 0.11*(b-y)) / 0.59

    r = y + 0.9468822170900693*i + 0.6235565819861433*q
    g = y - 0.27478764629897834*i - 0.6356910791873801*q
    b = y - 1.1085450346420322*i + 1.7090069284064666*q

    if r < 0.0:
        r = 0.0
    if g < 0.0:
        g = 0.0
    if b < 0.0:
        b = 0.0
    if r > 1.0:
        r = 1.0
    if g > 1.0:
        g = 1.0
    if b > 1.0:
        b = 1.0
    return (r, g, b)


# HLS: Hue, Luminance, Saturation
# H: position in the spectrum
# L: color lightness
# S: color saturation

def rgb_to_hls(r, g, b):
    maxc = max(r, g, b)
    minc = min(r, g, b)
    # XXX Can optimize (maxc+minc) and (maxc-minc)
    l = (minc+maxc)/2.0
    if minc == maxc:
        return 0.0, l, 0.0
    if l <= 0.5:
        s = (maxc-minc) / (maxc+minc)
    else:
        s = (maxc-minc) / (2.0-maxc-minc)
    rc = (maxc-r) / (maxc-minc)
    gc = (maxc-g) / (maxc-minc)
    bc = (maxc-b) / (maxc-minc)
    if r == maxc:
        h = bc-gc
    elif g == maxc:
        h = 2.0+rc-bc
    else:
        h = 4.0+gc-rc
    h = (h/6.0) % 1.0
    return h, l, s

def hls_to_rgb(h, l, s):
    if s == 0.0:
        return l, l, l
    if l <= 0.5:
        m2 = l * (1.0+s)
    else:
        m2 = l+s-(l*s)
    m1 = 2.0*l - m2
    return (_v(m1, m2, h+ONE_THIRD), _v(m1, m2, h), _v(m1, m2, h-ONE_THIRD))

def _v(m1, m2, hue):
    hue = hue % 1.0
    if hue < ONE_SIXTH:
        return m1 + (m2-m1)*hue*6.0
    if hue < 0.5:
        return m2
    if hue < TWO_THIRD:
        return m1 + (m2-m1)*(TWO_THIRD-hue)*6.0
    return m1


# HSV: Hue, Saturation, Value
# H: position in the spectrum
# S: color saturation ("purity")
# V: color brightness

def rgb_to_hsv(r, g, b):
    maxc = max(r, g, b)
    minc = min(r, g, b)
    v = maxc
    if minc == maxc:
        return 0.0, 0.0, v
    s = (maxc-minc) / maxc
    rc = (maxc-r) / (maxc-minc)
    gc = (maxc-g) / (maxc-minc)
    bc = (maxc-b) / (maxc-minc)
    if r == maxc:
        h = bc-gc
    elif g == maxc:
        h = 2.0+rc-bc
    else:
        h = 4.0+gc-rc
    h = (h/6.0) % 1.0
    return h, s, v

def hsv_to_rgb(h, s, v):
    if s == 0.0:
        return v, v, v
    i = int(h*6.0) # XXX assume int() truncates!
    f = (h*6.0) - i
    p = v*(1.0 - s)
    q = v*(1.0 - s*f)
    t = v*(1.0 - s*(1.0-f))
    i = i%6
    if i == 0:
        return v, t, p
    if i == 1:
        return q, v, p
    if i == 2:
        return p, v, t
    if i == 3:
        return p, q, v
    if i == 4:
        return t, p, v
    if i == 5:
        return v, p, q
    # Cannot get here
lib\compileall.py
"""Module/script to byte-compile all .py files to .pyc (or .pyo) files.

When called as a script with arguments, this compiles the directories
given as arguments recursively; the -l option prevents it from
recursing into directories.

Without arguments, if compiles all modules on sys.path, without
recursing into subdirectories.  (Even though it should do so for
packages -- for now, you'll have to deal with packages separately.)

See module py_compile for details of the actual byte-compilation.
"""
import os
import sys
import importlib.util
import py_compile
import struct

__all__ = ["compile_dir","compile_file","compile_path"]

def compile_dir(dir, maxlevels=10, ddir=None, force=False, rx=None,
                quiet=False, legacy=False, optimize=-1):
    """Byte-compile all modules in the given directory tree.

    Arguments (only dir is required):

    dir:       the directory to byte-compile
    maxlevels: maximum recursion level (default 10)
    ddir:      the directory that will be prepended to the path to the
               file as it is compiled into each byte-code file.
    force:     if True, force compilation, even if timestamps are up-to-date
    quiet:     if True, be quiet during compilation
    legacy:    if True, produce legacy pyc paths instead of PEP 3147 paths
    optimize:  optimization level or -1 for level of the interpreter
    """
    if not quiet:
        print('Listing {!r}...'.format(dir))
    try:
        names = os.listdir(dir)
    except OSError:
        print("Can't list {!r}".format(dir))
        names = []
    names.sort()
    success = 1
    for name in names:
        if name == '__pycache__':
            continue
        fullname = os.path.join(dir, name)
        if ddir is not None:
            dfile = os.path.join(ddir, name)
        else:
            dfile = None
        if not os.path.isdir(fullname):
            if not compile_file(fullname, ddir, force, rx, quiet,
                                legacy, optimize):
                success = 0
        elif (maxlevels > 0 and name != os.curdir and name != os.pardir and
              os.path.isdir(fullname) and not os.path.islink(fullname)):
            if not compile_dir(fullname, maxlevels - 1, dfile, force, rx,
                               quiet, legacy, optimize):
                success = 0
    return success

def compile_file(fullname, ddir=None, force=False, rx=None, quiet=False,
                 legacy=False, optimize=-1):
    """Byte-compile one file.

    Arguments (only fullname is required):

    fullname:  the file to byte-compile
    ddir:      if given, the directory name compiled in to the
               byte-code file.
    force:     if True, force compilation, even if timestamps are up-to-date
    quiet:     if True, be quiet during compilation
    legacy:    if True, produce legacy pyc paths instead of PEP 3147 paths
    optimize:  optimization level or -1 for level of the interpreter
    """
    success = 1
    name = os.path.basename(fullname)
    if ddir is not None:
        dfile = os.path.join(ddir, name)
    else:
        dfile = None
    if rx is not None:
        mo = rx.search(fullname)
        if mo:
            return success
    if os.path.isfile(fullname):
        if legacy:
            cfile = fullname + ('c' if __debug__ else 'o')
        else:
            if optimize >= 0:
                cfile = importlib.util.cache_from_source(
                                fullname, debug_override=not optimize)
            else:
                cfile = importlib.util.cache_from_source(fullname)
            cache_dir = os.path.dirname(cfile)
        head, tail = name[:-3], name[-3:]
        if tail == '.py':
            if not force:
                try:
                    mtime = int(os.stat(fullname).st_mtime)
                    expect = struct.pack('<4sl', importlib.util.MAGIC_NUMBER,
                                         mtime)
                    with open(cfile, 'rb') as chandle:
                        actual = chandle.read(8)
                    if expect == actual:
                        return success
                except OSError:
                    pass
            if not quiet:
                print('Compiling {!r}...'.format(fullname))
            try:
                ok = py_compile.compile(fullname, cfile, dfile, True,
                                        optimize=optimize)
            except py_compile.PyCompileError as err:
                if quiet:
                    print('*** Error compiling {!r}...'.format(fullname))
                else:
                    print('*** ', end='')
                # escape non-printable characters in msg
                msg = err.msg.encode(sys.stdout.encoding,
                                     errors='backslashreplace')
                msg = msg.decode(sys.stdout.encoding)
                print(msg)
                success = 0
            except (SyntaxError, UnicodeError, OSError) as e:
                if quiet:
                    print('*** Error compiling {!r}...'.format(fullname))
                else:
                    print('*** ', end='')
                print(e.__class__.__name__ + ':', e)
                success = 0
            else:
                if ok == 0:
                    success = 0
    return success

def compile_path(skip_curdir=1, maxlevels=0, force=False, quiet=False,
                 legacy=False, optimize=-1):
    """Byte-compile all module on sys.path.

    Arguments (all optional):

    skip_curdir: if true, skip current directory (default True)
    maxlevels:   max recursion level (default 0)
    force: as for compile_dir() (default False)
    quiet: as for compile_dir() (default False)
    legacy: as for compile_dir() (default False)
    optimize: as for compile_dir() (default -1)
    """
    success = 1
    for dir in sys.path:
        if (not dir or dir == os.curdir) and skip_curdir:
            print('Skipping current directory')
        else:
            success = success and compile_dir(dir, maxlevels, None,
                                              force, quiet=quiet,
                                              legacy=legacy, optimize=optimize)
    return success


def main():
    """Script main program."""
    import argparse

    parser = argparse.ArgumentParser(
        description='Utilities to support installing Python libraries.')
    parser.add_argument('-l', action='store_const', const=0,
                        default=10, dest='maxlevels',
                        help="don't recurse into subdirectories")
    parser.add_argument('-f', action='store_true', dest='force',
                        help='force rebuild even if timestamps are up to date')
    parser.add_argument('-q', action='store_true', dest='quiet',
                        help='output only error messages')
    parser.add_argument('-b', action='store_true', dest='legacy',
                        help='use legacy (pre-PEP3147) compiled file locations')
    parser.add_argument('-d', metavar='DESTDIR',  dest='ddir', default=None,
                        help=('directory to prepend to file paths for use in '
                              'compile-time tracebacks and in runtime '
                              'tracebacks in cases where the source file is '
                              'unavailable'))
    parser.add_argument('-x', metavar='REGEXP', dest='rx', default=None,
                        help=('skip files matching the regular expression; '
                              'the regexp is searched for in the full path '
                              'of each file considered for compilation'))
    parser.add_argument('-i', metavar='FILE', dest='flist',
                        help=('add all the files and directories listed in '
                              'FILE to the list considered for compilation; '
                              'if "-", names are read from stdin'))
    parser.add_argument('compile_dest', metavar='FILE|DIR', nargs='*',
                        help=('zero or more file and directory names '
                              'to compile; if no arguments given, defaults '
                              'to the equivalent of -l sys.path'))
    args = parser.parse_args()

    compile_dests = args.compile_dest

    if args.rx:
        import re
        args.rx = re.compile(args.rx)

    # if flist is provided then load it
    if args.flist:
        try:
            with (sys.stdin if args.flist=='-' else open(args.flist)) as f:
                for line in f:
                    compile_dests.append(line.strip())
        except OSError:
            print("Error reading file list {}".format(args.flist))
            return False

    success = True
    try:
        if compile_dests:
            for dest in compile_dests:
                if os.path.isfile(dest):
                    if not compile_file(dest, args.ddir, args.force, args.rx,
                                        args.quiet, args.legacy):
                        success = False
                else:
                    if not compile_dir(dest, args.maxlevels, args.ddir,
                                       args.force, args.rx, args.quiet,
                                       args.legacy):
                        success = False
            return success
        else:
            return compile_path(legacy=args.legacy, force=args.force,
                                quiet=args.quiet)
    except KeyboardInterrupt:
        print("\n[interrupted]")
        return False
    return True


if __name__ == '__main__':
    exit_status = int(not main())
    sys.exit(exit_status)
lib\configparser.py
"""Configuration file parser.

A configuration file consists of sections, lead by a "[section]" header,
and followed by "name: value" entries, with continuations and such in
the style of RFC 822.

Intrinsic defaults can be specified by passing them into the
ConfigParser constructor as a dictionary.

class:

ConfigParser -- responsible for parsing a list of
                    configuration files, and managing the parsed database.

    methods:

    __init__(defaults=None, dict_type=_default_dict, allow_no_value=False,
             delimiters=('=', ':'), comment_prefixes=('#', ';'),
             inline_comment_prefixes=None, strict=True,
             empty_lines_in_values=True):
        Create the parser. When `defaults' is given, it is initialized into the
        dictionary or intrinsic defaults. The keys must be strings, the values
        must be appropriate for %()s string interpolation.

        When `dict_type' is given, it will be used to create the dictionary
        objects for the list of sections, for the options within a section, and
        for the default values.

        When `delimiters' is given, it will be used as the set of substrings
        that divide keys from values.

        When `comment_prefixes' is given, it will be used as the set of
        substrings that prefix comments in empty lines. Comments can be
        indented.

        When `inline_comment_prefixes' is given, it will be used as the set of
        substrings that prefix comments in non-empty lines.

        When `strict` is True, the parser won't allow for any section or option
        duplicates while reading from a single source (file, string or
        dictionary). Default is True.

        When `empty_lines_in_values' is False (default: True), each empty line
        marks the end of an option. Otherwise, internal empty lines of
        a multiline option are kept as part of the value.

        When `allow_no_value' is True (default: False), options without
        values are accepted; the value presented for these is None.

    sections()
        Return all the configuration section names, sans DEFAULT.

    has_section(section)
        Return whether the given section exists.

    has_option(section, option)
        Return whether the given option exists in the given section.

    options(section)
        Return list of configuration options for the named section.

    read(filenames, encoding=None)
        Read and parse the list of named configuration files, given by
        name.  A single filename is also allowed.  Non-existing files
        are ignored.  Return list of successfully read files.

    read_file(f, filename=None)
        Read and parse one configuration file, given as a file object.
        The filename defaults to f.name; it is only used in error
        messages (if f has no `name' attribute, the string `<???>' is used).

    read_string(string)
        Read configuration from a given string.

    read_dict(dictionary)
        Read configuration from a dictionary. Keys are section names,
        values are dictionaries with keys and values that should be present
        in the section. If the used dictionary type preserves order, sections
        and their keys will be added in order. Values are automatically
        converted to strings.

    get(section, option, raw=False, vars=None, fallback=_UNSET)
        Return a string value for the named option.  All % interpolations are
        expanded in the return values, based on the defaults passed into the
        constructor and the DEFAULT section.  Additional substitutions may be
        provided using the `vars' argument, which must be a dictionary whose
        contents override any pre-existing defaults. If `option' is a key in
        `vars', the value from `vars' is used.

    getint(section, options, raw=False, vars=None, fallback=_UNSET)
        Like get(), but convert value to an integer.

    getfloat(section, options, raw=False, vars=None, fallback=_UNSET)
        Like get(), but convert value to a float.

    getboolean(section, options, raw=False, vars=None, fallback=_UNSET)
        Like get(), but convert value to a boolean (currently case
        insensitively defined as 0, false, no, off for False, and 1, true,
        yes, on for True).  Returns False or True.

    items(section=_UNSET, raw=False, vars=None)
        If section is given, return a list of tuples with (name, value) for
        each option in the section. Otherwise, return a list of tuples with
        (section_name, section_proxy) for each section, including DEFAULTSECT.

    remove_section(section)
        Remove the given file section and all its options.

    remove_option(section, option)
        Remove the given option from the given section.

    set(section, option, value)
        Set the given option.

    write(fp, space_around_delimiters=True)
        Write the configuration state in .ini format. If
        `space_around_delimiters' is True (the default), delimiters
        between keys and values are surrounded by spaces.
"""

from collections.abc import MutableMapping
from collections import OrderedDict as _default_dict, ChainMap as _ChainMap
import functools
import io
import itertools
import re
import sys
import warnings

__all__ = ["NoSectionError", "DuplicateOptionError", "DuplicateSectionError",
           "NoOptionError", "InterpolationError", "InterpolationDepthError",
           "InterpolationSyntaxError", "ParsingError",
           "MissingSectionHeaderError",
           "ConfigParser", "SafeConfigParser", "RawConfigParser",
           "DEFAULTSECT", "MAX_INTERPOLATION_DEPTH"]

DEFAULTSECT = "DEFAULT"

MAX_INTERPOLATION_DEPTH = 10



# exception classes
class Error(Exception):
    """Base class for ConfigParser exceptions."""

    def __init__(self, msg=''):
        self.message = msg
        Exception.__init__(self, msg)

    def __repr__(self):
        return self.message

    __str__ = __repr__


class NoSectionError(Error):
    """Raised when no section matches a requested option."""

    def __init__(self, section):
        Error.__init__(self, 'No section: %r' % (section,))
        self.section = section
        self.args = (section, )


class DuplicateSectionError(Error):
    """Raised when a section is repeated in an input source.

    Possible repetitions that raise this exception are: multiple creation
    using the API or in strict parsers when a section is found more than once
    in a single input file, string or dictionary.
    """

    def __init__(self, section, source=None, lineno=None):
        msg = [repr(section), " already exists"]
        if source is not None:
            message = ["While reading from ", repr(source)]
            if lineno is not None:
                message.append(" [line {0:2d}]".format(lineno))
            message.append(": section ")
            message.extend(msg)
            msg = message
        else:
            msg.insert(0, "Section ")
        Error.__init__(self, "".join(msg))
        self.section = section
        self.source = source
        self.lineno = lineno
        self.args = (section, source, lineno)


class DuplicateOptionError(Error):
    """Raised by strict parsers when an option is repeated in an input source.

    Current implementation raises this exception only when an option is found
    more than once in a single file, string or dictionary.
    """

    def __init__(self, section, option, source=None, lineno=None):
        msg = [repr(option), " in section ", repr(section),
               " already exists"]
        if source is not None:
            message = ["While reading from ", repr(source)]
            if lineno is not None:
                message.append(" [line {0:2d}]".format(lineno))
            message.append(": option ")
            message.extend(msg)
            msg = message
        else:
            msg.insert(0, "Option ")
        Error.__init__(self, "".join(msg))
        self.section = section
        self.option = option
        self.source = source
        self.lineno = lineno
        self.args = (section, option, source, lineno)


class NoOptionError(Error):
    """A requested option was not found."""

    def __init__(self, option, section):
        Error.__init__(self, "No option %r in section: %r" %
                       (option, section))
        self.option = option
        self.section = section
        self.args = (option, section)


class InterpolationError(Error):
    """Base class for interpolation-related exceptions."""

    def __init__(self, option, section, msg):
        Error.__init__(self, msg)
        self.option = option
        self.section = section
        self.args = (option, section, msg)


class InterpolationMissingOptionError(InterpolationError):
    """A string substitution required a setting which was not available."""

    def __init__(self, option, section, rawval, reference):
        msg = ("Bad value substitution: option {!r} in section {!r} contains "
               "an interpolation key {!r} which is not a valid option name. "
               "Raw value: {!r}".format(option, section, reference, rawval))
        InterpolationError.__init__(self, option, section, msg)
        self.reference = reference
        self.args = (option, section, rawval, reference)


class InterpolationSyntaxError(InterpolationError):
    """Raised when the source text contains invalid syntax.

    Current implementation raises this exception when the source text into
    which substitutions are made does not conform to the required syntax.
    """


class InterpolationDepthError(InterpolationError):
    """Raised when substitutions are nested too deeply."""

    def __init__(self, option, section, rawval):
        msg = ("Recursion limit exceeded in value substitution: option {!r} "
               "in section {!r} contains an interpolation key which "
               "cannot be substituted in {} steps. Raw value: {!r}"
               "".format(option, section, MAX_INTERPOLATION_DEPTH,
                         rawval))
        InterpolationError.__init__(self, option, section, msg)
        self.args = (option, section, rawval)


class ParsingError(Error):
    """Raised when a configuration file does not follow legal syntax."""

    def __init__(self, source=None, filename=None):
        # Exactly one of `source'/`filename' arguments has to be given.
        # `filename' kept for compatibility.
        if filename and source:
            raise ValueError("Cannot specify both `filename' and `source'. "
                             "Use `source'.")
        elif not filename and not source:
            raise ValueError("Required argument `source' not given.")
        elif filename:
            source = filename
        Error.__init__(self, 'Source contains parsing errors: %r' % source)
        self.source = source
        self.errors = []
        self.args = (source, )

    @property
    def filename(self):
        """Deprecated, use `source'."""
        warnings.warn(
            "The 'filename' attribute will be removed in future versions.  "
            "Use 'source' instead.",
            DeprecationWarning, stacklevel=2
        )
        return self.source

    @filename.setter
    def filename(self, value):
        """Deprecated, user `source'."""
        warnings.warn(
            "The 'filename' attribute will be removed in future versions.  "
            "Use 'source' instead.",
            DeprecationWarning, stacklevel=2
        )
        self.source = value

    def append(self, lineno, line):
        self.errors.append((lineno, line))
        self.message += '\n\t[line %2d]: %s' % (lineno, line)


class MissingSectionHeaderError(ParsingError):
    """Raised when a key-value pair is found before any section header."""

    def __init__(self, filename, lineno, line):
        Error.__init__(
            self,
            'File contains no section headers.\nfile: %r, line: %d\n%r' %
            (filename, lineno, line))
        self.source = filename
        self.lineno = lineno
        self.line = line
        self.args = (filename, lineno, line)


# Used in parser getters to indicate the default behaviour when a specific
# option is not found it to raise an exception. Created to enable `None' as
# a valid fallback value.
_UNSET = object()


class Interpolation:
    """Dummy interpolation that passes the value through with no changes."""

    def before_get(self, parser, section, option, value, defaults):
        return value

    def before_set(self, parser, section, option, value):
        return value

    def before_read(self, parser, section, option, value):
        return value

    def before_write(self, parser, section, option, value):
        return value


class BasicInterpolation(Interpolation):
    """Interpolation as implemented in the classic ConfigParser.

    The option values can contain format strings which refer to other values in
    the same section, or values in the special default section.

    For example:

        something: %(dir)s/whatever

    would resolve the "%(dir)s" to the value of dir.  All reference
    expansions are done late, on demand. If a user needs to use a bare % in
    a configuration file, she can escape it by writing %%. Other % usage
    is considered a user error and raises `InterpolationSyntaxError'."""

    _KEYCRE = re.compile(r"%\(([^)]+)\)s")

    def before_get(self, parser, section, option, value, defaults):
        L = []
        self._interpolate_some(parser, option, L, value, section, defaults, 1)
        return ''.join(L)

    def before_set(self, parser, section, option, value):
        tmp_value = value.replace('%%', '') # escaped percent signs
        tmp_value = self._KEYCRE.sub('', tmp_value) # valid syntax
        if '%' in tmp_value:
            raise ValueError("invalid interpolation syntax in %r at "
                             "position %d" % (value, tmp_value.find('%')))
        return value

    def _interpolate_some(self, parser, option, accum, rest, section, map,
                          depth):
        rawval = parser.get(section, option, raw=True, fallback=rest)
        if depth > MAX_INTERPOLATION_DEPTH:
            raise InterpolationDepthError(option, section, rawval)
        while rest:
            p = rest.find("%")
            if p < 0:
                accum.append(rest)
                return
            if p > 0:
                accum.append(rest[:p])
                rest = rest[p:]
            # p is no longer used
            c = rest[1:2]
            if c == "%":
                accum.append("%")
                rest = rest[2:]
            elif c == "(":
                m = self._KEYCRE.match(rest)
                if m is None:
                    raise InterpolationSyntaxError(option, section,
                        "bad interpolation variable reference %r" % rest)
                var = parser.optionxform(m.group(1))
                rest = rest[m.end():]
                try:
                    v = map[var]
                except KeyError:
                    raise InterpolationMissingOptionError(
                        option, section, rawval, var)
                if "%" in v:
                    self._interpolate_some(parser, option, accum, v,
                                           section, map, depth + 1)
                else:
                    accum.append(v)
            else:
                raise InterpolationSyntaxError(
                    option, section,
                    "'%%' must be followed by '%%' or '(', "
                    "found: %r" % (rest,))


class ExtendedInterpolation(Interpolation):
    """Advanced variant of interpolation, supports the syntax used by
    `zc.buildout'. Enables interpolation between sections."""

    _KEYCRE = re.compile(r"\$\{([^}]+)\}")

    def before_get(self, parser, section, option, value, defaults):
        L = []
        self._interpolate_some(parser, option, L, value, section, defaults, 1)
        return ''.join(L)

    def before_set(self, parser, section, option, value):
        tmp_value = value.replace('$$', '') # escaped dollar signs
        tmp_value = self._KEYCRE.sub('', tmp_value) # valid syntax
        if '$' in tmp_value:
            raise ValueError("invalid interpolation syntax in %r at "
                             "position %d" % (value, tmp_value.find('$')))
        return value

    def _interpolate_some(self, parser, option, accum, rest, section, map,
                          depth):
        rawval = parser.get(section, option, raw=True, fallback=rest)
        if depth > MAX_INTERPOLATION_DEPTH:
            raise InterpolationDepthError(option, section, rawval)
        while rest:
            p = rest.find("$")
            if p < 0:
                accum.append(rest)
                return
            if p > 0:
                accum.append(rest[:p])
                rest = rest[p:]
            # p is no longer used
            c = rest[1:2]
            if c == "$":
                accum.append("$")
                rest = rest[2:]
            elif c == "{":
                m = self._KEYCRE.match(rest)
                if m is None:
                    raise InterpolationSyntaxError(option, section,
                        "bad interpolation variable reference %r" % rest)
                path = m.group(1).split(':')
                rest = rest[m.end():]
                sect = section
                opt = option
                try:
                    if len(path) == 1:
                        opt = parser.optionxform(path[0])
                        v = map[opt]
                    elif len(path) == 2:
                        sect = path[0]
                        opt = parser.optionxform(path[1])
                        v = parser.get(sect, opt, raw=True)
                    else:
                        raise InterpolationSyntaxError(
                            option, section,
                            "More than one ':' found: %r" % (rest,))
                except (KeyError, NoSectionError, NoOptionError):
                    raise InterpolationMissingOptionError(
                        option, section, rawval, ":".join(path))
                if "$" in v:
                    self._interpolate_some(parser, opt, accum, v, sect,
                                           dict(parser.items(sect, raw=True)),
                                           depth + 1)
                else:
                    accum.append(v)
            else:
                raise InterpolationSyntaxError(
                    option, section,
                    "'$' must be followed by '$' or '{', "
                    "found: %r" % (rest,))


class LegacyInterpolation(Interpolation):
    """Deprecated interpolation used in old versions of ConfigParser.
    Use BasicInterpolation or ExtendedInterpolation instead."""

    _KEYCRE = re.compile(r"%\(([^)]*)\)s|.")

    def before_get(self, parser, section, option, value, vars):
        rawval = value
        depth = MAX_INTERPOLATION_DEPTH
        while depth:                    # Loop through this until it's done
            depth -= 1
            if value and "%(" in value:
                replace = functools.partial(self._interpolation_replace,
                                            parser=parser)
                value = self._KEYCRE.sub(replace, value)
                try:
                    value = value % vars
                except KeyError as e:
                    raise InterpolationMissingOptionError(
                        option, section, rawval, e.args[0])
            else:
                break
        if value and "%(" in value:
            raise InterpolationDepthError(option, section, rawval)
        return value

    def before_set(self, parser, section, option, value):
        return value

    @staticmethod
    def _interpolation_replace(match, parser):
        s = match.group(1)
        if s is None:
            return match.group()
        else:
            return "%%(%s)s" % parser.optionxform(s)


class RawConfigParser(MutableMapping):
    """ConfigParser that does not do interpolation."""

    # Regular expressions for parsing section headers and options
    _SECT_TMPL = r"""
        \[                                 # [
        (?P<header>[^]]+)                  # very permissive!
        \]                                 # ]
        """
    _OPT_TMPL = r"""
        (?P<option>.*?)                    # very permissive!
        \s*(?P<vi>{delim})\s*              # any number of space/tab,
                                           # followed by any of the
                                           # allowed delimiters,
                                           # followed by any space/tab
        (?P<value>.*)$                     # everything up to eol
        """
    _OPT_NV_TMPL = r"""
        (?P<option>.*?)                    # very permissive!
        \s*(?:                             # any number of space/tab,
        (?P<vi>{delim})\s*                 # optionally followed by
                                           # any of the allowed
                                           # delimiters, followed by any
                                           # space/tab
        (?P<value>.*))?$                   # everything up to eol
        """
    # Interpolation algorithm to be used if the user does not specify another
    _DEFAULT_INTERPOLATION = Interpolation()
    # Compiled regular expression for matching sections
    SECTCRE = re.compile(_SECT_TMPL, re.VERBOSE)
    # Compiled regular expression for matching options with typical separators
    OPTCRE = re.compile(_OPT_TMPL.format(delim="=|:"), re.VERBOSE)
    # Compiled regular expression for matching options with optional values
    # delimited using typical separators
    OPTCRE_NV = re.compile(_OPT_NV_TMPL.format(delim="=|:"), re.VERBOSE)
    # Compiled regular expression for matching leading whitespace in a line
    NONSPACECRE = re.compile(r"\S")
    # Possible boolean values in the configuration.
    BOOLEAN_STATES = {'1': True, 'yes': True, 'true': True, 'on': True,
                      '0': False, 'no': False, 'false': False, 'off': False}

    def __init__(self, defaults=None, dict_type=_default_dict,
                 allow_no_value=False, *, delimiters=('=', ':'),
                 comment_prefixes=('#', ';'), inline_comment_prefixes=None,
                 strict=True, empty_lines_in_values=True,
                 default_section=DEFAULTSECT,
                 interpolation=_UNSET):

        self._dict = dict_type
        self._sections = self._dict()
        self._defaults = self._dict()
        self._proxies = self._dict()
        self._proxies[default_section] = SectionProxy(self, default_section)
        if defaults:
            for key, value in defaults.items():
                self._defaults[self.optionxform(key)] = value
        self._delimiters = tuple(delimiters)
        if delimiters == ('=', ':'):
            self._optcre = self.OPTCRE_NV if allow_no_value else self.OPTCRE
        else:
            d = "|".join(re.escape(d) for d in delimiters)
            if allow_no_value:
                self._optcre = re.compile(self._OPT_NV_TMPL.format(delim=d),
                                          re.VERBOSE)
            else:
                self._optcre = re.compile(self._OPT_TMPL.format(delim=d),
                                          re.VERBOSE)
        self._comment_prefixes = tuple(comment_prefixes or ())
        self._inline_comment_prefixes = tuple(inline_comment_prefixes or ())
        self._strict = strict
        self._allow_no_value = allow_no_value
        self._empty_lines_in_values = empty_lines_in_values
        self.default_section=default_section
        self._interpolation = interpolation
        if self._interpolation is _UNSET:
            self._interpolation = self._DEFAULT_INTERPOLATION
        if self._interpolation is None:
            self._interpolation = Interpolation()

    def defaults(self):
        return self._defaults

    def sections(self):
        """Return a list of section names, excluding [DEFAULT]"""
        # self._sections will never have [DEFAULT] in it
        return list(self._sections.keys())

    def add_section(self, section):
        """Create a new section in the configuration.

        Raise DuplicateSectionError if a section by the specified name
        already exists. Raise ValueError if name is DEFAULT.
        """
        if section == self.default_section:
            raise ValueError('Invalid section name: %r' % section)

        if section in self._sections:
            raise DuplicateSectionError(section)
        self._sections[section] = self._dict()
        self._proxies[section] = SectionProxy(self, section)

    def has_section(self, section):
        """Indicate whether the named section is present in the configuration.

        The DEFAULT section is not acknowledged.
        """
        return section in self._sections

    def options(self, section):
        """Return a list of option names for the given section name."""
        try:
            opts = self._sections[section].copy()
        except KeyError:
            raise NoSectionError(section)
        opts.update(self._defaults)
        return list(opts.keys())

    def read(self, filenames, encoding=None):
        """Read and parse a filename or a list of filenames.

        Files that cannot be opened are silently ignored; this is
        designed so that you can specify a list of potential
        configuration file locations (e.g. current directory, user's
        home directory, systemwide directory), and all existing
        configuration files in the list will be read.  A single
        filename may also be given.

        Return list of successfully read files.
        """
        if isinstance(filenames, str):
            filenames = [filenames]
        read_ok = []
        for filename in filenames:
            try:
                with open(filename, encoding=encoding) as fp:
                    self._read(fp, filename)
            except OSError:
                continue
            read_ok.append(filename)
        return read_ok

    def read_file(self, f, source=None):
        """Like read() but the argument must be a file-like object.

        The `f' argument must be iterable, returning one line at a time.
        Optional second argument is the `source' specifying the name of the
        file being read. If not given, it is taken from f.name. If `f' has no
        `name' attribute, `<???>' is used.
        """
        if source is None:
            try:
                source = f.name
            except AttributeError:
                source = '<???>'
        self._read(f, source)

    def read_string(self, string, source='<string>'):
        """Read configuration from a given string."""
        sfile = io.StringIO(string)
        self.read_file(sfile, source)

    def read_dict(self, dictionary, source='<dict>'):
        """Read configuration from a dictionary.

        Keys are section names, values are dictionaries with keys and values
        that should be present in the section. If the used dictionary type
        preserves order, sections and their keys will be added in order.

        All types held in the dictionary are converted to strings during
        reading, including section names, option names and keys.

        Optional second argument is the `source' specifying the name of the
        dictionary being read.
        """
        elements_added = set()
        for section, keys in dictionary.items():
            section = str(section)
            try:
                self.add_section(section)
            except (DuplicateSectionError, ValueError):
                if self._strict and section in elements_added:
                    raise
            elements_added.add(section)
            for key, value in keys.items():
                key = self.optionxform(str(key))
                if value is not None:
                    value = str(value)
                if self._strict and (section, key) in elements_added:
                    raise DuplicateOptionError(section, key, source)
                elements_added.add((section, key))
                self.set(section, key, value)

    def readfp(self, fp, filename=None):
        """Deprecated, use read_file instead."""
        warnings.warn(
            "This method will be removed in future versions.  "
            "Use 'parser.read_file()' instead.",
            DeprecationWarning, stacklevel=2
        )
        self.read_file(fp, source=filename)

    def get(self, section, option, *, raw=False, vars=None, fallback=_UNSET):
        """Get an option value for a given section.

        If `vars' is provided, it must be a dictionary. The option is looked up
        in `vars' (if provided), `section', and in `DEFAULTSECT' in that order.
        If the key is not found and `fallback' is provided, it is used as
        a fallback value. `None' can be provided as a `fallback' value.

        If interpolation is enabled and the optional argument `raw' is False,
        all interpolations are expanded in the return values.

        Arguments `raw', `vars', and `fallback' are keyword only.

        The section DEFAULT is special.
        """
        try:
            d = self._unify_values(section, vars)
        except NoSectionError:
            if fallback is _UNSET:
                raise
            else:
                return fallback
        option = self.optionxform(option)
        try:
            value = d[option]
        except KeyError:
            if fallback is _UNSET:
                raise NoOptionError(option, section)
            else:
                return fallback

        if raw or value is None:
            return value
        else:
            return self._interpolation.before_get(self, section, option, value,
                                                  d)

    def _get(self, section, conv, option, **kwargs):
        return conv(self.get(section, option, **kwargs))

    def getint(self, section, option, *, raw=False, vars=None,
               fallback=_UNSET):
        try:
            return self._get(section, int, option, raw=raw, vars=vars)
        except (NoSectionError, NoOptionError):
            if fallback is _UNSET:
                raise
            else:
                return fallback

    def getfloat(self, section, option, *, raw=False, vars=None,
                 fallback=_UNSET):
        try:
            return self._get(section, float, option, raw=raw, vars=vars)
        except (NoSectionError, NoOptionError):
            if fallback is _UNSET:
                raise
            else:
                return fallback

    def getboolean(self, section, option, *, raw=False, vars=None,
                   fallback=_UNSET):
        try:
            return self._get(section, self._convert_to_boolean, option,
                             raw=raw, vars=vars)
        except (NoSectionError, NoOptionError):
            if fallback is _UNSET:
                raise
            else:
                return fallback

    def items(self, section=_UNSET, raw=False, vars=None):
        """Return a list of (name, value) tuples for each option in a section.

        All % interpolations are expanded in the return values, based on the
        defaults passed into the constructor, unless the optional argument
        `raw' is true.  Additional substitutions may be provided using the
        `vars' argument, which must be a dictionary whose contents overrides
        any pre-existing defaults.

        The section DEFAULT is special.
        """
        if section is _UNSET:
            return super().items()
        d = self._defaults.copy()
        try:
            d.update(self._sections[section])
        except KeyError:
            if section != self.default_section:
                raise NoSectionError(section)
        # Update with the entry specific variables
        if vars:
            for key, value in vars.items():
                d[self.optionxform(key)] = value
        value_getter = lambda option: self._interpolation.before_get(self,
            section, option, d[option], d)
        if raw:
            value_getter = lambda option: d[option]
        return [(option, value_getter(option)) for option in d.keys()]

    def popitem(self):
        """Remove a section from the parser and return it as
        a (section_name, section_proxy) tuple. If no section is present, raise
        KeyError.

        The section DEFAULT is never returned because it cannot be removed.
        """
        for key in self.sections():
            value = self[key]
            del self[key]
            return key, value
        raise KeyError

    def optionxform(self, optionstr):
        return optionstr.lower()

    def has_option(self, section, option):
        """Check for the existence of a given option in a given section.
        If the specified `section' is None or an empty string, DEFAULT is
        assumed. If the specified `section' does not exist, returns False."""
        if not section or section == self.default_section:
            option = self.optionxform(option)
            return option in self._defaults
        elif section not in self._sections:
            return False
        else:
            option = self.optionxform(option)
            return (option in self._sections[section]
                    or option in self._defaults)

    def set(self, section, option, value=None):
        """Set an option."""
        if value:
            value = self._interpolation.before_set(self, section, option,
                                                   value)
        if not section or section == self.default_section:
            sectdict = self._defaults
        else:
            try:
                sectdict = self._sections[section]
            except KeyError:
                raise NoSectionError(section)
        sectdict[self.optionxform(option)] = value

    def write(self, fp, space_around_delimiters=True):
        """Write an .ini-format representation of the configuration state.

        If `space_around_delimiters' is True (the default), delimiters
        between keys and values are surrounded by spaces.
        """
        if space_around_delimiters:
            d = " {} ".format(self._delimiters[0])
        else:
            d = self._delimiters[0]
        if self._defaults:
            self._write_section(fp, self.default_section,
                                    self._defaults.items(), d)
        for section in self._sections:
            self._write_section(fp, section,
                                self._sections[section].items(), d)

    def _write_section(self, fp, section_name, section_items, delimiter):
        """Write a single section to the specified `fp'."""
        fp.write("[{}]\n".format(section_name))
        for key, value in section_items:
            value = self._interpolation.before_write(self, section_name, key,
                                                     value)
            if value is not None or not self._allow_no_value:
                value = delimiter + str(value).replace('\n', '\n\t')
            else:
                value = ""
            fp.write("{}{}\n".format(key, value))
        fp.write("\n")

    def remove_option(self, section, option):
        """Remove an option."""
        if not section or section == self.default_section:
            sectdict = self._defaults
        else:
            try:
                sectdict = self._sections[section]
            except KeyError:
                raise NoSectionError(section)
        option = self.optionxform(option)
        existed = option in sectdict
        if existed:
            del sectdict[option]
        return existed

    def remove_section(self, section):
        """Remove a file section."""
        existed = section in self._sections
        if existed:
            del self._sections[section]
            del self._proxies[section]
        return existed

    def __getitem__(self, key):
        if key != self.default_section and not self.has_section(key):
            raise KeyError(key)
        return self._proxies[key]

    def __setitem__(self, key, value):
        # To conform with the mapping protocol, overwrites existing values in
        # the section.

        # XXX this is not atomic if read_dict fails at any point. Then again,
        # no update method in configparser is atomic in this implementation.
        if key == self.default_section:
            self._defaults.clear()
        elif key in self._sections:
            self._sections[key].clear()
        self.read_dict({key: value})

    def __delitem__(self, key):
        if key == self.default_section:
            raise ValueError("Cannot remove the default section.")
        if not self.has_section(key):
            raise KeyError(key)
        self.remove_section(key)

    def __contains__(self, key):
        return key == self.default_section or self.has_section(key)

    def __len__(self):
        return len(self._sections) + 1 # the default section

    def __iter__(self):
        # XXX does it break when underlying container state changed?
        return itertools.chain((self.default_section,), self._sections.keys())

    def _read(self, fp, fpname):
        """Parse a sectioned configuration file.

        Each section in a configuration file contains a header, indicated by
        a name in square brackets (`[]'), plus key/value options, indicated by
        `name' and `value' delimited with a specific substring (`=' or `:' by
        default).

        Values can span multiple lines, as long as they are indented deeper
        than the first line of the value. Depending on the parser's mode, blank
        lines may be treated as parts of multiline values or ignored.

        Configuration files may include comments, prefixed by specific
        characters (`#' and `;' by default). Comments may appear on their own
        in an otherwise empty line or may be entered in lines holding values or
        section names.
        """
        elements_added = set()
        cursect = None                        # None, or a dictionary
        sectname = None
        optname = None
        lineno = 0
        indent_level = 0
        e = None                              # None, or an exception
        for lineno, line in enumerate(fp, start=1):
            comment_start = sys.maxsize
            # strip inline comments
            inline_prefixes = {p: -1 for p in self._inline_comment_prefixes}
            while comment_start == sys.maxsize and inline_prefixes:
                next_prefixes = {}
                for prefix, index in inline_prefixes.items():
                    index = line.find(prefix, index+1)
                    if index == -1:
                        continue
                    next_prefixes[prefix] = index
                    if index == 0 or (index > 0 and line[index-1].isspace()):
                        comment_start = min(comment_start, index)
                inline_prefixes = next_prefixes
            # strip full line comments
            for prefix in self._comment_prefixes:
                if line.strip().startswith(prefix):
                    comment_start = 0
                    break
            if comment_start == sys.maxsize:
                comment_start = None
            value = line[:comment_start].strip()
            if not value:
                if self._empty_lines_in_values:
                    # add empty line to the value, but only if there was no
                    # comment on the line
                    if (comment_start is None and
                        cursect is not None and
                        optname and
                        cursect[optname] is not None):
                        cursect[optname].append('') # newlines added at join
                else:
                    # empty line marks end of value
                    indent_level = sys.maxsize
                continue
            # continuation line?
            first_nonspace = self.NONSPACECRE.search(line)
            cur_indent_level = first_nonspace.start() if first_nonspace else 0
            if (cursect is not None and optname and
                cur_indent_level > indent_level):
                cursect[optname].append(value)
            # a section header or option header?
            else:
                indent_level = cur_indent_level
                # is it a section header?
                mo = self.SECTCRE.match(value)
                if mo:
                    sectname = mo.group('header')
                    if sectname in self._sections:
                        if self._strict and sectname in elements_added:
                            raise DuplicateSectionError(sectname, fpname,
                                                        lineno)
                        cursect = self._sections[sectname]
                        elements_added.add(sectname)
                    elif sectname == self.default_section:
                        cursect = self._defaults
                    else:
                        cursect = self._dict()
                        self._sections[sectname] = cursect
                        self._proxies[sectname] = SectionProxy(self, sectname)
                        elements_added.add(sectname)
                    # So sections can't start with a continuation line
                    optname = None
                # no section header in the file?
                elif cursect is None:
                    raise MissingSectionHeaderError(fpname, lineno, line)
                # an option line?
                else:
                    mo = self._optcre.match(value)
                    if mo:
                        optname, vi, optval = mo.group('option', 'vi', 'value')
                        if not optname:
                            e = self._handle_error(e, fpname, lineno, line)
                        optname = self.optionxform(optname.rstrip())
                        if (self._strict and
                            (sectname, optname) in elements_added):
                            raise DuplicateOptionError(sectname, optname,
                                                       fpname, lineno)
                        elements_added.add((sectname, optname))
                        # This check is fine because the OPTCRE cannot
                        # match if it would set optval to None
                        if optval is not None:
                            optval = optval.strip()
                            cursect[optname] = [optval]
                        else:
                            # valueless option handling
                            cursect[optname] = None
                    else:
                        # a non-fatal parsing error occurred. set up the
                        # exception but keep going. the exception will be
                        # raised at the end of the file and will contain a
                        # list of all bogus lines
                        e = self._handle_error(e, fpname, lineno, line)
        # if any parsing errors occurred, raise an exception
        if e:
            raise e
        self._join_multiline_values()

    def _join_multiline_values(self):
        defaults = self.default_section, self._defaults
        all_sections = itertools.chain((defaults,),
                                       self._sections.items())
        for section, options in all_sections:
            for name, val in options.items():
                if isinstance(val, list):
                    val = '\n'.join(val).rstrip()
                options[name] = self._interpolation.before_read(self,
                                                                section,
                                                                name, val)

    def _handle_error(self, exc, fpname, lineno, line):
        if not exc:
            exc = ParsingError(fpname)
        exc.append(lineno, repr(line))
        return exc

    def _unify_values(self, section, vars):
        """Create a sequence of lookups with 'vars' taking priority over
        the 'section' which takes priority over the DEFAULTSECT.

        """
        sectiondict = {}
        try:
            sectiondict = self._sections[section]
        except KeyError:
            if section != self.default_section:
                raise NoSectionError(section)
        # Update with the entry specific variables
        vardict = {}
        if vars:
            for key, value in vars.items():
                if value is not None:
                    value = str(value)
                vardict[self.optionxform(key)] = value
        return _ChainMap(vardict, sectiondict, self._defaults)

    def _convert_to_boolean(self, value):
        """Return a boolean value translating from other types if necessary.
        """
        if value.lower() not in self.BOOLEAN_STATES:
            raise ValueError('Not a boolean: %s' % value)
        return self.BOOLEAN_STATES[value.lower()]

    def _validate_value_types(self, *, section="", option="", value=""):
        """Raises a TypeError for non-string values.

        The only legal non-string value if we allow valueless
        options is None, so we need to check if the value is a
        string if:
        - we do not allow valueless options, or
        - we allow valueless options but the value is not None

        For compatibility reasons this method is not used in classic set()
        for RawConfigParsers. It is invoked in every case for mapping protocol
        access and in ConfigParser.set().
        """
        if not isinstance(section, str):
            raise TypeError("section names must be strings")
        if not isinstance(option, str):
            raise TypeError("option keys must be strings")
        if not self._allow_no_value or value:
            if not isinstance(value, str):
                raise TypeError("option values must be strings")


class ConfigParser(RawConfigParser):
    """ConfigParser implementing interpolation."""

    _DEFAULT_INTERPOLATION = BasicInterpolation()

    def set(self, section, option, value=None):
        """Set an option.  Extends RawConfigParser.set by validating type and
        interpolation syntax on the value."""
        self._validate_value_types(option=option, value=value)
        super().set(section, option, value)

    def add_section(self, section):
        """Create a new section in the configuration.  Extends
        RawConfigParser.add_section by validating if the section name is
        a string."""
        self._validate_value_types(section=section)
        super().add_section(section)


class SafeConfigParser(ConfigParser):
    """ConfigParser alias for backwards compatibility purposes."""

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        warnings.warn(
            "The SafeConfigParser class has been renamed to ConfigParser "
            "in Python 3.2. This alias will be removed in future versions."
            " Use ConfigParser directly instead.",
            DeprecationWarning, stacklevel=2
        )


class SectionProxy(MutableMapping):
    """A proxy for a single section from a parser."""

    def __init__(self, parser, name):
        """Creates a view on a section of the specified `name` in `parser`."""
        self._parser = parser
        self._name = name

    def __repr__(self):
        return '<Section: {}>'.format(self._name)

    def __getitem__(self, key):
        if not self._parser.has_option(self._name, key):
            raise KeyError(key)
        return self._parser.get(self._name, key)

    def __setitem__(self, key, value):
        self._parser._validate_value_types(option=key, value=value)
        return self._parser.set(self._name, key, value)

    def __delitem__(self, key):
        if not (self._parser.has_option(self._name, key) and
                self._parser.remove_option(self._name, key)):
            raise KeyError(key)

    def __contains__(self, key):
        return self._parser.has_option(self._name, key)

    def __len__(self):
        return len(self._options())

    def __iter__(self):
        return self._options().__iter__()

    def _options(self):
        if self._name != self._parser.default_section:
            return self._parser.options(self._name)
        else:
            return self._parser.defaults()

    def get(self, option, fallback=None, *, raw=False, vars=None):
        return self._parser.get(self._name, option, raw=raw, vars=vars,
                                fallback=fallback)

    def getint(self, option, fallback=None, *, raw=False, vars=None):
        return self._parser.getint(self._name, option, raw=raw, vars=vars,
                                   fallback=fallback)

    def getfloat(self, option, fallback=None, *, raw=False, vars=None):
        return self._parser.getfloat(self._name, option, raw=raw, vars=vars,
                                     fallback=fallback)

    def getboolean(self, option, fallback=None, *, raw=False, vars=None):
        return self._parser.getboolean(self._name, option, raw=raw, vars=vars,
                                       fallback=fallback)

    @property
    def parser(self):
        # The parser object of the proxy is read-only.
        return self._parser

    @property
    def name(self):
        # The name of the section on a proxy is read-only.
        return self._name
lib\contextlib.py
"""Utilities for with-statement contexts.  See PEP 343."""

import sys
from collections import deque
from functools import wraps

__all__ = ["contextmanager", "closing", "ContextDecorator", "ExitStack",
           "redirect_stdout", "suppress"]


class ContextDecorator(object):
    "A base class or mixin that enables context managers to work as decorators."

    def _recreate_cm(self):
        """Return a recreated instance of self.

        Allows an otherwise one-shot context manager like
        _GeneratorContextManager to support use as
        a decorator via implicit recreation.

        This is a private interface just for _GeneratorContextManager.
        See issue #11647 for details.
        """
        return self

    def __call__(self, func):
        @wraps(func)
        def inner(*args, **kwds):
            with self._recreate_cm():
                return func(*args, **kwds)
        return inner


class _GeneratorContextManager(ContextDecorator):
    """Helper for @contextmanager decorator."""

    def __init__(self, func, args, kwds):
        self.gen = func(*args, **kwds)
        self.func, self.args, self.kwds = func, args, kwds
        # Issue 19330: ensure context manager instances have good docstrings
        doc = getattr(func, "__doc__", None)
        if doc is None:
            doc = type(self).__doc__
        self.__doc__ = doc
        # Unfortunately, this still doesn't provide good help output when
        # inspecting the created context manager instances, since pydoc
        # currently bypasses the instance docstring and shows the docstring
        # for the class instead.
        # See http://bugs.python.org/issue19404 for more details.

    def _recreate_cm(self):
        # _GCM instances are one-shot context managers, so the
        # CM must be recreated each time a decorated function is
        # called
        return self.__class__(self.func, self.args, self.kwds)

    def __enter__(self):
        try:
            return next(self.gen)
        except StopIteration:
            raise RuntimeError("generator didn't yield") from None

    def __exit__(self, type, value, traceback):
        if type is None:
            try:
                next(self.gen)
            except StopIteration:
                return
            else:
                raise RuntimeError("generator didn't stop")
        else:
            if value is None:
                # Need to force instantiation so we can reliably
                # tell if we get the same exception back
                value = type()
            try:
                self.gen.throw(type, value, traceback)
                raise RuntimeError("generator didn't stop after throw()")
            except StopIteration as exc:
                # Suppress the exception *unless* it's the same exception that
                # was passed to throw().  This prevents a StopIteration
                # raised inside the "with" statement from being suppressed
                return exc is not value
            except:
                # only re-raise if it's *not* the exception that was
                # passed to throw(), because __exit__() must not raise
                # an exception unless __exit__() itself failed.  But throw()
                # has to raise the exception to signal propagation, so this
                # fixes the impedance mismatch between the throw() protocol
                # and the __exit__() protocol.
                #
                if sys.exc_info()[1] is not value:
                    raise


def contextmanager(func):
    """@contextmanager decorator.

    Typical usage:

        @contextmanager
        def some_generator(<arguments>):
            <setup>
            try:
                yield <value>
            finally:
                <cleanup>

    This makes this:

        with some_generator(<arguments>) as <variable>:
            <body>

    equivalent to this:

        <setup>
        try:
            <variable> = <value>
            <body>
        finally:
            <cleanup>

    """
    @wraps(func)
    def helper(*args, **kwds):
        return _GeneratorContextManager(func, args, kwds)
    return helper


class closing(object):
    """Context to automatically close something at the end of a block.

    Code like this:

        with closing(<module>.open(<arguments>)) as f:
            <block>

    is equivalent to this:

        f = <module>.open(<arguments>)
        try:
            <block>
        finally:
            f.close()

    """
    def __init__(self, thing):
        self.thing = thing
    def __enter__(self):
        return self.thing
    def __exit__(self, *exc_info):
        self.thing.close()

class redirect_stdout:
    """Context manager for temporarily redirecting stdout to another file

        # How to send help() to stderr
        with redirect_stdout(sys.stderr):
            help(dir)

        # How to write help() to a file
        with open('help.txt', 'w') as f:
            with redirect_stdout(f):
                help(pow)
    """

    def __init__(self, new_target):
        self._new_target = new_target
        # We use a list of old targets to make this CM re-entrant
        self._old_targets = []

    def __enter__(self):
        self._old_targets.append(sys.stdout)
        sys.stdout = self._new_target
        return self._new_target

    def __exit__(self, exctype, excinst, exctb):
        sys.stdout = self._old_targets.pop()


class suppress:
    """Context manager to suppress specified exceptions

    After the exception is suppressed, execution proceeds with the next
    statement following the with statement.

         with suppress(FileNotFoundError):
             os.remove(somefile)
         # Execution still resumes here if the file was already removed
    """

    def __init__(self, *exceptions):
        self._exceptions = exceptions

    def __enter__(self):
        pass

    def __exit__(self, exctype, excinst, exctb):
        # Unlike isinstance and issubclass, CPython exception handling
        # currently only looks at the concrete type hierarchy (ignoring
        # the instance and subclass checking hooks). While Guido considers
        # that a bug rather than a feature, it's a fairly hard one to fix
        # due to various internal implementation details. suppress provides
        # the simpler issubclass based semantics, rather than trying to
        # exactly reproduce the limitations of the CPython interpreter.
        #
        # See http://bugs.python.org/issue12029 for more details
        return exctype is not None and issubclass(exctype, self._exceptions)


# Inspired by discussions on http://bugs.python.org/issue13585
class ExitStack(object):
    """Context manager for dynamic management of a stack of exit callbacks

    For example:

        with ExitStack() as stack:
            files = [stack.enter_context(open(fname)) for fname in filenames]
            # All opened files will automatically be closed at the end of
            # the with statement, even if attempts to open files later
            # in the list raise an exception

    """
    def __init__(self):
        self._exit_callbacks = deque()

    def pop_all(self):
        """Preserve the context stack by transferring it to a new instance"""
        new_stack = type(self)()
        new_stack._exit_callbacks = self._exit_callbacks
        self._exit_callbacks = deque()
        return new_stack

    def _push_cm_exit(self, cm, cm_exit):
        """Helper to correctly register callbacks to __exit__ methods"""
        def _exit_wrapper(*exc_details):
            return cm_exit(cm, *exc_details)
        _exit_wrapper.__self__ = cm
        self.push(_exit_wrapper)

    def push(self, exit):
        """Registers a callback with the standard __exit__ method signature

        Can suppress exceptions the same way __exit__ methods can.

        Also accepts any object with an __exit__ method (registering a call
        to the method instead of the object itself)
        """
        # We use an unbound method rather than a bound method to follow
        # the standard lookup behaviour for special methods
        _cb_type = type(exit)
        try:
            exit_method = _cb_type.__exit__
        except AttributeError:
            # Not a context manager, so assume its a callable
            self._exit_callbacks.append(exit)
        else:
            self._push_cm_exit(exit, exit_method)
        return exit # Allow use as a decorator

    def callback(self, callback, *args, **kwds):
        """Registers an arbitrary callback and arguments.

        Cannot suppress exceptions.
        """
        def _exit_wrapper(exc_type, exc, tb):
            callback(*args, **kwds)
        # We changed the signature, so using @wraps is not appropriate, but
        # setting __wrapped__ may still help with introspection
        _exit_wrapper.__wrapped__ = callback
        self.push(_exit_wrapper)
        return callback # Allow use as a decorator

    def enter_context(self, cm):
        """Enters the supplied context manager

        If successful, also pushes its __exit__ method as a callback and
        returns the result of the __enter__ method.
        """
        # We look up the special methods on the type to match the with statement
        _cm_type = type(cm)
        _exit = _cm_type.__exit__
        result = _cm_type.__enter__(cm)
        self._push_cm_exit(cm, _exit)
        return result

    def close(self):
        """Immediately unwind the context stack"""
        self.__exit__(None, None, None)

    def __enter__(self):
        return self

    def __exit__(self, *exc_details):
        received_exc = exc_details[0] is not None

        # We manipulate the exception state so it behaves as though
        # we were actually nesting multiple with statements
        frame_exc = sys.exc_info()[1]
        def _fix_exception_context(new_exc, old_exc):
            # Context may not be correct, so find the end of the chain
            while 1:
                exc_context = new_exc.__context__
                if exc_context is old_exc:
                    # Context is already set correctly (see issue 20317)
                    return
                if exc_context is None or exc_context is frame_exc:
                    break
                new_exc = exc_context
            # Change the end of the chain to point to the exception
            # we expect it to reference
            new_exc.__context__ = old_exc

        # Callbacks are invoked in LIFO order to match the behaviour of
        # nested context managers
        suppressed_exc = False
        pending_raise = False
        while self._exit_callbacks:
            cb = self._exit_callbacks.pop()
            try:
                if cb(*exc_details):
                    suppressed_exc = True
                    pending_raise = False
                    exc_details = (None, None, None)
            except:
                new_exc_details = sys.exc_info()
                # simulate the stack of exceptions by setting the context
                _fix_exception_context(new_exc_details[1], exc_details[1])
                pending_raise = True
                exc_details = new_exc_details
        if pending_raise:
            try:
                # bare "raise exc_details[1]" replaces our carefully
                # set-up context
                fixed_ctx = exc_details[1].__context__
                raise exc_details[1]
            except BaseException:
                exc_details[1].__context__ = fixed_ctx
                raise
        return received_exc and suppressed_exc
lib\copy.py
"""Generic (shallow and deep) copying operations.

Interface summary:

        import copy

        x = copy.copy(y)        # make a shallow copy of y
        x = copy.deepcopy(y)    # make a deep copy of y

For module specific errors, copy.Error is raised.

The difference between shallow and deep copying is only relevant for
compound objects (objects that contain other objects, like lists or
class instances).

- A shallow copy constructs a new compound object and then (to the
  extent possible) inserts *the same objects* into it that the
  original contains.

- A deep copy constructs a new compound object and then, recursively,
  inserts *copies* into it of the objects found in the original.

Two problems often exist with deep copy operations that don't exist
with shallow copy operations:

 a) recursive objects (compound objects that, directly or indirectly,
    contain a reference to themselves) may cause a recursive loop

 b) because deep copy copies *everything* it may copy too much, e.g.
    administrative data structures that should be shared even between
    copies

Python's deep copy operation avoids these problems by:

 a) keeping a table of objects already copied during the current
    copying pass

 b) letting user-defined classes override the copying operation or the
    set of components copied

This version does not copy types like module, class, function, method,
nor stack trace, stack frame, nor file, socket, window, nor array, nor
any similar types.

Classes can use the same interfaces to control copying that they use
to control pickling: they can define methods called __getinitargs__(),
__getstate__() and __setstate__().  See the documentation for module
"pickle" for information on these methods.
"""

import types
import weakref
from copyreg import dispatch_table
import builtins

class Error(Exception):
    pass
error = Error   # backward compatibility

try:
    from org.python.core import PyStringMap
except ImportError:
    PyStringMap = None

__all__ = ["Error", "copy", "deepcopy"]

def copy(x):
    """Shallow copy operation on arbitrary Python objects.

    See the module's __doc__ string for more info.
    """

    cls = type(x)

    copier = _copy_dispatch.get(cls)
    if copier:
        return copier(x)

    try:
        issc = issubclass(cls, type)
    except TypeError: # cls is not a class
        issc = False
    if issc:
        # treat it as a regular class:
        return _copy_immutable(x)

    copier = getattr(cls, "__copy__", None)
    if copier:
        return copier(x)

    reductor = dispatch_table.get(cls)
    if reductor:
        rv = reductor(x)
    else:
        reductor = getattr(x, "__reduce_ex__", None)
        if reductor:
            rv = reductor(2)
        else:
            reductor = getattr(x, "__reduce__", None)
            if reductor:
                rv = reductor()
            else:
                raise Error("un(shallow)copyable object of type %s" % cls)

    return _reconstruct(x, rv, 0)


_copy_dispatch = d = {}

def _copy_immutable(x):
    return x
for t in (type(None), int, float, bool, str, tuple,
          bytes, frozenset, type, range,
          types.BuiltinFunctionType, type(Ellipsis),
          types.FunctionType, weakref.ref):
    d[t] = _copy_immutable
t = getattr(types, "CodeType", None)
if t is not None:
    d[t] = _copy_immutable
for name in ("complex", "unicode"):
    t = getattr(builtins, name, None)
    if t is not None:
        d[t] = _copy_immutable

def _copy_with_constructor(x):
    return type(x)(x)
for t in (list, dict, set):
    d[t] = _copy_with_constructor

def _copy_with_copy_method(x):
    return x.copy()
if PyStringMap is not None:
    d[PyStringMap] = _copy_with_copy_method

del d

def deepcopy(x, memo=None, _nil=[]):
    """Deep copy operation on arbitrary Python objects.

    See the module's __doc__ string for more info.
    """

    if memo is None:
        memo = {}

    d = id(x)
    y = memo.get(d, _nil)
    if y is not _nil:
        return y

    cls = type(x)

    copier = _deepcopy_dispatch.get(cls)
    if copier:
        y = copier(x, memo)
    else:
        try:
            issc = issubclass(cls, type)
        except TypeError: # cls is not a class (old Boost; see SF #502085)
            issc = 0
        if issc:
            y = _deepcopy_atomic(x, memo)
        else:
            copier = getattr(x, "__deepcopy__", None)
            if copier:
                y = copier(memo)
            else:
                reductor = dispatch_table.get(cls)
                if reductor:
                    rv = reductor(x)
                else:
                    reductor = getattr(x, "__reduce_ex__", None)
                    if reductor:
                        rv = reductor(2)
                    else:
                        reductor = getattr(x, "__reduce__", None)
                        if reductor:
                            rv = reductor()
                        else:
                            raise Error(
                                "un(deep)copyable object of type %s" % cls)
                y = _reconstruct(x, rv, 1, memo)

    # If is its own copy, don't memoize.
    if y is not x:
        memo[d] = y
        _keep_alive(x, memo) # Make sure x lives at least as long as d
    return y

_deepcopy_dispatch = d = {}

def _deepcopy_atomic(x, memo):
    return x
d[type(None)] = _deepcopy_atomic
d[type(Ellipsis)] = _deepcopy_atomic
d[int] = _deepcopy_atomic
d[float] = _deepcopy_atomic
d[bool] = _deepcopy_atomic
try:
    d[complex] = _deepcopy_atomic
except NameError:
    pass
d[bytes] = _deepcopy_atomic
d[str] = _deepcopy_atomic
try:
    d[types.CodeType] = _deepcopy_atomic
except AttributeError:
    pass
d[type] = _deepcopy_atomic
d[range] = _deepcopy_atomic
d[types.BuiltinFunctionType] = _deepcopy_atomic
d[types.FunctionType] = _deepcopy_atomic
d[weakref.ref] = _deepcopy_atomic

def _deepcopy_list(x, memo):
    y = []
    memo[id(x)] = y
    for a in x:
        y.append(deepcopy(a, memo))
    return y
d[list] = _deepcopy_list

def _deepcopy_tuple(x, memo):
    y = []
    for a in x:
        y.append(deepcopy(a, memo))
    # We're not going to put the tuple in the memo, but it's still important we
    # check for it, in case the tuple contains recursive mutable structures.
    try:
        return memo[id(x)]
    except KeyError:
        pass
    for i in range(len(x)):
        if x[i] is not y[i]:
            y = tuple(y)
            break
    else:
        y = x
    return y
d[tuple] = _deepcopy_tuple

def _deepcopy_dict(x, memo):
    y = {}
    memo[id(x)] = y
    for key, value in x.items():
        y[deepcopy(key, memo)] = deepcopy(value, memo)
    return y
d[dict] = _deepcopy_dict
if PyStringMap is not None:
    d[PyStringMap] = _deepcopy_dict

def _deepcopy_method(x, memo): # Copy instance methods
    return type(x)(x.__func__, deepcopy(x.__self__, memo))
_deepcopy_dispatch[types.MethodType] = _deepcopy_method

def _keep_alive(x, memo):
    """Keeps a reference to the object x in the memo.

    Because we remember objects by their id, we have
    to assure that possibly temporary objects are kept
    alive by referencing them.
    We store a reference at the id of the memo, which should
    normally not be used unless someone tries to deepcopy
    the memo itself...
    """
    try:
        memo[id(memo)].append(x)
    except KeyError:
        # aha, this is the first one :-)
        memo[id(memo)]=[x]

def _reconstruct(x, info, deep, memo=None):
    if isinstance(info, str):
        return x
    assert isinstance(info, tuple)
    if memo is None:
        memo = {}
    n = len(info)
    assert n in (2, 3, 4, 5)
    callable, args = info[:2]
    if n > 2:
        state = info[2]
    else:
        state = None
    if n > 3:
        listiter = info[3]
    else:
        listiter = None
    if n > 4:
        dictiter = info[4]
    else:
        dictiter = None
    if deep:
        args = deepcopy(args, memo)
    y = callable(*args)
    memo[id(x)] = y

    if state is not None:
        if deep:
            state = deepcopy(state, memo)
        if hasattr(y, '__setstate__'):
            y.__setstate__(state)
        else:
            if isinstance(state, tuple) and len(state) == 2:
                state, slotstate = state
            else:
                slotstate = None
            if state is not None:
                y.__dict__.update(state)
            if slotstate is not None:
                for key, value in slotstate.items():
                    setattr(y, key, value)

    if listiter is not None:
        for item in listiter:
            if deep:
                item = deepcopy(item, memo)
            y.append(item)
    if dictiter is not None:
        for key, value in dictiter:
            if deep:
                key = deepcopy(key, memo)
                value = deepcopy(value, memo)
            y[key] = value
    return y

del d

del types

# Helper for instance creation without calling __init__
class _EmptyClass:
    pass
lib\copyreg.py
"""Helper to provide extensibility for pickle.

This is only useful to add pickle support for extension types defined in
C, not for instances of user-defined classes.
"""

__all__ = ["pickle", "constructor",
           "add_extension", "remove_extension", "clear_extension_cache"]

dispatch_table = {}

def pickle(ob_type, pickle_function, constructor_ob=None):
    if not callable(pickle_function):
        raise TypeError("reduction functions must be callable")
    dispatch_table[ob_type] = pickle_function

    # The constructor_ob function is a vestige of safe for unpickling.
    # There is no reason for the caller to pass it anymore.
    if constructor_ob is not None:
        constructor(constructor_ob)

def constructor(object):
    if not callable(object):
        raise TypeError("constructors must be callable")

# Example: provide pickling support for complex numbers.

try:
    complex
except NameError:
    pass
else:

    def pickle_complex(c):
        return complex, (c.real, c.imag)

    pickle(complex, pickle_complex, complex)

# Support for pickling new-style objects

def _reconstructor(cls, base, state):
    if base is object:
        obj = object.__new__(cls)
    else:
        obj = base.__new__(cls, state)
        if base.__init__ != object.__init__:
            base.__init__(obj, state)
    return obj

_HEAPTYPE = 1<<9

# Python code for object.__reduce_ex__ for protocols 0 and 1

def _reduce_ex(self, proto):
    assert proto < 2
    for base in self.__class__.__mro__:
        if hasattr(base, '__flags__') and not base.__flags__ & _HEAPTYPE:
            break
    else:
        base = object # not really reachable
    if base is object:
        state = None
    else:
        if base is self.__class__:
            raise TypeError("can't pickle %s objects" % base.__name__)
        state = base(self)
    args = (self.__class__, base, state)
    try:
        getstate = self.__getstate__
    except AttributeError:
        if getattr(self, "__slots__", None):
            raise TypeError("a class that defines __slots__ without "
                            "defining __getstate__ cannot be pickled")
        try:
            dict = self.__dict__
        except AttributeError:
            dict = None
    else:
        dict = getstate()
    if dict:
        return _reconstructor, args, dict
    else:
        return _reconstructor, args

# Helper for __reduce_ex__ protocol 2

def __newobj__(cls, *args):
    return cls.__new__(cls, *args)

def __newobj_ex__(cls, args, kwargs):
    """Used by pickle protocol 4, instead of __newobj__ to allow classes with
    keyword-only arguments to be pickled correctly.
    """
    return cls.__new__(cls, *args, **kwargs)

def _slotnames(cls):
    """Return a list of slot names for a given class.

    This needs to find slots defined by the class and its bases, so we
    can't simply return the __slots__ attribute.  We must walk down
    the Method Resolution Order and concatenate the __slots__ of each
    class found there.  (This assumes classes don't modify their
    __slots__ attribute to misrepresent their slots after the class is
    defined.)
    """

    # Get the value from a cache in the class if possible
    names = cls.__dict__.get("__slotnames__")
    if names is not None:
        return names

    # Not cached -- calculate the value
    names = []
    if not hasattr(cls, "__slots__"):
        # This class has no slots
        pass
    else:
        # Slots found -- gather slot names from all base classes
        for c in cls.__mro__:
            if "__slots__" in c.__dict__:
                slots = c.__dict__['__slots__']
                # if class has a single slot, it can be given as a string
                if isinstance(slots, str):
                    slots = (slots,)
                for name in slots:
                    # special descriptors
                    if name in ("__dict__", "__weakref__"):
                        continue
                    # mangled names
                    elif name.startswith('__') and not name.endswith('__'):
                        names.append('_%s%s' % (c.__name__, name))
                    else:
                        names.append(name)

    # Cache the outcome in the class if at all possible
    try:
        cls.__slotnames__ = names
    except:
        pass # But don't die if we can't

    return names

# A registry of extension codes.  This is an ad-hoc compression
# mechanism.  Whenever a global reference to <module>, <name> is about
# to be pickled, the (<module>, <name>) tuple is looked up here to see
# if it is a registered extension code for it.  Extension codes are
# universal, so that the meaning of a pickle does not depend on
# context.  (There are also some codes reserved for local use that
# don't have this restriction.)  Codes are positive ints; 0 is
# reserved.

_extension_registry = {}                # key -> code
_inverted_registry = {}                 # code -> key
_extension_cache = {}                   # code -> object
# Don't ever rebind those names:  pickling grabs a reference to them when
# it's initialized, and won't see a rebinding.

def add_extension(module, name, code):
    """Register an extension code."""
    code = int(code)
    if not 1 <= code <= 0x7fffffff:
        raise ValueError("code out of range")
    key = (module, name)
    if (_extension_registry.get(key) == code and
        _inverted_registry.get(code) == key):
        return # Redundant registrations are benign
    if key in _extension_registry:
        raise ValueError("key %s is already registered with code %s" %
                         (key, _extension_registry[key]))
    if code in _inverted_registry:
        raise ValueError("code %s is already in use for key %s" %
                         (code, _inverted_registry[code]))
    _extension_registry[key] = code
    _inverted_registry[code] = key

def remove_extension(module, name, code):
    """Unregister an extension code.  For testing only."""
    key = (module, name)
    if (_extension_registry.get(key) != code or
        _inverted_registry.get(code) != key):
        raise ValueError("key %s is not registered with code %s" %
                         (key, code))
    del _extension_registry[key]
    del _inverted_registry[code]
    if code in _extension_cache:
        del _extension_cache[code]

def clear_extension_cache():
    _extension_cache.clear()

# Standard extension code assignments

# Reserved ranges

# First  Last Count  Purpose
#     1   127   127  Reserved for Python standard library
#   128   191    64  Reserved for Zope
#   192   239    48  Reserved for 3rd parties
#   240   255    16  Reserved for private use (will never be assigned)
#   256   Inf   Inf  Reserved for future assignment

# Extension codes are assigned by the Python Software Foundation.
lib\cProfile.py
#! /usr/bin/env python3

"""Python interface for the 'lsprof' profiler.
   Compatible with the 'profile' module.
"""

__all__ = ["run", "runctx", "Profile"]

import _lsprof
import profile as _pyprofile

# ____________________________________________________________
# Simple interface

def run(statement, filename=None, sort=-1):
    return _pyprofile._Utils(Profile).run(statement, filename, sort)

def runctx(statement, globals, locals, filename=None, sort=-1):
    return _pyprofile._Utils(Profile).runctx(statement, globals, locals,
                                             filename, sort)

run.__doc__ = _pyprofile.run.__doc__
runctx.__doc__ = _pyprofile.runctx.__doc__

# ____________________________________________________________

class Profile(_lsprof.Profiler):
    """Profile(custom_timer=None, time_unit=None, subcalls=True, builtins=True)

    Builds a profiler object using the specified timer function.
    The default timer is a fast built-in one based on real time.
    For custom timer functions returning integers, time_unit can
    be a float specifying a scale (i.e. how long each integer unit
    is, in seconds).
    """

    # Most of the functionality is in the base class.
    # This subclass only adds convenient and backward-compatible methods.

    def print_stats(self, sort=-1):
        import pstats
        pstats.Stats(self).strip_dirs().sort_stats(sort).print_stats()

    def dump_stats(self, file):
        import marshal
        with open(file, 'wb') as f:
            self.create_stats()
            marshal.dump(self.stats, f)

    def create_stats(self):
        self.disable()
        self.snapshot_stats()

    def snapshot_stats(self):
        entries = self.getstats()
        self.stats = {}
        callersdicts = {}
        # call information
        for entry in entries:
            func = label(entry.code)
            nc = entry.callcount         # ncalls column of pstats (before '/')
            cc = nc - entry.reccallcount # ncalls column of pstats (after '/')
            tt = entry.inlinetime        # tottime column of pstats
            ct = entry.totaltime         # cumtime column of pstats
            callers = {}
            callersdicts[id(entry.code)] = callers
            self.stats[func] = cc, nc, tt, ct, callers
        # subcall information
        for entry in entries:
            if entry.calls:
                func = label(entry.code)
                for subentry in entry.calls:
                    try:
                        callers = callersdicts[id(subentry.code)]
                    except KeyError:
                        continue
                    nc = subentry.callcount
                    cc = nc - subentry.reccallcount
                    tt = subentry.inlinetime
                    ct = subentry.totaltime
                    if func in callers:
                        prev = callers[func]
                        nc += prev[0]
                        cc += prev[1]
                        tt += prev[2]
                        ct += prev[3]
                    callers[func] = nc, cc, tt, ct

    # The following two methods can be called by clients to use
    # a profiler to profile a statement, given as a string.

    def run(self, cmd):
        import __main__
        dict = __main__.__dict__
        return self.runctx(cmd, dict, dict)

    def runctx(self, cmd, globals, locals):
        self.enable()
        try:
            exec(cmd, globals, locals)
        finally:
            self.disable()
        return self

    # This method is more useful to profile a single function call.
    def runcall(self, func, *args, **kw):
        self.enable()
        try:
            return func(*args, **kw)
        finally:
            self.disable()

# ____________________________________________________________

def label(code):
    if isinstance(code, str):
        return ('~', 0, code)    # built-in functions ('~' sorts at the end)
    else:
        return (code.co_filename, code.co_firstlineno, code.co_name)

# ____________________________________________________________

def main():
    import os, sys
    from optparse import OptionParser
    usage = "cProfile.py [-o output_file_path] [-s sort] scriptfile [arg] ..."
    parser = OptionParser(usage=usage)
    parser.allow_interspersed_args = False
    parser.add_option('-o', '--outfile', dest="outfile",
        help="Save stats to <outfile>", default=None)
    parser.add_option('-s', '--sort', dest="sort",
        help="Sort order when printing to stdout, based on pstats.Stats class",
        default=-1)

    if not sys.argv[1:]:
        parser.print_usage()
        sys.exit(2)

    (options, args) = parser.parse_args()
    sys.argv[:] = args

    if len(args) > 0:
        progname = args[0]
        sys.path.insert(0, os.path.dirname(progname))
        with open(progname, 'rb') as fp:
            code = compile(fp.read(), progname, 'exec')
        globs = {
            '__file__': progname,
            '__name__': '__main__',
            '__package__': None,
            '__cached__': None,
        }
        runctx(code, globs, None, options.outfile, options.sort)
    else:
        parser.print_usage()
    return parser

# When invoked as main program, invoke the profiler on a script
if __name__ == '__main__':
    main()
lib\crypt.py
"""Wrapper to the POSIX crypt library call and associated functionality."""

import _crypt
import string as _string
from random import SystemRandom as _SystemRandom
from collections import namedtuple as _namedtuple


_saltchars = _string.ascii_letters + _string.digits + './'
_sr = _SystemRandom()


class _Method(_namedtuple('_Method', 'name ident salt_chars total_size')):

    """Class representing a salt method per the Modular Crypt Format or the
    legacy 2-character crypt method."""

    def __repr__(self):
        return '<crypt.METHOD_{}>'.format(self.name)


def mksalt(method=None):
    """Generate a salt for the specified method.

    If not specified, the strongest available method will be used.

    """
    if method is None:
        method = methods[0]
    s = '${}$'.format(method.ident) if method.ident else ''
    s += ''.join(_sr.choice(_saltchars) for char in range(method.salt_chars))
    return s


def crypt(word, salt=None):
    """Return a string representing the one-way hash of a password, with a salt
    prepended.

    If ``salt`` is not specified or is ``None``, the strongest
    available method will be selected and a salt generated.  Otherwise,
    ``salt`` may be one of the ``crypt.METHOD_*`` values, or a string as
    returned by ``crypt.mksalt()``.

    """
    if salt is None or isinstance(salt, _Method):
        salt = mksalt(salt)
    return _crypt.crypt(word, salt)


#  available salting/crypto methods
METHOD_CRYPT = _Method('CRYPT', None, 2, 13)
METHOD_MD5 = _Method('MD5', '1', 8, 34)
METHOD_SHA256 = _Method('SHA256', '5', 16, 63)
METHOD_SHA512 = _Method('SHA512', '6', 16, 106)

methods = []
for _method in (METHOD_SHA512, METHOD_SHA256, METHOD_MD5):
    _result = crypt('', _method)
    if _result and len(_result) == _method.total_size:
        methods.append(_method)
methods.append(METHOD_CRYPT)
del _result, _method
lib\csv.py

"""
csv.py - read/write/investigate CSV files
"""

import re
from _csv import Error, __version__, writer, reader, register_dialect, \
                 unregister_dialect, get_dialect, list_dialects, \
                 field_size_limit, \
                 QUOTE_MINIMAL, QUOTE_ALL, QUOTE_NONNUMERIC, QUOTE_NONE, \
                 __doc__
from _csv import Dialect as _Dialect

from io import StringIO

__all__ = [ "QUOTE_MINIMAL", "QUOTE_ALL", "QUOTE_NONNUMERIC", "QUOTE_NONE",
            "Error", "Dialect", "__doc__", "excel", "excel_tab",
            "field_size_limit", "reader", "writer",
            "register_dialect", "get_dialect", "list_dialects", "Sniffer",
            "unregister_dialect", "__version__", "DictReader", "DictWriter" ]

class Dialect:
    """Describe a CSV dialect.

    This must be subclassed (see csv.excel).  Valid attributes are:
    delimiter, quotechar, escapechar, doublequote, skipinitialspace,
    lineterminator, quoting.

    """
    _name = ""
    _valid = False
    # placeholders
    delimiter = None
    quotechar = None
    escapechar = None
    doublequote = None
    skipinitialspace = None
    lineterminator = None
    quoting = None

    def __init__(self):
        if self.__class__ != Dialect:
            self._valid = True
        self._validate()

    def _validate(self):
        try:
            _Dialect(self)
        except TypeError as e:
            # We do this for compatibility with py2.3
            raise Error(str(e))

class excel(Dialect):
    """Describe the usual properties of Excel-generated CSV files."""
    delimiter = ','
    quotechar = '"'
    doublequote = True
    skipinitialspace = False
    lineterminator = '\r\n'
    quoting = QUOTE_MINIMAL
register_dialect("excel", excel)

class excel_tab(excel):
    """Describe the usual properties of Excel-generated TAB-delimited files."""
    delimiter = '\t'
register_dialect("excel-tab", excel_tab)

class unix_dialect(Dialect):
    """Describe the usual properties of Unix-generated CSV files."""
    delimiter = ','
    quotechar = '"'
    doublequote = True
    skipinitialspace = False
    lineterminator = '\n'
    quoting = QUOTE_ALL
register_dialect("unix", unix_dialect)


class DictReader:
    def __init__(self, f, fieldnames=None, restkey=None, restval=None,
                 dialect="excel", *args, **kwds):
        self._fieldnames = fieldnames   # list of keys for the dict
        self.restkey = restkey          # key to catch long rows
        self.restval = restval          # default value for short rows
        self.reader = reader(f, dialect, *args, **kwds)
        self.dialect = dialect
        self.line_num = 0

    def __iter__(self):
        return self

    @property
    def fieldnames(self):
        if self._fieldnames is None:
            try:
                self._fieldnames = next(self.reader)
            except StopIteration:
                pass
        self.line_num = self.reader.line_num
        return self._fieldnames

    @fieldnames.setter
    def fieldnames(self, value):
        self._fieldnames = value

    def __next__(self):
        if self.line_num == 0:
            # Used only for its side effect.
            self.fieldnames
        row = next(self.reader)
        self.line_num = self.reader.line_num

        # unlike the basic reader, we prefer not to return blanks,
        # because we will typically wind up with a dict full of None
        # values
        while row == []:
            row = next(self.reader)
        d = dict(zip(self.fieldnames, row))
        lf = len(self.fieldnames)
        lr = len(row)
        if lf < lr:
            d[self.restkey] = row[lf:]
        elif lf > lr:
            for key in self.fieldnames[lr:]:
                d[key] = self.restval
        return d


class DictWriter:
    def __init__(self, f, fieldnames, restval="", extrasaction="raise",
                 dialect="excel", *args, **kwds):
        self.fieldnames = fieldnames    # list of keys for the dict
        self.restval = restval          # for writing short dicts
        if extrasaction.lower() not in ("raise", "ignore"):
            raise ValueError("extrasaction (%s) must be 'raise' or 'ignore'"
                             % extrasaction)
        self.extrasaction = extrasaction
        self.writer = writer(f, dialect, *args, **kwds)

    def writeheader(self):
        header = dict(zip(self.fieldnames, self.fieldnames))
        self.writerow(header)

    def _dict_to_list(self, rowdict):
        if self.extrasaction == "raise":
            wrong_fields = [k for k in rowdict if k not in self.fieldnames]
            if wrong_fields:
                raise ValueError("dict contains fields not in fieldnames: "
                                 + ", ".join([repr(x) for x in wrong_fields]))
        return [rowdict.get(key, self.restval) for key in self.fieldnames]

    def writerow(self, rowdict):
        return self.writer.writerow(self._dict_to_list(rowdict))

    def writerows(self, rowdicts):
        rows = []
        for rowdict in rowdicts:
            rows.append(self._dict_to_list(rowdict))
        return self.writer.writerows(rows)

# Guard Sniffer's type checking against builds that exclude complex()
try:
    complex
except NameError:
    complex = float

class Sniffer:
    '''
    "Sniffs" the format of a CSV file (i.e. delimiter, quotechar)
    Returns a Dialect object.
    '''
    def __init__(self):
        # in case there is more than one possible delimiter
        self.preferred = [',', '\t', ';', ' ', ':']


    def sniff(self, sample, delimiters=None):
        """
        Returns a dialect (or None) corresponding to the sample
        """

        quotechar, doublequote, delimiter, skipinitialspace = \
                   self._guess_quote_and_delimiter(sample, delimiters)
        if not delimiter:
            delimiter, skipinitialspace = self._guess_delimiter(sample,
                                                                delimiters)

        if not delimiter:
            raise Error("Could not determine delimiter")

        class dialect(Dialect):
            _name = "sniffed"
            lineterminator = '\r\n'
            quoting = QUOTE_MINIMAL
            # escapechar = ''

        dialect.doublequote = doublequote
        dialect.delimiter = delimiter
        # _csv.reader won't accept a quotechar of ''
        dialect.quotechar = quotechar or '"'
        dialect.skipinitialspace = skipinitialspace

        return dialect


    def _guess_quote_and_delimiter(self, data, delimiters):
        """
        Looks for text enclosed between two identical quotes
        (the probable quotechar) which are preceded and followed
        by the same character (the probable delimiter).
        For example:
                         ,'some text',
        The quote with the most wins, same with the delimiter.
        If there is no quotechar the delimiter can't be determined
        this way.
        """

        matches = []
        for restr in ('(?P<delim>[^\w\n"\'])(?P<space> ?)(?P<quote>["\']).*?(?P=quote)(?P=delim)', # ,".*?",
                      '(?:^|\n)(?P<quote>["\']).*?(?P=quote)(?P<delim>[^\w\n"\'])(?P<space> ?)',   #  ".*?",
                      '(?P<delim>>[^\w\n"\'])(?P<space> ?)(?P<quote>["\']).*?(?P=quote)(?:$|\n)',  # ,".*?"
                      '(?:^|\n)(?P<quote>["\']).*?(?P=quote)(?:$|\n)'):                            #  ".*?" (no delim, no space)
            regexp = re.compile(restr, re.DOTALL | re.MULTILINE)
            matches = regexp.findall(data)
            if matches:
                break

        if not matches:
            # (quotechar, doublequote, delimiter, skipinitialspace)
            return ('', False, None, 0)
        quotes = {}
        delims = {}
        spaces = 0
        for m in matches:
            n = regexp.groupindex['quote'] - 1
            key = m[n]
            if key:
                quotes[key] = quotes.get(key, 0) + 1
            try:
                n = regexp.groupindex['delim'] - 1
                key = m[n]
            except KeyError:
                continue
            if key and (delimiters is None or key in delimiters):
                delims[key] = delims.get(key, 0) + 1
            try:
                n = regexp.groupindex['space'] - 1
            except KeyError:
                continue
            if m[n]:
                spaces += 1

        quotechar = max(quotes, key=quotes.get)

        if delims:
            delim = max(delims, key=delims.get)
            skipinitialspace = delims[delim] == spaces
            if delim == '\n': # most likely a file with a single column
                delim = ''
        else:
            # there is *no* delimiter, it's a single column of quoted data
            delim = ''
            skipinitialspace = 0

        # if we see an extra quote between delimiters, we've got a
        # double quoted format
        dq_regexp = re.compile(
                               r"((%(delim)s)|^)\W*%(quote)s[^%(delim)s\n]*%(quote)s[^%(delim)s\n]*%(quote)s\W*((%(delim)s)|$)" % \
                               {'delim':re.escape(delim), 'quote':quotechar}, re.MULTILINE)



        if dq_regexp.search(data):
            doublequote = True
        else:
            doublequote = False

        return (quotechar, doublequote, delim, skipinitialspace)


    def _guess_delimiter(self, data, delimiters):
        """
        The delimiter /should/ occur the same number of times on
        each row. However, due to malformed data, it may not. We don't want
        an all or nothing approach, so we allow for small variations in this
        number.
          1) build a table of the frequency of each character on every line.
          2) build a table of frequencies of this frequency (meta-frequency?),
             e.g.  'x occurred 5 times in 10 rows, 6 times in 1000 rows,
             7 times in 2 rows'
          3) use the mode of the meta-frequency to determine the /expected/
             frequency for that character
          4) find out how often the character actually meets that goal
          5) the character that best meets its goal is the delimiter
        For performance reasons, the data is evaluated in chunks, so it can
        try and evaluate the smallest portion of the data possible, evaluating
        additional chunks as necessary.
        """

        data = list(filter(None, data.split('\n')))

        ascii = [chr(c) for c in range(127)] # 7-bit ASCII

        # build frequency tables
        chunkLength = min(10, len(data))
        iteration = 0
        charFrequency = {}
        modes = {}
        delims = {}
        start, end = 0, min(chunkLength, len(data))
        while start < len(data):
            iteration += 1
            for line in data[start:end]:
                for char in ascii:
                    metaFrequency = charFrequency.get(char, {})
                    # must count even if frequency is 0
                    freq = line.count(char)
                    # value is the mode
                    metaFrequency[freq] = metaFrequency.get(freq, 0) + 1
                    charFrequency[char] = metaFrequency

            for char in charFrequency.keys():
                items = list(charFrequency[char].items())
                if len(items) == 1 and items[0][0] == 0:
                    continue
                # get the mode of the frequencies
                if len(items) > 1:
                    modes[char] = max(items, key=lambda x: x[1])
                    # adjust the mode - subtract the sum of all
                    # other frequencies
                    items.remove(modes[char])
                    modes[char] = (modes[char][0], modes[char][1]
                                   - sum(item[1] for item in items))
                else:
                    modes[char] = items[0]

            # build a list of possible delimiters
            modeList = modes.items()
            total = float(chunkLength * iteration)
            # (rows of consistent data) / (number of rows) = 100%
            consistency = 1.0
            # minimum consistency threshold
            threshold = 0.9
            while len(delims) == 0 and consistency >= threshold:
                for k, v in modeList:
                    if v[0] > 0 and v[1] > 0:
                        if ((v[1]/total) >= consistency and
                            (delimiters is None or k in delimiters)):
                            delims[k] = v
                consistency -= 0.01

            if len(delims) == 1:
                delim = list(delims.keys())[0]
                skipinitialspace = (data[0].count(delim) ==
                                    data[0].count("%c " % delim))
                return (delim, skipinitialspace)

            # analyze another chunkLength lines
            start = end
            end += chunkLength

        if not delims:
            return ('', 0)

        # if there's more than one, fall back to a 'preferred' list
        if len(delims) > 1:
            for d in self.preferred:
                if d in delims.keys():
                    skipinitialspace = (data[0].count(d) ==
                                        data[0].count("%c " % d))
                    return (d, skipinitialspace)

        # nothing else indicates a preference, pick the character that
        # dominates(?)
        items = [(v,k) for (k,v) in delims.items()]
        items.sort()
        delim = items[-1][1]

        skipinitialspace = (data[0].count(delim) ==
                            data[0].count("%c " % delim))
        return (delim, skipinitialspace)


    def has_header(self, sample):
        # Creates a dictionary of types of data in each column. If any
        # column is of a single type (say, integers), *except* for the first
        # row, then the first row is presumed to be labels. If the type
        # can't be determined, it is assumed to be a string in which case
        # the length of the string is the determining factor: if all of the
        # rows except for the first are the same length, it's a header.
        # Finally, a 'vote' is taken at the end for each column, adding or
        # subtracting from the likelihood of the first row being a header.

        rdr = reader(StringIO(sample), self.sniff(sample))

        header = next(rdr) # assume first row is header

        columns = len(header)
        columnTypes = {}
        for i in range(columns): columnTypes[i] = None

        checked = 0
        for row in rdr:
            # arbitrary number of rows to check, to keep it sane
            if checked > 20:
                break
            checked += 1

            if len(row) != columns:
                continue # skip rows that have irregular number of columns

            for col in list(columnTypes.keys()):

                for thisType in [int, float, complex]:
                    try:
                        thisType(row[col])
                        break
                    except (ValueError, OverflowError):
                        pass
                else:
                    # fallback to length of string
                    thisType = len(row[col])

                if thisType != columnTypes[col]:
                    if columnTypes[col] is None: # add new column type
                        columnTypes[col] = thisType
                    else:
                        # type is inconsistent, remove column from
                        # consideration
                        del columnTypes[col]

        # finally, compare results against first row and "vote"
        # on whether it's a header
        hasHeader = 0
        for col, colType in columnTypes.items():
            if type(colType) == type(0): # it's a length
                if len(header[col]) != colType:
                    hasHeader += 1
                else:
                    hasHeader -= 1
            else: # attempt typecast
                try:
                    colType(header[col])
                except (ValueError, TypeError):
                    hasHeader += 1
                else:
                    hasHeader -= 1

        return hasHeader > 0
lib\datetime.py
"""Concrete date/time and related types.

See http://www.iana.org/time-zones/repository/tz-link.html for
time zone and DST data sources.
"""

import time as _time
import math as _math

def _cmp(x, y):
    return 0 if x == y else 1 if x > y else -1

MINYEAR = 1
MAXYEAR = 9999
_MAXORDINAL = 3652059 # date.max.toordinal()

# Utility functions, adapted from Python's Demo/classes/Dates.py, which
# also assumes the current Gregorian calendar indefinitely extended in
# both directions.  Difference:  Dates.py calls January 1 of year 0 day
# number 1.  The code here calls January 1 of year 1 day number 1.  This is
# to match the definition of the "proleptic Gregorian" calendar in Dershowitz
# and Reingold's "Calendrical Calculations", where it's the base calendar
# for all computations.  See the book for algorithms for converting between
# proleptic Gregorian ordinals and many other calendar systems.

# -1 is a placeholder for indexing purposes.
_DAYS_IN_MONTH = [-1, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]

_DAYS_BEFORE_MONTH = [-1] # -1 is a placeholder for indexing purposes.
dbm = 0
for dim in _DAYS_IN_MONTH[1:]:
    _DAYS_BEFORE_MONTH.append(dbm)
    dbm += dim
del dbm, dim

def _is_leap(year):
    "year -> 1 if leap year, else 0."
    return year % 4 == 0 and (year % 100 != 0 or year % 400 == 0)

def _days_before_year(year):
    "year -> number of days before January 1st of year."
    y = year - 1
    return y*365 + y//4 - y//100 + y//400

def _days_in_month(year, month):
    "year, month -> number of days in that month in that year."
    assert 1 <= month <= 12, month
    if month == 2 and _is_leap(year):
        return 29
    return _DAYS_IN_MONTH[month]

def _days_before_month(year, month):
    "year, month -> number of days in year preceding first day of month."
    assert 1 <= month <= 12, 'month must be in 1..12'
    return _DAYS_BEFORE_MONTH[month] + (month > 2 and _is_leap(year))

def _ymd2ord(year, month, day):
    "year, month, day -> ordinal, considering 01-Jan-0001 as day 1."
    assert 1 <= month <= 12, 'month must be in 1..12'
    dim = _days_in_month(year, month)
    assert 1 <= day <= dim, ('day must be in 1..%d' % dim)
    return (_days_before_year(year) +
            _days_before_month(year, month) +
            day)

_DI400Y = _days_before_year(401)    # number of days in 400 years
_DI100Y = _days_before_year(101)    #    "    "   "   " 100   "
_DI4Y   = _days_before_year(5)      #    "    "   "   "   4   "

# A 4-year cycle has an extra leap day over what we'd get from pasting
# together 4 single years.
assert _DI4Y == 4 * 365 + 1

# Similarly, a 400-year cycle has an extra leap day over what we'd get from
# pasting together 4 100-year cycles.
assert _DI400Y == 4 * _DI100Y + 1

# OTOH, a 100-year cycle has one fewer leap day than we'd get from
# pasting together 25 4-year cycles.
assert _DI100Y == 25 * _DI4Y - 1

def _ord2ymd(n):
    "ordinal -> (year, month, day), considering 01-Jan-0001 as day 1."

    # n is a 1-based index, starting at 1-Jan-1.  The pattern of leap years
    # repeats exactly every 400 years.  The basic strategy is to find the
    # closest 400-year boundary at or before n, then work with the offset
    # from that boundary to n.  Life is much clearer if we subtract 1 from
    # n first -- then the values of n at 400-year boundaries are exactly
    # those divisible by _DI400Y:
    #
    #     D  M   Y            n              n-1
    #     -- --- ----        ----------     ----------------
    #     31 Dec -400        -_DI400Y       -_DI400Y -1
    #      1 Jan -399         -_DI400Y +1   -_DI400Y      400-year boundary
    #     ...
    #     30 Dec  000        -1             -2
    #     31 Dec  000         0             -1
    #      1 Jan  001         1              0            400-year boundary
    #      2 Jan  001         2              1
    #      3 Jan  001         3              2
    #     ...
    #     31 Dec  400         _DI400Y        _DI400Y -1
    #      1 Jan  401         _DI400Y +1     _DI400Y      400-year boundary
    n -= 1
    n400, n = divmod(n, _DI400Y)
    year = n400 * 400 + 1   # ..., -399, 1, 401, ...

    # Now n is the (non-negative) offset, in days, from January 1 of year, to
    # the desired date.  Now compute how many 100-year cycles precede n.
    # Note that it's possible for n100 to equal 4!  In that case 4 full
    # 100-year cycles precede the desired day, which implies the desired
    # day is December 31 at the end of a 400-year cycle.
    n100, n = divmod(n, _DI100Y)

    # Now compute how many 4-year cycles precede it.
    n4, n = divmod(n, _DI4Y)

    # And now how many single years.  Again n1 can be 4, and again meaning
    # that the desired day is December 31 at the end of the 4-year cycle.
    n1, n = divmod(n, 365)

    year += n100 * 100 + n4 * 4 + n1
    if n1 == 4 or n100 == 4:
        assert n == 0
        return year-1, 12, 31

    # Now the year is correct, and n is the offset from January 1.  We find
    # the month via an estimate that's either exact or one too large.
    leapyear = n1 == 3 and (n4 != 24 or n100 == 3)
    assert leapyear == _is_leap(year)
    month = (n + 50) >> 5
    preceding = _DAYS_BEFORE_MONTH[month] + (month > 2 and leapyear)
    if preceding > n:  # estimate is too large
        month -= 1
        preceding -= _DAYS_IN_MONTH[month] + (month == 2 and leapyear)
    n -= preceding
    assert 0 <= n < _days_in_month(year, month)

    # Now the year and month are correct, and n is the offset from the
    # start of that month:  we're done!
    return year, month, n+1

# Month and day names.  For localized versions, see the calendar module.
_MONTHNAMES = [None, "Jan", "Feb", "Mar", "Apr", "May", "Jun",
                     "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
_DAYNAMES = [None, "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"]


def _build_struct_time(y, m, d, hh, mm, ss, dstflag):
    wday = (_ymd2ord(y, m, d) + 6) % 7
    dnum = _days_before_month(y, m) + d
    return _time.struct_time((y, m, d, hh, mm, ss, wday, dnum, dstflag))

def _format_time(hh, mm, ss, us):
    # Skip trailing microseconds when us==0.
    result = "%02d:%02d:%02d" % (hh, mm, ss)
    if us:
        result += ".%06d" % us
    return result

# Correctly substitute for %z and %Z escapes in strftime formats.
def _wrap_strftime(object, format, timetuple):
    # Don't call utcoffset() or tzname() unless actually needed.
    freplace = None # the string to use for %f
    zreplace = None # the string to use for %z
    Zreplace = None # the string to use for %Z

    # Scan format for %z and %Z escapes, replacing as needed.
    newformat = []
    push = newformat.append
    i, n = 0, len(format)
    while i < n:
        ch = format[i]
        i += 1
        if ch == '%':
            if i < n:
                ch = format[i]
                i += 1
                if ch == 'f':
                    if freplace is None:
                        freplace = '%06d' % getattr(object,
                                                    'microsecond', 0)
                    newformat.append(freplace)
                elif ch == 'z':
                    if zreplace is None:
                        zreplace = ""
                        if hasattr(object, "utcoffset"):
                            offset = object.utcoffset()
                            if offset is not None:
                                sign = '+'
                                if offset.days < 0:
                                    offset = -offset
                                    sign = '-'
                                h, m = divmod(offset, timedelta(hours=1))
                                assert not m % timedelta(minutes=1), "whole minute"
                                m //= timedelta(minutes=1)
                                zreplace = '%c%02d%02d' % (sign, h, m)
                    assert '%' not in zreplace
                    newformat.append(zreplace)
                elif ch == 'Z':
                    if Zreplace is None:
                        Zreplace = ""
                        if hasattr(object, "tzname"):
                            s = object.tzname()
                            if s is not None:
                                # strftime is going to have at this: escape %
                                Zreplace = s.replace('%', '%%')
                    newformat.append(Zreplace)
                else:
                    push('%')
                    push(ch)
            else:
                push('%')
        else:
            push(ch)
    newformat = "".join(newformat)
    return _time.strftime(newformat, timetuple)

def _call_tzinfo_method(tzinfo, methname, tzinfoarg):
    if tzinfo is None:
        return None
    return getattr(tzinfo, methname)(tzinfoarg)

# Just raise TypeError if the arg isn't None or a string.
def _check_tzname(name):
    if name is not None and not isinstance(name, str):
        raise TypeError("tzinfo.tzname() must return None or string, "
                        "not '%s'" % type(name))

# name is the offset-producing method, "utcoffset" or "dst".
# offset is what it returned.
# If offset isn't None or timedelta, raises TypeError.
# If offset is None, returns None.
# Else offset is checked for being in range, and a whole # of minutes.
# If it is, its integer value is returned.  Else ValueError is raised.
def _check_utc_offset(name, offset):
    assert name in ("utcoffset", "dst")
    if offset is None:
        return
    if not isinstance(offset, timedelta):
        raise TypeError("tzinfo.%s() must return None "
                        "or timedelta, not '%s'" % (name, type(offset)))
    if offset % timedelta(minutes=1) or offset.microseconds:
        raise ValueError("tzinfo.%s() must return a whole number "
                         "of minutes, got %s" % (name, offset))
    if not -timedelta(1) < offset < timedelta(1):
        raise ValueError("%s()=%s, must be must be strictly between"
                         " -timedelta(hours=24) and timedelta(hours=24)"
                         % (name, offset))

def _check_date_fields(year, month, day):
    if not isinstance(year, int):
        raise TypeError('int expected')
    if not MINYEAR <= year <= MAXYEAR:
        raise ValueError('year must be in %d..%d' % (MINYEAR, MAXYEAR), year)
    if not 1 <= month <= 12:
        raise ValueError('month must be in 1..12', month)
    dim = _days_in_month(year, month)
    if not 1 <= day <= dim:
        raise ValueError('day must be in 1..%d' % dim, day)

def _check_time_fields(hour, minute, second, microsecond):
    if not isinstance(hour, int):
        raise TypeError('int expected')
    if not 0 <= hour <= 23:
        raise ValueError('hour must be in 0..23', hour)
    if not 0 <= minute <= 59:
        raise ValueError('minute must be in 0..59', minute)
    if not 0 <= second <= 59:
        raise ValueError('second must be in 0..59', second)
    if not 0 <= microsecond <= 999999:
        raise ValueError('microsecond must be in 0..999999', microsecond)

def _check_tzinfo_arg(tz):
    if tz is not None and not isinstance(tz, tzinfo):
        raise TypeError("tzinfo argument must be None or of a tzinfo subclass")

def _cmperror(x, y):
    raise TypeError("can't compare '%s' to '%s'" % (
                    type(x).__name__, type(y).__name__))

def _divide_and_round(a, b):
    """divide a by b and round result to the nearest integer

    When the ratio is exactly half-way between two integers,
    the even integer is returned.
    """
    # Based on the reference implementation for divmod_near
    # in Objects/longobject.c.
    q, r = divmod(a, b)
    # round up if either r / b > 0.5, or r / b == 0.5 and q is odd.
    # The expression r / b > 0.5 is equivalent to 2 * r > b if b is
    # positive, 2 * r < b if b negative.
    r *= 2
    greater_than_half = r > b if b > 0 else r < b
    if greater_than_half or r == b and q % 2 == 1:
        q += 1

    return q

class timedelta:
    """Represent the difference between two datetime objects.

    Supported operators:

    - add, subtract timedelta
    - unary plus, minus, abs
    - compare to timedelta
    - multiply, divide by int

    In addition, datetime supports subtraction of two datetime objects
    returning a timedelta, and addition or subtraction of a datetime
    and a timedelta giving a datetime.

    Representation: (days, seconds, microseconds).  Why?  Because I
    felt like it.
    """
    __slots__ = '_days', '_seconds', '_microseconds'

    def __new__(cls, days=0, seconds=0, microseconds=0,
                milliseconds=0, minutes=0, hours=0, weeks=0):
        # Doing this efficiently and accurately in C is going to be difficult
        # and error-prone, due to ubiquitous overflow possibilities, and that
        # C double doesn't have enough bits of precision to represent
        # microseconds over 10K years faithfully.  The code here tries to make
        # explicit where go-fast assumptions can be relied on, in order to
        # guide the C implementation; it's way more convoluted than speed-
        # ignoring auto-overflow-to-long idiomatic Python could be.

        # XXX Check that all inputs are ints or floats.

        # Final values, all integer.
        # s and us fit in 32-bit signed ints; d isn't bounded.
        d = s = us = 0

        # Normalize everything to days, seconds, microseconds.
        days += weeks*7
        seconds += minutes*60 + hours*3600
        microseconds += milliseconds*1000

        # Get rid of all fractions, and normalize s and us.
        # Take a deep breath <wink>.
        if isinstance(days, float):
            dayfrac, days = _math.modf(days)
            daysecondsfrac, daysecondswhole = _math.modf(dayfrac * (24.*3600.))
            assert daysecondswhole == int(daysecondswhole)  # can't overflow
            s = int(daysecondswhole)
            assert days == int(days)
            d = int(days)
        else:
            daysecondsfrac = 0.0
            d = days
        assert isinstance(daysecondsfrac, float)
        assert abs(daysecondsfrac) <= 1.0
        assert isinstance(d, int)
        assert abs(s) <= 24 * 3600
        # days isn't referenced again before redefinition

        if isinstance(seconds, float):
            secondsfrac, seconds = _math.modf(seconds)
            assert seconds == int(seconds)
            seconds = int(seconds)
            secondsfrac += daysecondsfrac
            assert abs(secondsfrac) <= 2.0
        else:
            secondsfrac = daysecondsfrac
        # daysecondsfrac isn't referenced again
        assert isinstance(secondsfrac, float)
        assert abs(secondsfrac) <= 2.0

        assert isinstance(seconds, int)
        days, seconds = divmod(seconds, 24*3600)
        d += days
        s += int(seconds)    # can't overflow
        assert isinstance(s, int)
        assert abs(s) <= 2 * 24 * 3600
        # seconds isn't referenced again before redefinition

        usdouble = secondsfrac * 1e6
        assert abs(usdouble) < 2.1e6    # exact value not critical
        # secondsfrac isn't referenced again

        if isinstance(microseconds, float):
            microseconds += usdouble
            microseconds = round(microseconds, 0)
            seconds, microseconds = divmod(microseconds, 1e6)
            assert microseconds == int(microseconds)
            assert seconds == int(seconds)
            days, seconds = divmod(seconds, 24.*3600.)
            assert days == int(days)
            assert seconds == int(seconds)
            d += int(days)
            s += int(seconds)   # can't overflow
            assert isinstance(s, int)
            assert abs(s) <= 3 * 24 * 3600
        else:
            seconds, microseconds = divmod(microseconds, 1000000)
            days, seconds = divmod(seconds, 24*3600)
            d += days
            s += int(seconds)    # can't overflow
            assert isinstance(s, int)
            assert abs(s) <= 3 * 24 * 3600
            microseconds = float(microseconds)
            microseconds += usdouble
            microseconds = round(microseconds, 0)
        assert abs(s) <= 3 * 24 * 3600
        assert abs(microseconds) < 3.1e6

        # Just a little bit of carrying possible for microseconds and seconds.
        assert isinstance(microseconds, float)
        assert int(microseconds) == microseconds
        us = int(microseconds)
        seconds, us = divmod(us, 1000000)
        s += seconds    # cant't overflow
        assert isinstance(s, int)
        days, s = divmod(s, 24*3600)
        d += days

        assert isinstance(d, int)
        assert isinstance(s, int) and 0 <= s < 24*3600
        assert isinstance(us, int) and 0 <= us < 1000000

        self = object.__new__(cls)

        self._days = d
        self._seconds = s
        self._microseconds = us
        if abs(d) > 999999999:
            raise OverflowError("timedelta # of days is too large: %d" % d)

        return self

    def __repr__(self):
        if self._microseconds:
            return "%s(%d, %d, %d)" % ('datetime.' + self.__class__.__name__,
                                       self._days,
                                       self._seconds,
                                       self._microseconds)
        if self._seconds:
            return "%s(%d, %d)" % ('datetime.' + self.__class__.__name__,
                                   self._days,
                                   self._seconds)
        return "%s(%d)" % ('datetime.' + self.__class__.__name__, self._days)

    def __str__(self):
        mm, ss = divmod(self._seconds, 60)
        hh, mm = divmod(mm, 60)
        s = "%d:%02d:%02d" % (hh, mm, ss)
        if self._days:
            def plural(n):
                return n, abs(n) != 1 and "s" or ""
            s = ("%d day%s, " % plural(self._days)) + s
        if self._microseconds:
            s = s + ".%06d" % self._microseconds
        return s

    def total_seconds(self):
        """Total seconds in the duration."""
        return ((self.days * 86400 + self.seconds)*10**6 +
                self.microseconds) / 10**6

    # Read-only field accessors
    @property
    def days(self):
        """days"""
        return self._days

    @property
    def seconds(self):
        """seconds"""
        return self._seconds

    @property
    def microseconds(self):
        """microseconds"""
        return self._microseconds

    def __add__(self, other):
        if isinstance(other, timedelta):
            # for CPython compatibility, we cannot use
            # our __class__ here, but need a real timedelta
            return timedelta(self._days + other._days,
                             self._seconds + other._seconds,
                             self._microseconds + other._microseconds)
        return NotImplemented

    __radd__ = __add__

    def __sub__(self, other):
        if isinstance(other, timedelta):
            # for CPython compatibility, we cannot use
            # our __class__ here, but need a real timedelta
            return timedelta(self._days - other._days,
                             self._seconds - other._seconds,
                             self._microseconds - other._microseconds)
        return NotImplemented

    def __rsub__(self, other):
        if isinstance(other, timedelta):
            return -self + other
        return NotImplemented

    def __neg__(self):
        # for CPython compatibility, we cannot use
        # our __class__ here, but need a real timedelta
        return timedelta(-self._days,
                         -self._seconds,
                         -self._microseconds)

    def __pos__(self):
        return self

    def __abs__(self):
        if self._days < 0:
            return -self
        else:
            return self

    def __mul__(self, other):
        if isinstance(other, int):
            # for CPython compatibility, we cannot use
            # our __class__ here, but need a real timedelta
            return timedelta(self._days * other,
                             self._seconds * other,
                             self._microseconds * other)
        if isinstance(other, float):
            usec = self._to_microseconds()
            a, b = other.as_integer_ratio()
            return timedelta(0, 0, _divide_and_round(usec * a, b))
        return NotImplemented

    __rmul__ = __mul__

    def _to_microseconds(self):
        return ((self._days * (24*3600) + self._seconds) * 1000000 +
                self._microseconds)

    def __floordiv__(self, other):
        if not isinstance(other, (int, timedelta)):
            return NotImplemented
        usec = self._to_microseconds()
        if isinstance(other, timedelta):
            return usec // other._to_microseconds()
        if isinstance(other, int):
            return timedelta(0, 0, usec // other)

    def __truediv__(self, other):
        if not isinstance(other, (int, float, timedelta)):
            return NotImplemented
        usec = self._to_microseconds()
        if isinstance(other, timedelta):
            return usec / other._to_microseconds()
        if isinstance(other, int):
            return timedelta(0, 0, _divide_and_round(usec, other))
        if isinstance(other, float):
            a, b = other.as_integer_ratio()
            return timedelta(0, 0, _divide_and_round(b * usec, a))

    def __mod__(self, other):
        if isinstance(other, timedelta):
            r = self._to_microseconds() % other._to_microseconds()
            return timedelta(0, 0, r)
        return NotImplemented

    def __divmod__(self, other):
        if isinstance(other, timedelta):
            q, r = divmod(self._to_microseconds(),
                          other._to_microseconds())
            return q, timedelta(0, 0, r)
        return NotImplemented

    # Comparisons of timedelta objects with other.

    def __eq__(self, other):
        if isinstance(other, timedelta):
            return self._cmp(other) == 0
        else:
            return False

    def __ne__(self, other):
        if isinstance(other, timedelta):
            return self._cmp(other) != 0
        else:
            return True

    def __le__(self, other):
        if isinstance(other, timedelta):
            return self._cmp(other) <= 0
        else:
            _cmperror(self, other)

    def __lt__(self, other):
        if isinstance(other, timedelta):
            return self._cmp(other) < 0
        else:
            _cmperror(self, other)

    def __ge__(self, other):
        if isinstance(other, timedelta):
            return self._cmp(other) >= 0
        else:
            _cmperror(self, other)

    def __gt__(self, other):
        if isinstance(other, timedelta):
            return self._cmp(other) > 0
        else:
            _cmperror(self, other)

    def _cmp(self, other):
        assert isinstance(other, timedelta)
        return _cmp(self._getstate(), other._getstate())

    def __hash__(self):
        return hash(self._getstate())

    def __bool__(self):
        return (self._days != 0 or
                self._seconds != 0 or
                self._microseconds != 0)

    # Pickle support.

    def _getstate(self):
        return (self._days, self._seconds, self._microseconds)

    def __reduce__(self):
        return (self.__class__, self._getstate())

timedelta.min = timedelta(-999999999)
timedelta.max = timedelta(days=999999999, hours=23, minutes=59, seconds=59,
                          microseconds=999999)
timedelta.resolution = timedelta(microseconds=1)

class date:
    """Concrete date type.

    Constructors:

    __new__()
    fromtimestamp()
    today()
    fromordinal()

    Operators:

    __repr__, __str__
    __eq__, __le__, __lt__, __ge__, __gt__, __hash__
    __add__, __radd__, __sub__ (add/radd only with timedelta arg)

    Methods:

    timetuple()
    toordinal()
    weekday()
    isoweekday(), isocalendar(), isoformat()
    ctime()
    strftime()

    Properties (readonly):
    year, month, day
    """
    __slots__ = '_year', '_month', '_day'

    def __new__(cls, year, month=None, day=None):
        """Constructor.

        Arguments:

        year, month, day (required, base 1)
        """
        if (isinstance(year, bytes) and len(year) == 4 and
            1 <= year[2] <= 12 and month is None):  # Month is sane
            # Pickle support
            self = object.__new__(cls)
            self.__setstate(year)
            return self
        _check_date_fields(year, month, day)
        self = object.__new__(cls)
        self._year = year
        self._month = month
        self._day = day
        return self

    # Additional constructors

    @classmethod
    def fromtimestamp(cls, t):
        "Construct a date from a POSIX timestamp (like time.time())."
        y, m, d, hh, mm, ss, weekday, jday, dst = _time.localtime(t)
        return cls(y, m, d)

    @classmethod
    def today(cls):
        "Construct a date from time.time()."
        t = _time.time()
        return cls.fromtimestamp(t)

    @classmethod
    def fromordinal(cls, n):
        """Contruct a date from a proleptic Gregorian ordinal.

        January 1 of year 1 is day 1.  Only the year, month and day are
        non-zero in the result.
        """
        y, m, d = _ord2ymd(n)
        return cls(y, m, d)

    # Conversions to string

    def __repr__(self):
        """Convert to formal string, for repr().

        >>> dt = datetime(2010, 1, 1)
        >>> repr(dt)
        'datetime.datetime(2010, 1, 1, 0, 0)'

        >>> dt = datetime(2010, 1, 1, tzinfo=timezone.utc)
        >>> repr(dt)
        'datetime.datetime(2010, 1, 1, 0, 0, tzinfo=datetime.timezone.utc)'
        """
        return "%s(%d, %d, %d)" % ('datetime.' + self.__class__.__name__,
                                   self._year,
                                   self._month,
                                   self._day)
    # XXX These shouldn't depend on time.localtime(), because that
    # clips the usable dates to [1970 .. 2038).  At least ctime() is
    # easily done without using strftime() -- that's better too because
    # strftime("%c", ...) is locale specific.


    def ctime(self):
        "Return ctime() style string."
        weekday = self.toordinal() % 7 or 7
        return "%s %s %2d 00:00:00 %04d" % (
            _DAYNAMES[weekday],
            _MONTHNAMES[self._month],
            self._day, self._year)

    def strftime(self, fmt):
        "Format using strftime()."
        return _wrap_strftime(self, fmt, self.timetuple())

    def __format__(self, fmt):
        if len(fmt) != 0:
            return self.strftime(fmt)
        return str(self)

    def isoformat(self):
        """Return the date formatted according to ISO.

        This is 'YYYY-MM-DD'.

        References:
        - http://www.w3.org/TR/NOTE-datetime
        - http://www.cl.cam.ac.uk/~mgk25/iso-time.html
        """
        return "%04d-%02d-%02d" % (self._year, self._month, self._day)

    __str__ = isoformat

    # Read-only field accessors
    @property
    def year(self):
        """year (1-9999)"""
        return self._year

    @property
    def month(self):
        """month (1-12)"""
        return self._month

    @property
    def day(self):
        """day (1-31)"""
        return self._day

    # Standard conversions, __eq__, __le__, __lt__, __ge__, __gt__,
    # __hash__ (and helpers)

    def timetuple(self):
        "Return local time tuple compatible with time.localtime()."
        return _build_struct_time(self._year, self._month, self._day,
                                  0, 0, 0, -1)

    def toordinal(self):
        """Return proleptic Gregorian ordinal for the year, month and day.

        January 1 of year 1 is day 1.  Only the year, month and day values
        contribute to the result.
        """
        return _ymd2ord(self._year, self._month, self._day)

    def replace(self, year=None, month=None, day=None):
        """Return a new date with new values for the specified fields."""
        if year is None:
            year = self._year
        if month is None:
            month = self._month
        if day is None:
            day = self._day
        _check_date_fields(year, month, day)
        return date(year, month, day)

    # Comparisons of date objects with other.

    def __eq__(self, other):
        if isinstance(other, date):
            return self._cmp(other) == 0
        return NotImplemented

    def __ne__(self, other):
        if isinstance(other, date):
            return self._cmp(other) != 0
        return NotImplemented

    def __le__(self, other):
        if isinstance(other, date):
            return self._cmp(other) <= 0
        return NotImplemented

    def __lt__(self, other):
        if isinstance(other, date):
            return self._cmp(other) < 0
        return NotImplemented

    def __ge__(self, other):
        if isinstance(other, date):
            return self._cmp(other) >= 0
        return NotImplemented

    def __gt__(self, other):
        if isinstance(other, date):
            return self._cmp(other) > 0
        return NotImplemented

    def _cmp(self, other):
        assert isinstance(other, date)
        y, m, d = self._year, self._month, self._day
        y2, m2, d2 = other._year, other._month, other._day
        return _cmp((y, m, d), (y2, m2, d2))

    def __hash__(self):
        "Hash."
        return hash(self._getstate())

    # Computations

    def __add__(self, other):
        "Add a date to a timedelta."
        if isinstance(other, timedelta):
            o = self.toordinal() + other.days
            if 0 < o <= _MAXORDINAL:
                return date.fromordinal(o)
            raise OverflowError("result out of range")
        return NotImplemented

    __radd__ = __add__

    def __sub__(self, other):
        """Subtract two dates, or a date and a timedelta."""
        if isinstance(other, timedelta):
            return self + timedelta(-other.days)
        if isinstance(other, date):
            days1 = self.toordinal()
            days2 = other.toordinal()
            return timedelta(days1 - days2)
        return NotImplemented

    def weekday(self):
        "Return day of the week, where Monday == 0 ... Sunday == 6."
        return (self.toordinal() + 6) % 7

    # Day-of-the-week and week-of-the-year, according to ISO

    def isoweekday(self):
        "Return day of the week, where Monday == 1 ... Sunday == 7."
        # 1-Jan-0001 is a Monday
        return self.toordinal() % 7 or 7

    def isocalendar(self):
        """Return a 3-tuple containing ISO year, week number, and weekday.

        The first ISO week of the year is the (Mon-Sun) week
        containing the year's first Thursday; everything else derives
        from that.

        The first week is 1; Monday is 1 ... Sunday is 7.

        ISO calendar algorithm taken from
        http://www.phys.uu.nl/~vgent/calendar/isocalendar.htm
        """
        year = self._year
        week1monday = _isoweek1monday(year)
        today = _ymd2ord(self._year, self._month, self._day)
        # Internally, week and day have origin 0
        week, day = divmod(today - week1monday, 7)
        if week < 0:
            year -= 1
            week1monday = _isoweek1monday(year)
            week, day = divmod(today - week1monday, 7)
        elif week >= 52:
            if today >= _isoweek1monday(year+1):
                year += 1
                week = 0
        return year, week+1, day+1

    # Pickle support.

    def _getstate(self):
        yhi, ylo = divmod(self._year, 256)
        return bytes([yhi, ylo, self._month, self._day]),

    def __setstate(self, string):
        if len(string) != 4 or not (1 <= string[2] <= 12):
            raise TypeError("not enough arguments")
        yhi, ylo, self._month, self._day = string
        self._year = yhi * 256 + ylo

    def __reduce__(self):
        return (self.__class__, self._getstate())

_date_class = date  # so functions w/ args named "date" can get at the class

date.min = date(1, 1, 1)
date.max = date(9999, 12, 31)
date.resolution = timedelta(days=1)

class tzinfo:
    """Abstract base class for time zone info classes.

    Subclasses must override the name(), utcoffset() and dst() methods.
    """
    __slots__ = ()
    def tzname(self, dt):
        "datetime -> string name of time zone."
        raise NotImplementedError("tzinfo subclass must override tzname()")

    def utcoffset(self, dt):
        "datetime -> minutes east of UTC (negative for west of UTC)"
        raise NotImplementedError("tzinfo subclass must override utcoffset()")

    def dst(self, dt):
        """datetime -> DST offset in minutes east of UTC.

        Return 0 if DST not in effect.  utcoffset() must include the DST
        offset.
        """
        raise NotImplementedError("tzinfo subclass must override dst()")

    def fromutc(self, dt):
        "datetime in UTC -> datetime in local time."

        if not isinstance(dt, datetime):
            raise TypeError("fromutc() requires a datetime argument")
        if dt.tzinfo is not self:
            raise ValueError("dt.tzinfo is not self")

        dtoff = dt.utcoffset()
        if dtoff is None:
            raise ValueError("fromutc() requires a non-None utcoffset() "
                             "result")

        # See the long comment block at the end of this file for an
        # explanation of this algorithm.
        dtdst = dt.dst()
        if dtdst is None:
            raise ValueError("fromutc() requires a non-None dst() result")
        delta = dtoff - dtdst
        if delta:
            dt += delta
            dtdst = dt.dst()
            if dtdst is None:
                raise ValueError("fromutc(): dt.dst gave inconsistent "
                                 "results; cannot convert")
        return dt + dtdst

    # Pickle support.

    def __reduce__(self):
        getinitargs = getattr(self, "__getinitargs__", None)
        if getinitargs:
            args = getinitargs()
        else:
            args = ()
        getstate = getattr(self, "__getstate__", None)
        if getstate:
            state = getstate()
        else:
            state = getattr(self, "__dict__", None) or None
        if state is None:
            return (self.__class__, args)
        else:
            return (self.__class__, args, state)

_tzinfo_class = tzinfo

class time:
    """Time with time zone.

    Constructors:

    __new__()

    Operators:

    __repr__, __str__
    __eq__, __le__, __lt__, __ge__, __gt__, __hash__

    Methods:

    strftime()
    isoformat()
    utcoffset()
    tzname()
    dst()

    Properties (readonly):
    hour, minute, second, microsecond, tzinfo
    """

    def __new__(cls, hour=0, minute=0, second=0, microsecond=0, tzinfo=None):
        """Constructor.

        Arguments:

        hour, minute (required)
        second, microsecond (default to zero)
        tzinfo (default to None)
        """
        self = object.__new__(cls)
        if isinstance(hour, bytes) and len(hour) == 6:
            # Pickle support
            self.__setstate(hour, minute or None)
            return self
        _check_tzinfo_arg(tzinfo)
        _check_time_fields(hour, minute, second, microsecond)
        self._hour = hour
        self._minute = minute
        self._second = second
        self._microsecond = microsecond
        self._tzinfo = tzinfo
        return self

    # Read-only field accessors
    @property
    def hour(self):
        """hour (0-23)"""
        return self._hour

    @property
    def minute(self):
        """minute (0-59)"""
        return self._minute

    @property
    def second(self):
        """second (0-59)"""
        return self._second

    @property
    def microsecond(self):
        """microsecond (0-999999)"""
        return self._microsecond

    @property
    def tzinfo(self):
        """timezone info object"""
        return self._tzinfo

    # Standard conversions, __hash__ (and helpers)

    # Comparisons of time objects with other.

    def __eq__(self, other):
        if isinstance(other, time):
            return self._cmp(other, allow_mixed=True) == 0
        else:
            return False

    def __ne__(self, other):
        if isinstance(other, time):
            return self._cmp(other, allow_mixed=True) != 0
        else:
            return True

    def __le__(self, other):
        if isinstance(other, time):
            return self._cmp(other) <= 0
        else:
            _cmperror(self, other)

    def __lt__(self, other):
        if isinstance(other, time):
            return self._cmp(other) < 0
        else:
            _cmperror(self, other)

    def __ge__(self, other):
        if isinstance(other, time):
            return self._cmp(other) >= 0
        else:
            _cmperror(self, other)

    def __gt__(self, other):
        if isinstance(other, time):
            return self._cmp(other) > 0
        else:
            _cmperror(self, other)

    def _cmp(self, other, allow_mixed=False):
        assert isinstance(other, time)
        mytz = self._tzinfo
        ottz = other._tzinfo
        myoff = otoff = None

        if mytz is ottz:
            base_compare = True
        else:
            myoff = self.utcoffset()
            otoff = other.utcoffset()
            base_compare = myoff == otoff

        if base_compare:
            return _cmp((self._hour, self._minute, self._second,
                         self._microsecond),
                       (other._hour, other._minute, other._second,
                        other._microsecond))
        if myoff is None or otoff is None:
            if allow_mixed:
                return 2 # arbitrary non-zero value
            else:
                raise TypeError("cannot compare naive and aware times")
        myhhmm = self._hour * 60 + self._minute - myoff//timedelta(minutes=1)
        othhmm = other._hour * 60 + other._minute - otoff//timedelta(minutes=1)
        return _cmp((myhhmm, self._second, self._microsecond),
                    (othhmm, other._second, other._microsecond))

    def __hash__(self):
        """Hash."""
        tzoff = self.utcoffset()
        if not tzoff: # zero or None
            return hash(self._getstate()[0])
        h, m = divmod(timedelta(hours=self.hour, minutes=self.minute) - tzoff,
                      timedelta(hours=1))
        assert not m % timedelta(minutes=1), "whole minute"
        m //= timedelta(minutes=1)
        if 0 <= h < 24:
            return hash(time(h, m, self.second, self.microsecond))
        return hash((h, m, self.second, self.microsecond))

    # Conversion to string

    def _tzstr(self, sep=":"):
        """Return formatted timezone offset (+xx:xx) or None."""
        off = self.utcoffset()
        if off is not None:
            if off.days < 0:
                sign = "-"
                off = -off
            else:
                sign = "+"
            hh, mm = divmod(off, timedelta(hours=1))
            assert not mm % timedelta(minutes=1), "whole minute"
            mm //= timedelta(minutes=1)
            assert 0 <= hh < 24
            off = "%s%02d%s%02d" % (sign, hh, sep, mm)
        return off

    def __repr__(self):
        """Convert to formal string, for repr()."""
        if self._microsecond != 0:
            s = ", %d, %d" % (self._second, self._microsecond)
        elif self._second != 0:
            s = ", %d" % self._second
        else:
            s = ""
        s= "%s(%d, %d%s)" % ('datetime.' + self.__class__.__name__,
                             self._hour, self._minute, s)
        if self._tzinfo is not None:
            assert s[-1:] == ")"
            s = s[:-1] + ", tzinfo=%r" % self._tzinfo + ")"
        return s

    def isoformat(self):
        """Return the time formatted according to ISO.

        This is 'HH:MM:SS.mmmmmm+zz:zz', or 'HH:MM:SS+zz:zz' if
        self.microsecond == 0.
        """
        s = _format_time(self._hour, self._minute, self._second,
                         self._microsecond)
        tz = self._tzstr()
        if tz:
            s += tz
        return s

    __str__ = isoformat

    def strftime(self, fmt):
        """Format using strftime().  The date part of the timestamp passed
        to underlying strftime should not be used.
        """
        # The year must be >= 1000 else Python's strftime implementation
        # can raise a bogus exception.
        timetuple = (1900, 1, 1,
                     self._hour, self._minute, self._second,
                     0, 1, -1)
        return _wrap_strftime(self, fmt, timetuple)

    def __format__(self, fmt):
        if len(fmt) != 0:
            return self.strftime(fmt)
        return str(self)

    # Timezone functions

    def utcoffset(self):
        """Return the timezone offset in minutes east of UTC (negative west of
        UTC)."""
        if self._tzinfo is None:
            return None
        offset = self._tzinfo.utcoffset(None)
        _check_utc_offset("utcoffset", offset)
        return offset

    def tzname(self):
        """Return the timezone name.

        Note that the name is 100% informational -- there's no requirement that
        it mean anything in particular. For example, "GMT", "UTC", "-500",
        "-5:00", "EDT", "US/Eastern", "America/New York" are all valid replies.
        """
        if self._tzinfo is None:
            return None
        name = self._tzinfo.tzname(None)
        _check_tzname(name)
        return name

    def dst(self):
        """Return 0 if DST is not in effect, or the DST offset (in minutes
        eastward) if DST is in effect.

        This is purely informational; the DST offset has already been added to
        the UTC offset returned by utcoffset() if applicable, so there's no
        need to consult dst() unless you're interested in displaying the DST
        info.
        """
        if self._tzinfo is None:
            return None
        offset = self._tzinfo.dst(None)
        _check_utc_offset("dst", offset)
        return offset

    def replace(self, hour=None, minute=None, second=None, microsecond=None,
                tzinfo=True):
        """Return a new time with new values for the specified fields."""
        if hour is None:
            hour = self.hour
        if minute is None:
            minute = self.minute
        if second is None:
            second = self.second
        if microsecond is None:
            microsecond = self.microsecond
        if tzinfo is True:
            tzinfo = self.tzinfo
        _check_time_fields(hour, minute, second, microsecond)
        _check_tzinfo_arg(tzinfo)
        return time(hour, minute, second, microsecond, tzinfo)

    def __bool__(self):
        if self.second or self.microsecond:
            return True
        offset = self.utcoffset() or timedelta(0)
        return timedelta(hours=self.hour, minutes=self.minute) != offset

    # Pickle support.

    def _getstate(self):
        us2, us3 = divmod(self._microsecond, 256)
        us1, us2 = divmod(us2, 256)
        basestate = bytes([self._hour, self._minute, self._second,
                           us1, us2, us3])
        if self._tzinfo is None:
            return (basestate,)
        else:
            return (basestate, self._tzinfo)

    def __setstate(self, string, tzinfo):
        if len(string) != 6 or string[0] >= 24:
            raise TypeError("an integer is required")
        (self._hour, self._minute, self._second,
         us1, us2, us3) = string
        self._microsecond = (((us1 << 8) | us2) << 8) | us3
        if tzinfo is None or isinstance(tzinfo, _tzinfo_class):
            self._tzinfo = tzinfo
        else:
            raise TypeError("bad tzinfo state arg %r" % tzinfo)

    def __reduce__(self):
        return (time, self._getstate())

_time_class = time  # so functions w/ args named "time" can get at the class

time.min = time(0, 0, 0)
time.max = time(23, 59, 59, 999999)
time.resolution = timedelta(microseconds=1)

class datetime(date):
    """datetime(year, month, day[, hour[, minute[, second[, microsecond[,tzinfo]]]]])

    The year, month and day arguments are required. tzinfo may be None, or an
    instance of a tzinfo subclass. The remaining arguments may be ints.
    """

    __slots__ = date.__slots__ + (
        '_hour', '_minute', '_second',
        '_microsecond', '_tzinfo')
    def __new__(cls, year, month=None, day=None, hour=0, minute=0, second=0,
                microsecond=0, tzinfo=None):
        if isinstance(year, bytes) and len(year) == 10:
            # Pickle support
            self = date.__new__(cls, year[:4])
            self.__setstate(year, month)
            return self
        _check_tzinfo_arg(tzinfo)
        _check_time_fields(hour, minute, second, microsecond)
        self = date.__new__(cls, year, month, day)
        self._hour = hour
        self._minute = minute
        self._second = second
        self._microsecond = microsecond
        self._tzinfo = tzinfo
        return self

    # Read-only field accessors
    @property
    def hour(self):
        """hour (0-23)"""
        return self._hour

    @property
    def minute(self):
        """minute (0-59)"""
        return self._minute

    @property
    def second(self):
        """second (0-59)"""
        return self._second

    @property
    def microsecond(self):
        """microsecond (0-999999)"""
        return self._microsecond

    @property
    def tzinfo(self):
        """timezone info object"""
        return self._tzinfo

    @classmethod
    def _fromtimestamp(cls, t, utc, tz):
        """Construct a datetime from a POSIX timestamp (like time.time()).

        A timezone info object may be passed in as well.
        """
        frac, t = _math.modf(t)
        us = round(frac * 1e6)
        if us >= 1000000:
            t += 1
            us -= 1000000
        elif us < 0:
            t -= 1
            us += 1000000

        converter = _time.gmtime if utc else _time.localtime
        y, m, d, hh, mm, ss, weekday, jday, dst = converter(t)
        ss = min(ss, 59)    # clamp out leap seconds if the platform has them
        return cls(y, m, d, hh, mm, ss, us, tz)

    @classmethod
    def fromtimestamp(cls, t, tz=None):
        """Construct a datetime from a POSIX timestamp (like time.time()).

        A timezone info object may be passed in as well.
        """
        _check_tzinfo_arg(tz)

        result = cls._fromtimestamp(t, tz is not None, tz)
        if tz is not None:
            result = tz.fromutc(result)
        return result

    @classmethod
    def utcfromtimestamp(cls, t):
        """Construct a naive UTC datetime from a POSIX timestamp."""
        return cls._fromtimestamp(t, True, None)

    # XXX This is supposed to do better than we *can* do by using time.time(),
    # XXX if the platform supports a more accurate way.  The C implementation
    # XXX uses gettimeofday on platforms that have it, but that isn't
    # XXX available from Python.  So now() may return different results
    # XXX across the implementations.
    @classmethod
    def now(cls, tz=None):
        "Construct a datetime from time.time() and optional time zone info."
        t = _time.time()
        return cls.fromtimestamp(t, tz)

    @classmethod
    def utcnow(cls):
        "Construct a UTC datetime from time.time()."
        t = _time.time()
        return cls.utcfromtimestamp(t)

    @classmethod
    def combine(cls, date, time):
        "Construct a datetime from a given date and a given time."
        if not isinstance(date, _date_class):
            raise TypeError("date argument must be a date instance")
        if not isinstance(time, _time_class):
            raise TypeError("time argument must be a time instance")
        return cls(date.year, date.month, date.day,
                   time.hour, time.minute, time.second, time.microsecond,
                   time.tzinfo)

    def timetuple(self):
        "Return local time tuple compatible with time.localtime()."
        dst = self.dst()
        if dst is None:
            dst = -1
        elif dst:
            dst = 1
        else:
            dst = 0
        return _build_struct_time(self.year, self.month, self.day,
                                  self.hour, self.minute, self.second,
                                  dst)

    def timestamp(self):
        "Return POSIX timestamp as float"
        if self._tzinfo is None:
            return _time.mktime((self.year, self.month, self.day,
                                 self.hour, self.minute, self.second,
                                 -1, -1, -1)) + self.microsecond / 1e6
        else:
            return (self - _EPOCH).total_seconds()

    def utctimetuple(self):
        "Return UTC time tuple compatible with time.gmtime()."
        offset = self.utcoffset()
        if offset:
            self -= offset
        y, m, d = self.year, self.month, self.day
        hh, mm, ss = self.hour, self.minute, self.second
        return _build_struct_time(y, m, d, hh, mm, ss, 0)

    def date(self):
        "Return the date part."
        return date(self._year, self._month, self._day)

    def time(self):
        "Return the time part, with tzinfo None."
        return time(self.hour, self.minute, self.second, self.microsecond)

    def timetz(self):
        "Return the time part, with same tzinfo."
        return time(self.hour, self.minute, self.second, self.microsecond,
                    self._tzinfo)

    def replace(self, year=None, month=None, day=None, hour=None,
                minute=None, second=None, microsecond=None, tzinfo=True):
        """Return a new datetime with new values for the specified fields."""
        if year is None:
            year = self.year
        if month is None:
            month = self.month
        if day is None:
            day = self.day
        if hour is None:
            hour = self.hour
        if minute is None:
            minute = self.minute
        if second is None:
            second = self.second
        if microsecond is None:
            microsecond = self.microsecond
        if tzinfo is True:
            tzinfo = self.tzinfo
        _check_date_fields(year, month, day)
        _check_time_fields(hour, minute, second, microsecond)
        _check_tzinfo_arg(tzinfo)
        return datetime(year, month, day, hour, minute, second,
                          microsecond, tzinfo)

    def astimezone(self, tz=None):
        if tz is None:
            if self.tzinfo is None:
                raise ValueError("astimezone() requires an aware datetime")
            ts = (self - _EPOCH) // timedelta(seconds=1)
            localtm = _time.localtime(ts)
            local = datetime(*localtm[:6])
            try:
                # Extract TZ data if available
                gmtoff = localtm.tm_gmtoff
                zone = localtm.tm_zone
            except AttributeError:
                # Compute UTC offset and compare with the value implied
                # by tm_isdst.  If the values match, use the zone name
                # implied by tm_isdst.
                delta = local - datetime(*_time.gmtime(ts)[:6])
                dst = _time.daylight and localtm.tm_isdst > 0
                gmtoff = -(_time.altzone if dst else _time.timezone)
                if delta == timedelta(seconds=gmtoff):
                    tz = timezone(delta, _time.tzname[dst])
                else:
                    tz = timezone(delta)
            else:
                tz = timezone(timedelta(seconds=gmtoff), zone)

        elif not isinstance(tz, tzinfo):
            raise TypeError("tz argument must be an instance of tzinfo")

        mytz = self.tzinfo
        if mytz is None:
            raise ValueError("astimezone() requires an aware datetime")

        if tz is mytz:
            return self

        # Convert self to UTC, and attach the new time zone object.
        myoffset = self.utcoffset()
        if myoffset is None:
            raise ValueError("astimezone() requires an aware datetime")
        utc = (self - myoffset).replace(tzinfo=tz)

        # Convert from UTC to tz's local time.
        return tz.fromutc(utc)

    # Ways to produce a string.

    def ctime(self):
        "Return ctime() style string."
        weekday = self.toordinal() % 7 or 7
        return "%s %s %2d %02d:%02d:%02d %04d" % (
            _DAYNAMES[weekday],
            _MONTHNAMES[self._month],
            self._day,
            self._hour, self._minute, self._second,
            self._year)

    def isoformat(self, sep='T'):
        """Return the time formatted according to ISO.

        This is 'YYYY-MM-DD HH:MM:SS.mmmmmm', or 'YYYY-MM-DD HH:MM:SS' if
        self.microsecond == 0.

        If self.tzinfo is not None, the UTC offset is also attached, giving
        'YYYY-MM-DD HH:MM:SS.mmmmmm+HH:MM' or 'YYYY-MM-DD HH:MM:SS+HH:MM'.

        Optional argument sep specifies the separator between date and
        time, default 'T'.
        """
        s = ("%04d-%02d-%02d%c" % (self._year, self._month, self._day,
                                  sep) +
                _format_time(self._hour, self._minute, self._second,
                             self._microsecond))
        off = self.utcoffset()
        if off is not None:
            if off.days < 0:
                sign = "-"
                off = -off
            else:
                sign = "+"
            hh, mm = divmod(off, timedelta(hours=1))
            assert not mm % timedelta(minutes=1), "whole minute"
            mm //= timedelta(minutes=1)
            s += "%s%02d:%02d" % (sign, hh, mm)
        return s

    def __repr__(self):
        """Convert to formal string, for repr()."""
        L = [self._year, self._month, self._day, # These are never zero
             self._hour, self._minute, self._second, self._microsecond]
        if L[-1] == 0:
            del L[-1]
        if L[-1] == 0:
            del L[-1]
        s = ", ".join(map(str, L))
        s = "%s(%s)" % ('datetime.' + self.__class__.__name__, s)
        if self._tzinfo is not None:
            assert s[-1:] == ")"
            s = s[:-1] + ", tzinfo=%r" % self._tzinfo + ")"
        return s

    def __str__(self):
        "Convert to string, for str()."
        return self.isoformat(sep=' ')

    @classmethod
    def strptime(cls, date_string, format):
        'string, format -> new datetime parsed from a string (like time.strptime()).'
        import _strptime
        return _strptime._strptime_datetime(cls, date_string, format)

    def utcoffset(self):
        """Return the timezone offset in minutes east of UTC (negative west of
        UTC)."""
        if self._tzinfo is None:
            return None
        offset = self._tzinfo.utcoffset(self)
        _check_utc_offset("utcoffset", offset)
        return offset

    def tzname(self):
        """Return the timezone name.

        Note that the name is 100% informational -- there's no requirement that
        it mean anything in particular. For example, "GMT", "UTC", "-500",
        "-5:00", "EDT", "US/Eastern", "America/New York" are all valid replies.
        """
        name = _call_tzinfo_method(self._tzinfo, "tzname", self)
        _check_tzname(name)
        return name

    def dst(self):
        """Return 0 if DST is not in effect, or the DST offset (in minutes
        eastward) if DST is in effect.

        This is purely informational; the DST offset has already been added to
        the UTC offset returned by utcoffset() if applicable, so there's no
        need to consult dst() unless you're interested in displaying the DST
        info.
        """
        if self._tzinfo is None:
            return None
        offset = self._tzinfo.dst(self)
        _check_utc_offset("dst", offset)
        return offset

    # Comparisons of datetime objects with other.

    def __eq__(self, other):
        if isinstance(other, datetime):
            return self._cmp(other, allow_mixed=True) == 0
        elif not isinstance(other, date):
            return NotImplemented
        else:
            return False

    def __ne__(self, other):
        if isinstance(other, datetime):
            return self._cmp(other, allow_mixed=True) != 0
        elif not isinstance(other, date):
            return NotImplemented
        else:
            return True

    def __le__(self, other):
        if isinstance(other, datetime):
            return self._cmp(other) <= 0
        elif not isinstance(other, date):
            return NotImplemented
        else:
            _cmperror(self, other)

    def __lt__(self, other):
        if isinstance(other, datetime):
            return self._cmp(other) < 0
        elif not isinstance(other, date):
            return NotImplemented
        else:
            _cmperror(self, other)

    def __ge__(self, other):
        if isinstance(other, datetime):
            return self._cmp(other) >= 0
        elif not isinstance(other, date):
            return NotImplemented
        else:
            _cmperror(self, other)

    def __gt__(self, other):
        if isinstance(other, datetime):
            return self._cmp(other) > 0
        elif not isinstance(other, date):
            return NotImplemented
        else:
            _cmperror(self, other)

    def _cmp(self, other, allow_mixed=False):
        assert isinstance(other, datetime)
        mytz = self._tzinfo
        ottz = other._tzinfo
        myoff = otoff = None

        if mytz is ottz:
            base_compare = True
        else:
            myoff = self.utcoffset()
            otoff = other.utcoffset()
            base_compare = myoff == otoff

        if base_compare:
            return _cmp((self._year, self._month, self._day,
                         self._hour, self._minute, self._second,
                         self._microsecond),
                       (other._year, other._month, other._day,
                        other._hour, other._minute, other._second,
                        other._microsecond))
        if myoff is None or otoff is None:
            if allow_mixed:
                return 2 # arbitrary non-zero value
            else:
                raise TypeError("cannot compare naive and aware datetimes")
        # XXX What follows could be done more efficiently...
        diff = self - other     # this will take offsets into account
        if diff.days < 0:
            return -1
        return diff and 1 or 0

    def __add__(self, other):
        "Add a datetime and a timedelta."
        if not isinstance(other, timedelta):
            return NotImplemented
        delta = timedelta(self.toordinal(),
                          hours=self._hour,
                          minutes=self._minute,
                          seconds=self._second,
                          microseconds=self._microsecond)
        delta += other
        hour, rem = divmod(delta.seconds, 3600)
        minute, second = divmod(rem, 60)
        if 0 < delta.days <= _MAXORDINAL:
            return datetime.combine(date.fromordinal(delta.days),
                                    time(hour, minute, second,
                                         delta.microseconds,
                                         tzinfo=self._tzinfo))
        raise OverflowError("result out of range")

    __radd__ = __add__

    def __sub__(self, other):
        "Subtract two datetimes, or a datetime and a timedelta."
        if not isinstance(other, datetime):
            if isinstance(other, timedelta):
                return self + -other
            return NotImplemented

        days1 = self.toordinal()
        days2 = other.toordinal()
        secs1 = self._second + self._minute * 60 + self._hour * 3600
        secs2 = other._second + other._minute * 60 + other._hour * 3600
        base = timedelta(days1 - days2,
                         secs1 - secs2,
                         self._microsecond - other._microsecond)
        if self._tzinfo is other._tzinfo:
            return base
        myoff = self.utcoffset()
        otoff = other.utcoffset()
        if myoff == otoff:
            return base
        if myoff is None or otoff is None:
            raise TypeError("cannot mix naive and timezone-aware time")
        return base + otoff - myoff

    def __hash__(self):
        tzoff = self.utcoffset()
        if tzoff is None:
            return hash(self._getstate()[0])
        days = _ymd2ord(self.year, self.month, self.day)
        seconds = self.hour * 3600 + self.minute * 60 + self.second
        return hash(timedelta(days, seconds, self.microsecond) - tzoff)

    # Pickle support.

    def _getstate(self):
        yhi, ylo = divmod(self._year, 256)
        us2, us3 = divmod(self._microsecond, 256)
        us1, us2 = divmod(us2, 256)
        basestate = bytes([yhi, ylo, self._month, self._day,
                           self._hour, self._minute, self._second,
                           us1, us2, us3])
        if self._tzinfo is None:
            return (basestate,)
        else:
            return (basestate, self._tzinfo)

    def __setstate(self, string, tzinfo):
        (yhi, ylo, self._month, self._day, self._hour,
         self._minute, self._second, us1, us2, us3) = string
        self._year = yhi * 256 + ylo
        self._microsecond = (((us1 << 8) | us2) << 8) | us3
        if tzinfo is None or isinstance(tzinfo, _tzinfo_class):
            self._tzinfo = tzinfo
        else:
            raise TypeError("bad tzinfo state arg %r" % tzinfo)

    def __reduce__(self):
        return (self.__class__, self._getstate())


datetime.min = datetime(1, 1, 1)
datetime.max = datetime(9999, 12, 31, 23, 59, 59, 999999)
datetime.resolution = timedelta(microseconds=1)


def _isoweek1monday(year):
    # Helper to calculate the day number of the Monday starting week 1
    # XXX This could be done more efficiently
    THURSDAY = 3
    firstday = _ymd2ord(year, 1, 1)
    firstweekday = (firstday + 6) % 7 # See weekday() above
    week1monday = firstday - firstweekday
    if firstweekday > THURSDAY:
        week1monday += 7
    return week1monday

class timezone(tzinfo):
    __slots__ = '_offset', '_name'

    # Sentinel value to disallow None
    _Omitted = object()
    def __new__(cls, offset, name=_Omitted):
        if not isinstance(offset, timedelta):
            raise TypeError("offset must be a timedelta")
        if name is cls._Omitted:
            if not offset:
                return cls.utc
            name = None
        elif not isinstance(name, str):
            raise TypeError("name must be a string")
        if not cls._minoffset <= offset <= cls._maxoffset:
            raise ValueError("offset must be a timedelta"
                             " strictly between -timedelta(hours=24) and"
                             " timedelta(hours=24).")
        if (offset.microseconds != 0 or
            offset.seconds % 60 != 0):
            raise ValueError("offset must be a timedelta"
                             " representing a whole number of minutes")
        return cls._create(offset, name)

    @classmethod
    def _create(cls, offset, name=None):
        self = tzinfo.__new__(cls)
        self._offset = offset
        self._name = name
        return self

    def __getinitargs__(self):
        """pickle support"""
        if self._name is None:
            return (self._offset,)
        return (self._offset, self._name)

    def __eq__(self, other):
        if type(other) != timezone:
            return False
        return self._offset == other._offset

    def __hash__(self):
        return hash(self._offset)

    def __repr__(self):
        """Convert to formal string, for repr().

        >>> tz = timezone.utc
        >>> repr(tz)
        'datetime.timezone.utc'
        >>> tz = timezone(timedelta(hours=-5), 'EST')
        >>> repr(tz)
        "datetime.timezone(datetime.timedelta(-1, 68400), 'EST')"
        """
        if self is self.utc:
            return 'datetime.timezone.utc'
        if self._name is None:
            return "%s(%r)" % ('datetime.' + self.__class__.__name__,
                               self._offset)
        return "%s(%r, %r)" % ('datetime.' + self.__class__.__name__,
                               self._offset, self._name)

    def __str__(self):
        return self.tzname(None)

    def utcoffset(self, dt):
        if isinstance(dt, datetime) or dt is None:
            return self._offset
        raise TypeError("utcoffset() argument must be a datetime instance"
                        " or None")

    def tzname(self, dt):
        if isinstance(dt, datetime) or dt is None:
            if self._name is None:
                return self._name_from_offset(self._offset)
            return self._name
        raise TypeError("tzname() argument must be a datetime instance"
                        " or None")

    def dst(self, dt):
        if isinstance(dt, datetime) or dt is None:
            return None
        raise TypeError("dst() argument must be a datetime instance"
                        " or None")

    def fromutc(self, dt):
        if isinstance(dt, datetime):
            if dt.tzinfo is not self:
                raise ValueError("fromutc: dt.tzinfo "
                                 "is not self")
            return dt + self._offset
        raise TypeError("fromutc() argument must be a datetime instance"
                        " or None")

    _maxoffset = timedelta(hours=23, minutes=59)
    _minoffset = -_maxoffset

    @staticmethod
    def _name_from_offset(delta):
        if delta < timedelta(0):
            sign = '-'
            delta = -delta
        else:
            sign = '+'
        hours, rest = divmod(delta, timedelta(hours=1))
        minutes = rest // timedelta(minutes=1)
        return 'UTC{}{:02d}:{:02d}'.format(sign, hours, minutes)

timezone.utc = timezone._create(timedelta(0))
timezone.min = timezone._create(timezone._minoffset)
timezone.max = timezone._create(timezone._maxoffset)
_EPOCH = datetime(1970, 1, 1, tzinfo=timezone.utc)

# Some time zone algebra.  For a datetime x, let
#     x.n = x stripped of its timezone -- its naive time.
#     x.o = x.utcoffset(), and assuming that doesn't raise an exception or
#           return None
#     x.d = x.dst(), and assuming that doesn't raise an exception or
#           return None
#     x.s = x's standard offset, x.o - x.d
#
# Now some derived rules, where k is a duration (timedelta).
#
# 1. x.o = x.s + x.d
#    This follows from the definition of x.s.
#
# 2. If x and y have the same tzinfo member, x.s = y.s.
#    This is actually a requirement, an assumption we need to make about
#    sane tzinfo classes.
#
# 3. The naive UTC time corresponding to x is x.n - x.o.
#    This is again a requirement for a sane tzinfo class.
#
# 4. (x+k).s = x.s
#    This follows from #2, and that datimetimetz+timedelta preserves tzinfo.
#
# 5. (x+k).n = x.n + k
#    Again follows from how arithmetic is defined.
#
# Now we can explain tz.fromutc(x).  Let's assume it's an interesting case
# (meaning that the various tzinfo methods exist, and don't blow up or return
# None when called).
#
# The function wants to return a datetime y with timezone tz, equivalent to x.
# x is already in UTC.
#
# By #3, we want
#
#     y.n - y.o = x.n                             [1]
#
# The algorithm starts by attaching tz to x.n, and calling that y.  So
# x.n = y.n at the start.  Then it wants to add a duration k to y, so that [1]
# becomes true; in effect, we want to solve [2] for k:
#
#    (y+k).n - (y+k).o = x.n                      [2]
#
# By #1, this is the same as
#
#    (y+k).n - ((y+k).s + (y+k).d) = x.n          [3]
#
# By #5, (y+k).n = y.n + k, which equals x.n + k because x.n=y.n at the start.
# Substituting that into [3],
#
#    x.n + k - (y+k).s - (y+k).d = x.n; the x.n terms cancel, leaving
#    k - (y+k).s - (y+k).d = 0; rearranging,
#    k = (y+k).s - (y+k).d; by #4, (y+k).s == y.s, so
#    k = y.s - (y+k).d
#
# On the RHS, (y+k).d can't be computed directly, but y.s can be, and we
# approximate k by ignoring the (y+k).d term at first.  Note that k can't be
# very large, since all offset-returning methods return a duration of magnitude
# less than 24 hours.  For that reason, if y is firmly in std time, (y+k).d must
# be 0, so ignoring it has no consequence then.
#
# In any case, the new value is
#
#     z = y + y.s                                 [4]
#
# It's helpful to step back at look at [4] from a higher level:  it's simply
# mapping from UTC to tz's standard time.
#
# At this point, if
#
#     z.n - z.o = x.n                             [5]
#
# we have an equivalent time, and are almost done.  The insecurity here is
# at the start of daylight time.  Picture US Eastern for concreteness.  The wall
# time jumps from 1:59 to 3:00, and wall hours of the form 2:MM don't make good
# sense then.  The docs ask that an Eastern tzinfo class consider such a time to
# be EDT (because it's "after 2"), which is a redundant spelling of 1:MM EST
# on the day DST starts.  We want to return the 1:MM EST spelling because that's
# the only spelling that makes sense on the local wall clock.
#
# In fact, if [5] holds at this point, we do have the standard-time spelling,
# but that takes a bit of proof.  We first prove a stronger result.  What's the
# difference between the LHS and RHS of [5]?  Let
#
#     diff = x.n - (z.n - z.o)                    [6]
#
# Now
#     z.n =                       by [4]
#     (y + y.s).n =               by #5
#     y.n + y.s =                 since y.n = x.n
#     x.n + y.s =                 since z and y are have the same tzinfo member,
#                                     y.s = z.s by #2
#     x.n + z.s
#
# Plugging that back into [6] gives
#
#     diff =
#     x.n - ((x.n + z.s) - z.o) =     expanding
#     x.n - x.n - z.s + z.o =         cancelling
#     - z.s + z.o =                   by #2
#     z.d
#
# So diff = z.d.
#
# If [5] is true now, diff = 0, so z.d = 0 too, and we have the standard-time
# spelling we wanted in the endcase described above.  We're done.  Contrarily,
# if z.d = 0, then we have a UTC equivalent, and are also done.
#
# If [5] is not true now, diff = z.d != 0, and z.d is the offset we need to
# add to z (in effect, z is in tz's standard time, and we need to shift the
# local clock into tz's daylight time).
#
# Let
#
#     z' = z + z.d = z + diff                     [7]
#
# and we can again ask whether
#
#     z'.n - z'.o = x.n                           [8]
#
# If so, we're done.  If not, the tzinfo class is insane, according to the
# assumptions we've made.  This also requires a bit of proof.  As before, let's
# compute the difference between the LHS and RHS of [8] (and skipping some of
# the justifications for the kinds of substitutions we've done several times
# already):
#
#     diff' = x.n - (z'.n - z'.o) =           replacing z'.n via [7]
#             x.n  - (z.n + diff - z'.o) =    replacing diff via [6]
#             x.n - (z.n + x.n - (z.n - z.o) - z'.o) =
#             x.n - z.n - x.n + z.n - z.o + z'.o =    cancel x.n
#             - z.n + z.n - z.o + z'.o =              cancel z.n
#             - z.o + z'.o =                      #1 twice
#             -z.s - z.d + z'.s + z'.d =          z and z' have same tzinfo
#             z'.d - z.d
#
# So z' is UTC-equivalent to x iff z'.d = z.d at this point.  If they are equal,
# we've found the UTC-equivalent so are done.  In fact, we stop with [7] and
# return z', not bothering to compute z'.d.
#
# How could z.d and z'd differ?  z' = z + z.d [7], so merely moving z' by
# a dst() offset, and starting *from* a time already in DST (we know z.d != 0),
# would have to change the result dst() returns:  we start in DST, and moving
# a little further into it takes us out of DST.
#
# There isn't a sane case where this can happen.  The closest it gets is at
# the end of DST, where there's an hour in UTC with no spelling in a hybrid
# tzinfo class.  In US Eastern, that's 5:MM UTC = 0:MM EST = 1:MM EDT.  During
# that hour, on an Eastern clock 1:MM is taken as being in standard time (6:MM
# UTC) because the docs insist on that, but 0:MM is taken as being in daylight
# time (4:MM UTC).  There is no local time mapping to 5:MM UTC.  The local
# clock jumps from 1:59 back to 1:00 again, and repeats the 1:MM hour in
# standard time.  Since that's what the local clock *does*, we want to map both
# UTC hours 5:MM and 6:MM to 1:MM Eastern.  The result is ambiguous
# in local time, but so it goes -- it's the way the local clock works.
#
# When x = 5:MM UTC is the input to this algorithm, x.o=0, y.o=-5 and y.d=0,
# so z=0:MM.  z.d=60 (minutes) then, so [5] doesn't hold and we keep going.
# z' = z + z.d = 1:MM then, and z'.d=0, and z'.d - z.d = -60 != 0 so [8]
# (correctly) concludes that z' is not UTC-equivalent to x.
#
# Because we know z.d said z was in daylight time (else [5] would have held and
# we would have stopped then), and we know z.d != z'.d (else [8] would have held
# and we have stopped then), and there are only 2 possible values dst() can
# return in Eastern, it follows that z'.d must be 0 (which it is in the example,
# but the reasoning doesn't depend on the example -- it depends on there being
# two possible dst() outcomes, one zero and the other non-zero).  Therefore
# z' must be in standard time, and is the spelling we want in this case.
#
# Note again that z' is not UTC-equivalent as far as the hybrid tzinfo class is
# concerned (because it takes z' as being in standard time rather than the
# daylight time we intend here), but returning it gives the real-life "local
# clock repeats an hour" behavior when mapping the "unspellable" UTC hour into
# tz.
#
# When the input is 6:MM, z=1:MM and z.d=0, and we stop at once, again with
# the 1:MM standard time spelling we want.
#
# So how can this break?  One of the assumptions must be violated.  Two
# possibilities:
#
# 1) [2] effectively says that y.s is invariant across all y belong to a given
#    time zone.  This isn't true if, for political reasons or continental drift,
#    a region decides to change its base offset from UTC.
#
# 2) There may be versions of "double daylight" time where the tail end of
#    the analysis gives up a step too early.  I haven't thought about that
#    enough to say.
#
# In any case, it's clear that the default fromutc() is strong enough to handle
# "almost all" time zones:  so long as the standard offset is invariant, it
# doesn't matter if daylight time transition points change from year to year, or
# if daylight time is skipped in some years; it doesn't matter how large or
# small dst() may get within its bounds; and it doesn't even matter if some
# perverse time zone returns a negative dst()).  So a breaking case must be
# pretty bizarre, and a tzinfo subclass can override fromutc() if it is.

try:
    from _datetime import *
except ImportError:
    pass
else:
    # Clean up unused names
    del (_DAYNAMES, _DAYS_BEFORE_MONTH, _DAYS_IN_MONTH,
         _DI100Y, _DI400Y, _DI4Y, _MAXORDINAL, _MONTHNAMES,
         _build_struct_time, _call_tzinfo_method, _check_date_fields,
         _check_time_fields, _check_tzinfo_arg, _check_tzname,
         _check_utc_offset, _cmp, _cmperror, _date_class, _days_before_month,
         _days_before_year, _days_in_month, _format_time, _is_leap,
         _isoweek1monday, _math, _ord2ymd, _time, _time_class, _tzinfo_class,
         _wrap_strftime, _ymd2ord)
    # XXX Since import * above excludes names that start with _,
    # docstring does not get overwritten. In the future, it may be
    # appropriate to maintain a single module level docstring and
    # remove the following line.
    from _datetime import __doc__
lib\decimal.py
# Copyright (c) 2004 Python Software Foundation.
# All rights reserved.

# Written by Eric Price <eprice at tjhsst.edu>
#    and Facundo Batista <facundo at taniquetil.com.ar>
#    and Raymond Hettinger <python at rcn.com>
#    and Aahz <aahz at pobox.com>
#    and Tim Peters

# This module should be kept in sync with the latest updates of the
# IBM specification as it evolves.  Those updates will be treated
# as bug fixes (deviation from the spec is a compatibility, usability
# bug) and will be backported.  At this point the spec is stabilizing
# and the updates are becoming fewer, smaller, and less significant.

"""
This is an implementation of decimal floating point arithmetic based on
the General Decimal Arithmetic Specification:

    http://speleotrove.com/decimal/decarith.html

and IEEE standard 854-1987:

    http://en.wikipedia.org/wiki/IEEE_854-1987

Decimal floating point has finite precision with arbitrarily large bounds.

The purpose of this module is to support arithmetic using familiar
"schoolhouse" rules and to avoid some of the tricky representation
issues associated with binary floating point.  The package is especially
useful for financial applications or for contexts where users have
expectations that are at odds with binary floating point (for instance,
in binary floating point, 1.00 % 0.1 gives 0.09999999999999995 instead
of 0.0; Decimal('1.00') % Decimal('0.1') returns the expected
Decimal('0.00')).

Here are some examples of using the decimal module:

>>> from decimal import *
>>> setcontext(ExtendedContext)
>>> Decimal(0)
Decimal('0')
>>> Decimal('1')
Decimal('1')
>>> Decimal('-.0123')
Decimal('-0.0123')
>>> Decimal(123456)
Decimal('123456')
>>> Decimal('123.45e12345678')
Decimal('1.2345E+12345680')
>>> Decimal('1.33') + Decimal('1.27')
Decimal('2.60')
>>> Decimal('12.34') + Decimal('3.87') - Decimal('18.41')
Decimal('-2.20')
>>> dig = Decimal(1)
>>> print(dig / Decimal(3))
0.333333333
>>> getcontext().prec = 18
>>> print(dig / Decimal(3))
0.333333333333333333
>>> print(dig.sqrt())
1
>>> print(Decimal(3).sqrt())
1.73205080756887729
>>> print(Decimal(3) ** 123)
4.85192780976896427E+58
>>> inf = Decimal(1) / Decimal(0)
>>> print(inf)
Infinity
>>> neginf = Decimal(-1) / Decimal(0)
>>> print(neginf)
-Infinity
>>> print(neginf + inf)
NaN
>>> print(neginf * inf)
-Infinity
>>> print(dig / 0)
Infinity
>>> getcontext().traps[DivisionByZero] = 1
>>> print(dig / 0)
Traceback (most recent call last):
  ...
  ...
  ...
decimal.DivisionByZero: x / 0
>>> c = Context()
>>> c.traps[InvalidOperation] = 0
>>> print(c.flags[InvalidOperation])
0
>>> c.divide(Decimal(0), Decimal(0))
Decimal('NaN')
>>> c.traps[InvalidOperation] = 1
>>> print(c.flags[InvalidOperation])
1
>>> c.flags[InvalidOperation] = 0
>>> print(c.flags[InvalidOperation])
0
>>> print(c.divide(Decimal(0), Decimal(0)))
Traceback (most recent call last):
  ...
  ...
  ...
decimal.InvalidOperation: 0 / 0
>>> print(c.flags[InvalidOperation])
1
>>> c.flags[InvalidOperation] = 0
>>> c.traps[InvalidOperation] = 0
>>> print(c.divide(Decimal(0), Decimal(0)))
NaN
>>> print(c.flags[InvalidOperation])
1
>>>
"""

__all__ = [
    # Two major classes
    'Decimal', 'Context',

    # Named tuple representation
    'DecimalTuple',

    # Contexts
    'DefaultContext', 'BasicContext', 'ExtendedContext',

    # Exceptions
    'DecimalException', 'Clamped', 'InvalidOperation', 'DivisionByZero',
    'Inexact', 'Rounded', 'Subnormal', 'Overflow', 'Underflow',
    'FloatOperation',

    # Exceptional conditions that trigger InvalidOperation
    'DivisionImpossible', 'InvalidContext', 'ConversionSyntax', 'DivisionUndefined',

    # Constants for use in setting up contexts
    'ROUND_DOWN', 'ROUND_HALF_UP', 'ROUND_HALF_EVEN', 'ROUND_CEILING',
    'ROUND_FLOOR', 'ROUND_UP', 'ROUND_HALF_DOWN', 'ROUND_05UP',

    # Functions for manipulating contexts
    'setcontext', 'getcontext', 'localcontext',

    # Limits for the C version for compatibility
    'MAX_PREC',  'MAX_EMAX', 'MIN_EMIN', 'MIN_ETINY',

    # C version: compile time choice that enables the thread local context
    'HAVE_THREADS'
]

__version__ = '1.70'    # Highest version of the spec this complies with
                        # See http://speleotrove.com/decimal/
__libmpdec_version__ = "2.4.1" # compatible libmpdec version

import math as _math
import numbers as _numbers
import sys

is_cli = sys.implementation.name == 'ironpython'

try:
    from collections import namedtuple as _namedtuple
    DecimalTuple = _namedtuple('DecimalTuple', 'sign digits exponent')
except ImportError:
    DecimalTuple = lambda *args: args

# Rounding
ROUND_DOWN = 'ROUND_DOWN'
ROUND_HALF_UP = 'ROUND_HALF_UP'
ROUND_HALF_EVEN = 'ROUND_HALF_EVEN'
ROUND_CEILING = 'ROUND_CEILING'
ROUND_FLOOR = 'ROUND_FLOOR'
ROUND_UP = 'ROUND_UP'
ROUND_HALF_DOWN = 'ROUND_HALF_DOWN'
ROUND_05UP = 'ROUND_05UP'

# Compatibility with the C version
HAVE_THREADS = True
if sys.maxsize == 2**63-1:
    MAX_PREC = 999999999999999999
    MAX_EMAX = 999999999999999999
    MIN_EMIN = -999999999999999999
else:
    MAX_PREC = 425000000
    MAX_EMAX = 425000000
    MIN_EMIN = -425000000

MIN_ETINY = MIN_EMIN - (MAX_PREC-1)

# Errors

class DecimalException(ArithmeticError):
    """Base exception class.

    Used exceptions derive from this.
    If an exception derives from another exception besides this (such as
    Underflow (Inexact, Rounded, Subnormal) that indicates that it is only
    called if the others are present.  This isn't actually used for
    anything, though.

    handle  -- Called when context._raise_error is called and the
               trap_enabler is not set.  First argument is self, second is the
               context.  More arguments can be given, those being after
               the explanation in _raise_error (For example,
               context._raise_error(NewError, '(-x)!', self._sign) would
               call NewError().handle(context, self._sign).)

    To define a new exception, it should be sufficient to have it derive
    from DecimalException.
    """
    def handle(self, context, *args):
        pass


class Clamped(DecimalException):
    """Exponent of a 0 changed to fit bounds.

    This occurs and signals clamped if the exponent of a result has been
    altered in order to fit the constraints of a specific concrete
    representation.  This may occur when the exponent of a zero result would
    be outside the bounds of a representation, or when a large normal
    number would have an encoded exponent that cannot be represented.  In
    this latter case, the exponent is reduced to fit and the corresponding
    number of zero digits are appended to the coefficient ("fold-down").
    """

class InvalidOperation(DecimalException):
    """An invalid operation was performed.

    Various bad things cause this:

    Something creates a signaling NaN
    -INF + INF
    0 * (+-)INF
    (+-)INF / (+-)INF
    x % 0
    (+-)INF % x
    x._rescale( non-integer )
    sqrt(-x) , x > 0
    0 ** 0
    x ** (non-integer)
    x ** (+-)INF
    An operand is invalid

    The result of the operation after these is a quiet positive NaN,
    except when the cause is a signaling NaN, in which case the result is
    also a quiet NaN, but with the original sign, and an optional
    diagnostic information.
    """
    def handle(self, context, *args):
        if args:
            ans = _dec_from_triple(args[0]._sign, args[0]._int, 'n', True)
            return ans._fix_nan(context)
        return _NaN

class ConversionSyntax(InvalidOperation):
    """Trying to convert badly formed string.

    This occurs and signals invalid-operation if an string is being
    converted to a number and it does not conform to the numeric string
    syntax.  The result is [0,qNaN].
    """
    def handle(self, context, *args):
        return _NaN

class DivisionByZero(DecimalException, ZeroDivisionError):
    """Division by 0.

    This occurs and signals division-by-zero if division of a finite number
    by zero was attempted (during a divide-integer or divide operation, or a
    power operation with negative right-hand operand), and the dividend was
    not zero.

    The result of the operation is [sign,inf], where sign is the exclusive
    or of the signs of the operands for divide, or is 1 for an odd power of
    -0, for power.
    """

    def handle(self, context, sign, *args):
        return _SignedInfinity[sign]

class DivisionImpossible(InvalidOperation):
    """Cannot perform the division adequately.

    This occurs and signals invalid-operation if the integer result of a
    divide-integer or remainder operation had too many digits (would be
    longer than precision).  The result is [0,qNaN].
    """

    def handle(self, context, *args):
        return _NaN

class DivisionUndefined(InvalidOperation, ZeroDivisionError):
    """Undefined result of division.

    This occurs and signals invalid-operation if division by zero was
    attempted (during a divide-integer, divide, or remainder operation), and
    the dividend is also zero.  The result is [0,qNaN].
    """

    def handle(self, context, *args):
        return _NaN

class Inexact(DecimalException):
    """Had to round, losing information.

    This occurs and signals inexact whenever the result of an operation is
    not exact (that is, it needed to be rounded and any discarded digits
    were non-zero), or if an overflow or underflow condition occurs.  The
    result in all cases is unchanged.

    The inexact signal may be tested (or trapped) to determine if a given
    operation (or sequence of operations) was inexact.
    """

class InvalidContext(InvalidOperation):
    """Invalid context.  Unknown rounding, for example.

    This occurs and signals invalid-operation if an invalid context was
    detected during an operation.  This can occur if contexts are not checked
    on creation and either the precision exceeds the capability of the
    underlying concrete representation or an unknown or unsupported rounding
    was specified.  These aspects of the context need only be checked when
    the values are required to be used.  The result is [0,qNaN].
    """

    def handle(self, context, *args):
        return _NaN

class Rounded(DecimalException):
    """Number got rounded (not  necessarily changed during rounding).

    This occurs and signals rounded whenever the result of an operation is
    rounded (that is, some zero or non-zero digits were discarded from the
    coefficient), or if an overflow or underflow condition occurs.  The
    result in all cases is unchanged.

    The rounded signal may be tested (or trapped) to determine if a given
    operation (or sequence of operations) caused a loss of precision.
    """

class Subnormal(DecimalException):
    """Exponent < Emin before rounding.

    This occurs and signals subnormal whenever the result of a conversion or
    operation is subnormal (that is, its adjusted exponent is less than
    Emin, before any rounding).  The result in all cases is unchanged.

    The subnormal signal may be tested (or trapped) to determine if a given
    or operation (or sequence of operations) yielded a subnormal result.
    """

class Overflow(Inexact, Rounded):
    """Numerical overflow.

    This occurs and signals overflow if the adjusted exponent of a result
    (from a conversion or from an operation that is not an attempt to divide
    by zero), after rounding, would be greater than the largest value that
    can be handled by the implementation (the value Emax).

    The result depends on the rounding mode:

    For round-half-up and round-half-even (and for round-half-down and
    round-up, if implemented), the result of the operation is [sign,inf],
    where sign is the sign of the intermediate result.  For round-down, the
    result is the largest finite number that can be represented in the
    current precision, with the sign of the intermediate result.  For
    round-ceiling, the result is the same as for round-down if the sign of
    the intermediate result is 1, or is [0,inf] otherwise.  For round-floor,
    the result is the same as for round-down if the sign of the intermediate
    result is 0, or is [1,inf] otherwise.  In all cases, Inexact and Rounded
    will also be raised.
    """

    def handle(self, context, sign, *args):
        if context.rounding in (ROUND_HALF_UP, ROUND_HALF_EVEN,
                                ROUND_HALF_DOWN, ROUND_UP):
            return _SignedInfinity[sign]
        if sign == 0:
            if context.rounding == ROUND_CEILING:
                return _SignedInfinity[sign]
            return _dec_from_triple(sign, '9'*context.prec,
                            context.Emax-context.prec+1)
        if sign == 1:
            if context.rounding == ROUND_FLOOR:
                return _SignedInfinity[sign]
            return _dec_from_triple(sign, '9'*context.prec,
                             context.Emax-context.prec+1)


class Underflow(Inexact, Rounded, Subnormal):
    """Numerical underflow with result rounded to 0.

    This occurs and signals underflow if a result is inexact and the
    adjusted exponent of the result would be smaller (more negative) than
    the smallest value that can be handled by the implementation (the value
    Emin).  That is, the result is both inexact and subnormal.

    The result after an underflow will be a subnormal number rounded, if
    necessary, so that its exponent is not less than Etiny.  This may result
    in 0 with the sign of the intermediate result and an exponent of Etiny.

    In all cases, Inexact, Rounded, and Subnormal will also be raised.
    """

class FloatOperation(DecimalException, TypeError):
    """Enable stricter semantics for mixing floats and Decimals.

    If the signal is not trapped (default), mixing floats and Decimals is
    permitted in the Decimal() constructor, context.create_decimal() and
    all comparison operators. Both conversion and comparisons are exact.
    Any occurrence of a mixed operation is silently recorded by setting
    FloatOperation in the context flags.  Explicit conversions with
    Decimal.from_float() or context.create_decimal_from_float() do not
    set the flag.

    Otherwise (the signal is trapped), only equality comparisons and explicit
    conversions are silent. All other mixed operations raise FloatOperation.
    """

# List of public traps and flags
_signals = [Clamped, DivisionByZero, Inexact, Overflow, Rounded,
            Underflow, InvalidOperation, Subnormal, FloatOperation]

# Map conditions (per the spec) to signals
_condition_map = {ConversionSyntax:InvalidOperation,
                  DivisionImpossible:InvalidOperation,
                  DivisionUndefined:InvalidOperation,
                  InvalidContext:InvalidOperation}

# Valid rounding modes
_rounding_modes = (ROUND_DOWN, ROUND_HALF_UP, ROUND_HALF_EVEN, ROUND_CEILING,
                   ROUND_FLOOR, ROUND_UP, ROUND_HALF_DOWN, ROUND_05UP)

##### Context Functions ##################################################

# The getcontext() and setcontext() function manage access to a thread-local
# current context.  Py2.4 offers direct support for thread locals.  If that
# is not available, use threading.current_thread() which is slower but will
# work for older Pythons.  If threads are not part of the build, create a
# mock threading object with threading.local() returning the module namespace.

try:
    import threading
except ImportError:
    # Python was compiled without threads; create a mock object instead
    class MockThreading(object):
        def local(self, sys=sys):
            return sys.modules[__name__]
    threading = MockThreading()
    del MockThreading

try:
    threading.local

except AttributeError:

    # To fix reloading, force it to create a new context
    # Old contexts have different exceptions in their dicts, making problems.
    if hasattr(threading.current_thread(), '__decimal_context__'):
        del threading.current_thread().__decimal_context__

    def setcontext(context):
        """Set this thread's context to context."""
        if context in (DefaultContext, BasicContext, ExtendedContext):
            context = context.copy()
            context.clear_flags()
        threading.current_thread().__decimal_context__ = context

    def getcontext():
        """Returns this thread's context.

        If this thread does not yet have a context, returns
        a new context and sets this thread's context.
        New contexts are copies of DefaultContext.
        """
        try:
            return threading.current_thread().__decimal_context__
        except AttributeError:
            context = Context()
            threading.current_thread().__decimal_context__ = context
            return context

else:

    local = threading.local()
    if hasattr(local, '__decimal_context__'):
        del local.__decimal_context__

    def getcontext(_local=local):
        """Returns this thread's context.

        If this thread does not yet have a context, returns
        a new context and sets this thread's context.
        New contexts are copies of DefaultContext.
        """
        try:
            return _local.__decimal_context__
        except AttributeError:
            context = Context()
            _local.__decimal_context__ = context
            return context

    def setcontext(context, _local=local):
        """Set this thread's context to context."""
        if context in (DefaultContext, BasicContext, ExtendedContext):
            context = context.copy()
            context.clear_flags()
        _local.__decimal_context__ = context

    del threading, local        # Don't contaminate the namespace

def localcontext(ctx=None):
    """Return a context manager for a copy of the supplied context

    Uses a copy of the current context if no context is specified
    The returned context manager creates a local decimal context
    in a with statement:
        def sin(x):
             with localcontext() as ctx:
                 ctx.prec += 2
                 # Rest of sin calculation algorithm
                 # uses a precision 2 greater than normal
             return +s  # Convert result to normal precision

         def sin(x):
             with localcontext(ExtendedContext):
                 # Rest of sin calculation algorithm
                 # uses the Extended Context from the
                 # General Decimal Arithmetic Specification
             return +s  # Convert result to normal context

    >>> setcontext(DefaultContext)
    >>> print(getcontext().prec)
    28
    >>> with localcontext():
    ...     ctx = getcontext()
    ...     ctx.prec += 2
    ...     print(ctx.prec)
    ...
    30
    >>> with localcontext(ExtendedContext):
    ...     print(getcontext().prec)
    ...
    9
    >>> print(getcontext().prec)
    28
    """
    if ctx is None: ctx = getcontext()
    return _ContextManager(ctx)


##### Decimal class #######################################################

# Do not subclass Decimal from numbers.Real and do not register it as such
# (because Decimals are not interoperable with floats).  See the notes in
# numbers.py for more detail.

class Decimal(object):
    """Floating point class for decimal arithmetic."""

    __slots__ = ('_exp','_int','_sign', '_is_special')
    # Generally, the value of the Decimal instance is given by
    #  (-1)**_sign * _int * 10**_exp
    # Special values are signified by _is_special == True

    # We're immutable, so use __new__ not __init__
    def __new__(cls, value="0", context=None):
        """Create a decimal point instance.

        >>> Decimal('3.14')              # string input
        Decimal('3.14')
        >>> Decimal((0, (3, 1, 4), -2))  # tuple (sign, digit_tuple, exponent)
        Decimal('3.14')
        >>> Decimal(314)                 # int
        Decimal('314')
        >>> Decimal(Decimal(314))        # another decimal instance
        Decimal('314')
        >>> Decimal('  3.14  \\n')        # leading and trailing whitespace okay
        Decimal('3.14')
        """

        # Note that the coefficient, self._int, is actually stored as
        # a string rather than as a tuple of digits.  This speeds up
        # the "digits to integer" and "integer to digits" conversions
        # that are used in almost every arithmetic operation on
        # Decimals.  This is an internal detail: the as_tuple function
        # and the Decimal constructor still deal with tuples of
        # digits.

        self = object.__new__(cls)

        if is_cli:
            import System
            if isinstance(value, System.Decimal):
                value = str(value)

        # From a string
        # REs insist on real strings, so we can too.
        if isinstance(value, str):
            m = _parser(value.strip())
            if m is None:
                if context is None:
                    context = getcontext()
                return context._raise_error(ConversionSyntax,
                                "Invalid literal for Decimal: %r" % value)

            if m.group('sign') == "-":
                self._sign = 1
            else:
                self._sign = 0
            intpart = m.group('int')
            if intpart is not None:
                # finite number
                fracpart = m.group('frac') or ''
                exp = int(m.group('exp') or '0')
                self._int = str(int(intpart+fracpart))
                self._exp = exp - len(fracpart)
                self._is_special = False
            else:
                diag = m.group('diag')
                if diag is not None:
                    # NaN
                    self._int = str(int(diag or '0')).lstrip('0')
                    if m.group('signal'):
                        self._exp = 'N'
                    else:
                        self._exp = 'n'
                else:
                    # infinity
                    self._int = '0'
                    self._exp = 'F'
                self._is_special = True
            return self

        # From an integer
        if isinstance(value, int):
            if value >= 0:
                self._sign = 0
            else:
                self._sign = 1
            self._exp = 0
            self._int = str(abs(value))
            self._is_special = False
            return self

        # From another decimal
        if isinstance(value, Decimal):
            self._exp  = value._exp
            self._sign = value._sign
            self._int  = value._int
            self._is_special  = value._is_special
            return self

        # From an internal working value
        if isinstance(value, _WorkRep):
            self._sign = value.sign
            self._int = str(value.int)
            self._exp = int(value.exp)
            self._is_special = False
            return self

        # tuple/list conversion (possibly from as_tuple())
        if isinstance(value, (list,tuple)):
            if len(value) != 3:
                raise ValueError('Invalid tuple size in creation of Decimal '
                                 'from list or tuple.  The list or tuple '
                                 'should have exactly three elements.')
            # process sign.  The isinstance test rejects floats
            if not (isinstance(value[0], int) and value[0] in (0,1)):
                raise ValueError("Invalid sign.  The first value in the tuple "
                                 "should be an integer; either 0 for a "
                                 "positive number or 1 for a negative number.")
            self._sign = value[0]
            if value[2] == 'F':
                # infinity: value[1] is ignored
                self._int = '0'
                self._exp = value[2]
                self._is_special = True
            else:
                # process and validate the digits in value[1]
                digits = []
                for digit in value[1]:
                    if isinstance(digit, int) and 0 <= digit <= 9:
                        # skip leading zeros
                        if digits or digit != 0:
                            digits.append(digit)
                    else:
                        raise ValueError("The second value in the tuple must "
                                         "be composed of integers in the range "
                                         "0 through 9.")
                if value[2] in ('n', 'N'):
                    # NaN: digits form the diagnostic
                    self._int = ''.join(map(str, digits))
                    self._exp = value[2]
                    self._is_special = True
                elif isinstance(value[2], int):
                    # finite number: digits give the coefficient
                    self._int = ''.join(map(str, digits or [0]))
                    self._exp = value[2]
                    self._is_special = False
                else:
                    raise ValueError("The third value in the tuple must "
                                     "be an integer, or one of the "
                                     "strings 'F', 'n', 'N'.")
            return self

        if isinstance(value, float):
            if context is None:
                context = getcontext()
            context._raise_error(FloatOperation,
                "strict semantics for mixing floats and Decimals are "
                "enabled")
            value = Decimal.from_float(value)
            self._exp  = value._exp
            self._sign = value._sign
            self._int  = value._int
            self._is_special  = value._is_special
            return self

        raise TypeError("Cannot convert %r to Decimal" % value)

    @classmethod
    def from_float(cls, f):
        """Converts a float to a decimal number, exactly.

        Note that Decimal.from_float(0.1) is not the same as Decimal('0.1').
        Since 0.1 is not exactly representable in binary floating point, the
        value is stored as the nearest representable value which is
        0x1.999999999999ap-4.  The exact equivalent of the value in decimal
        is 0.1000000000000000055511151231257827021181583404541015625.

        >>> Decimal.from_float(0.1)
        Decimal('0.1000000000000000055511151231257827021181583404541015625')
        >>> Decimal.from_float(float('nan'))
        Decimal('NaN')
        >>> Decimal.from_float(float('inf'))
        Decimal('Infinity')
        >>> Decimal.from_float(-float('inf'))
        Decimal('-Infinity')
        >>> Decimal.from_float(-0.0)
        Decimal('-0')

        """
        if isinstance(f, int):                # handle integer inputs
            return cls(f)
        if not isinstance(f, float):
            raise TypeError("argument must be int or float.")
        if _math.isinf(f) or _math.isnan(f):
            return cls(repr(f))
        if _math.copysign(1.0, f) == 1.0:
            sign = 0
        else:
            sign = 1
        n, d = abs(f).as_integer_ratio()
        k = d.bit_length() - 1
        result = _dec_from_triple(sign, str(n*5**k), -k)
        if cls is Decimal:
            return result
        else:
            return cls(result)

    def _isnan(self):
        """Returns whether the number is not actually one.

        0 if a number
        1 if NaN
        2 if sNaN
        """
        if self._is_special:
            exp = self._exp
            if exp == 'n':
                return 1
            elif exp == 'N':
                return 2
        return 0

    def _isinfinity(self):
        """Returns whether the number is infinite

        0 if finite or not a number
        1 if +INF
        -1 if -INF
        """
        if self._exp == 'F':
            if self._sign:
                return -1
            return 1
        return 0

    def _check_nans(self, other=None, context=None):
        """Returns whether the number is not actually one.

        if self, other are sNaN, signal
        if self, other are NaN return nan
        return 0

        Done before operations.
        """

        self_is_nan = self._isnan()
        if other is None:
            other_is_nan = False
        else:
            other_is_nan = other._isnan()

        if self_is_nan or other_is_nan:
            if context is None:
                context = getcontext()

            if self_is_nan == 2:
                return context._raise_error(InvalidOperation, 'sNaN',
                                        self)
            if other_is_nan == 2:
                return context._raise_error(InvalidOperation, 'sNaN',
                                        other)
            if self_is_nan:
                return self._fix_nan(context)

            return other._fix_nan(context)
        return 0

    def _compare_check_nans(self, other, context):
        """Version of _check_nans used for the signaling comparisons
        compare_signal, __le__, __lt__, __ge__, __gt__.

        Signal InvalidOperation if either self or other is a (quiet
        or signaling) NaN.  Signaling NaNs take precedence over quiet
        NaNs.

        Return 0 if neither operand is a NaN.

        """
        if context is None:
            context = getcontext()

        if self._is_special or other._is_special:
            if self.is_snan():
                return context._raise_error(InvalidOperation,
                                            'comparison involving sNaN',
                                            self)
            elif other.is_snan():
                return context._raise_error(InvalidOperation,
                                            'comparison involving sNaN',
                                            other)
            elif self.is_qnan():
                return context._raise_error(InvalidOperation,
                                            'comparison involving NaN',
                                            self)
            elif other.is_qnan():
                return context._raise_error(InvalidOperation,
                                            'comparison involving NaN',
                                            other)
        return 0

    def __bool__(self):
        """Return True if self is nonzero; otherwise return False.

        NaNs and infinities are considered nonzero.
        """
        return self._is_special or self._int != '0'

    def _cmp(self, other):
        """Compare the two non-NaN decimal instances self and other.

        Returns -1 if self < other, 0 if self == other and 1
        if self > other.  This routine is for internal use only."""

        if self._is_special or other._is_special:
            self_inf = self._isinfinity()
            other_inf = other._isinfinity()
            if self_inf == other_inf:
                return 0
            elif self_inf < other_inf:
                return -1
            else:
                return 1

        # check for zeros;  Decimal('0') == Decimal('-0')
        if not self:
            if not other:
                return 0
            else:
                return -((-1)**other._sign)
        if not other:
            return (-1)**self._sign

        # If different signs, neg one is less
        if other._sign < self._sign:
            return -1
        if self._sign < other._sign:
            return 1

        self_adjusted = self.adjusted()
        other_adjusted = other.adjusted()
        if self_adjusted == other_adjusted:
            self_padded = self._int + '0'*(self._exp - other._exp)
            other_padded = other._int + '0'*(other._exp - self._exp)
            if self_padded == other_padded:
                return 0
            elif self_padded < other_padded:
                return -(-1)**self._sign
            else:
                return (-1)**self._sign
        elif self_adjusted > other_adjusted:
            return (-1)**self._sign
        else: # self_adjusted < other_adjusted
            return -((-1)**self._sign)

    # Note: The Decimal standard doesn't cover rich comparisons for
    # Decimals.  In particular, the specification is silent on the
    # subject of what should happen for a comparison involving a NaN.
    # We take the following approach:
    #
    #   == comparisons involving a quiet NaN always return False
    #   != comparisons involving a quiet NaN always return True
    #   == or != comparisons involving a signaling NaN signal
    #      InvalidOperation, and return False or True as above if the
    #      InvalidOperation is not trapped.
    #   <, >, <= and >= comparisons involving a (quiet or signaling)
    #      NaN signal InvalidOperation, and return False if the
    #      InvalidOperation is not trapped.
    #
    # This behavior is designed to conform as closely as possible to
    # that specified by IEEE 754.

    def __eq__(self, other, context=None):
        self, other = _convert_for_comparison(self, other, equality_op=True)
        if other is NotImplemented:
            return other
        if self._check_nans(other, context):
            return False
        return self._cmp(other) == 0

    def __ne__(self, other, context=None):
        self, other = _convert_for_comparison(self, other, equality_op=True)
        if other is NotImplemented:
            return other
        if self._check_nans(other, context):
            return True
        return self._cmp(other) != 0


    def __lt__(self, other, context=None):
        self, other = _convert_for_comparison(self, other)
        if other is NotImplemented:
            return other
        ans = self._compare_check_nans(other, context)
        if ans:
            return False
        return self._cmp(other) < 0

    def __le__(self, other, context=None):
        self, other = _convert_for_comparison(self, other)
        if other is NotImplemented:
            return other
        ans = self._compare_check_nans(other, context)
        if ans:
            return False
        return self._cmp(other) <= 0

    def __gt__(self, other, context=None):
        self, other = _convert_for_comparison(self, other)
        if other is NotImplemented:
            return other
        ans = self._compare_check_nans(other, context)
        if ans:
            return False
        return self._cmp(other) > 0

    def __ge__(self, other, context=None):
        self, other = _convert_for_comparison(self, other)
        if other is NotImplemented:
            return other
        ans = self._compare_check_nans(other, context)
        if ans:
            return False
        return self._cmp(other) >= 0

    def compare(self, other, context=None):
        """Compare self to other.  Return a decimal value:

        a or b is a NaN ==> Decimal('NaN')
        a < b           ==> Decimal('-1')
        a == b          ==> Decimal('0')
        a > b           ==> Decimal('1')
        """
        other = _convert_other(other, raiseit=True)

        # Compare(NaN, NaN) = NaN
        if (self._is_special or other and other._is_special):
            ans = self._check_nans(other, context)
            if ans:
                return ans

        return Decimal(self._cmp(other))

    def __hash__(self):
        """x.__hash__() <==> hash(x)"""

        # In order to make sure that the hash of a Decimal instance
        # agrees with the hash of a numerically equal integer, float
        # or Fraction, we follow the rules for numeric hashes outlined
        # in the documentation.  (See library docs, 'Built-in Types').
        if self._is_special:
            if self.is_snan():
                raise TypeError('Cannot hash a signaling NaN value.')
            elif self.is_nan():
                return _PyHASH_NAN
            else:
                if self._sign:
                    return -_PyHASH_INF
                else:
                    return _PyHASH_INF

        if self._exp >= 0:
            exp_hash = pow(10, self._exp, _PyHASH_MODULUS)
        else:
            exp_hash = pow(_PyHASH_10INV, -self._exp, _PyHASH_MODULUS)
        hash_ = int(self._int) * exp_hash % _PyHASH_MODULUS
        ans = hash_ if self >= 0 else -hash_
        return -2 if ans == -1 else ans

    def as_tuple(self):
        """Represents the number as a triple tuple.

        To show the internals exactly as they are.
        """
        return DecimalTuple(self._sign, tuple(map(int, self._int)), self._exp)

    def __repr__(self):
        """Represents the number as an instance of Decimal."""
        # Invariant:  eval(repr(d)) == d
        return "Decimal('%s')" % str(self)

    def __str__(self, eng=False, context=None):
        """Return string representation of the number in scientific notation.

        Captures all of the information in the underlying representation.
        """

        sign = ['', '-'][self._sign]
        if self._is_special:
            if self._exp == 'F':
                return sign + 'Infinity'
            elif self._exp == 'n':
                return sign + 'NaN' + self._int
            else: # self._exp == 'N'
                return sign + 'sNaN' + self._int

        # number of digits of self._int to left of decimal point
        leftdigits = self._exp + len(self._int)

        # dotplace is number of digits of self._int to the left of the
        # decimal point in the mantissa of the output string (that is,
        # after adjusting the exponent)
        if self._exp <= 0 and leftdigits > -6:
            # no exponent required
            dotplace = leftdigits
        elif not eng:
            # usual scientific notation: 1 digit on left of the point
            dotplace = 1
        elif self._int == '0':
            # engineering notation, zero
            dotplace = (leftdigits + 1) % 3 - 1
        else:
            # engineering notation, nonzero
            dotplace = (leftdigits - 1) % 3 + 1

        if dotplace <= 0:
            intpart = '0'
            fracpart = '.' + '0'*(-dotplace) + self._int
        elif dotplace >= len(self._int):
            intpart = self._int+'0'*(dotplace-len(self._int))
            fracpart = ''
        else:
            intpart = self._int[:dotplace]
            fracpart = '.' + self._int[dotplace:]
        if leftdigits == dotplace:
            exp = ''
        else:
            if context is None:
                context = getcontext()
            exp = ['e', 'E'][context.capitals] + "%+d" % (leftdigits-dotplace)

        return sign + intpart + fracpart + exp

    def to_eng_string(self, context=None):
        """Convert to engineering-type string.

        Engineering notation has an exponent which is a multiple of 3, so there
        are up to 3 digits left of the decimal place.

        Same rules for when in exponential and when as a value as in __str__.
        """
        return self.__str__(eng=True, context=context)

    def __neg__(self, context=None):
        """Returns a copy with the sign switched.

        Rounds, if it has reason.
        """
        if self._is_special:
            ans = self._check_nans(context=context)
            if ans:
                return ans

        if context is None:
            context = getcontext()

        if not self and context.rounding != ROUND_FLOOR:
            # -Decimal('0') is Decimal('0'), not Decimal('-0'), except
            # in ROUND_FLOOR rounding mode.
            ans = self.copy_abs()
        else:
            ans = self.copy_negate()

        return ans._fix(context)

    def __pos__(self, context=None):
        """Returns a copy, unless it is a sNaN.

        Rounds the number (if more then precision digits)
        """
        if self._is_special:
            ans = self._check_nans(context=context)
            if ans:
                return ans

        if context is None:
            context = getcontext()

        if not self and context.rounding != ROUND_FLOOR:
            # + (-0) = 0, except in ROUND_FLOOR rounding mode.
            ans = self.copy_abs()
        else:
            ans = Decimal(self)

        return ans._fix(context)

    def __abs__(self, round=True, context=None):
        """Returns the absolute value of self.

        If the keyword argument 'round' is false, do not round.  The
        expression self.__abs__(round=False) is equivalent to
        self.copy_abs().
        """
        if not round:
            return self.copy_abs()

        if self._is_special:
            ans = self._check_nans(context=context)
            if ans:
                return ans

        if self._sign:
            ans = self.__neg__(context=context)
        else:
            ans = self.__pos__(context=context)

        return ans

    def __add__(self, other, context=None):
        """Returns self + other.

        -INF + INF (or the reverse) cause InvalidOperation errors.
        """
        other = _convert_other(other)
        if other is NotImplemented:
            return other

        if context is None:
            context = getcontext()

        if self._is_special or other._is_special:
            ans = self._check_nans(other, context)
            if ans:
                return ans

            if self._isinfinity():
                # If both INF, same sign => same as both, opposite => error.
                if self._sign != other._sign and other._isinfinity():
                    return context._raise_error(InvalidOperation, '-INF + INF')
                return Decimal(self)
            if other._isinfinity():
                return Decimal(other)  # Can't both be infinity here

        exp = min(self._exp, other._exp)
        negativezero = 0
        if context.rounding == ROUND_FLOOR and self._sign != other._sign:
            # If the answer is 0, the sign should be negative, in this case.
            negativezero = 1

        if not self and not other:
            sign = min(self._sign, other._sign)
            if negativezero:
                sign = 1
            ans = _dec_from_triple(sign, '0', exp)
            ans = ans._fix(context)
            return ans
        if not self:
            exp = max(exp, other._exp - context.prec-1)
            ans = other._rescale(exp, context.rounding)
            ans = ans._fix(context)
            return ans
        if not other:
            exp = max(exp, self._exp - context.prec-1)
            ans = self._rescale(exp, context.rounding)
            ans = ans._fix(context)
            return ans

        op1 = _WorkRep(self)
        op2 = _WorkRep(other)
        op1, op2 = _normalize(op1, op2, context.prec)

        result = _WorkRep()
        if op1.sign != op2.sign:
            # Equal and opposite
            if op1.int == op2.int:
                ans = _dec_from_triple(negativezero, '0', exp)
                ans = ans._fix(context)
                return ans
            if op1.int < op2.int:
                op1, op2 = op2, op1
                # OK, now abs(op1) > abs(op2)
            if op1.sign == 1:
                result.sign = 1
                op1.sign, op2.sign = op2.sign, op1.sign
            else:
                result.sign = 0
                # So we know the sign, and op1 > 0.
        elif op1.sign == 1:
            result.sign = 1
            op1.sign, op2.sign = (0, 0)
        else:
            result.sign = 0
        # Now, op1 > abs(op2) > 0

        if op2.sign == 0:
            result.int = op1.int + op2.int
        else:
            result.int = op1.int - op2.int

        result.exp = op1.exp
        ans = Decimal(result)
        ans = ans._fix(context)
        return ans

    __radd__ = __add__

    def __sub__(self, other, context=None):
        """Return self - other"""
        other = _convert_other(other)
        if other is NotImplemented:
            return other

        if self._is_special or other._is_special:
            ans = self._check_nans(other, context=context)
            if ans:
                return ans

        # self - other is computed as self + other.copy_negate()
        return self.__add__(other.copy_negate(), context=context)

    def __rsub__(self, other, context=None):
        """Return other - self"""
        other = _convert_other(other)
        if other is NotImplemented:
            return other

        return other.__sub__(self, context=context)

    def __mul__(self, other, context=None):
        """Return self * other.

        (+-) INF * 0 (or its reverse) raise InvalidOperation.
        """
        other = _convert_other(other)
        if other is NotImplemented:
            return other

        if context is None:
            context = getcontext()

        resultsign = self._sign ^ other._sign

        if self._is_special or other._is_special:
            ans = self._check_nans(other, context)
            if ans:
                return ans

            if self._isinfinity():
                if not other:
                    return context._raise_error(InvalidOperation, '(+-)INF * 0')
                return _SignedInfinity[resultsign]

            if other._isinfinity():
                if not self:
                    return context._raise_error(InvalidOperation, '0 * (+-)INF')
                return _SignedInfinity[resultsign]

        resultexp = self._exp + other._exp

        # Special case for multiplying by zero
        if not self or not other:
            ans = _dec_from_triple(resultsign, '0', resultexp)
            # Fixing in case the exponent is out of bounds
            ans = ans._fix(context)
            return ans

        # Special case for multiplying by power of 10
        if self._int == '1':
            ans = _dec_from_triple(resultsign, other._int, resultexp)
            ans = ans._fix(context)
            return ans
        if other._int == '1':
            ans = _dec_from_triple(resultsign, self._int, resultexp)
            ans = ans._fix(context)
            return ans

        op1 = _WorkRep(self)
        op2 = _WorkRep(other)

        ans = _dec_from_triple(resultsign, str(op1.int * op2.int), resultexp)
        ans = ans._fix(context)

        return ans
    __rmul__ = __mul__

    def __truediv__(self, other, context=None):
        """Return self / other."""
        other = _convert_other(other)
        if other is NotImplemented:
            return NotImplemented

        if context is None:
            context = getcontext()

        sign = self._sign ^ other._sign

        if self._is_special or other._is_special:
            ans = self._check_nans(other, context)
            if ans:
                return ans

            if self._isinfinity() and other._isinfinity():
                return context._raise_error(InvalidOperation, '(+-)INF/(+-)INF')

            if self._isinfinity():
                return _SignedInfinity[sign]

            if other._isinfinity():
                context._raise_error(Clamped, 'Division by infinity')
                return _dec_from_triple(sign, '0', context.Etiny())

        # Special cases for zeroes
        if not other:
            if not self:
                return context._raise_error(DivisionUndefined, '0 / 0')
            return context._raise_error(DivisionByZero, 'x / 0', sign)

        if not self:
            exp = self._exp - other._exp
            coeff = 0
        else:
            # OK, so neither = 0, INF or NaN
            shift = len(other._int) - len(self._int) + context.prec + 1
            exp = self._exp - other._exp - shift
            op1 = _WorkRep(self)
            op2 = _WorkRep(other)
            if shift >= 0:
                coeff, remainder = divmod(op1.int * 10**shift, op2.int)
            else:
                coeff, remainder = divmod(op1.int, op2.int * 10**-shift)
            if remainder:
                # result is not exact; adjust to ensure correct rounding
                if coeff % 5 == 0:
                    coeff += 1
            else:
                # result is exact; get as close to ideal exponent as possible
                ideal_exp = self._exp - other._exp
                while exp < ideal_exp and coeff % 10 == 0:
                    coeff //= 10
                    exp += 1

        ans = _dec_from_triple(sign, str(coeff), exp)
        return ans._fix(context)

    def _divide(self, other, context):
        """Return (self // other, self % other), to context.prec precision.

        Assumes that neither self nor other is a NaN, that self is not
        infinite and that other is nonzero.
        """
        sign = self._sign ^ other._sign
        if other._isinfinity():
            ideal_exp = self._exp
        else:
            ideal_exp = min(self._exp, other._exp)

        expdiff = self.adjusted() - other.adjusted()
        if not self or other._isinfinity() or expdiff <= -2:
            return (_dec_from_triple(sign, '0', 0),
                    self._rescale(ideal_exp, context.rounding))
        if expdiff <= context.prec:
            op1 = _WorkRep(self)
            op2 = _WorkRep(other)
            if op1.exp >= op2.exp:
                op1.int *= 10**(op1.exp - op2.exp)
            else:
                op2.int *= 10**(op2.exp - op1.exp)
            q, r = divmod(op1.int, op2.int)
            if q < 10**context.prec:
                return (_dec_from_triple(sign, str(q), 0),
                        _dec_from_triple(self._sign, str(r), ideal_exp))

        # Here the quotient is too large to be representable
        ans = context._raise_error(DivisionImpossible,
                                   'quotient too large in //, % or divmod')
        return ans, ans

    def __rtruediv__(self, other, context=None):
        """Swaps self/other and returns __truediv__."""
        other = _convert_other(other)
        if other is NotImplemented:
            return other
        return other.__truediv__(self, context=context)

    def __divmod__(self, other, context=None):
        """
        Return (self // other, self % other)
        """
        other = _convert_other(other)
        if other is NotImplemented:
            return other

        if context is None:
            context = getcontext()

        ans = self._check_nans(other, context)
        if ans:
            return (ans, ans)

        sign = self._sign ^ other._sign
        if self._isinfinity():
            if other._isinfinity():
                ans = context._raise_error(InvalidOperation, 'divmod(INF, INF)')
                return ans, ans
            else:
                return (_SignedInfinity[sign],
                        context._raise_error(InvalidOperation, 'INF % x'))

        if not other:
            if not self:
                ans = context._raise_error(DivisionUndefined, 'divmod(0, 0)')
                return ans, ans
            else:
                return (context._raise_error(DivisionByZero, 'x // 0', sign),
                        context._raise_error(InvalidOperation, 'x % 0'))

        quotient, remainder = self._divide(other, context)
        remainder = remainder._fix(context)
        return quotient, remainder

    def __rdivmod__(self, other, context=None):
        """Swaps self/other and returns __divmod__."""
        other = _convert_other(other)
        if other is NotImplemented:
            return other
        return other.__divmod__(self, context=context)

    def __mod__(self, other, context=None):
        """
        self % other
        """
        other = _convert_other(other)
        if other is NotImplemented:
            return other

        if context is None:
            context = getcontext()

        ans = self._check_nans(other, context)
        if ans:
            return ans

        if self._isinfinity():
            return context._raise_error(InvalidOperation, 'INF % x')
        elif not other:
            if self:
                return context._raise_error(InvalidOperation, 'x % 0')
            else:
                return context._raise_error(DivisionUndefined, '0 % 0')

        remainder = self._divide(other, context)[1]
        remainder = remainder._fix(context)
        return remainder

    def __rmod__(self, other, context=None):
        """Swaps self/other and returns __mod__."""
        other = _convert_other(other)
        if other is NotImplemented:
            return other
        return other.__mod__(self, context=context)

    def remainder_near(self, other, context=None):
        """
        Remainder nearest to 0-  abs(remainder-near) <= other/2
        """
        if context is None:
            context = getcontext()

        other = _convert_other(other, raiseit=True)

        ans = self._check_nans(other, context)
        if ans:
            return ans

        # self == +/-infinity -> InvalidOperation
        if self._isinfinity():
            return context._raise_error(InvalidOperation,
                                        'remainder_near(infinity, x)')

        # other == 0 -> either InvalidOperation or DivisionUndefined
        if not other:
            if self:
                return context._raise_error(InvalidOperation,
                                            'remainder_near(x, 0)')
            else:
                return context._raise_error(DivisionUndefined,
                                            'remainder_near(0, 0)')

        # other = +/-infinity -> remainder = self
        if other._isinfinity():
            ans = Decimal(self)
            return ans._fix(context)

        # self = 0 -> remainder = self, with ideal exponent
        ideal_exponent = min(self._exp, other._exp)
        if not self:
            ans = _dec_from_triple(self._sign, '0', ideal_exponent)
            return ans._fix(context)

        # catch most cases of large or small quotient
        expdiff = self.adjusted() - other.adjusted()
        if expdiff >= context.prec + 1:
            # expdiff >= prec+1 => abs(self/other) > 10**prec
            return context._raise_error(DivisionImpossible)
        if expdiff <= -2:
            # expdiff <= -2 => abs(self/other) < 0.1
            ans = self._rescale(ideal_exponent, context.rounding)
            return ans._fix(context)

        # adjust both arguments to have the same exponent, then divide
        op1 = _WorkRep(self)
        op2 = _WorkRep(other)
        if op1.exp >= op2.exp:
            op1.int *= 10**(op1.exp - op2.exp)
        else:
            op2.int *= 10**(op2.exp - op1.exp)
        q, r = divmod(op1.int, op2.int)
        # remainder is r*10**ideal_exponent; other is +/-op2.int *
        # 10**ideal_exponent.   Apply correction to ensure that
        # abs(remainder) <= abs(other)/2
        if 2*r + (q&1) > op2.int:
            r -= op2.int
            q += 1

        if q >= 10**context.prec:
            return context._raise_error(DivisionImpossible)

        # result has same sign as self unless r is negative
        sign = self._sign
        if r < 0:
            sign = 1-sign
            r = -r

        ans = _dec_from_triple(sign, str(r), ideal_exponent)
        return ans._fix(context)

    def __floordiv__(self, other, context=None):
        """self // other"""
        other = _convert_other(other)
        if other is NotImplemented:
            return other

        if context is None:
            context = getcontext()

        ans = self._check_nans(other, context)
        if ans:
            return ans

        if self._isinfinity():
            if other._isinfinity():
                return context._raise_error(InvalidOperation, 'INF // INF')
            else:
                return _SignedInfinity[self._sign ^ other._sign]

        if not other:
            if self:
                return context._raise_error(DivisionByZero, 'x // 0',
                                            self._sign ^ other._sign)
            else:
                return context._raise_error(DivisionUndefined, '0 // 0')

        return self._divide(other, context)[0]

    def __rfloordiv__(self, other, context=None):
        """Swaps self/other and returns __floordiv__."""
        other = _convert_other(other)
        if other is NotImplemented:
            return other
        return other.__floordiv__(self, context=context)

    def __float__(self):
        """Float representation."""
        if self._isnan():
            if self.is_snan():
                raise ValueError("Cannot convert signaling NaN to float")
            s = "-nan" if self._sign else "nan"
        else:
            s = str(self)
        return float(s)

    def __int__(self):
        """Converts self to an int, truncating if necessary."""
        if self._is_special:
            if self._isnan():
                raise ValueError("Cannot convert NaN to integer")
            elif self._isinfinity():
                raise OverflowError("Cannot convert infinity to integer")
        s = (-1)**self._sign
        if self._exp >= 0:
            return s*int(self._int)*10**self._exp
        else:
            return s*int(self._int[:self._exp] or '0')

    __trunc__ = __int__

    def real(self):
        return self
    real = property(real)

    def imag(self):
        return Decimal(0)
    imag = property(imag)

    def conjugate(self):
        return self

    def __complex__(self):
        return complex(float(self))

    def _fix_nan(self, context):
        """Decapitate the payload of a NaN to fit the context"""
        payload = self._int

        # maximum length of payload is precision if clamp=0,
        # precision-1 if clamp=1.
        max_payload_len = context.prec - context.clamp
        if len(payload) > max_payload_len:
            payload = payload[len(payload)-max_payload_len:].lstrip('0')
            return _dec_from_triple(self._sign, payload, self._exp, True)
        return Decimal(self)

    def _fix(self, context):
        """Round if it is necessary to keep self within prec precision.

        Rounds and fixes the exponent.  Does not raise on a sNaN.

        Arguments:
        self - Decimal instance
        context - context used.
        """

        if self._is_special:
            if self._isnan():
                # decapitate payload if necessary
                return self._fix_nan(context)
            else:
                # self is +/-Infinity; return unaltered
                return Decimal(self)

        # if self is zero then exponent should be between Etiny and
        # Emax if clamp==0, and between Etiny and Etop if clamp==1.
        Etiny = context.Etiny()
        Etop = context.Etop()
        if not self:
            exp_max = [context.Emax, Etop][context.clamp]
            new_exp = min(max(self._exp, Etiny), exp_max)
            if new_exp != self._exp:
                context._raise_error(Clamped)
                return _dec_from_triple(self._sign, '0', new_exp)
            else:
                return Decimal(self)

        # exp_min is the smallest allowable exponent of the result,
        # equal to max(self.adjusted()-context.prec+1, Etiny)
        exp_min = len(self._int) + self._exp - context.prec
        if exp_min > Etop:
            # overflow: exp_min > Etop iff self.adjusted() > Emax
            ans = context._raise_error(Overflow, 'above Emax', self._sign)
            context._raise_error(Inexact)
            context._raise_error(Rounded)
            return ans

        self_is_subnormal = exp_min < Etiny
        if self_is_subnormal:
            exp_min = Etiny

        # round if self has too many digits
        if self._exp < exp_min:
            digits = len(self._int) + self._exp - exp_min
            if digits < 0:
                self = _dec_from_triple(self._sign, '1', exp_min-1)
                digits = 0
            rounding_method = self._pick_rounding_function[context.rounding]
            changed = rounding_method(self, digits)
            coeff = self._int[:digits] or '0'
            if changed > 0:
                coeff = str(int(coeff)+1)
                if len(coeff) > context.prec:
                    coeff = coeff[:-1]
                    exp_min += 1

            # check whether the rounding pushed the exponent out of range
            if exp_min > Etop:
                ans = context._raise_error(Overflow, 'above Emax', self._sign)
            else:
                ans = _dec_from_triple(self._sign, coeff, exp_min)

            # raise the appropriate signals, taking care to respect
            # the precedence described in the specification
            if changed and self_is_subnormal:
                context._raise_error(Underflow)
            if self_is_subnormal:
                context._raise_error(Subnormal)
            if changed:
                context._raise_error(Inexact)
            context._raise_error(Rounded)
            if not ans:
                # raise Clamped on underflow to 0
                context._raise_error(Clamped)
            return ans

        if self_is_subnormal:
            context._raise_error(Subnormal)

        # fold down if clamp == 1 and self has too few digits
        if context.clamp == 1 and self._exp > Etop:
            context._raise_error(Clamped)
            self_padded = self._int + '0'*(self._exp - Etop)
            return _dec_from_triple(self._sign, self_padded, Etop)

        # here self was representable to begin with; return unchanged
        return Decimal(self)

    # for each of the rounding functions below:
    #   self is a finite, nonzero Decimal
    #   prec is an integer satisfying 0 <= prec < len(self._int)
    #
    # each function returns either -1, 0, or 1, as follows:
    #   1 indicates that self should be rounded up (away from zero)
    #   0 indicates that self should be truncated, and that all the
    #     digits to be truncated are zeros (so the value is unchanged)
    #  -1 indicates that there are nonzero digits to be truncated

    def _round_down(self, prec):
        """Also known as round-towards-0, truncate."""
        if _all_zeros(self._int, prec):
            return 0
        else:
            return -1

    def _round_up(self, prec):
        """Rounds away from 0."""
        return -self._round_down(prec)

    def _round_half_up(self, prec):
        """Rounds 5 up (away from 0)"""
        if self._int[prec] in '56789':
            return 1
        elif _all_zeros(self._int, prec):
            return 0
        else:
            return -1

    def _round_half_down(self, prec):
        """Round 5 down"""
        if _exact_half(self._int, prec):
            return -1
        else:
            return self._round_half_up(prec)

    def _round_half_even(self, prec):
        """Round 5 to even, rest to nearest."""
        if _exact_half(self._int, prec) and \
                (prec == 0 or self._int[prec-1] in '02468'):
            return -1
        else:
            return self._round_half_up(prec)

    def _round_ceiling(self, prec):
        """Rounds up (not away from 0 if negative.)"""
        if self._sign:
            return self._round_down(prec)
        else:
            return -self._round_down(prec)

    def _round_floor(self, prec):
        """Rounds down (not towards 0 if negative)"""
        if not self._sign:
            return self._round_down(prec)
        else:
            return -self._round_down(prec)

    def _round_05up(self, prec):
        """Round down unless digit prec-1 is 0 or 5."""
        if prec and self._int[prec-1] not in '05':
            return self._round_down(prec)
        else:
            return -self._round_down(prec)

    _pick_rounding_function = dict(
        ROUND_DOWN = _round_down,
        ROUND_UP = _round_up,
        ROUND_HALF_UP = _round_half_up,
        ROUND_HALF_DOWN = _round_half_down,
        ROUND_HALF_EVEN = _round_half_even,
        ROUND_CEILING = _round_ceiling,
        ROUND_FLOOR = _round_floor,
        ROUND_05UP = _round_05up,
    )

    def __round__(self, n=None):
        """Round self to the nearest integer, or to a given precision.

        If only one argument is supplied, round a finite Decimal
        instance self to the nearest integer.  If self is infinite or
        a NaN then a Python exception is raised.  If self is finite
        and lies exactly halfway between two integers then it is
        rounded to the integer with even last digit.

        >>> round(Decimal('123.456'))
        123
        >>> round(Decimal('-456.789'))
        -457
        >>> round(Decimal('-3.0'))
        -3
        >>> round(Decimal('2.5'))
        2
        >>> round(Decimal('3.5'))
        4
        >>> round(Decimal('Inf'))
        Traceback (most recent call last):
          ...
        OverflowError: cannot round an infinity
        >>> round(Decimal('NaN'))
        Traceback (most recent call last):
          ...
        ValueError: cannot round a NaN

        If a second argument n is supplied, self is rounded to n
        decimal places using the rounding mode for the current
        context.

        For an integer n, round(self, -n) is exactly equivalent to
        self.quantize(Decimal('1En')).

        >>> round(Decimal('123.456'), 0)
        Decimal('123')
        >>> round(Decimal('123.456'), 2)
        Decimal('123.46')
        >>> round(Decimal('123.456'), -2)
        Decimal('1E+2')
        >>> round(Decimal('-Infinity'), 37)
        Decimal('NaN')
        >>> round(Decimal('sNaN123'), 0)
        Decimal('NaN123')

        """
        if n is not None:
            # two-argument form: use the equivalent quantize call
            if not isinstance(n, int):
                raise TypeError('Second argument to round should be integral')
            exp = _dec_from_triple(0, '1', -n)
            return self.quantize(exp)

        # one-argument form
        if self._is_special:
            if self.is_nan():
                raise ValueError("cannot round a NaN")
            else:
                raise OverflowError("cannot round an infinity")
        return int(self._rescale(0, ROUND_HALF_EVEN))

    def __floor__(self):
        """Return the floor of self, as an integer.

        For a finite Decimal instance self, return the greatest
        integer n such that n <= self.  If self is infinite or a NaN
        then a Python exception is raised.

        """
        if self._is_special:
            if self.is_nan():
                raise ValueError("cannot round a NaN")
            else:
                raise OverflowError("cannot round an infinity")
        return int(self._rescale(0, ROUND_FLOOR))

    def __ceil__(self):
        """Return the ceiling of self, as an integer.

        For a finite Decimal instance self, return the least integer n
        such that n >= self.  If self is infinite or a NaN then a
        Python exception is raised.

        """
        if self._is_special:
            if self.is_nan():
                raise ValueError("cannot round a NaN")
            else:
                raise OverflowError("cannot round an infinity")
        return int(self._rescale(0, ROUND_CEILING))

    def fma(self, other, third, context=None):
        """Fused multiply-add.

        Returns self*other+third with no rounding of the intermediate
        product self*other.

        self and other are multiplied together, with no rounding of
        the result.  The third operand is then added to the result,
        and a single final rounding is performed.
        """

        other = _convert_other(other, raiseit=True)
        third = _convert_other(third, raiseit=True)

        # compute product; raise InvalidOperation if either operand is
        # a signaling NaN or if the product is zero times infinity.
        if self._is_special or other._is_special:
            if context is None:
                context = getcontext()
            if self._exp == 'N':
                return context._raise_error(InvalidOperation, 'sNaN', self)
            if other._exp == 'N':
                return context._raise_error(InvalidOperation, 'sNaN', other)
            if self._exp == 'n':
                product = self
            elif other._exp == 'n':
                product = other
            elif self._exp == 'F':
                if not other:
                    return context._raise_error(InvalidOperation,
                                                'INF * 0 in fma')
                product = _SignedInfinity[self._sign ^ other._sign]
            elif other._exp == 'F':
                if not self:
                    return context._raise_error(InvalidOperation,
                                                '0 * INF in fma')
                product = _SignedInfinity[self._sign ^ other._sign]
        else:
            product = _dec_from_triple(self._sign ^ other._sign,
                                       str(int(self._int) * int(other._int)),
                                       self._exp + other._exp)

        return product.__add__(third, context)

    def _power_modulo(self, other, modulo, context=None):
        """Three argument version of __pow__"""

        other = _convert_other(other)
        if other is NotImplemented:
            return other
        modulo = _convert_other(modulo)
        if modulo is NotImplemented:
            return modulo

        if context is None:
            context = getcontext()

        # deal with NaNs: if there are any sNaNs then first one wins,
        # (i.e. behaviour for NaNs is identical to that of fma)
        self_is_nan = self._isnan()
        other_is_nan = other._isnan()
        modulo_is_nan = modulo._isnan()
        if self_is_nan or other_is_nan or modulo_is_nan:
            if self_is_nan == 2:
                return context._raise_error(InvalidOperation, 'sNaN',
                                        self)
            if other_is_nan == 2:
                return context._raise_error(InvalidOperation, 'sNaN',
                                        other)
            if modulo_is_nan == 2:
                return context._raise_error(InvalidOperation, 'sNaN',
                                        modulo)
            if self_is_nan:
                return self._fix_nan(context)
            if other_is_nan:
                return other._fix_nan(context)
            return modulo._fix_nan(context)

        # check inputs: we apply same restrictions as Python's pow()
        if not (self._isinteger() and
                other._isinteger() and
                modulo._isinteger()):
            return context._raise_error(InvalidOperation,
                                        'pow() 3rd argument not allowed '
                                        'unless all arguments are integers')
        if other < 0:
            return context._raise_error(InvalidOperation,
                                        'pow() 2nd argument cannot be '
                                        'negative when 3rd argument specified')
        if not modulo:
            return context._raise_error(InvalidOperation,
                                        'pow() 3rd argument cannot be 0')

        # additional restriction for decimal: the modulus must be less
        # than 10**prec in absolute value
        if modulo.adjusted() >= context.prec:
            return context._raise_error(InvalidOperation,
                                        'insufficient precision: pow() 3rd '
                                        'argument must not have more than '
                                        'precision digits')

        # define 0**0 == NaN, for consistency with two-argument pow
        # (even though it hurts!)
        if not other and not self:
            return context._raise_error(InvalidOperation,
                                        'at least one of pow() 1st argument '
                                        'and 2nd argument must be nonzero ;'
                                        '0**0 is not defined')

        # compute sign of result
        if other._iseven():
            sign = 0
        else:
            sign = self._sign

        # convert modulo to a Python integer, and self and other to
        # Decimal integers (i.e. force their exponents to be >= 0)
        modulo = abs(int(modulo))
        base = _WorkRep(self.to_integral_value())
        exponent = _WorkRep(other.to_integral_value())

        # compute result using integer pow()
        base = (base.int % modulo * pow(10, base.exp, modulo)) % modulo
        for i in range(exponent.exp):
            base = pow(base, 10, modulo)
        base = pow(base, exponent.int, modulo)

        return _dec_from_triple(sign, str(base), 0)

    def _power_exact(self, other, p):
        """Attempt to compute self**other exactly.

        Given Decimals self and other and an integer p, attempt to
        compute an exact result for the power self**other, with p
        digits of precision.  Return None if self**other is not
        exactly representable in p digits.

        Assumes that elimination of special cases has already been
        performed: self and other must both be nonspecial; self must
        be positive and not numerically equal to 1; other must be
        nonzero.  For efficiency, other._exp should not be too large,
        so that 10**abs(other._exp) is a feasible calculation."""

        # In the comments below, we write x for the value of self and y for the
        # value of other.  Write x = xc*10**xe and abs(y) = yc*10**ye, with xc
        # and yc positive integers not divisible by 10.

        # The main purpose of this method is to identify the *failure*
        # of x**y to be exactly representable with as little effort as
        # possible.  So we look for cheap and easy tests that
        # eliminate the possibility of x**y being exact.  Only if all
        # these tests are passed do we go on to actually compute x**y.

        # Here's the main idea.  Express y as a rational number m/n, with m and
        # n relatively prime and n>0.  Then for x**y to be exactly
        # representable (at *any* precision), xc must be the nth power of a
        # positive integer and xe must be divisible by n.  If y is negative
        # then additionally xc must be a power of either 2 or 5, hence a power
        # of 2**n or 5**n.
        #
        # There's a limit to how small |y| can be: if y=m/n as above
        # then:
        #
        #  (1) if xc != 1 then for the result to be representable we
        #      need xc**(1/n) >= 2, and hence also xc**|y| >= 2.  So
        #      if |y| <= 1/nbits(xc) then xc < 2**nbits(xc) <=
        #      2**(1/|y|), hence xc**|y| < 2 and the result is not
        #      representable.
        #
        #  (2) if xe != 0, |xe|*(1/n) >= 1, so |xe|*|y| >= 1.  Hence if
        #      |y| < 1/|xe| then the result is not representable.
        #
        # Note that since x is not equal to 1, at least one of (1) and
        # (2) must apply.  Now |y| < 1/nbits(xc) iff |yc|*nbits(xc) <
        # 10**-ye iff len(str(|yc|*nbits(xc)) <= -ye.
        #
        # There's also a limit to how large y can be, at least if it's
        # positive: the normalized result will have coefficient xc**y,
        # so if it's representable then xc**y < 10**p, and y <
        # p/log10(xc).  Hence if y*log10(xc) >= p then the result is
        # not exactly representable.

        # if len(str(abs(yc*xe)) <= -ye then abs(yc*xe) < 10**-ye,
        # so |y| < 1/xe and the result is not representable.
        # Similarly, len(str(abs(yc)*xc_bits)) <= -ye implies |y|
        # < 1/nbits(xc).

        x = _WorkRep(self)
        xc, xe = x.int, x.exp
        while xc % 10 == 0:
            xc //= 10
            xe += 1

        y = _WorkRep(other)
        yc, ye = y.int, y.exp
        while yc % 10 == 0:
            yc //= 10
            ye += 1

        # case where xc == 1: result is 10**(xe*y), with xe*y
        # required to be an integer
        if xc == 1:
            xe *= yc
            # result is now 10**(xe * 10**ye);  xe * 10**ye must be integral
            while xe % 10 == 0:
                xe //= 10
                ye += 1
            if ye < 0:
                return None
            exponent = xe * 10**ye
            if y.sign == 1:
                exponent = -exponent
            # if other is a nonnegative integer, use ideal exponent
            if other._isinteger() and other._sign == 0:
                ideal_exponent = self._exp*int(other)
                zeros = min(exponent-ideal_exponent, p-1)
            else:
                zeros = 0
            return _dec_from_triple(0, '1' + '0'*zeros, exponent-zeros)

        # case where y is negative: xc must be either a power
        # of 2 or a power of 5.
        if y.sign == 1:
            last_digit = xc % 10
            if last_digit in (2,4,6,8):
                # quick test for power of 2
                if xc & -xc != xc:
                    return None
                # now xc is a power of 2; e is its exponent
                e = _nbits(xc)-1

                # We now have:
                #
                #   x = 2**e * 10**xe, e > 0, and y < 0.
                #
                # The exact result is:
                #
                #   x**y = 5**(-e*y) * 10**(e*y + xe*y)
                #
                # provided that both e*y and xe*y are integers.  Note that if
                # 5**(-e*y) >= 10**p, then the result can't be expressed
                # exactly with p digits of precision.
                #
                # Using the above, we can guard against large values of ye.
                # 93/65 is an upper bound for log(10)/log(5), so if
                #
                #   ye >= len(str(93*p//65))
                #
                # then
                #
                #   -e*y >= -y >= 10**ye > 93*p/65 > p*log(10)/log(5),
                #
                # so 5**(-e*y) >= 10**p, and the coefficient of the result
                # can't be expressed in p digits.

                # emax >= largest e such that 5**e < 10**p.
                emax = p*93//65
                if ye >= len(str(emax)):
                    return None

                # Find -e*y and -xe*y; both must be integers
                e = _decimal_lshift_exact(e * yc, ye)
                xe = _decimal_lshift_exact(xe * yc, ye)
                if e is None or xe is None:
                    return None

                if e > emax:
                    return None
                xc = 5**e

            elif last_digit == 5:
                # e >= log_5(xc) if xc is a power of 5; we have
                # equality all the way up to xc=5**2658
                e = _nbits(xc)*28//65
                xc, remainder = divmod(5**e, xc)
                if remainder:
                    return None
                while xc % 5 == 0:
                    xc //= 5
                    e -= 1

                # Guard against large values of ye, using the same logic as in
                # the 'xc is a power of 2' branch.  10/3 is an upper bound for
                # log(10)/log(2).
                emax = p*10//3
                if ye >= len(str(emax)):
                    return None

                e = _decimal_lshift_exact(e * yc, ye)
                xe = _decimal_lshift_exact(xe * yc, ye)
                if e is None or xe is None:
                    return None

                if e > emax:
                    return None
                xc = 2**e
            else:
                return None

            if xc >= 10**p:
                return None
            xe = -e-xe
            return _dec_from_triple(0, str(xc), xe)

        # now y is positive; find m and n such that y = m/n
        if ye >= 0:
            m, n = yc*10**ye, 1
        else:
            if xe != 0 and len(str(abs(yc*xe))) <= -ye:
                return None
            xc_bits = _nbits(xc)
            if xc != 1 and len(str(abs(yc)*xc_bits)) <= -ye:
                return None
            m, n = yc, 10**(-ye)
            while m % 2 == n % 2 == 0:
                m //= 2
                n //= 2
            while m % 5 == n % 5 == 0:
                m //= 5
                n //= 5

        # compute nth root of xc*10**xe
        if n > 1:
            # if 1 < xc < 2**n then xc isn't an nth power
            if xc != 1 and xc_bits <= n:
                return None

            xe, rem = divmod(xe, n)
            if rem != 0:
                return None

            # compute nth root of xc using Newton's method
            a = 1 << -(-_nbits(xc)//n) # initial estimate
            while True:
                q, r = divmod(xc, a**(n-1))
                if a <= q:
                    break
                else:
                    a = (a*(n-1) + q)//n
            if not (a == q and r == 0):
                return None
            xc = a

        # now xc*10**xe is the nth root of the original xc*10**xe
        # compute mth power of xc*10**xe

        # if m > p*100//_log10_lb(xc) then m > p/log10(xc), hence xc**m >
        # 10**p and the result is not representable.
        if xc > 1 and m > p*100//_log10_lb(xc):
            return None
        xc = xc**m
        xe *= m
        if xc > 10**p:
            return None

        # by this point the result *is* exactly representable
        # adjust the exponent to get as close as possible to the ideal
        # exponent, if necessary
        str_xc = str(xc)
        if other._isinteger() and other._sign == 0:
            ideal_exponent = self._exp*int(other)
            zeros = min(xe-ideal_exponent, p-len(str_xc))
        else:
            zeros = 0
        return _dec_from_triple(0, str_xc+'0'*zeros, xe-zeros)

    def __pow__(self, other, modulo=None, context=None):
        """Return self ** other [ % modulo].

        With two arguments, compute self**other.

        With three arguments, compute (self**other) % modulo.  For the
        three argument form, the following restrictions on the
        arguments hold:

         - all three arguments must be integral
         - other must be nonnegative
         - either self or other (or both) must be nonzero
         - modulo must be nonzero and must have at most p digits,
           where p is the context precision.

        If any of these restrictions is violated the InvalidOperation
        flag is raised.

        The result of pow(self, other, modulo) is identical to the
        result that would be obtained by computing (self**other) %
        modulo with unbounded precision, but is computed more
        efficiently.  It is always exact.
        """

        if modulo is not None:
            return self._power_modulo(other, modulo, context)

        other = _convert_other(other)
        if other is NotImplemented:
            return other

        if context is None:
            context = getcontext()

        # either argument is a NaN => result is NaN
        ans = self._check_nans(other, context)
        if ans:
            return ans

        # 0**0 = NaN (!), x**0 = 1 for nonzero x (including +/-Infinity)
        if not other:
            if not self:
                return context._raise_error(InvalidOperation, '0 ** 0')
            else:
                return _One

        # result has sign 1 iff self._sign is 1 and other is an odd integer
        result_sign = 0
        if self._sign == 1:
            if other._isinteger():
                if not other._iseven():
                    result_sign = 1
            else:
                # -ve**noninteger = NaN
                # (-0)**noninteger = 0**noninteger
                if self:
                    return context._raise_error(InvalidOperation,
                        'x ** y with x negative and y not an integer')
            # negate self, without doing any unwanted rounding
            self = self.copy_negate()

        # 0**(+ve or Inf)= 0; 0**(-ve or -Inf) = Infinity
        if not self:
            if other._sign == 0:
                return _dec_from_triple(result_sign, '0', 0)
            else:
                return _SignedInfinity[result_sign]

        # Inf**(+ve or Inf) = Inf; Inf**(-ve or -Inf) = 0
        if self._isinfinity():
            if other._sign == 0:
                return _SignedInfinity[result_sign]
            else:
                return _dec_from_triple(result_sign, '0', 0)

        # 1**other = 1, but the choice of exponent and the flags
        # depend on the exponent of self, and on whether other is a
        # positive integer, a negative integer, or neither
        if self == _One:
            if other._isinteger():
                # exp = max(self._exp*max(int(other), 0),
                # 1-context.prec) but evaluating int(other) directly
                # is dangerous until we know other is small (other
                # could be 1e999999999)
                if other._sign == 1:
                    multiplier = 0
                elif other > context.prec:
                    multiplier = context.prec
                else:
                    multiplier = int(other)

                exp = self._exp * multiplier
                if exp < 1-context.prec:
                    exp = 1-context.prec
                    context._raise_error(Rounded)
            else:
                context._raise_error(Inexact)
                context._raise_error(Rounded)
                exp = 1-context.prec

            return _dec_from_triple(result_sign, '1'+'0'*-exp, exp)

        # compute adjusted exponent of self
        self_adj = self.adjusted()

        # self ** infinity is infinity if self > 1, 0 if self < 1
        # self ** -infinity is infinity if self < 1, 0 if self > 1
        if other._isinfinity():
            if (other._sign == 0) == (self_adj < 0):
                return _dec_from_triple(result_sign, '0', 0)
            else:
                return _SignedInfinity[result_sign]

        # from here on, the result always goes through the call
        # to _fix at the end of this function.
        ans = None
        exact = False

        # crude test to catch cases of extreme overflow/underflow.  If
        # log10(self)*other >= 10**bound and bound >= len(str(Emax))
        # then 10**bound >= 10**len(str(Emax)) >= Emax+1 and hence
        # self**other >= 10**(Emax+1), so overflow occurs.  The test
        # for underflow is similar.
        bound = self._log10_exp_bound() + other.adjusted()
        if (self_adj >= 0) == (other._sign == 0):
            # self > 1 and other +ve, or self < 1 and other -ve
            # possibility of overflow
            if bound >= len(str(context.Emax)):
                ans = _dec_from_triple(result_sign, '1', context.Emax+1)
        else:
            # self > 1 and other -ve, or self < 1 and other +ve
            # possibility of underflow to 0
            Etiny = context.Etiny()
            if bound >= len(str(-Etiny)):
                ans = _dec_from_triple(result_sign, '1', Etiny-1)

        # try for an exact result with precision +1
        if ans is None:
            ans = self._power_exact(other, context.prec + 1)
            if ans is not None:
                if result_sign == 1:
                    ans = _dec_from_triple(1, ans._int, ans._exp)
                exact = True

        # usual case: inexact result, x**y computed directly as exp(y*log(x))
        if ans is None:
            p = context.prec
            x = _WorkRep(self)
            xc, xe = x.int, x.exp
            y = _WorkRep(other)
            yc, ye = y.int, y.exp
            if y.sign == 1:
                yc = -yc

            # compute correctly rounded result:  start with precision +3,
            # then increase precision until result is unambiguously roundable
            extra = 3
            while True:
                coeff, exp = _dpower(xc, xe, yc, ye, p+extra)
                if coeff % (5*10**(len(str(coeff))-p-1)):
                    break
                extra += 3

            ans = _dec_from_triple(result_sign, str(coeff), exp)

        # unlike exp, ln and log10, the power function respects the
        # rounding mode; no need to switch to ROUND_HALF_EVEN here

        # There's a difficulty here when 'other' is not an integer and
        # the result is exact.  In this case, the specification
        # requires that the Inexact flag be raised (in spite of
        # exactness), but since the result is exact _fix won't do this
        # for us.  (Correspondingly, the Underflow signal should also
        # be raised for subnormal results.)  We can't directly raise
        # these signals either before or after calling _fix, since
        # that would violate the precedence for signals.  So we wrap
        # the ._fix call in a temporary context, and reraise
        # afterwards.
        if exact and not other._isinteger():
            # pad with zeros up to length context.prec+1 if necessary; this
            # ensures that the Rounded signal will be raised.
            if len(ans._int) <= context.prec:
                expdiff = context.prec + 1 - len(ans._int)
                ans = _dec_from_triple(ans._sign, ans._int+'0'*expdiff,
                                       ans._exp-expdiff)

            # create a copy of the current context, with cleared flags/traps
            newcontext = context.copy()
            newcontext.clear_flags()
            for exception in _signals:
                newcontext.traps[exception] = 0

            # round in the new context
            ans = ans._fix(newcontext)

            # raise Inexact, and if necessary, Underflow
            newcontext._raise_error(Inexact)
            if newcontext.flags[Subnormal]:
                newcontext._raise_error(Underflow)

            # propagate signals to the original context; _fix could
            # have raised any of Overflow, Underflow, Subnormal,
            # Inexact, Rounded, Clamped.  Overflow needs the correct
            # arguments.  Note that the order of the exceptions is
            # important here.
            if newcontext.flags[Overflow]:
                context._raise_error(Overflow, 'above Emax', ans._sign)
            for exception in Underflow, Subnormal, Inexact, Rounded, Clamped:
                if newcontext.flags[exception]:
                    context._raise_error(exception)

        else:
            ans = ans._fix(context)

        return ans

    def __rpow__(self, other, context=None):
        """Swaps self/other and returns __pow__."""
        other = _convert_other(other)
        if other is NotImplemented:
            return other
        return other.__pow__(self, context=context)

    def normalize(self, context=None):
        """Normalize- strip trailing 0s, change anything equal to 0 to 0e0"""

        if context is None:
            context = getcontext()

        if self._is_special:
            ans = self._check_nans(context=context)
            if ans:
                return ans

        dup = self._fix(context)
        if dup._isinfinity():
            return dup

        if not dup:
            return _dec_from_triple(dup._sign, '0', 0)
        exp_max = [context.Emax, context.Etop()][context.clamp]
        end = len(dup._int)
        exp = dup._exp
        while dup._int[end-1] == '0' and exp < exp_max:
            exp += 1
            end -= 1
        return _dec_from_triple(dup._sign, dup._int[:end], exp)

    def quantize(self, exp, rounding=None, context=None, watchexp=True):
        """Quantize self so its exponent is the same as that of exp.

        Similar to self._rescale(exp._exp) but with error checking.
        """
        exp = _convert_other(exp, raiseit=True)

        if context is None:
            context = getcontext()
        if rounding is None:
            rounding = context.rounding

        if self._is_special or exp._is_special:
            ans = self._check_nans(exp, context)
            if ans:
                return ans

            if exp._isinfinity() or self._isinfinity():
                if exp._isinfinity() and self._isinfinity():
                    return Decimal(self)  # if both are inf, it is OK
                return context._raise_error(InvalidOperation,
                                        'quantize with one INF')

        # if we're not watching exponents, do a simple rescale
        if not watchexp:
            ans = self._rescale(exp._exp, rounding)
            # raise Inexact and Rounded where appropriate
            if ans._exp > self._exp:
                context._raise_error(Rounded)
                if ans != self:
                    context._raise_error(Inexact)
            return ans

        # exp._exp should be between Etiny and Emax
        if not (context.Etiny() <= exp._exp <= context.Emax):
            return context._raise_error(InvalidOperation,
                   'target exponent out of bounds in quantize')

        if not self:
            ans = _dec_from_triple(self._sign, '0', exp._exp)
            return ans._fix(context)

        self_adjusted = self.adjusted()
        if self_adjusted > context.Emax:
            return context._raise_error(InvalidOperation,
                                        'exponent of quantize result too large for current context')
        if self_adjusted - exp._exp + 1 > context.prec:
            return context._raise_error(InvalidOperation,
                                        'quantize result has too many digits for current context')

        ans = self._rescale(exp._exp, rounding)
        if ans.adjusted() > context.Emax:
            return context._raise_error(InvalidOperation,
                                        'exponent of quantize result too large for current context')
        if len(ans._int) > context.prec:
            return context._raise_error(InvalidOperation,
                                        'quantize result has too many digits for current context')

        # raise appropriate flags
        if ans and ans.adjusted() < context.Emin:
            context._raise_error(Subnormal)
        if ans._exp > self._exp:
            if ans != self:
                context._raise_error(Inexact)
            context._raise_error(Rounded)

        # call to fix takes care of any necessary folddown, and
        # signals Clamped if necessary
        ans = ans._fix(context)
        return ans

    def same_quantum(self, other, context=None):
        """Return True if self and other have the same exponent; otherwise
        return False.

        If either operand is a special value, the following rules are used:
           * return True if both operands are infinities
           * return True if both operands are NaNs
           * otherwise, return False.
        """
        other = _convert_other(other, raiseit=True)
        if self._is_special or other._is_special:
            return (self.is_nan() and other.is_nan() or
                    self.is_infinite() and other.is_infinite())
        return self._exp == other._exp

    def _rescale(self, exp, rounding):
        """Rescale self so that the exponent is exp, either by padding with zeros
        or by truncating digits, using the given rounding mode.

        Specials are returned without change.  This operation is
        quiet: it raises no flags, and uses no information from the
        context.

        exp = exp to scale to (an integer)
        rounding = rounding mode
        """
        if self._is_special:
            return Decimal(self)
        if not self:
            return _dec_from_triple(self._sign, '0', exp)

        if self._exp >= exp:
            # pad answer with zeros if necessary
            return _dec_from_triple(self._sign,
                                        self._int + '0'*(self._exp - exp), exp)

        # too many digits; round and lose data.  If self.adjusted() <
        # exp-1, replace self by 10**(exp-1) before rounding
        digits = len(self._int) + self._exp - exp
        if digits < 0:
            self = _dec_from_triple(self._sign, '1', exp-1)
            digits = 0
        this_function = self._pick_rounding_function[rounding]
        changed = this_function(self, digits)
        coeff = self._int[:digits] or '0'
        if changed == 1:
            coeff = str(int(coeff)+1)
        return _dec_from_triple(self._sign, coeff, exp)

    def _round(self, places, rounding):
        """Round a nonzero, nonspecial Decimal to a fixed number of
        significant figures, using the given rounding mode.

        Infinities, NaNs and zeros are returned unaltered.

        This operation is quiet: it raises no flags, and uses no
        information from the context.

        """
        if places <= 0:
            raise ValueError("argument should be at least 1 in _round")
        if self._is_special or not self:
            return Decimal(self)
        ans = self._rescale(self.adjusted()+1-places, rounding)
        # it can happen that the rescale alters the adjusted exponent;
        # for example when rounding 99.97 to 3 significant figures.
        # When this happens we end up with an extra 0 at the end of
        # the number; a second rescale fixes this.
        if ans.adjusted() != self.adjusted():
            ans = ans._rescale(ans.adjusted()+1-places, rounding)
        return ans

    def to_integral_exact(self, rounding=None, context=None):
        """Rounds to a nearby integer.

        If no rounding mode is specified, take the rounding mode from
        the context.  This method raises the Rounded and Inexact flags
        when appropriate.

        See also: to_integral_value, which does exactly the same as
        this method except that it doesn't raise Inexact or Rounded.
        """
        if self._is_special:
            ans = self._check_nans(context=context)
            if ans:
                return ans
            return Decimal(self)
        if self._exp >= 0:
            return Decimal(self)
        if not self:
            return _dec_from_triple(self._sign, '0', 0)
        if context is None:
            context = getcontext()
        if rounding is None:
            rounding = context.rounding
        ans = self._rescale(0, rounding)
        if ans != self:
            context._raise_error(Inexact)
        context._raise_error(Rounded)
        return ans

    def to_integral_value(self, rounding=None, context=None):
        """Rounds to the nearest integer, without raising inexact, rounded."""
        if context is None:
            context = getcontext()
        if rounding is None:
            rounding = context.rounding
        if self._is_special:
            ans = self._check_nans(context=context)
            if ans:
                return ans
            return Decimal(self)
        if self._exp >= 0:
            return Decimal(self)
        else:
            return self._rescale(0, rounding)

    # the method name changed, but we provide also the old one, for compatibility
    to_integral = to_integral_value

    def sqrt(self, context=None):
        """Return the square root of self."""
        if context is None:
            context = getcontext()

        if self._is_special:
            ans = self._check_nans(context=context)
            if ans:
                return ans

            if self._isinfinity() and self._sign == 0:
                return Decimal(self)

        if not self:
            # exponent = self._exp // 2.  sqrt(-0) = -0
            ans = _dec_from_triple(self._sign, '0', self._exp // 2)
            return ans._fix(context)

        if self._sign == 1:
            return context._raise_error(InvalidOperation, 'sqrt(-x), x > 0')

        # At this point self represents a positive number.  Let p be
        # the desired precision and express self in the form c*100**e
        # with c a positive real number and e an integer, c and e
        # being chosen so that 100**(p-1) <= c < 100**p.  Then the
        # (exact) square root of self is sqrt(c)*10**e, and 10**(p-1)
        # <= sqrt(c) < 10**p, so the closest representable Decimal at
        # precision p is n*10**e where n = round_half_even(sqrt(c)),
        # the closest integer to sqrt(c) with the even integer chosen
        # in the case of a tie.
        #
        # To ensure correct rounding in all cases, we use the
        # following trick: we compute the square root to an extra
        # place (precision p+1 instead of precision p), rounding down.
        # Then, if the result is inexact and its last digit is 0 or 5,
        # we increase the last digit to 1 or 6 respectively; if it's
        # exact we leave the last digit alone.  Now the final round to
        # p places (or fewer in the case of underflow) will round
        # correctly and raise the appropriate flags.

        # use an extra digit of precision
        prec = context.prec+1

        # write argument in the form c*100**e where e = self._exp//2
        # is the 'ideal' exponent, to be used if the square root is
        # exactly representable.  l is the number of 'digits' of c in
        # base 100, so that 100**(l-1) <= c < 100**l.
        op = _WorkRep(self)
        e = op.exp >> 1
        if op.exp & 1:
            c = op.int * 10
            l = (len(self._int) >> 1) + 1
        else:
            c = op.int
            l = len(self._int)+1 >> 1

        # rescale so that c has exactly prec base 100 'digits'
        shift = prec-l
        if shift >= 0:
            c *= 100**shift
            exact = True
        else:
            c, remainder = divmod(c, 100**-shift)
            exact = not remainder
        e -= shift

        # find n = floor(sqrt(c)) using Newton's method
        n = 10**prec
        while True:
            q = c//n
            if n <= q:
                break
            else:
                n = n + q >> 1
        exact = exact and n*n == c

        if exact:
            # result is exact; rescale to use ideal exponent e
            if shift >= 0:
                # assert n % 10**shift == 0
                n //= 10**shift
            else:
                n *= 10**-shift
            e += shift
        else:
            # result is not exact; fix last digit as described above
            if n % 5 == 0:
                n += 1

        ans = _dec_from_triple(0, str(n), e)

        # round, and fit to current context
        context = context._shallow_copy()
        rounding = context._set_rounding(ROUND_HALF_EVEN)
        ans = ans._fix(context)
        context.rounding = rounding

        return ans

    def max(self, other, context=None):
        """Returns the larger value.

        Like max(self, other) except if one is not a number, returns
        NaN (and signals if one is sNaN).  Also rounds.
        """
        other = _convert_other(other, raiseit=True)

        if context is None:
            context = getcontext()

        if self._is_special or other._is_special:
            # If one operand is a quiet NaN and the other is number, then the
            # number is always returned
            sn = self._isnan()
            on = other._isnan()
            if sn or on:
                if on == 1 and sn == 0:
                    return self._fix(context)
                if sn == 1 and on == 0:
                    return other._fix(context)
                return self._check_nans(other, context)

        c = self._cmp(other)
        if c == 0:
            # If both operands are finite and equal in numerical value
            # then an ordering is applied:
            #
            # If the signs differ then max returns the operand with the
            # positive sign and min returns the operand with the negative sign
            #
            # If the signs are the same then the exponent is used to select
            # the result.  This is exactly the ordering used in compare_total.
            c = self.compare_total(other)

        if c == -1:
            ans = other
        else:
            ans = self

        return ans._fix(context)

    def min(self, other, context=None):
        """Returns the smaller value.

        Like min(self, other) except if one is not a number, returns
        NaN (and signals if one is sNaN).  Also rounds.
        """
        other = _convert_other(other, raiseit=True)

        if context is None:
            context = getcontext()

        if self._is_special or other._is_special:
            # If one operand is a quiet NaN and the other is number, then the
            # number is always returned
            sn = self._isnan()
            on = other._isnan()
            if sn or on:
                if on == 1 and sn == 0:
                    return self._fix(context)
                if sn == 1 and on == 0:
                    return other._fix(context)
                return self._check_nans(other, context)

        c = self._cmp(other)
        if c == 0:
            c = self.compare_total(other)

        if c == -1:
            ans = self
        else:
            ans = other

        return ans._fix(context)

    def _isinteger(self):
        """Returns whether self is an integer"""
        if self._is_special:
            return False
        if self._exp >= 0:
            return True
        rest = self._int[self._exp:]
        return rest == '0'*len(rest)

    def _iseven(self):
        """Returns True if self is even.  Assumes self is an integer."""
        if not self or self._exp > 0:
            return True
        return self._int[-1+self._exp] in '02468'

    def adjusted(self):
        """Return the adjusted exponent of self"""
        try:
            return self._exp + len(self._int) - 1
        # If NaN or Infinity, self._exp is string
        except TypeError:
            return 0

    def canonical(self):
        """Returns the same Decimal object.

        As we do not have different encodings for the same number, the
        received object already is in its canonical form.
        """
        return self

    def compare_signal(self, other, context=None):
        """Compares self to the other operand numerically.

        It's pretty much like compare(), but all NaNs signal, with signaling
        NaNs taking precedence over quiet NaNs.
        """
        other = _convert_other(other, raiseit = True)
        ans = self._compare_check_nans(other, context)
        if ans:
            return ans
        return self.compare(other, context=context)

    def compare_total(self, other, context=None):
        """Compares self to other using the abstract representations.

        This is not like the standard compare, which use their numerical
        value. Note that a total ordering is defined for all possible abstract
        representations.
        """
        other = _convert_other(other, raiseit=True)

        # if one is negative and the other is positive, it's easy
        if self._sign and not other._sign:
            return _NegativeOne
        if not self._sign and other._sign:
            return _One
        sign = self._sign

        # let's handle both NaN types
        self_nan = self._isnan()
        other_nan = other._isnan()
        if self_nan or other_nan:
            if self_nan == other_nan:
                # compare payloads as though they're integers
                self_key = len(self._int), self._int
                other_key = len(other._int), other._int
                if self_key < other_key:
                    if sign:
                        return _One
                    else:
                        return _NegativeOne
                if self_key > other_key:
                    if sign:
                        return _NegativeOne
                    else:
                        return _One
                return _Zero

            if sign:
                if self_nan == 1:
                    return _NegativeOne
                if other_nan == 1:
                    return _One
                if self_nan == 2:
                    return _NegativeOne
                if other_nan == 2:
                    return _One
            else:
                if self_nan == 1:
                    return _One
                if other_nan == 1:
                    return _NegativeOne
                if self_nan == 2:
                    return _One
                if other_nan == 2:
                    return _NegativeOne

        if self < other:
            return _NegativeOne
        if self > other:
            return _One

        if self._exp < other._exp:
            if sign:
                return _One
            else:
                return _NegativeOne
        if self._exp > other._exp:
            if sign:
                return _NegativeOne
            else:
                return _One
        return _Zero


    def compare_total_mag(self, other, context=None):
        """Compares self to other using abstract repr., ignoring sign.

        Like compare_total, but with operand's sign ignored and assumed to be 0.
        """
        other = _convert_other(other, raiseit=True)

        s = self.copy_abs()
        o = other.copy_abs()
        return s.compare_total(o)

    def copy_abs(self):
        """Returns a copy with the sign set to 0. """
        return _dec_from_triple(0, self._int, self._exp, self._is_special)

    def copy_negate(self):
        """Returns a copy with the sign inverted."""
        if self._sign:
            return _dec_from_triple(0, self._int, self._exp, self._is_special)
        else:
            return _dec_from_triple(1, self._int, self._exp, self._is_special)

    def copy_sign(self, other, context=None):
        """Returns self with the sign of other."""
        other = _convert_other(other, raiseit=True)
        return _dec_from_triple(other._sign, self._int,
                                self._exp, self._is_special)

    def exp(self, context=None):
        """Returns e ** self."""

        if context is None:
            context = getcontext()

        # exp(NaN) = NaN
        ans = self._check_nans(context=context)
        if ans:
            return ans

        # exp(-Infinity) = 0
        if self._isinfinity() == -1:
            return _Zero

        # exp(0) = 1
        if not self:
            return _One

        # exp(Infinity) = Infinity
        if self._isinfinity() == 1:
            return Decimal(self)

        # the result is now guaranteed to be inexact (the true
        # mathematical result is transcendental). There's no need to
        # raise Rounded and Inexact here---they'll always be raised as
        # a result of the call to _fix.
        p = context.prec
        adj = self.adjusted()

        # we only need to do any computation for quite a small range
        # of adjusted exponents---for example, -29 <= adj <= 10 for
        # the default context.  For smaller exponent the result is
        # indistinguishable from 1 at the given precision, while for
        # larger exponent the result either overflows or underflows.
        if self._sign == 0 and adj > len(str((context.Emax+1)*3)):
            # overflow
            ans = _dec_from_triple(0, '1', context.Emax+1)
        elif self._sign == 1 and adj > len(str((-context.Etiny()+1)*3)):
            # underflow to 0
            ans = _dec_from_triple(0, '1', context.Etiny()-1)
        elif self._sign == 0 and adj < -p:
            # p+1 digits; final round will raise correct flags
            ans = _dec_from_triple(0, '1' + '0'*(p-1) + '1', -p)
        elif self._sign == 1 and adj < -p-1:
            # p+1 digits; final round will raise correct flags
            ans = _dec_from_triple(0, '9'*(p+1), -p-1)
        # general case
        else:
            op = _WorkRep(self)
            c, e = op.int, op.exp
            if op.sign == 1:
                c = -c

            # compute correctly rounded result: increase precision by
            # 3 digits at a time until we get an unambiguously
            # roundable result
            extra = 3
            while True:
                coeff, exp = _dexp(c, e, p+extra)
                if coeff % (5*10**(len(str(coeff))-p-1)):
                    break
                extra += 3

            ans = _dec_from_triple(0, str(coeff), exp)

        # at this stage, ans should round correctly with *any*
        # rounding mode, not just with ROUND_HALF_EVEN
        context = context._shallow_copy()
        rounding = context._set_rounding(ROUND_HALF_EVEN)
        ans = ans._fix(context)
        context.rounding = rounding

        return ans

    def is_canonical(self):
        """Return True if self is canonical; otherwise return False.

        Currently, the encoding of a Decimal instance is always
        canonical, so this method returns True for any Decimal.
        """
        return True

    def is_finite(self):
        """Return True if self is finite; otherwise return False.

        A Decimal instance is considered finite if it is neither
        infinite nor a NaN.
        """
        return not self._is_special

    def is_infinite(self):
        """Return True if self is infinite; otherwise return False."""
        return self._exp == 'F'

    def is_nan(self):
        """Return True if self is a qNaN or sNaN; otherwise return False."""
        return self._exp in ('n', 'N')

    def is_normal(self, context=None):
        """Return True if self is a normal number; otherwise return False."""
        if self._is_special or not self:
            return False
        if context is None:
            context = getcontext()
        return context.Emin <= self.adjusted()

    def is_qnan(self):
        """Return True if self is a quiet NaN; otherwise return False."""
        return self._exp == 'n'

    def is_signed(self):
        """Return True if self is negative; otherwise return False."""
        return self._sign == 1

    def is_snan(self):
        """Return True if self is a signaling NaN; otherwise return False."""
        return self._exp == 'N'

    def is_subnormal(self, context=None):
        """Return True if self is subnormal; otherwise return False."""
        if self._is_special or not self:
            return False
        if context is None:
            context = getcontext()
        return self.adjusted() < context.Emin

    def is_zero(self):
        """Return True if self is a zero; otherwise return False."""
        return not self._is_special and self._int == '0'

    def _ln_exp_bound(self):
        """Compute a lower bound for the adjusted exponent of self.ln().
        In other words, compute r such that self.ln() >= 10**r.  Assumes
        that self is finite and positive and that self != 1.
        """

        # for 0.1 <= x <= 10 we use the inequalities 1-1/x <= ln(x) <= x-1
        adj = self._exp + len(self._int) - 1
        if adj >= 1:
            # argument >= 10; we use 23/10 = 2.3 as a lower bound for ln(10)
            return len(str(adj*23//10)) - 1
        if adj <= -2:
            # argument <= 0.1
            return len(str((-1-adj)*23//10)) - 1
        op = _WorkRep(self)
        c, e = op.int, op.exp
        if adj == 0:
            # 1 < self < 10
            num = str(c-10**-e)
            den = str(c)
            return len(num) - len(den) - (num < den)
        # adj == -1, 0.1 <= self < 1
        return e + len(str(10**-e - c)) - 1


    def ln(self, context=None):
        """Returns the natural (base e) logarithm of self."""

        if context is None:
            context = getcontext()

        # ln(NaN) = NaN
        ans = self._check_nans(context=context)
        if ans:
            return ans

        # ln(0.0) == -Infinity
        if not self:
            return _NegativeInfinity

        # ln(Infinity) = Infinity
        if self._isinfinity() == 1:
            return _Infinity

        # ln(1.0) == 0.0
        if self == _One:
            return _Zero

        # ln(negative) raises InvalidOperation
        if self._sign == 1:
            return context._raise_error(InvalidOperation,
                                        'ln of a negative value')

        # result is irrational, so necessarily inexact
        op = _WorkRep(self)
        c, e = op.int, op.exp
        p = context.prec

        # correctly rounded result: repeatedly increase precision by 3
        # until we get an unambiguously roundable result
        places = p - self._ln_exp_bound() + 2 # at least p+3 places
        while True:
            coeff = _dlog(c, e, places)
            # assert len(str(abs(coeff)))-p >= 1
            if coeff % (5*10**(len(str(abs(coeff)))-p-1)):
                break
            places += 3
        ans = _dec_from_triple(int(coeff<0), str(abs(coeff)), -places)

        context = context._shallow_copy()
        rounding = context._set_rounding(ROUND_HALF_EVEN)
        ans = ans._fix(context)
        context.rounding = rounding
        return ans

    def _log10_exp_bound(self):
        """Compute a lower bound for the adjusted exponent of self.log10().
        In other words, find r such that self.log10() >= 10**r.
        Assumes that self is finite and positive and that self != 1.
        """

        # For x >= 10 or x < 0.1 we only need a bound on the integer
        # part of log10(self), and this comes directly from the
        # exponent of x.  For 0.1 <= x <= 10 we use the inequalities
        # 1-1/x <= log(x) <= x-1. If x > 1 we have |log10(x)| >
        # (1-1/x)/2.31 > 0.  If x < 1 then |log10(x)| > (1-x)/2.31 > 0

        adj = self._exp + len(self._int) - 1
        if adj >= 1:
            # self >= 10
            return len(str(adj))-1
        if adj <= -2:
            # self < 0.1
            return len(str(-1-adj))-1
        op = _WorkRep(self)
        c, e = op.int, op.exp
        if adj == 0:
            # 1 < self < 10
            num = str(c-10**-e)
            den = str(231*c)
            return len(num) - len(den) - (num < den) + 2
        # adj == -1, 0.1 <= self < 1
        num = str(10**-e-c)
        return len(num) + e - (num < "231") - 1

    def log10(self, context=None):
        """Returns the base 10 logarithm of self."""

        if context is None:
            context = getcontext()

        # log10(NaN) = NaN
        ans = self._check_nans(context=context)
        if ans:
            return ans

        # log10(0.0) == -Infinity
        if not self:
            return _NegativeInfinity

        # log10(Infinity) = Infinity
        if self._isinfinity() == 1:
            return _Infinity

        # log10(negative or -Infinity) raises InvalidOperation
        if self._sign == 1:
            return context._raise_error(InvalidOperation,
                                        'log10 of a negative value')

        # log10(10**n) = n
        if self._int[0] == '1' and self._int[1:] == '0'*(len(self._int) - 1):
            # answer may need rounding
            ans = Decimal(self._exp + len(self._int) - 1)
        else:
            # result is irrational, so necessarily inexact
            op = _WorkRep(self)
            c, e = op.int, op.exp
            p = context.prec

            # correctly rounded result: repeatedly increase precision
            # until result is unambiguously roundable
            places = p-self._log10_exp_bound()+2
            while True:
                coeff = _dlog10(c, e, places)
                # assert len(str(abs(coeff)))-p >= 1
                if coeff % (5*10**(len(str(abs(coeff)))-p-1)):
                    break
                places += 3
            ans = _dec_from_triple(int(coeff<0), str(abs(coeff)), -places)

        context = context._shallow_copy()
        rounding = context._set_rounding(ROUND_HALF_EVEN)
        ans = ans._fix(context)
        context.rounding = rounding
        return ans

    def logb(self, context=None):
        """ Returns the exponent of the magnitude of self's MSD.

        The result is the integer which is the exponent of the magnitude
        of the most significant digit of self (as though it were truncated
        to a single digit while maintaining the value of that digit and
        without limiting the resulting exponent).
        """
        # logb(NaN) = NaN
        ans = self._check_nans(context=context)
        if ans:
            return ans

        if context is None:
            context = getcontext()

        # logb(+/-Inf) = +Inf
        if self._isinfinity():
            return _Infinity

        # logb(0) = -Inf, DivisionByZero
        if not self:
            return context._raise_error(DivisionByZero, 'logb(0)', 1)

        # otherwise, simply return the adjusted exponent of self, as a
        # Decimal.  Note that no attempt is made to fit the result
        # into the current context.
        ans = Decimal(self.adjusted())
        return ans._fix(context)

    def _islogical(self):
        """Return True if self is a logical operand.

        For being logical, it must be a finite number with a sign of 0,
        an exponent of 0, and a coefficient whose digits must all be
        either 0 or 1.
        """
        if self._sign != 0 or self._exp != 0:
            return False
        for dig in self._int:
            if dig not in '01':
                return False
        return True

    def _fill_logical(self, context, opa, opb):
        dif = context.prec - len(opa)
        if dif > 0:
            opa = '0'*dif + opa
        elif dif < 0:
            opa = opa[-context.prec:]
        dif = context.prec - len(opb)
        if dif > 0:
            opb = '0'*dif + opb
        elif dif < 0:
            opb = opb[-context.prec:]
        return opa, opb

    def logical_and(self, other, context=None):
        """Applies an 'and' operation between self and other's digits."""
        if context is None:
            context = getcontext()

        other = _convert_other(other, raiseit=True)

        if not self._islogical() or not other._islogical():
            return context._raise_error(InvalidOperation)

        # fill to context.prec
        (opa, opb) = self._fill_logical(context, self._int, other._int)

        # make the operation, and clean starting zeroes
        result = "".join([str(int(a)&int(b)) for a,b in zip(opa,opb)])
        return _dec_from_triple(0, result.lstrip('0') or '0', 0)

    def logical_invert(self, context=None):
        """Invert all its digits."""
        if context is None:
            context = getcontext()
        return self.logical_xor(_dec_from_triple(0,'1'*context.prec,0),
                                context)

    def logical_or(self, other, context=None):
        """Applies an 'or' operation between self and other's digits."""
        if context is None:
            context = getcontext()

        other = _convert_other(other, raiseit=True)

        if not self._islogical() or not other._islogical():
            return context._raise_error(InvalidOperation)

        # fill to context.prec
        (opa, opb) = self._fill_logical(context, self._int, other._int)

        # make the operation, and clean starting zeroes
        result = "".join([str(int(a)|int(b)) for a,b in zip(opa,opb)])
        return _dec_from_triple(0, result.lstrip('0') or '0', 0)

    def logical_xor(self, other, context=None):
        """Applies an 'xor' operation between self and other's digits."""
        if context is None:
            context = getcontext()

        other = _convert_other(other, raiseit=True)

        if not self._islogical() or not other._islogical():
            return context._raise_error(InvalidOperation)

        # fill to context.prec
        (opa, opb) = self._fill_logical(context, self._int, other._int)

        # make the operation, and clean starting zeroes
        result = "".join([str(int(a)^int(b)) for a,b in zip(opa,opb)])
        return _dec_from_triple(0, result.lstrip('0') or '0', 0)

    def max_mag(self, other, context=None):
        """Compares the values numerically with their sign ignored."""
        other = _convert_other(other, raiseit=True)

        if context is None:
            context = getcontext()

        if self._is_special or other._is_special:
            # If one operand is a quiet NaN and the other is number, then the
            # number is always returned
            sn = self._isnan()
            on = other._isnan()
            if sn or on:
                if on == 1 and sn == 0:
                    return self._fix(context)
                if sn == 1 and on == 0:
                    return other._fix(context)
                return self._check_nans(other, context)

        c = self.copy_abs()._cmp(other.copy_abs())
        if c == 0:
            c = self.compare_total(other)

        if c == -1:
            ans = other
        else:
            ans = self

        return ans._fix(context)

    def min_mag(self, other, context=None):
        """Compares the values numerically with their sign ignored."""
        other = _convert_other(other, raiseit=True)

        if context is None:
            context = getcontext()

        if self._is_special or other._is_special:
            # If one operand is a quiet NaN and the other is number, then the
            # number is always returned
            sn = self._isnan()
            on = other._isnan()
            if sn or on:
                if on == 1 and sn == 0:
                    return self._fix(context)
                if sn == 1 and on == 0:
                    return other._fix(context)
                return self._check_nans(other, context)

        c = self.copy_abs()._cmp(other.copy_abs())
        if c == 0:
            c = self.compare_total(other)

        if c == -1:
            ans = self
        else:
            ans = other

        return ans._fix(context)

    def next_minus(self, context=None):
        """Returns the largest representable number smaller than itself."""
        if context is None:
            context = getcontext()

        ans = self._check_nans(context=context)
        if ans:
            return ans

        if self._isinfinity() == -1:
            return _NegativeInfinity
        if self._isinfinity() == 1:
            return _dec_from_triple(0, '9'*context.prec, context.Etop())

        context = context.copy()
        context._set_rounding(ROUND_FLOOR)
        context._ignore_all_flags()
        new_self = self._fix(context)
        if new_self != self:
            return new_self
        return self.__sub__(_dec_from_triple(0, '1', context.Etiny()-1),
                            context)

    def next_plus(self, context=None):
        """Returns the smallest representable number larger than itself."""
        if context is None:
            context = getcontext()

        ans = self._check_nans(context=context)
        if ans:
            return ans

        if self._isinfinity() == 1:
            return _Infinity
        if self._isinfinity() == -1:
            return _dec_from_triple(1, '9'*context.prec, context.Etop())

        context = context.copy()
        context._set_rounding(ROUND_CEILING)
        context._ignore_all_flags()
        new_self = self._fix(context)
        if new_self != self:
            return new_self
        return self.__add__(_dec_from_triple(0, '1', context.Etiny()-1),
                            context)

    def next_toward(self, other, context=None):
        """Returns the number closest to self, in the direction towards other.

        The result is the closest representable number to self
        (excluding self) that is in the direction towards other,
        unless both have the same value.  If the two operands are
        numerically equal, then the result is a copy of self with the
        sign set to be the same as the sign of other.
        """
        other = _convert_other(other, raiseit=True)

        if context is None:
            context = getcontext()

        ans = self._check_nans(other, context)
        if ans:
            return ans

        comparison = self._cmp(other)
        if comparison == 0:
            return self.copy_sign(other)

        if comparison == -1:
            ans = self.next_plus(context)
        else: # comparison == 1
            ans = self.next_minus(context)

        # decide which flags to raise using value of ans
        if ans._isinfinity():
            context._raise_error(Overflow,
                                 'Infinite result from next_toward',
                                 ans._sign)
            context._raise_error(Inexact)
            context._raise_error(Rounded)
        elif ans.adjusted() < context.Emin:
            context._raise_error(Underflow)
            context._raise_error(Subnormal)
            context._raise_error(Inexact)
            context._raise_error(Rounded)
            # if precision == 1 then we don't raise Clamped for a
            # result 0E-Etiny.
            if not ans:
                context._raise_error(Clamped)

        return ans

    def number_class(self, context=None):
        """Returns an indication of the class of self.

        The class is one of the following strings:
          sNaN
          NaN
          -Infinity
          -Normal
          -Subnormal
          -Zero
          +Zero
          +Subnormal
          +Normal
          +Infinity
        """
        if self.is_snan():
            return "sNaN"
        if self.is_qnan():
            return "NaN"
        inf = self._isinfinity()
        if inf == 1:
            return "+Infinity"
        if inf == -1:
            return "-Infinity"
        if self.is_zero():
            if self._sign:
                return "-Zero"
            else:
                return "+Zero"
        if context is None:
            context = getcontext()
        if self.is_subnormal(context=context):
            if self._sign:
                return "-Subnormal"
            else:
                return "+Subnormal"
        # just a normal, regular, boring number, :)
        if self._sign:
            return "-Normal"
        else:
            return "+Normal"

    def radix(self):
        """Just returns 10, as this is Decimal, :)"""
        return Decimal(10)

    def rotate(self, other, context=None):
        """Returns a rotated copy of self, value-of-other times."""
        if context is None:
            context = getcontext()

        other = _convert_other(other, raiseit=True)

        ans = self._check_nans(other, context)
        if ans:
            return ans

        if other._exp != 0:
            return context._raise_error(InvalidOperation)
        if not (-context.prec <= int(other) <= context.prec):
            return context._raise_error(InvalidOperation)

        if self._isinfinity():
            return Decimal(self)

        # get values, pad if necessary
        torot = int(other)
        rotdig = self._int
        topad = context.prec - len(rotdig)
        if topad > 0:
            rotdig = '0'*topad + rotdig
        elif topad < 0:
            rotdig = rotdig[-topad:]

        # let's rotate!
        rotated = rotdig[torot:] + rotdig[:torot]
        return _dec_from_triple(self._sign,
                                rotated.lstrip('0') or '0', self._exp)

    def scaleb(self, other, context=None):
        """Returns self operand after adding the second value to its exp."""
        if context is None:
            context = getcontext()

        other = _convert_other(other, raiseit=True)

        ans = self._check_nans(other, context)
        if ans:
            return ans

        if other._exp != 0:
            return context._raise_error(InvalidOperation)
        liminf = -2 * (context.Emax + context.prec)
        limsup =  2 * (context.Emax + context.prec)
        if not (liminf <= int(other) <= limsup):
            return context._raise_error(InvalidOperation)

        if self._isinfinity():
            return Decimal(self)

        d = _dec_from_triple(self._sign, self._int, self._exp + int(other))
        d = d._fix(context)
        return d

    def shift(self, other, context=None):
        """Returns a shifted copy of self, value-of-other times."""
        if context is None:
            context = getcontext()

        other = _convert_other(other, raiseit=True)

        ans = self._check_nans(other, context)
        if ans:
            return ans

        if other._exp != 0:
            return context._raise_error(InvalidOperation)
        if not (-context.prec <= int(other) <= context.prec):
            return context._raise_error(InvalidOperation)

        if self._isinfinity():
            return Decimal(self)

        # get values, pad if necessary
        torot = int(other)
        rotdig = self._int
        topad = context.prec - len(rotdig)
        if topad > 0:
            rotdig = '0'*topad + rotdig
        elif topad < 0:
            rotdig = rotdig[-topad:]

        # let's shift!
        if torot < 0:
            shifted = rotdig[:torot]
        else:
            shifted = rotdig + '0'*torot
            shifted = shifted[-context.prec:]

        return _dec_from_triple(self._sign,
                                    shifted.lstrip('0') or '0', self._exp)

    # Support for pickling, copy, and deepcopy
    def __reduce__(self):
        return (self.__class__, (str(self),))

    def __copy__(self):
        if type(self) is Decimal:
            return self     # I'm immutable; therefore I am my own clone
        return self.__class__(str(self))

    def __deepcopy__(self, memo):
        if type(self) is Decimal:
            return self     # My components are also immutable
        return self.__class__(str(self))

    # PEP 3101 support.  the _localeconv keyword argument should be
    # considered private: it's provided for ease of testing only.
    def __format__(self, specifier, context=None, _localeconv=None):
        """Format a Decimal instance according to the given specifier.

        The specifier should be a standard format specifier, with the
        form described in PEP 3101.  Formatting types 'e', 'E', 'f',
        'F', 'g', 'G', 'n' and '%' are supported.  If the formatting
        type is omitted it defaults to 'g' or 'G', depending on the
        value of context.capitals.
        """

        # Note: PEP 3101 says that if the type is not present then
        # there should be at least one digit after the decimal point.
        # We take the liberty of ignoring this requirement for
        # Decimal---it's presumably there to make sure that
        # format(float, '') behaves similarly to str(float).
        if context is None:
            context = getcontext()

        spec = _parse_format_specifier(specifier, _localeconv=_localeconv)

        # special values don't care about the type or precision
        if self._is_special:
            sign = _format_sign(self._sign, spec)
            body = str(self.copy_abs())
            if spec['type'] == '%':
                body += '%'
            return _format_align(sign, body, spec)

        # a type of None defaults to 'g' or 'G', depending on context
        if spec['type'] is None:
            spec['type'] = ['g', 'G'][context.capitals]

        # if type is '%', adjust exponent of self accordingly
        if spec['type'] == '%':
            self = _dec_from_triple(self._sign, self._int, self._exp+2)

        # round if necessary, taking rounding mode from the context
        rounding = context.rounding
        precision = spec['precision']
        if precision is not None:
            if spec['type'] in 'eE':
                self = self._round(precision+1, rounding)
            elif spec['type'] in 'fF%':
                self = self._rescale(-precision, rounding)
            elif spec['type'] in 'gG' and len(self._int) > precision:
                self = self._round(precision, rounding)
        # special case: zeros with a positive exponent can't be
        # represented in fixed point; rescale them to 0e0.
        if not self and self._exp > 0 and spec['type'] in 'fF%':
            self = self._rescale(0, rounding)

        # figure out placement of the decimal point
        leftdigits = self._exp + len(self._int)
        if spec['type'] in 'eE':
            if not self and precision is not None:
                dotplace = 1 - precision
            else:
                dotplace = 1
        elif spec['type'] in 'fF%':
            dotplace = leftdigits
        elif spec['type'] in 'gG':
            if self._exp <= 0 and leftdigits > -6:
                dotplace = leftdigits
            else:
                dotplace = 1

        # find digits before and after decimal point, and get exponent
        if dotplace < 0:
            intpart = '0'
            fracpart = '0'*(-dotplace) + self._int
        elif dotplace > len(self._int):
            intpart = self._int + '0'*(dotplace-len(self._int))
            fracpart = ''
        else:
            intpart = self._int[:dotplace] or '0'
            fracpart = self._int[dotplace:]
        exp = leftdigits-dotplace

        # done with the decimal-specific stuff;  hand over the rest
        # of the formatting to the _format_number function
        return _format_number(self._sign, intpart, fracpart, exp, spec)

def _dec_from_triple(sign, coefficient, exponent, special=False):
    """Create a decimal instance directly, without any validation,
    normalization (e.g. removal of leading zeros) or argument
    conversion.

    This function is for *internal use only*.
    """

    self = object.__new__(Decimal)
    self._sign = sign
    self._int = coefficient
    self._exp = exponent
    self._is_special = special

    return self

# Register Decimal as a kind of Number (an abstract base class).
# However, do not register it as Real (because Decimals are not
# interoperable with floats).
_numbers.Number.register(Decimal)


##### Context class #######################################################

class _ContextManager(object):
    """Context manager class to support localcontext().

      Sets a copy of the supplied context in __enter__() and restores
      the previous decimal context in __exit__()
    """
    def __init__(self, new_context):
        self.new_context = new_context.copy()
    def __enter__(self):
        self.saved_context = getcontext()
        setcontext(self.new_context)
        return self.new_context
    def __exit__(self, t, v, tb):
        setcontext(self.saved_context)

class Context(object):
    """Contains the context for a Decimal instance.

    Contains:
    prec - precision (for use in rounding, division, square roots..)
    rounding - rounding type (how you round)
    traps - If traps[exception] = 1, then the exception is
                    raised when it is caused.  Otherwise, a value is
                    substituted in.
    flags  - When an exception is caused, flags[exception] is set.
             (Whether or not the trap_enabler is set)
             Should be reset by user of Decimal instance.
    Emin -   Minimum exponent
    Emax -   Maximum exponent
    capitals -      If 1, 1*10^1 is printed as 1E+1.
                    If 0, printed as 1e1
    clamp -  If 1, change exponents if too high (Default 0)
    """

    def __init__(self, prec=None, rounding=None, Emin=None, Emax=None,
                       capitals=None, clamp=None, flags=None, traps=None,
                       _ignored_flags=None):
        # Set defaults; for everything except flags and _ignored_flags,
        # inherit from DefaultContext.
        try:
            dc = DefaultContext
        except NameError:
            pass

        self.prec = prec if prec is not None else dc.prec
        self.rounding = rounding if rounding is not None else dc.rounding
        self.Emin = Emin if Emin is not None else dc.Emin
        self.Emax = Emax if Emax is not None else dc.Emax
        self.capitals = capitals if capitals is not None else dc.capitals
        self.clamp = clamp if clamp is not None else dc.clamp

        if _ignored_flags is None:
            self._ignored_flags = []
        else:
            self._ignored_flags = _ignored_flags

        if traps is None:
            self.traps = dc.traps.copy()
        elif not isinstance(traps, dict):
            self.traps = dict((s, int(s in traps)) for s in _signals + traps)
        else:
            self.traps = traps

        if flags is None:
            self.flags = dict.fromkeys(_signals, 0)
        elif not isinstance(flags, dict):
            self.flags = dict((s, int(s in flags)) for s in _signals + flags)
        else:
            self.flags = flags

    def _set_integer_check(self, name, value, vmin, vmax):
        if not isinstance(value, int):
            raise TypeError("%s must be an integer" % name)
        if vmin == '-inf':
            if value > vmax:
                raise ValueError("%s must be in [%s, %d]. got: %s" % (name, vmin, vmax, value))
        elif vmax == 'inf':
            if value < vmin:
                raise ValueError("%s must be in [%d, %s]. got: %s" % (name, vmin, vmax, value))
        else:
            if value < vmin or value > vmax:
                raise ValueError("%s must be in [%d, %d]. got %s" % (name, vmin, vmax, value))
        return object.__setattr__(self, name, value)

    def _set_signal_dict(self, name, d):
        if not isinstance(d, dict):
            raise TypeError("%s must be a signal dict" % d)
        for key in d:
            if not key in _signals:
                raise KeyError("%s is not a valid signal dict" % d)
        for key in _signals:
            if not key in d:
                raise KeyError("%s is not a valid signal dict" % d)
        return object.__setattr__(self, name, d)

    def __setattr__(self, name, value):
        if name == 'prec':
            return self._set_integer_check(name, value, 1, 'inf')
        elif name == 'Emin':
            return self._set_integer_check(name, value, '-inf', 0)
        elif name == 'Emax':
            return self._set_integer_check(name, value, 0, 'inf')
        elif name == 'capitals':
            return self._set_integer_check(name, value, 0, 1)
        elif name == 'clamp':
            return self._set_integer_check(name, value, 0, 1)
        elif name == 'rounding':
            if not value in _rounding_modes:
                # raise TypeError even for strings to have consistency
                # among various implementations.
                raise TypeError("%s: invalid rounding mode" % value)
            return object.__setattr__(self, name, value)
        elif name == 'flags' or name == 'traps':
            return self._set_signal_dict(name, value)
        elif name == '_ignored_flags':
            return object.__setattr__(self, name, value)
        else:
            raise AttributeError(
                "'decimal.Context' object has no attribute '%s'" % name)

    def __delattr__(self, name):
        raise AttributeError("%s cannot be deleted" % name)

    # Support for pickling, copy, and deepcopy
    def __reduce__(self):
        flags = [sig for sig, v in self.flags.items() if v]
        traps = [sig for sig, v in self.traps.items() if v]
        return (self.__class__,
                (self.prec, self.rounding, self.Emin, self.Emax,
                 self.capitals, self.clamp, flags, traps))

    def __repr__(self):
        """Show the current context."""
        s = []
        s.append('Context(prec=%(prec)d, rounding=%(rounding)s, '
                 'Emin=%(Emin)d, Emax=%(Emax)d, capitals=%(capitals)d, '
                 'clamp=%(clamp)d'
                 % vars(self))
        names = [f.__name__ for f, v in self.flags.items() if v]
        s.append('flags=[' + ', '.join(names) + ']')
        names = [t.__name__ for t, v in self.traps.items() if v]
        s.append('traps=[' + ', '.join(names) + ']')
        return ', '.join(s) + ')'

    def clear_flags(self):
        """Reset all flags to zero"""
        for flag in self.flags:
            self.flags[flag] = 0

    def clear_traps(self):
        """Reset all traps to zero"""
        for flag in self.traps:
            self.traps[flag] = 0

    def _shallow_copy(self):
        """Returns a shallow copy from self."""
        nc = Context(self.prec, self.rounding, self.Emin, self.Emax,
                     self.capitals, self.clamp, self.flags, self.traps,
                     self._ignored_flags)
        return nc

    def copy(self):
        """Returns a deep copy from self."""
        nc = Context(self.prec, self.rounding, self.Emin, self.Emax,
                     self.capitals, self.clamp,
                     self.flags.copy(), self.traps.copy(),
                     self._ignored_flags)
        return nc
    __copy__ = copy

    def _raise_error(self, condition, explanation = None, *args):
        """Handles an error

        If the flag is in _ignored_flags, returns the default response.
        Otherwise, it sets the flag, then, if the corresponding
        trap_enabler is set, it reraises the exception.  Otherwise, it returns
        the default value after setting the flag.
        """
        error = _condition_map.get(condition, condition)
        if error in self._ignored_flags:
            # Don't touch the flag
            return error().handle(self, *args)

        self.flags[error] = 1
        if not self.traps[error]:
            # The errors define how to handle themselves.
            return condition().handle(self, *args)

        # Errors should only be risked on copies of the context
        # self._ignored_flags = []
        raise error(explanation)

    def _ignore_all_flags(self):
        """Ignore all flags, if they are raised"""
        return self._ignore_flags(*_signals)

    def _ignore_flags(self, *flags):
        """Ignore the flags, if they are raised"""
        # Do not mutate-- This way, copies of a context leave the original
        # alone.
        self._ignored_flags = (self._ignored_flags + list(flags))
        return list(flags)

    def _regard_flags(self, *flags):
        """Stop ignoring the flags, if they are raised"""
        if flags and isinstance(flags[0], (tuple,list)):
            flags = flags[0]
        for flag in flags:
            self._ignored_flags.remove(flag)

    # We inherit object.__hash__, so we must deny this explicitly
    __hash__ = None

    def Etiny(self):
        """Returns Etiny (= Emin - prec + 1)"""
        return int(self.Emin - self.prec + 1)

    def Etop(self):
        """Returns maximum exponent (= Emax - prec + 1)"""
        return int(self.Emax - self.prec + 1)

    def _set_rounding(self, type):
        """Sets the rounding type.

        Sets the rounding type, and returns the current (previous)
        rounding type.  Often used like:

        context = context.copy()
        # so you don't change the calling context
        # if an error occurs in the middle.
        rounding = context._set_rounding(ROUND_UP)
        val = self.__sub__(other, context=context)
        context._set_rounding(rounding)

        This will make it round up for that operation.
        """
        rounding = self.rounding
        self.rounding= type
        return rounding

    def create_decimal(self, num='0'):
        """Creates a new Decimal instance but using self as context.

        This method implements the to-number operation of the
        IBM Decimal specification."""

        if isinstance(num, str) and num != num.strip():
            return self._raise_error(ConversionSyntax,
                                     "no trailing or leading whitespace is "
                                     "permitted.")

        d = Decimal(num, context=self)
        if d._isnan() and len(d._int) > self.prec - self.clamp:
            return self._raise_error(ConversionSyntax,
                                     "diagnostic info too long in NaN")
        return d._fix(self)

    def create_decimal_from_float(self, f):
        """Creates a new Decimal instance from a float but rounding using self
        as the context.

        >>> context = Context(prec=5, rounding=ROUND_DOWN)
        >>> context.create_decimal_from_float(3.1415926535897932)
        Decimal('3.1415')
        >>> context = Context(prec=5, traps=[Inexact])
        >>> context.create_decimal_from_float(3.1415926535897932)
        Traceback (most recent call last):
            ...
        decimal.Inexact: None

        """
        d = Decimal.from_float(f)       # An exact conversion
        return d._fix(self)             # Apply the context rounding

    # Methods
    def abs(self, a):
        """Returns the absolute value of the operand.

        If the operand is negative, the result is the same as using the minus
        operation on the operand.  Otherwise, the result is the same as using
        the plus operation on the operand.

        >>> ExtendedContext.abs(Decimal('2.1'))
        Decimal('2.1')
        >>> ExtendedContext.abs(Decimal('-100'))
        Decimal('100')
        >>> ExtendedContext.abs(Decimal('101.5'))
        Decimal('101.5')
        >>> ExtendedContext.abs(Decimal('-101.5'))
        Decimal('101.5')
        >>> ExtendedContext.abs(-1)
        Decimal('1')
        """
        a = _convert_other(a, raiseit=True)
        return a.__abs__(context=self)

    def add(self, a, b):
        """Return the sum of the two operands.

        >>> ExtendedContext.add(Decimal('12'), Decimal('7.00'))
        Decimal('19.00')
        >>> ExtendedContext.add(Decimal('1E+2'), Decimal('1.01E+4'))
        Decimal('1.02E+4')
        >>> ExtendedContext.add(1, Decimal(2))
        Decimal('3')
        >>> ExtendedContext.add(Decimal(8), 5)
        Decimal('13')
        >>> ExtendedContext.add(5, 5)
        Decimal('10')
        """
        a = _convert_other(a, raiseit=True)
        r = a.__add__(b, context=self)
        if r is NotImplemented:
            raise TypeError("Unable to convert %s to Decimal" % b)
        else:
            return r

    def _apply(self, a):
        return str(a._fix(self))

    def canonical(self, a):
        """Returns the same Decimal object.

        As we do not have different encodings for the same number, the
        received object already is in its canonical form.

        >>> ExtendedContext.canonical(Decimal('2.50'))
        Decimal('2.50')
        """
        if not isinstance(a, Decimal):
            raise TypeError("canonical requires a Decimal as an argument.")
        return a.canonical()

    def compare(self, a, b):
        """Compares values numerically.

        If the signs of the operands differ, a value representing each operand
        ('-1' if the operand is less than zero, '0' if the operand is zero or
        negative zero, or '1' if the operand is greater than zero) is used in
        place of that operand for the comparison instead of the actual
        operand.

        The comparison is then effected by subtracting the second operand from
        the first and then returning a value according to the result of the
        subtraction: '-1' if the result is less than zero, '0' if the result is
        zero or negative zero, or '1' if the result is greater than zero.

        >>> ExtendedContext.compare(Decimal('2.1'), Decimal('3'))
        Decimal('-1')
        >>> ExtendedContext.compare(Decimal('2.1'), Decimal('2.1'))
        Decimal('0')
        >>> ExtendedContext.compare(Decimal('2.1'), Decimal('2.10'))
        Decimal('0')
        >>> ExtendedContext.compare(Decimal('3'), Decimal('2.1'))
        Decimal('1')
        >>> ExtendedContext.compare(Decimal('2.1'), Decimal('-3'))
        Decimal('1')
        >>> ExtendedContext.compare(Decimal('-3'), Decimal('2.1'))
        Decimal('-1')
        >>> ExtendedContext.compare(1, 2)
        Decimal('-1')
        >>> ExtendedContext.compare(Decimal(1), 2)
        Decimal('-1')
        >>> ExtendedContext.compare(1, Decimal(2))
        Decimal('-1')
        """
        a = _convert_other(a, raiseit=True)
        return a.compare(b, context=self)

    def compare_signal(self, a, b):
        """Compares the values of the two operands numerically.

        It's pretty much like compare(), but all NaNs signal, with signaling
        NaNs taking precedence over quiet NaNs.

        >>> c = ExtendedContext
        >>> c.compare_signal(Decimal('2.1'), Decimal('3'))
        Decimal('-1')
        >>> c.compare_signal(Decimal('2.1'), Decimal('2.1'))
        Decimal('0')
        >>> c.flags[InvalidOperation] = 0
        >>> print(c.flags[InvalidOperation])
        0
        >>> c.compare_signal(Decimal('NaN'), Decimal('2.1'))
        Decimal('NaN')
        >>> print(c.flags[InvalidOperation])
        1
        >>> c.flags[InvalidOperation] = 0
        >>> print(c.flags[InvalidOperation])
        0
        >>> c.compare_signal(Decimal('sNaN'), Decimal('2.1'))
        Decimal('NaN')
        >>> print(c.flags[InvalidOperation])
        1
        >>> c.compare_signal(-1, 2)
        Decimal('-1')
        >>> c.compare_signal(Decimal(-1), 2)
        Decimal('-1')
        >>> c.compare_signal(-1, Decimal(2))
        Decimal('-1')
        """
        a = _convert_other(a, raiseit=True)
        return a.compare_signal(b, context=self)

    def compare_total(self, a, b):
        """Compares two operands using their abstract representation.

        This is not like the standard compare, which use their numerical
        value. Note that a total ordering is defined for all possible abstract
        representations.

        >>> ExtendedContext.compare_total(Decimal('12.73'), Decimal('127.9'))
        Decimal('-1')
        >>> ExtendedContext.compare_total(Decimal('-127'),  Decimal('12'))
        Decimal('-1')
        >>> ExtendedContext.compare_total(Decimal('12.30'), Decimal('12.3'))
        Decimal('-1')
        >>> ExtendedContext.compare_total(Decimal('12.30'), Decimal('12.30'))
        Decimal('0')
        >>> ExtendedContext.compare_total(Decimal('12.3'),  Decimal('12.300'))
        Decimal('1')
        >>> ExtendedContext.compare_total(Decimal('12.3'),  Decimal('NaN'))
        Decimal('-1')
        >>> ExtendedContext.compare_total(1, 2)
        Decimal('-1')
        >>> ExtendedContext.compare_total(Decimal(1), 2)
        Decimal('-1')
        >>> ExtendedContext.compare_total(1, Decimal(2))
        Decimal('-1')
        """
        a = _convert_other(a, raiseit=True)
        return a.compare_total(b)

    def compare_total_mag(self, a, b):
        """Compares two operands using their abstract representation ignoring sign.

        Like compare_total, but with operand's sign ignored and assumed to be 0.
        """
        a = _convert_other(a, raiseit=True)
        return a.compare_total_mag(b)

    def copy_abs(self, a):
        """Returns a copy of the operand with the sign set to 0.

        >>> ExtendedContext.copy_abs(Decimal('2.1'))
        Decimal('2.1')
        >>> ExtendedContext.copy_abs(Decimal('-100'))
        Decimal('100')
        >>> ExtendedContext.copy_abs(-1)
        Decimal('1')
        """
        a = _convert_other(a, raiseit=True)
        return a.copy_abs()

    def copy_decimal(self, a):
        """Returns a copy of the decimal object.

        >>> ExtendedContext.copy_decimal(Decimal('2.1'))
        Decimal('2.1')
        >>> ExtendedContext.copy_decimal(Decimal('-1.00'))
        Decimal('-1.00')
        >>> ExtendedContext.copy_decimal(1)
        Decimal('1')
        """
        a = _convert_other(a, raiseit=True)
        return Decimal(a)

    def copy_negate(self, a):
        """Returns a copy of the operand with the sign inverted.

        >>> ExtendedContext.copy_negate(Decimal('101.5'))
        Decimal('-101.5')
        >>> ExtendedContext.copy_negate(Decimal('-101.5'))
        Decimal('101.5')
        >>> ExtendedContext.copy_negate(1)
        Decimal('-1')
        """
        a = _convert_other(a, raiseit=True)
        return a.copy_negate()

    def copy_sign(self, a, b):
        """Copies the second operand's sign to the first one.

        In detail, it returns a copy of the first operand with the sign
        equal to the sign of the second operand.

        >>> ExtendedContext.copy_sign(Decimal( '1.50'), Decimal('7.33'))
        Decimal('1.50')
        >>> ExtendedContext.copy_sign(Decimal('-1.50'), Decimal('7.33'))
        Decimal('1.50')
        >>> ExtendedContext.copy_sign(Decimal( '1.50'), Decimal('-7.33'))
        Decimal('-1.50')
        >>> ExtendedContext.copy_sign(Decimal('-1.50'), Decimal('-7.33'))
        Decimal('-1.50')
        >>> ExtendedContext.copy_sign(1, -2)
        Decimal('-1')
        >>> ExtendedContext.copy_sign(Decimal(1), -2)
        Decimal('-1')
        >>> ExtendedContext.copy_sign(1, Decimal(-2))
        Decimal('-1')
        """
        a = _convert_other(a, raiseit=True)
        return a.copy_sign(b)

    def divide(self, a, b):
        """Decimal division in a specified context.

        >>> ExtendedContext.divide(Decimal('1'), Decimal('3'))
        Decimal('0.333333333')
        >>> ExtendedContext.divide(Decimal('2'), Decimal('3'))
        Decimal('0.666666667')
        >>> ExtendedContext.divide(Decimal('5'), Decimal('2'))
        Decimal('2.5')
        >>> ExtendedContext.divide(Decimal('1'), Decimal('10'))
        Decimal('0.1')
        >>> ExtendedContext.divide(Decimal('12'), Decimal('12'))
        Decimal('1')
        >>> ExtendedContext.divide(Decimal('8.00'), Decimal('2'))
        Decimal('4.00')
        >>> ExtendedContext.divide(Decimal('2.400'), Decimal('2.0'))
        Decimal('1.20')
        >>> ExtendedContext.divide(Decimal('1000'), Decimal('100'))
        Decimal('10')
        >>> ExtendedContext.divide(Decimal('1000'), Decimal('1'))
        Decimal('1000')
        >>> ExtendedContext.divide(Decimal('2.40E+6'), Decimal('2'))
        Decimal('1.20E+6')
        >>> ExtendedContext.divide(5, 5)
        Decimal('1')
        >>> ExtendedContext.divide(Decimal(5), 5)
        Decimal('1')
        >>> ExtendedContext.divide(5, Decimal(5))
        Decimal('1')
        """
        a = _convert_other(a, raiseit=True)
        r = a.__truediv__(b, context=self)
        if r is NotImplemented:
            raise TypeError("Unable to convert %s to Decimal" % b)
        else:
            return r

    def divide_int(self, a, b):
        """Divides two numbers and returns the integer part of the result.

        >>> ExtendedContext.divide_int(Decimal('2'), Decimal('3'))
        Decimal('0')
        >>> ExtendedContext.divide_int(Decimal('10'), Decimal('3'))
        Decimal('3')
        >>> ExtendedContext.divide_int(Decimal('1'), Decimal('0.3'))
        Decimal('3')
        >>> ExtendedContext.divide_int(10, 3)
        Decimal('3')
        >>> ExtendedContext.divide_int(Decimal(10), 3)
        Decimal('3')
        >>> ExtendedContext.divide_int(10, Decimal(3))
        Decimal('3')
        """
        a = _convert_other(a, raiseit=True)
        r = a.__floordiv__(b, context=self)
        if r is NotImplemented:
            raise TypeError("Unable to convert %s to Decimal" % b)
        else:
            return r

    def divmod(self, a, b):
        """Return (a // b, a % b).

        >>> ExtendedContext.divmod(Decimal(8), Decimal(3))
        (Decimal('2'), Decimal('2'))
        >>> ExtendedContext.divmod(Decimal(8), Decimal(4))
        (Decimal('2'), Decimal('0'))
        >>> ExtendedContext.divmod(8, 4)
        (Decimal('2'), Decimal('0'))
        >>> ExtendedContext.divmod(Decimal(8), 4)
        (Decimal('2'), Decimal('0'))
        >>> ExtendedContext.divmod(8, Decimal(4))
        (Decimal('2'), Decimal('0'))
        """
        a = _convert_other(a, raiseit=True)
        r = a.__divmod__(b, context=self)
        if r is NotImplemented:
            raise TypeError("Unable to convert %s to Decimal" % b)
        else:
            return r

    def exp(self, a):
        """Returns e ** a.

        >>> c = ExtendedContext.copy()
        >>> c.Emin = -999
        >>> c.Emax = 999
        >>> c.exp(D