AppPkg/Applications/Python: Add Python 2.7.2 sources since the release of Python...

[mirror_edk2.git] / AppPkg / Applications / Python / Python-2.7.2 / Lib / hashlib.py

# $Id$\r
#\r
#  Copyright (C) 2005   Gregory P. Smith (greg@krypto.org)\r
#  Licensed to PSF under a Contributor Agreement.\r
#\r
\r
__doc__ = """hashlib module - A common interface to many hash functions.\r
\r
new(name, string='') - returns a new hash object implementing the\r
                       given hash function; initializing the hash\r
                       using the given string data.\r
\r
Named constructor functions are also available, these are much faster\r
than using new():\r
\r
md5(), sha1(), sha224(), sha256(), sha384(), and sha512()\r
\r
More algorithms may be available on your platform but the above are\r
guaranteed to exist.\r
\r
NOTE: If you want the adler32 or crc32 hash functions they are available in\r
the zlib module.\r
\r
Choose your hash function wisely.  Some have known collision weaknesses.\r
sha384 and sha512 will be slow on 32 bit platforms.\r
\r
Hash objects have these methods:\r
 - update(arg): Update the hash object with the string arg. Repeated calls\r
                are equivalent to a single call with the concatenation of all\r
                the arguments.\r
 - digest():    Return the digest of the strings passed to the update() method\r
                so far. This may contain non-ASCII characters, including\r
                NUL bytes.\r
 - hexdigest(): Like digest() except the digest is returned as a string of\r
                double length, containing only hexadecimal digits.\r
 - copy():      Return a copy (clone) of the hash object. This can be used to\r
                efficiently compute the digests of strings that share a common\r
                initial substring.\r
\r
For example, to obtain the digest of the string 'Nobody inspects the\r
spammish repetition':\r
\r
    >>> import hashlib\r
    >>> m = hashlib.md5()\r
    >>> m.update("Nobody inspects")\r
    >>> m.update(" the spammish repetition")\r
    >>> m.digest()\r
    '\\xbbd\\x9c\\x83\\xdd\\x1e\\xa5\\xc9\\xd9\\xde\\xc9\\xa1\\x8d\\xf0\\xff\\xe9'\r
\r
More condensed:\r
\r
    >>> hashlib.sha224("Nobody inspects the spammish repetition").hexdigest()\r
    'a4337bc45a8fc544c03f52dc550cd6e1e87021bc896588bd79e901e2'\r
\r
"""\r
\r
# This tuple and __get_builtin_constructor() must be modified if a new\r
# always available algorithm is added.\r
__always_supported = ('md5', 'sha1', 'sha224', 'sha256', 'sha384', 'sha512')\r
\r
algorithms = __always_supported\r
\r
__all__ = __always_supported + ('new', 'algorithms')\r
\r
\r
def __get_builtin_constructor(name):\r
    try:\r
        if name in ('SHA1', 'sha1'):\r
            import _sha\r
            return _sha.new\r
        elif name in ('MD5', 'md5'):\r
            import _md5\r
            return _md5.new\r
        elif name in ('SHA256', 'sha256', 'SHA224', 'sha224'):\r
            import _sha256\r
            bs = name[3:]\r
            if bs == '256':\r
                return _sha256.sha256\r
            elif bs == '224':\r
                return _sha256.sha224\r
        elif name in ('SHA512', 'sha512', 'SHA384', 'sha384'):\r
            import _sha512\r
            bs = name[3:]\r
            if bs == '512':\r
                return _sha512.sha512\r
            elif bs == '384':\r
                return _sha512.sha384\r
    except ImportError:\r
        pass  # no extension module, this hash is unsupported.\r
\r
    raise ValueError('unsupported hash type %s' % name)\r
\r
\r
def __get_openssl_constructor(name):\r
    try:\r
        f = getattr(_hashlib, 'openssl_' + name)\r
        # Allow the C module to raise ValueError.  The function will be\r
        # defined but the hash not actually available thanks to OpenSSL.\r
        f()\r
        # Use the C function directly (very fast)\r
        return f\r
    except (AttributeError, ValueError):\r
        return __get_builtin_constructor(name)\r
\r
\r
def __py_new(name, string=''):\r
    """new(name, string='') - Return a new hashing object using the named algorithm;\r
    optionally initialized with a string.\r
    """\r
    return __get_builtin_constructor(name)(string)\r
\r
\r
def __hash_new(name, string=''):\r
    """new(name, string='') - Return a new hashing object using the named algorithm;\r
    optionally initialized with a string.\r
    """\r
    try:\r
        return _hashlib.new(name, string)\r
    except ValueError:\r
        # If the _hashlib module (OpenSSL) doesn't support the named\r
        # hash, try using our builtin implementations.\r
        # This allows for SHA224/256 and SHA384/512 support even though\r
        # the OpenSSL library prior to 0.9.8 doesn't provide them.\r
        return __get_builtin_constructor(name)(string)\r
\r
\r
try:\r
    import _hashlib\r
    new = __hash_new\r
    __get_hash = __get_openssl_constructor\r
except ImportError:\r
    new = __py_new\r
    __get_hash = __get_builtin_constructor\r
\r
for __func_name in __always_supported:\r
    # try them all, some may not work due to the OpenSSL\r
    # version not supporting that algorithm.\r
    try:\r
        globals()[__func_name] = __get_hash(__func_name)\r
    except ValueError:\r
        import logging\r
        logging.exception('code for hash %s was not found.', __func_name)\r
\r
# Cleanup locals()\r
del __always_supported, __func_name, __get_hash\r
del __py_new, __hash_new, __get_openssl_constructor\r