# -*- coding: UTF-8 -*-

# Copyright (c) 2010, Pascal Volk

# See COPYING for distribution information.

"""

    VirtualMailManager.pycompat.hashlib

    VirtualMailManager's minimal hashlib emulation for Python 2.4

    hashlib.md5(...), hashlib.sha1(...), hashlib.new('md5', ...) and

    hashlib.new('sha1', ...) will work always.

    When the PyCrypto module <http://www.pycrypto.org/> could be found in

    sys.path hashlib.new('md4', ...) will also work.

    With PyCrypto >= 2.1.0alpha1 hashlib.new('sha256', ...) and

    hashlib.sha256(...) becomes functional.

"""

import md5 as _md5

import sha as _sha1

try:

    import Crypto

except ImportError:

    _md4 = None

    SHA256 = None

else:

    from Crypto.Hash import MD4 as _md4

    if hasattr(Crypto, 'version_info'):  # <- Available since v2.1.0alpha1

        from Crypto.Hash import SHA256   # SHA256 works since v2.1.0alpha1

        sha256 = SHA256.new

    else:

        SHA256 = None

    del Crypto

compat = 0x01

md5 = _md5.new

sha1 = _sha1.new

def new(name, string=''):

    """Return a new hashing object using the named algorithm, optionally

    initialized with the provided string.

    """

    if name in ('md5', 'MD5'):

        return _md5.new(string)

    if name in ('sha1', 'SHA1'):

        return _sha1.new(string)

    if not _md4:

        raise ValueError('unsupported hash type')

    if name in ('md4', 'MD4'):

        return _md4.new(string)

    if name in ('sha256', 'SHA256') and SHA256:

        return SHA256.new(string)

    raise ValueError('unsupported hash type')