Personal Computer World 2009 February/PCWFEB09.iso/Software/Linux/Kubuntu 8.10/kubuntu-8.10-desktop-i386.iso/casper/filesystem.squashfs/usr/lib/python2.5/base64.pyc

Python Compiled Bytecode | 2008-10-29 | 11KB | 379 lines

# Source Generated with Decompyle++
# File: in.pyc (Python 2.5)

'''RFC 3548: Base16, Base32, Base64 Data Encodings'''
import re
import struct
import binascii
__all__ = [
    'encode',
    'decode',
    'encodestring',
    'decodestring',
    'b64encode',
    'b64decode',
    'b32encode',
    'b32decode',
    'b16encode',
    'b16decode',
    'standard_b64encode',
    'standard_b64decode',
    'urlsafe_b64encode',
    'urlsafe_b64decode']
_translation = [ chr(_x) for _x in range(256) ]
EMPTYSTRING = ''

def _translate(s, altchars):
    translation = _translation[:]
    for k, v in altchars.items():
        translation[ord(k)] = v

    return s.translate(''.join(translation))


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

    s is the string to encode.  Optional altchars must be a string of at least
    length 2 (additional characters are ignored) 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 string is returned.
    """
    encoded = binascii.b2a_base64(s)[:-1]
    if altchars is not None:
        return _translate(encoded, {
            '+': altchars[0],
            '/': altchars[1] })

    return encoded


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

    s is the string to decode.  Optional altchars must be a string of at least
    length 2 (additional characters are ignored) which specifies the
    alternative alphabet used instead of the '+' and '/' characters.

    The decoded string is returned.  A TypeError is raised if s were
    incorrectly padded or if there are non-alphabet characters present in the
    string.
    """
    if altchars is not None:
        s = _translate(s, {
            altchars[0]: '+',
            altchars[1]: '/' })


    try:
        return binascii.a2b_base64(s)
    except binascii.Error:
        msg = None
        raise TypeError(msg)



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

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


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

    s is the string to decode.  The decoded string is returned.  A TypeError
    is raised if the string is incorrectly padded or if there are non-alphabet
    characters present in the string.
    '''
    return b64decode(s)


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

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


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

    s is the string to decode.  The decoded string is returned.  A TypeError
    is raised if the string is incorrectly padded or if there are non-alphabet
    characters present in the string.

    The alphabet uses '-' instead of '+' and '_' instead of '/'.
    """
    return b64decode(s, '-_')

_b32alphabet = {
    0: 'A',
    9: 'J',
    18: 'S',
    27: '3',
    1: 'B',
    10: 'K',
    19: 'T',
    28: '4',
    2: 'C',
    11: 'L',
    20: 'U',
    29: '5',
    3: 'D',
    12: 'M',
    21: 'V',
    30: '6',
    4: 'E',
    13: 'N',
    22: 'W',
    31: '7',
    5: 'F',
    14: 'O',
    23: 'X',
    6: 'G',
    15: 'P',
    24: 'Y',
    7: 'H',
    16: 'Q',
    25: 'Z',
    8: 'I',
    17: 'R',
    26: '2' }
_b32tab = _b32alphabet.items()
_b32tab.sort()
_b32tab = [ v for k, v in _b32tab ]
_b32rev = []([ (v, long(k)) for k, v in _b32alphabet.items() ])

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

    s is the string to encode.  The encoded string is returned.
    '''
    parts = []
    (quanta, leftover) = divmod(len(s), 5)
    if leftover:
        s += '\x00' * (5 - leftover)
        quanta += 1

    for i in range(quanta):
        (c1, c2, c3) = struct.unpack('!HHB', s[i * 5:(i + 1) * 5])
        c2 += (c1 & 1) << 16
        c3 += (c2 & 3) << 8
        parts.extend([
            _b32tab[c1 >> 11],
            _b32tab[c1 >> 6 & 31],
            _b32tab[c1 >> 1 & 31],
            _b32tab[c2 >> 12],
            _b32tab[c2 >> 7 & 31],
            _b32tab[c2 >> 2 & 31],
            _b32tab[c3 >> 5],
            _b32tab[c3 & 31]])

    encoded = EMPTYSTRING.join(parts)
    if leftover == 1:
        return encoded[:-6] + '======'
    elif leftover == 2:
        return encoded[:-4] + '===='
    elif leftover == 3:
        return encoded[:-3] + '==='
    elif leftover == 4:
        return encoded[:-1] + '='

    return encoded


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

    s is the 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 string is returned.  A TypeError is raised if s were
    incorrectly padded or if there are non-alphabet characters present in the
    string.
    '''
    (quanta, leftover) = divmod(len(s), 8)
    if leftover:
        raise TypeError('Incorrect padding')

    if map01:
        s = _translate(s, {
            '0': 'O',
            '1': map01 })

    if casefold:
        s = s.upper()

    padchars = 0
    mo = re.search('(?P<pad>[=]*)$', s)
    if mo:
        padchars = len(mo.group('pad'))
        if padchars > 0:
            s = s[:-padchars]


    parts = []
    acc = 0
    shift = 35
    for c in s:
        val = _b32rev.get(c)
        if val is None:
            raise TypeError('Non-base32 digit found')

        acc += _b32rev[c] << shift
        shift -= 5
        if shift < 0:
            parts.append(binascii.unhexlify('%010x' % acc))
            acc = 0
            shift = 35
            continue

    last = binascii.unhexlify('%010x' % acc)
    if padchars == 0:
        last = ''
    elif padchars == 1:
        last = last[:-1]
    elif padchars == 3:
        last = last[:-2]
    elif padchars == 4:
        last = last[:-3]
    elif padchars == 6:
        last = last[:-4]
    else:
        raise TypeError('Incorrect padding')
    parts.append(last)
    return EMPTYSTRING.join(parts)


def b16encode(s):
    '''Encode a string using Base16.

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


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

    s is the 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 string is returned.  A TypeError is raised if s were
    incorrectly padded or if there are non-alphabet characters present in the
    string.
    '''
    if casefold:
        s = s.upper()

    if re.search('[^0-9A-F]', s):
        raise TypeError('Non-base16 digit found')

    return binascii.unhexlify(s)

MAXLINESIZE = 76
MAXBINSIZE = (MAXLINESIZE // 4) * 3

def encode(input, output):
    '''Encode a file.'''
    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.'''
    while True:
        line = input.readline()
        if not line:
            break

        s = binascii.a2b_base64(line)
        output.write(s)


def encodestring(s):
    '''Encode a string.'''
    pieces = []
    for i in range(0, len(s), MAXBINSIZE):
        chunk = s[i:i + MAXBINSIZE]
        pieces.append(binascii.b2a_base64(chunk))

    return ''.join(pieces)


def decodestring(s):
    '''Decode a string.'''
    return binascii.a2b_base64(s)


def test():
    '''Small test program'''
    import sys as sys
    import getopt as getopt

    try:
        (opts, args) = getopt.getopt(sys.argv[1:], 'deut')
    except getopt.error:
        msg = None
        sys.stdout = sys.stderr
        print msg
        print "usage: %s [-d|-e|-u|-t] [file|-]\n        -d, -u: decode\n        -e: encode (default)\n        -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':
            test1()
            return None
            continue

    if args and args[0] != '-':
        func(open(args[0], 'rb'), sys.stdout)
    else:
        func(sys.stdin, sys.stdout)


def test1():
    s0 = 'Aladdin:open sesame'
    s1 = encodestring(s0)
    s2 = decodestring(s1)
    print s0, repr(s1), s2