322 lines
7.6 KiB
Python
322 lines
7.6 KiB
Python
import re
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import struct
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import binascii
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__all__ = [
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"encode",
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"decode",
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"encodebytes",
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"decodebytes",
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"b64encode",
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"b64decode",
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"b32encode",
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"b32decode",
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"b16encode",
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"b16decode",
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"standard_b64encode",
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"standard_b64decode",
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"urlsafe_b64encode",
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"urlsafe_b64decode",
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]
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bytes_types = (bytes, bytearray)
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def _bytes_from_decode_data(s):
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if isinstance(s, str):
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try:
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return s.encode("ascii")
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except:
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raise ValueError("string argument should contain only ASCII characters")
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elif isinstance(s, bytes_types):
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return s
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else:
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raise TypeError(
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"argument should be bytes or ASCII string, not %s" % s.__class__.__name__
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)
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def b64encode(s, altchars=None):
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if not isinstance(s, bytes_types):
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raise TypeError("expected bytes, not %s" % s.__class__.__name__)
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encoded = binascii.b2a_base64(s)[:-1]
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if altchars is not None:
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if not isinstance(altchars, bytes_types):
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raise TypeError("expected bytes, not %s" % altchars.__class__.__name__)
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assert len(altchars) == 2, repr(altchars)
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return encoded.translate(bytes.maketrans(b"+/", altchars))
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return encoded
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def b64decode(s, altchars=None, validate=False):
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s = _bytes_from_decode_data(s)
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if altchars is not None:
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altchars = _bytes_from_decode_data(altchars)
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assert len(altchars) == 2, repr(altchars)
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s = s.translate(bytes.maketrans(altchars, b"+/"))
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if validate and not re.match(b"^[A-Za-z0-9+/]*={0,2}$", s):
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raise binascii.Error("Non-base64 digit found")
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return binascii.a2b_base64(s)
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def standard_b64encode(s):
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return b64encode(s)
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def standard_b64decode(s):
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return b64decode(s)
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def urlsafe_b64encode(s):
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raise NotImplementedError()
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def urlsafe_b64decode(s):
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raise NotImplementedError()
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_b32alphabet = {
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0: b"A",
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9: b"J",
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18: b"S",
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27: b"3",
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1: b"B",
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10: b"K",
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19: b"T",
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28: b"4",
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2: b"C",
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11: b"L",
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20: b"U",
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29: b"5",
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3: b"D",
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12: b"M",
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21: b"V",
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30: b"6",
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4: b"E",
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13: b"N",
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22: b"W",
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31: b"7",
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5: b"F",
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14: b"O",
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23: b"X",
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6: b"G",
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15: b"P",
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24: b"Y",
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7: b"H",
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16: b"Q",
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25: b"Z",
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8: b"I",
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17: b"R",
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26: b"2",
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}
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_b32tab = [v[0] for k, v in sorted(_b32alphabet.items())]
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_b32rev = dict([(v[0], k) for k, v in _b32alphabet.items()])
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def b32encode(s):
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if not isinstance(s, bytes_types):
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raise TypeError("expected bytes, not %s" % s.__class__.__name__)
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quanta, leftover = divmod(len(s), 5)
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if leftover:
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s = s + bytes(5 - leftover) # Don't use += !
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quanta += 1
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encoded = bytearray()
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for i in range(quanta):
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c1, c2, c3 = struct.unpack("!HHB", s[i * 5 : (i + 1) * 5])
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c2 += (c1 & 1) << 16
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c3 += (c2 & 3) << 8
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encoded += bytes(
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[
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_b32tab[c1 >> 11],
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_b32tab[(c1 >> 6) & 0x1F],
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_b32tab[(c1 >> 1) & 0x1F],
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_b32tab[c2 >> 12],
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_b32tab[(c2 >> 7) & 0x1F],
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_b32tab[(c2 >> 2) & 0x1F],
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_b32tab[c3 >> 5],
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_b32tab[c3 & 0x1F],
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]
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)
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if leftover == 1:
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encoded = encoded[:-6] + b"======"
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elif leftover == 2:
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encoded = encoded[:-4] + b"===="
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elif leftover == 3:
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encoded = encoded[:-3] + b"==="
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elif leftover == 4:
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encoded = encoded[:-1] + b"="
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return bytes(encoded)
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def b32decode(s, casefold=False, map01=None):
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s = _bytes_from_decode_data(s)
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quanta, leftover = divmod(len(s), 8)
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if leftover:
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raise binascii.Error("Incorrect padding")
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if map01 is not None:
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map01 = _bytes_from_decode_data(map01)
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assert len(map01) == 1, repr(map01)
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s = s.translate(bytes.maketrans(b"01", b"O" + map01))
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if casefold:
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s = s.upper()
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padchars = s.find(b"=")
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if padchars > 0:
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padchars = len(s) - padchars
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s = s[:-padchars]
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else:
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padchars = 0
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parts = []
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acc = 0
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shift = 35
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for c in s:
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val = _b32rev.get(c)
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if val is None:
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raise binascii.Error("Non-base32 digit found")
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acc += _b32rev[c] << shift
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shift -= 5
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if shift < 0:
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parts.append(binascii.unhexlify(bytes("%010x" % acc, "ascii")))
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acc = 0
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shift = 35
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last = binascii.unhexlify(bytes("%010x" % acc, "ascii"))
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if padchars == 0:
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last = b""
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elif padchars == 1:
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last = last[:-1]
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elif padchars == 3:
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last = last[:-2]
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elif padchars == 4:
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last = last[:-3]
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elif padchars == 6:
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last = last[:-4]
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else:
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raise binascii.Error("Incorrect padding")
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parts.append(last)
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return b"".join(parts)
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def b16encode(s):
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if not isinstance(s, bytes_types):
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raise TypeError("expected bytes, not %s" % s.__class__.__name__)
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return binascii.hexlify(s).upper()
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def b16decode(s, casefold=False):
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s = _bytes_from_decode_data(s)
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if casefold:
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s = s.upper()
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if re.search(b"[^0-9A-F]", s):
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raise binascii.Error("Non-base16 digit found")
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return binascii.unhexlify(s)
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MAXLINESIZE = 76
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MAXBINSIZE = (MAXLINESIZE // 4) * 3
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def encode(input, output):
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while True:
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s = input.read(MAXBINSIZE)
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if not s:
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break
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while len(s) < MAXBINSIZE:
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ns = input.read(MAXBINSIZE - len(s))
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if not ns:
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break
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s += ns
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line = binascii.b2a_base64(s)
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output.write(line)
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def decode(input, output):
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while True:
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line = input.readline()
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if not line:
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break
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s = binascii.a2b_base64(line)
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output.write(s)
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def encodebytes(s):
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if not isinstance(s, bytes_types):
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raise TypeError("expected bytes, not %s" % s.__class__.__name__)
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pieces = []
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for i in range(0, len(s), MAXBINSIZE):
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chunk = s[i : i + MAXBINSIZE]
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pieces.append(binascii.b2a_base64(chunk))
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return b"".join(pieces)
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def encodestring(s):
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import warnings
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warnings.warn(
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"encodestring() is a deprecated alias, use encodebytes()", DeprecationWarning, 2
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)
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return encodebytes(s)
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def decodebytes(s):
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if not isinstance(s, bytes_types):
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raise TypeError("expected bytes, not %s" % s.__class__.__name__)
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return binascii.a2b_base64(s)
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def decodestring(s):
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import warnings
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warnings.warn(
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"decodestring() is a deprecated alias, use decodebytes()", DeprecationWarning, 2
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)
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return decodebytes(s)
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def main():
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import sys, getopt
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try:
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opts, args = getopt.getopt(sys.argv[1:], "deut")
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except getopt.error as msg:
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sys.stdout = sys.stderr
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print(msg)
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print(
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"""usage: %s [-d|-e|-u|-t] [file|-]
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-d, -u: decode
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-e: encode (default)
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-t: encode and decode string 'Aladdin:open sesame'"""
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% sys.argv[0]
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)
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sys.exit(2)
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func = encode
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for o, a in opts:
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if o == "-e":
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func = encode
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if o == "-d":
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func = decode
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if o == "-u":
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func = decode
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if o == "-t":
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test()
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return
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if args and args[0] != "-":
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with open(args[0], "rb") as f:
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func(f, sys.stdout.buffer)
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else:
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func(sys.stdin.buffer, sys.stdout.buffer)
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def test():
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s0 = b"Aladdin:open sesame"
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print(repr(s0))
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s1 = encodebytes(s0)
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print(repr(s1))
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s2 = decodebytes(s1)
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print(repr(s2))
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assert s0 == s2
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if __name__ == "__main__":
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main()
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