raise binascii.Error('Non-base16 digit found')
return binascii.unhexlify(s)
+#
+# Ascii85 encoding/decoding
+#
+
+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)
+
+ a85chars2 = _a85chars2
+ a85chars = _a85chars
+ 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)
+
+_A85START = b"<~"
+_A85END = b"~>"
+_a85chars = [bytes([i]) for i in range(33, 118)]
+_a85chars2 = [(a + b) for a in _a85chars for b in _a85chars]
+
+def a85encode(b, *, foldspaces=False, wrapcol=0, pad=False, adobe=False):
+ """Encode a byte string using Ascii85.
- "by {} and {}".format(_A85START, _A85END))
+ 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.
+ """
+ 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
+
+_b85chars = b"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
+ b"abcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~"
+_b85chars = [bytes([i]) for i in _b85chars]
+_b85chars2 = [(a + b) for a in _b85chars for b in _b85chars]
+_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.
+ """
+ return _85encode(b, _b85chars, _b85chars2, pad)
+
+def b85decode(b):
+ """Decode base85-encoded byte array"""
+ b = _bytes_from_decode_data(b)
+ global _b85dec
+ if _b85dec is None:
+ _b85dec = [None] * 256
+ for i, c in enumerate(_b85chars):
+ _b85dec[c[0]] = i
+
+ 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
projects / python / commitdiff