Python code coverage for Lib/base64.py

#	count	content
1	n/a	#! /usr/bin/env python3
2	n/a
3	n/a	"""Base16, Base32, Base64 (RFC 3548), Base85 and Ascii85 data encodings"""
4	n/a
5	n/a	# Modified 04-Oct-1995 by Jack Jansen to use binascii module
6	n/a	# Modified 30-Dec-2003 by Barry Warsaw to add full RFC 3548 support
7	n/a	# Modified 22-May-2007 by Guido van Rossum to use bytes everywhere
8	n/a
9	n/a	import re
10	n/a	import struct
11	n/a	import binascii
12	n/a
13	n/a
14	n/a	__all__ = [
15	n/a	# Legacy interface exports traditional RFC 2045 Base64 encodings
16	n/a	'encode', 'decode', 'encodebytes', 'decodebytes',
17	n/a	# Generalized interface for other encodings
18	n/a	'b64encode', 'b64decode', 'b32encode', 'b32decode',
19	n/a	'b16encode', 'b16decode',
20	n/a	# Base85 and Ascii85 encodings
21	n/a	'b85encode', 'b85decode', 'a85encode', 'a85decode',
22	n/a	# Standard Base64 encoding
23	n/a	'standard_b64encode', 'standard_b64decode',
24	n/a	# Some common Base64 alternatives. As referenced by RFC 3458, see thread
25	n/a	# starting at:
26	n/a	#
27	n/a	# http://zgp.org/pipermail/p2p-hackers/2001-September/000316.html
28	n/a	'urlsafe_b64encode', 'urlsafe_b64decode',
29	n/a	]
30	n/a
31	n/a
32	n/a	bytes_types = (bytes, bytearray) # Types acceptable as binary data
33	n/a
34	n/a	def _bytes_from_decode_data(s):
35	n/a	if isinstance(s, str):
36	n/a	try:
37	n/a	return s.encode('ascii')
38	n/a	except UnicodeEncodeError:
39	n/a	raise ValueError('string argument should contain only ASCII characters')
40	n/a	if isinstance(s, bytes_types):
41	n/a	return s
42	n/a	try:
43	n/a	return memoryview(s).tobytes()
44	n/a	except TypeError:
45	n/a	raise TypeError("argument should be a bytes-like object or ASCII "
46	n/a	"string, not %r" % s.__class__.__name__) from None
47	n/a
48	n/a
49	n/a	# Base64 encoding/decoding uses binascii
50	n/a
51	n/a	def b64encode(s, altchars=None):
52	n/a	"""Encode the bytes-like object s using Base64 and return a bytes object.
53	n/a
54	n/a	Optional altchars should be a byte string of length 2 which specifies an
55	n/a	alternative alphabet for the '+' and '/' characters. This allows an
56	n/a	application to e.g. generate url or filesystem safe Base64 strings.
57	n/a	"""
58	n/a	encoded = binascii.b2a_base64(s, newline=False)
59	n/a	if altchars is not None:
60	n/a	assert len(altchars) == 2, repr(altchars)
61	n/a	return encoded.translate(bytes.maketrans(b'+/', altchars))
62	n/a	return encoded
63	n/a
64	n/a
65	n/a	def b64decode(s, altchars=None, validate=False):
66	n/a	"""Decode the Base64 encoded bytes-like object or ASCII string s.
67	n/a
68	n/a	Optional altchars must be a bytes-like object or ASCII string of length 2
69	n/a	which specifies the alternative alphabet used instead of the '+' and '/'
70	n/a	characters.
71	n/a
72	n/a	The result is returned as a bytes object. A binascii.Error is raised if
73	n/a	s is incorrectly padded.
74	n/a
75	n/a	If validate is False (the default), characters that are neither in the
76	n/a	normal base-64 alphabet nor the alternative alphabet are discarded prior
77	n/a	to the padding check. If validate is True, these non-alphabet characters
78	n/a	in the input result in a binascii.Error.
79	n/a	"""
80	n/a	s = _bytes_from_decode_data(s)
81	n/a	if altchars is not None:
82	n/a	altchars = _bytes_from_decode_data(altchars)
83	n/a	assert len(altchars) == 2, repr(altchars)
84	n/a	s = s.translate(bytes.maketrans(altchars, b'+/'))
85	n/a	if validate and not re.match(b'^[A-Za-z0-9+/]*={0,2}$', s):
86	n/a	raise binascii.Error('Non-base64 digit found')
87	n/a	return binascii.a2b_base64(s)
88	n/a
89	n/a
90	n/a	def standard_b64encode(s):
91	n/a	"""Encode bytes-like object s using the standard Base64 alphabet.
92	n/a
93	n/a	The result is returned as a bytes object.
94	n/a	"""
95	n/a	return b64encode(s)
96	n/a
97	n/a	def standard_b64decode(s):
98	n/a	"""Decode bytes encoded with the standard Base64 alphabet.
99	n/a
100	n/a	Argument s is a bytes-like object or ASCII string to decode. The result
101	n/a	is returned as a bytes object. A binascii.Error is raised if the input
102	n/a	is incorrectly padded. Characters that are not in the standard alphabet
103	n/a	are discarded prior to the padding check.
104	n/a	"""
105	n/a	return b64decode(s)
106	n/a
107	n/a
108	n/a	_urlsafe_encode_translation = bytes.maketrans(b'+/', b'-_')
109	n/a	_urlsafe_decode_translation = bytes.maketrans(b'-_', b'+/')
110	n/a
111	n/a	def urlsafe_b64encode(s):
112	n/a	"""Encode bytes using the URL- and filesystem-safe Base64 alphabet.
113	n/a
114	n/a	Argument s is a bytes-like object to encode. The result is returned as a
115	n/a	bytes object. The alphabet uses '-' instead of '+' and '_' instead of
116	n/a	'/'.
117	n/a	"""
118	n/a	return b64encode(s).translate(_urlsafe_encode_translation)
119	n/a
120	n/a	def urlsafe_b64decode(s):
121	n/a	"""Decode bytes using the URL- and filesystem-safe Base64 alphabet.
122	n/a
123	n/a	Argument s is a bytes-like object or ASCII string to decode. The result
124	n/a	is returned as a bytes object. A binascii.Error is raised if the input
125	n/a	is incorrectly padded. Characters that are not in the URL-safe base-64
126	n/a	alphabet, and are not a plus '+' or slash '/', are discarded prior to the
127	n/a	padding check.
128	n/a
129	n/a	The alphabet uses '-' instead of '+' and '_' instead of '/'.
130	n/a	"""
131	n/a	s = _bytes_from_decode_data(s)
132	n/a	s = s.translate(_urlsafe_decode_translation)
133	n/a	return b64decode(s)
134	n/a
135	n/a
136	n/a
137	n/a	# Base32 encoding/decoding must be done in Python
138	n/a	_b32alphabet = b'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567'
139	n/a	_b32tab2 = None
140	n/a	_b32rev = None
141	n/a
142	n/a	def b32encode(s):
143	n/a	"""Encode the bytes-like object s using Base32 and return a bytes object.
144	n/a	"""
145	n/a	global _b32tab2
146	n/a	# Delay the initialization of the table to not waste memory
147	n/a	# if the function is never called
148	n/a	if _b32tab2 is None:
149	n/a	b32tab = [bytes((i,)) for i in _b32alphabet]
150	n/a	_b32tab2 = [a + b for a in b32tab for b in b32tab]
151	n/a	b32tab = None
152	n/a
153	n/a	if not isinstance(s, bytes_types):
154	n/a	s = memoryview(s).tobytes()
155	n/a	leftover = len(s) % 5
156	n/a	# Pad the last quantum with zero bits if necessary
157	n/a	if leftover:
158	n/a	s = s + b'\0' * (5 - leftover) # Don't use += !
159	n/a	encoded = bytearray()
160	n/a	from_bytes = int.from_bytes
161	n/a	b32tab2 = _b32tab2
162	n/a	for i in range(0, len(s), 5):
163	n/a	c = from_bytes(s[i: i + 5], 'big')
164	n/a	encoded += (b32tab2[c >> 30] + # bits 1 - 10
165	n/a	b32tab2[(c >> 20) & 0x3ff] + # bits 11 - 20
166	n/a	b32tab2[(c >> 10) & 0x3ff] + # bits 21 - 30
167	n/a	b32tab2[c & 0x3ff] # bits 31 - 40
168	n/a	)
169	n/a	# Adjust for any leftover partial quanta
170	n/a	if leftover == 1:
171	n/a	encoded[-6:] = b'======'
172	n/a	elif leftover == 2:
173	n/a	encoded[-4:] = b'===='
174	n/a	elif leftover == 3:
175	n/a	encoded[-3:] = b'==='
176	n/a	elif leftover == 4:
177	n/a	encoded[-1:] = b'='
178	n/a	return bytes(encoded)
179	n/a
180	n/a	def b32decode(s, casefold=False, map01=None):
181	n/a	"""Decode the Base32 encoded bytes-like object or ASCII string s.
182	n/a
183	n/a	Optional casefold is a flag specifying whether a lowercase alphabet is
184	n/a	acceptable as input. For security purposes, the default is False.
185	n/a
186	n/a	RFC 3548 allows for optional mapping of the digit 0 (zero) to the
187	n/a	letter O (oh), and for optional mapping of the digit 1 (one) to
188	n/a	either the letter I (eye) or letter L (el). The optional argument
189	n/a	map01 when not None, specifies which letter the digit 1 should be
190	n/a	mapped to (when map01 is not None, the digit 0 is always mapped to
191	n/a	the letter O). For security purposes the default is None, so that
192	n/a	0 and 1 are not allowed in the input.
193	n/a
194	n/a	The result is returned as a bytes object. A binascii.Error is raised if
195	n/a	the input is incorrectly padded or if there are non-alphabet
196	n/a	characters present in the input.
197	n/a	"""
198	n/a	global _b32rev
199	n/a	# Delay the initialization of the table to not waste memory
200	n/a	# if the function is never called
201	n/a	if _b32rev is None:
202	n/a	_b32rev = {v: k for k, v in enumerate(_b32alphabet)}
203	n/a	s = _bytes_from_decode_data(s)
204	n/a	if len(s) % 8:
205	n/a	raise binascii.Error('Incorrect padding')
206	n/a	# Handle section 2.4 zero and one mapping. The flag map01 will be either
207	n/a	# False, or the character to map the digit 1 (one) to. It should be
208	n/a	# either L (el) or I (eye).
209	n/a	if map01 is not None:
210	n/a	map01 = _bytes_from_decode_data(map01)
211	n/a	assert len(map01) == 1, repr(map01)
212	n/a	s = s.translate(bytes.maketrans(b'01', b'O' + map01))
213	n/a	if casefold:
214	n/a	s = s.upper()
215	n/a	# Strip off pad characters from the right. We need to count the pad
216	n/a	# characters because this will tell us how many null bytes to remove from
217	n/a	# the end of the decoded string.
218	n/a	l = len(s)
219	n/a	s = s.rstrip(b'=')
220	n/a	padchars = l - len(s)
221	n/a	# Now decode the full quanta
222	n/a	decoded = bytearray()
223	n/a	b32rev = _b32rev
224	n/a	for i in range(0, len(s), 8):
225	n/a	quanta = s[i: i + 8]
226	n/a	acc = 0
227	n/a	try:
228	n/a	for c in quanta:
229	n/a	acc = (acc << 5) + b32rev[c]
230	n/a	except KeyError:
231	n/a	raise binascii.Error('Non-base32 digit found') from None
232	n/a	decoded += acc.to_bytes(5, 'big')
233	n/a	# Process the last, partial quanta
234	n/a	if padchars:
235	n/a	acc <<= 5 * padchars
236	n/a	last = acc.to_bytes(5, 'big')
237	n/a	if padchars == 1:
238	n/a	decoded[-5:] = last[:-1]
239	n/a	elif padchars == 3:
240	n/a	decoded[-5:] = last[:-2]
241	n/a	elif padchars == 4:
242	n/a	decoded[-5:] = last[:-3]
243	n/a	elif padchars == 6:
244	n/a	decoded[-5:] = last[:-4]
245	n/a	else:
246	n/a	raise binascii.Error('Incorrect padding')
247	n/a	return bytes(decoded)
248	n/a
249	n/a
250	n/a
251	n/a	# RFC 3548, Base 16 Alphabet specifies uppercase, but hexlify() returns
252	n/a	# lowercase. The RFC also recommends against accepting input case
253	n/a	# insensitively.
254	n/a	def b16encode(s):
255	n/a	"""Encode the bytes-like object s using Base16 and return a bytes object.
256	n/a	"""
257	n/a	return binascii.hexlify(s).upper()
258	n/a
259	n/a
260	n/a	def b16decode(s, casefold=False):
261	n/a	"""Decode the Base16 encoded bytes-like object or ASCII string s.
262	n/a
263	n/a	Optional casefold is a flag specifying whether a lowercase alphabet is
264	n/a	acceptable as input. For security purposes, the default is False.
265	n/a
266	n/a	The result is returned as a bytes object. A binascii.Error is raised if
267	n/a	s is incorrectly padded or if there are non-alphabet characters present
268	n/a	in the input.
269	n/a	"""
270	n/a	s = _bytes_from_decode_data(s)
271	n/a	if casefold:
272	n/a	s = s.upper()
273	n/a	if re.search(b'[^0-9A-F]', s):
274	n/a	raise binascii.Error('Non-base16 digit found')
275	n/a	return binascii.unhexlify(s)
276	n/a
277	n/a	#
278	n/a	# Ascii85 encoding/decoding
279	n/a	#
280	n/a
281	n/a	_a85chars = None
282	n/a	_a85chars2 = None
283	n/a	_A85START = b"<~"
284	n/a	_A85END = b"~>"
285	n/a
286	n/a	def _85encode(b, chars, chars2, pad=False, foldnuls=False, foldspaces=False):
287	n/a	# Helper function for a85encode and b85encode
288	n/a	if not isinstance(b, bytes_types):
289	n/a	b = memoryview(b).tobytes()
290	n/a
291	n/a	padding = (-len(b)) % 4
292	n/a	if padding:
293	n/a	b = b + b'\0' * padding
294	n/a	words = struct.Struct('!%dI' % (len(b) // 4)).unpack(b)
295	n/a
296	n/a	chunks = [b'z' if foldnuls and not word else
297	n/a	b'y' if foldspaces and word == 0x20202020 else
298	n/a	(chars2[word // 614125] +
299	n/a	chars2[word // 85 % 7225] +
300	n/a	chars[word % 85])
301	n/a	for word in words]
302	n/a
303	n/a	if padding and not pad:
304	n/a	if chunks[-1] == b'z':
305	n/a	chunks[-1] = chars[0] * 5
306	n/a	chunks[-1] = chunks[-1][:-padding]
307	n/a
308	n/a	return b''.join(chunks)
309	n/a
310	n/a	def a85encode(b, *, foldspaces=False, wrapcol=0, pad=False, adobe=False):
311	n/a	"""Encode bytes-like object b using Ascii85 and return a bytes object.
312	n/a
313	n/a	foldspaces is an optional flag that uses the special short sequence 'y'
314	n/a	instead of 4 consecutive spaces (ASCII 0x20) as supported by 'btoa'. This
315	n/a	feature is not supported by the "standard" Adobe encoding.
316	n/a
317	n/a	wrapcol controls whether the output should have newline (b'\\n') characters
318	n/a	added to it. If this is non-zero, each output line will be at most this
319	n/a	many characters long.
320	n/a
321	n/a	pad controls whether the input is padded to a multiple of 4 before
322	n/a	encoding. Note that the btoa implementation always pads.
323	n/a
324	n/a	adobe controls whether the encoded byte sequence is framed with <~ and ~>,
325	n/a	which is used by the Adobe implementation.
326	n/a	"""
327	n/a	global _a85chars, _a85chars2
328	n/a	# Delay the initialization of tables to not waste memory
329	n/a	# if the function is never called
330	n/a	if _a85chars is None:
331	n/a	_a85chars = [bytes((i,)) for i in range(33, 118)]
332	n/a	_a85chars2 = [(a + b) for a in _a85chars for b in _a85chars]
333	n/a
334	n/a	result = _85encode(b, _a85chars, _a85chars2, pad, True, foldspaces)
335	n/a
336	n/a	if adobe:
337	n/a	result = _A85START + result
338	n/a	if wrapcol:
339	n/a	wrapcol = max(2 if adobe else 1, wrapcol)
340	n/a	chunks = [result[i: i + wrapcol]
341	n/a	for i in range(0, len(result), wrapcol)]
342	n/a	if adobe:
343	n/a	if len(chunks[-1]) + 2 > wrapcol:
344	n/a	chunks.append(b'')
345	n/a	result = b'\n'.join(chunks)
346	n/a	if adobe:
347	n/a	result += _A85END
348	n/a
349	n/a	return result
350	n/a
351	n/a	def a85decode(b, *, foldspaces=False, adobe=False, ignorechars=b' \t\n\r\v'):
352	n/a	"""Decode the Ascii85 encoded bytes-like object or ASCII string b.
353	n/a
354	n/a	foldspaces is a flag that specifies whether the 'y' short sequence should be
355	n/a	accepted as shorthand for 4 consecutive spaces (ASCII 0x20). This feature is
356	n/a	not supported by the "standard" Adobe encoding.
357	n/a
358	n/a	adobe controls whether the input sequence is in Adobe Ascii85 format (i.e.
359	n/a	is framed with <~ and ~>).
360	n/a
361	n/a	ignorechars should be a byte string containing characters to ignore from the
362	n/a	input. This should only contain whitespace characters, and by default
363	n/a	contains all whitespace characters in ASCII.
364	n/a
365	n/a	The result is returned as a bytes object.
366	n/a	"""
367	n/a	b = _bytes_from_decode_data(b)
368	n/a	if adobe:
369	n/a	if not b.endswith(_A85END):
370	n/a	raise ValueError(
371	n/a	"Ascii85 encoded byte sequences must end "
372	n/a	"with {!r}".format(_A85END)
373	n/a	)
374	n/a	if b.startswith(_A85START):
375	n/a	b = b[2:-2] # Strip off start/end markers
376	n/a	else:
377	n/a	b = b[:-2]
378	n/a	#
379	n/a	# We have to go through this stepwise, so as to ignore spaces and handle
380	n/a	# special short sequences
381	n/a	#
382	n/a	packI = struct.Struct('!I').pack
383	n/a	decoded = []
384	n/a	decoded_append = decoded.append
385	n/a	curr = []
386	n/a	curr_append = curr.append
387	n/a	curr_clear = curr.clear
388	n/a	for x in b + b'u' * 4:
389	n/a	if b'!'[0] <= x <= b'u'[0]:
390	n/a	curr_append(x)
391	n/a	if len(curr) == 5:
392	n/a	acc = 0
393	n/a	for x in curr:
394	n/a	acc = 85 * acc + (x - 33)
395	n/a	try:
396	n/a	decoded_append(packI(acc))
397	n/a	except struct.error:
398	n/a	raise ValueError('Ascii85 overflow') from None
399	n/a	curr_clear()
400	n/a	elif x == b'z'[0]:
401	n/a	if curr:
402	n/a	raise ValueError('z inside Ascii85 5-tuple')
403	n/a	decoded_append(b'\0\0\0\0')
404	n/a	elif foldspaces and x == b'y'[0]:
405	n/a	if curr:
406	n/a	raise ValueError('y inside Ascii85 5-tuple')
407	n/a	decoded_append(b'\x20\x20\x20\x20')
408	n/a	elif x in ignorechars:
409	n/a	# Skip whitespace
410	n/a	continue
411	n/a	else:
412	n/a	raise ValueError('Non-Ascii85 digit found: %c' % x)
413	n/a
414	n/a	result = b''.join(decoded)
415	n/a	padding = 4 - len(curr)
416	n/a	if padding:
417	n/a	# Throw away the extra padding
418	n/a	result = result[:-padding]
419	n/a	return result
420	n/a
421	n/a	# The following code is originally taken (with permission) from Mercurial
422	n/a
423	n/a	_b85alphabet = (b"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
424	n/a	b"abcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{\|}~")
425	n/a	_b85chars = None
426	n/a	_b85chars2 = None
427	n/a	_b85dec = None
428	n/a
429	n/a	def b85encode(b, pad=False):
430	n/a	"""Encode bytes-like object b in base85 format and return a bytes object.
431	n/a
432	n/a	If pad is true, the input is padded with b'\\0' so its length is a multiple of
433	n/a	4 bytes before encoding.
434	n/a	"""
435	n/a	global _b85chars, _b85chars2
436	n/a	# Delay the initialization of tables to not waste memory
437	n/a	# if the function is never called
438	n/a	if _b85chars is None:
439	n/a	_b85chars = [bytes((i,)) for i in _b85alphabet]
440	n/a	_b85chars2 = [(a + b) for a in _b85chars for b in _b85chars]
441	n/a	return _85encode(b, _b85chars, _b85chars2, pad)
442	n/a
443	n/a	def b85decode(b):
444	n/a	"""Decode the base85-encoded bytes-like object or ASCII string b
445	n/a
446	n/a	The result is returned as a bytes object.
447	n/a	"""
448	n/a	global _b85dec
449	n/a	# Delay the initialization of tables to not waste memory
450	n/a	# if the function is never called
451	n/a	if _b85dec is None:
452	n/a	_b85dec = [None] * 256
453	n/a	for i, c in enumerate(_b85alphabet):
454	n/a	_b85dec[c] = i
455	n/a
456	n/a	b = _bytes_from_decode_data(b)
457	n/a	padding = (-len(b)) % 5
458	n/a	b = b + b'~' * padding
459	n/a	out = []
460	n/a	packI = struct.Struct('!I').pack
461	n/a	for i in range(0, len(b), 5):
462	n/a	chunk = b[i:i + 5]
463	n/a	acc = 0
464	n/a	try:
465	n/a	for c in chunk:
466	n/a	acc = acc * 85 + _b85dec[c]
467	n/a	except TypeError:
468	n/a	for j, c in enumerate(chunk):
469	n/a	if _b85dec[c] is None:
470	n/a	raise ValueError('bad base85 character at position %d'
471	n/a	% (i + j)) from None
472	n/a	raise
473	n/a	try:
474	n/a	out.append(packI(acc))
475	n/a	except struct.error:
476	n/a	raise ValueError('base85 overflow in hunk starting at byte %d'
477	n/a	% i) from None
478	n/a
479	n/a	result = b''.join(out)
480	n/a	if padding:
481	n/a	result = result[:-padding]
482	n/a	return result
483	n/a
484	n/a	# Legacy interface. This code could be cleaned up since I don't believe
485	n/a	# binascii has any line length limitations. It just doesn't seem worth it
486	n/a	# though. The files should be opened in binary mode.
487	n/a
488	n/a	MAXLINESIZE = 76 # Excluding the CRLF
489	n/a	MAXBINSIZE = (MAXLINESIZE//4)*3
490	n/a
491	n/a	def encode(input, output):
492	n/a	"""Encode a file; input and output are binary files."""
493	n/a	while True:
494	n/a	s = input.read(MAXBINSIZE)
495	n/a	if not s:
496	n/a	break
497	n/a	while len(s) < MAXBINSIZE:
498	n/a	ns = input.read(MAXBINSIZE-len(s))
499	n/a	if not ns:
500	n/a	break
501	n/a	s += ns
502	n/a	line = binascii.b2a_base64(s)
503	n/a	output.write(line)
504	n/a
505	n/a
506	n/a	def decode(input, output):
507	n/a	"""Decode a file; input and output are binary files."""
508	n/a	while True:
509	n/a	line = input.readline()
510	n/a	if not line:
511	n/a	break
512	n/a	s = binascii.a2b_base64(line)
513	n/a	output.write(s)
514	n/a
515	n/a	def _input_type_check(s):
516	n/a	try:
517	n/a	m = memoryview(s)
518	n/a	except TypeError as err:
519	n/a	msg = "expected bytes-like object, not %s" % s.__class__.__name__
520	n/a	raise TypeError(msg) from err
521	n/a	if m.format not in ('c', 'b', 'B'):
522	n/a	msg = ("expected single byte elements, not %r from %s" %
523	n/a	(m.format, s.__class__.__name__))
524	n/a	raise TypeError(msg)
525	n/a	if m.ndim != 1:
526	n/a	msg = ("expected 1-D data, not %d-D data from %s" %
527	n/a	(m.ndim, s.__class__.__name__))
528	n/a	raise TypeError(msg)
529	n/a
530	n/a
531	n/a	def encodebytes(s):
532	n/a	"""Encode a bytestring into a bytes object containing multiple lines
533	n/a	of base-64 data."""
534	n/a	_input_type_check(s)
535	n/a	pieces = []
536	n/a	for i in range(0, len(s), MAXBINSIZE):
537	n/a	chunk = s[i : i + MAXBINSIZE]
538	n/a	pieces.append(binascii.b2a_base64(chunk))
539	n/a	return b"".join(pieces)
540	n/a
541	n/a	def encodestring(s):
542	n/a	"""Legacy alias of encodebytes()."""
543	n/a	import warnings
544	n/a	warnings.warn("encodestring() is a deprecated alias, use encodebytes()",
545	n/a	DeprecationWarning, 2)
546	n/a	return encodebytes(s)
547	n/a
548	n/a
549	n/a	def decodebytes(s):
550	n/a	"""Decode a bytestring of base-64 data into a bytes object."""
551	n/a	_input_type_check(s)
552	n/a	return binascii.a2b_base64(s)
553	n/a
554	n/a	def decodestring(s):
555	n/a	"""Legacy alias of decodebytes()."""
556	n/a	import warnings
557	n/a	warnings.warn("decodestring() is a deprecated alias, use decodebytes()",
558	n/a	DeprecationWarning, 2)
559	n/a	return decodebytes(s)
560	n/a
561	n/a
562	n/a	# Usable as a script...
563	n/a	def main():
564	n/a	"""Small main program"""
565	n/a	import sys, getopt
566	n/a	try:
567	n/a	opts, args = getopt.getopt(sys.argv[1:], 'deut')
568	n/a	except getopt.error as msg:
569	n/a	sys.stdout = sys.stderr
570	n/a	print(msg)
571	n/a	print("""usage: %s [-d\|-e\|-u\|-t] [file\|-]
572	n/a	-d, -u: decode
573	n/a	-e: encode (default)
574	n/a	-t: encode and decode string 'Aladdin:open sesame'"""%sys.argv[0])
575	n/a	sys.exit(2)
576	n/a	func = encode
577	n/a	for o, a in opts:
578	n/a	if o == '-e': func = encode
579	n/a	if o == '-d': func = decode
580	n/a	if o == '-u': func = decode
581	n/a	if o == '-t': test(); return
582	n/a	if args and args[0] != '-':
583	n/a	with open(args[0], 'rb') as f:
584	n/a	func(f, sys.stdout.buffer)
585	n/a	else:
586	n/a	func(sys.stdin.buffer, sys.stdout.buffer)
587	n/a
588	n/a
589	n/a	def test():
590	n/a	s0 = b"Aladdin:open sesame"
591	n/a	print(repr(s0))
592	n/a	s1 = encodebytes(s0)
593	n/a	print(repr(s1))
594	n/a	s2 = decodebytes(s1)
595	n/a	print(repr(s2))
596	n/a	assert s0 == s2
597	n/a
598	n/a
599	n/a	if __name__ == '__main__':
600	n/a	main()