1 /* -*- buffer-read-only: t -*- vi: set ro: */
2 /* DO NOT EDIT! GENERATED AUTOMATICALLY! */
3 /* base64.c -- Encode binary data using printable characters.
4 Copyright (C) 1999, 2000, 2001, 2004, 2005, 2006, 2007 Free Software
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software Foundation,
19 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
21 /* Written by Simon Josefsson. Partially adapted from GNU MailUtils
22 * (mailbox/filter_trans.c, as of 2004-11-28). Improved by review
23 * from Paul Eggert, Bruno Haible, and Stepan Kasal.
25 * See also RFC 3548 <http://www.ietf.org/rfc/rfc3548.txt>.
27 * Be careful with error checking. Here is how you would typically
28 * use these functions:
30 * bool ok = base64_decode_alloc (in, inlen, &out, &outlen);
32 * FAIL: input was not valid base64
34 * FAIL: memory allocation error
35 * OK: data in OUT/OUTLEN
37 * size_t outlen = base64_encode_alloc (in, inlen, &out);
38 * if (out == NULL && outlen == 0 && inlen != 0)
39 * FAIL: input too long
41 * FAIL: memory allocation error
42 * OK: data in OUT/OUTLEN.
59 /* C89 compliant way to cast 'char' to 'unsigned char'. */
60 static inline unsigned char
66 /* Base64 encode IN array of size INLEN into OUT array of size OUTLEN.
67 If OUTLEN is less than BASE64_LENGTH(INLEN), write as many bytes as
68 possible. If OUTLEN is larger than BASE64_LENGTH(INLEN), also zero
69 terminate the output buffer. */
71 base64_encode (const char *restrict in, size_t inlen,
72 char *restrict out, size_t outlen)
74 static const char b64str[64] =
75 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
77 while (inlen && outlen)
79 *out++ = b64str[(to_uchar (in[0]) >> 2) & 0x3f];
82 *out++ = b64str[((to_uchar (in[0]) << 4)
83 + (--inlen ? to_uchar (in[1]) >> 4 : 0))
89 ? b64str[((to_uchar (in[1]) << 2)
90 + (--inlen ? to_uchar (in[2]) >> 6 : 0))
95 *out++ = inlen ? b64str[to_uchar (in[2]) & 0x3f] : '=';
108 /* Allocate a buffer and store zero terminated base64 encoded data
109 from array IN of size INLEN, returning BASE64_LENGTH(INLEN), i.e.,
110 the length of the encoded data, excluding the terminating zero. On
111 return, the OUT variable will hold a pointer to newly allocated
112 memory that must be deallocated by the caller. If output string
113 length would overflow, 0 is returned and OUT is set to NULL. If
114 memory allocation failed, OUT is set to NULL, and the return value
115 indicates length of the requested memory block, i.e.,
116 BASE64_LENGTH(inlen) + 1. */
118 base64_encode_alloc (const char *in, size_t inlen, char **out)
120 size_t outlen = 1 + BASE64_LENGTH (inlen);
122 /* Check for overflow in outlen computation.
124 * If there is no overflow, outlen >= inlen.
126 * If the operation (inlen + 2) overflows then it yields at most +1, so
129 * If the multiplication overflows, we lose at least half of the
130 * correct value, so the result is < ((inlen + 2) / 3) * 2, which is
131 * less than (inlen + 2) * 0.66667, which is less than inlen as soon as
140 *out = malloc (outlen);
144 base64_encode (in, inlen, *out, outlen);
149 /* With this approach this file works independent of the charset used
150 (think EBCDIC). However, it does assume that the characters in the
151 Base64 alphabet (A-Za-z0-9+/) are encoded in 0..255. POSIX
152 1003.1-2001 require that char and unsigned char are 8-bit
153 quantities, though, taking care of that problem. But this may be a
154 potential problem on non-POSIX C99 platforms.
156 IBM C V6 for AIX mishandles "#define B64(x) ...'x'...", so use "_"
157 as the formal parameter rather than "x". */
225 static const signed char b64[0x100] = {
226 B64 (0), B64 (1), B64 (2), B64 (3),
227 B64 (4), B64 (5), B64 (6), B64 (7),
228 B64 (8), B64 (9), B64 (10), B64 (11),
229 B64 (12), B64 (13), B64 (14), B64 (15),
230 B64 (16), B64 (17), B64 (18), B64 (19),
231 B64 (20), B64 (21), B64 (22), B64 (23),
232 B64 (24), B64 (25), B64 (26), B64 (27),
233 B64 (28), B64 (29), B64 (30), B64 (31),
234 B64 (32), B64 (33), B64 (34), B64 (35),
235 B64 (36), B64 (37), B64 (38), B64 (39),
236 B64 (40), B64 (41), B64 (42), B64 (43),
237 B64 (44), B64 (45), B64 (46), B64 (47),
238 B64 (48), B64 (49), B64 (50), B64 (51),
239 B64 (52), B64 (53), B64 (54), B64 (55),
240 B64 (56), B64 (57), B64 (58), B64 (59),
241 B64 (60), B64 (61), B64 (62), B64 (63),
242 B64 (64), B64 (65), B64 (66), B64 (67),
243 B64 (68), B64 (69), B64 (70), B64 (71),
244 B64 (72), B64 (73), B64 (74), B64 (75),
245 B64 (76), B64 (77), B64 (78), B64 (79),
246 B64 (80), B64 (81), B64 (82), B64 (83),
247 B64 (84), B64 (85), B64 (86), B64 (87),
248 B64 (88), B64 (89), B64 (90), B64 (91),
249 B64 (92), B64 (93), B64 (94), B64 (95),
250 B64 (96), B64 (97), B64 (98), B64 (99),
251 B64 (100), B64 (101), B64 (102), B64 (103),
252 B64 (104), B64 (105), B64 (106), B64 (107),
253 B64 (108), B64 (109), B64 (110), B64 (111),
254 B64 (112), B64 (113), B64 (114), B64 (115),
255 B64 (116), B64 (117), B64 (118), B64 (119),
256 B64 (120), B64 (121), B64 (122), B64 (123),
257 B64 (124), B64 (125), B64 (126), B64 (127),
258 B64 (128), B64 (129), B64 (130), B64 (131),
259 B64 (132), B64 (133), B64 (134), B64 (135),
260 B64 (136), B64 (137), B64 (138), B64 (139),
261 B64 (140), B64 (141), B64 (142), B64 (143),
262 B64 (144), B64 (145), B64 (146), B64 (147),
263 B64 (148), B64 (149), B64 (150), B64 (151),
264 B64 (152), B64 (153), B64 (154), B64 (155),
265 B64 (156), B64 (157), B64 (158), B64 (159),
266 B64 (160), B64 (161), B64 (162), B64 (163),
267 B64 (164), B64 (165), B64 (166), B64 (167),
268 B64 (168), B64 (169), B64 (170), B64 (171),
269 B64 (172), B64 (173), B64 (174), B64 (175),
270 B64 (176), B64 (177), B64 (178), B64 (179),
271 B64 (180), B64 (181), B64 (182), B64 (183),
272 B64 (184), B64 (185), B64 (186), B64 (187),
273 B64 (188), B64 (189), B64 (190), B64 (191),
274 B64 (192), B64 (193), B64 (194), B64 (195),
275 B64 (196), B64 (197), B64 (198), B64 (199),
276 B64 (200), B64 (201), B64 (202), B64 (203),
277 B64 (204), B64 (205), B64 (206), B64 (207),
278 B64 (208), B64 (209), B64 (210), B64 (211),
279 B64 (212), B64 (213), B64 (214), B64 (215),
280 B64 (216), B64 (217), B64 (218), B64 (219),
281 B64 (220), B64 (221), B64 (222), B64 (223),
282 B64 (224), B64 (225), B64 (226), B64 (227),
283 B64 (228), B64 (229), B64 (230), B64 (231),
284 B64 (232), B64 (233), B64 (234), B64 (235),
285 B64 (236), B64 (237), B64 (238), B64 (239),
286 B64 (240), B64 (241), B64 (242), B64 (243),
287 B64 (244), B64 (245), B64 (246), B64 (247),
288 B64 (248), B64 (249), B64 (250), B64 (251),
289 B64 (252), B64 (253), B64 (254), B64 (255)
293 # define uchar_in_range(c) true
295 # define uchar_in_range(c) ((c) <= 255)
298 /* Return true if CH is a character from the Base64 alphabet, and
299 false otherwise. Note that '=' is padding and not considered to be
300 part of the alphabet. */
304 return uchar_in_range (to_uchar (ch)) && 0 <= b64[to_uchar (ch)];
307 /* Initialize decode-context buffer, CTX. */
309 base64_decode_ctx_init (struct base64_decode_context *ctx)
314 /* If CTX->i is 0 or 4, there are four or more bytes in [*IN..IN_END), and
315 none of those four is a newline, then return *IN. Otherwise, copy up to
316 4 - CTX->i non-newline bytes from that range into CTX->buf, starting at
317 index CTX->i and setting CTX->i to reflect the number of bytes copied,
318 and return CTX->buf. In either case, advance *IN to point to the byte
319 after the last one processed, and set *N_NON_NEWLINE to the number of
320 verified non-newline bytes accessible through the returned pointer. */
322 get_4 (struct base64_decode_context *ctx,
323 char const *restrict *in, char const *restrict in_end,
324 size_t *n_non_newline)
332 if (4 <= in_end - *in && memchr (t, '\n', 4) == NULL)
334 /* This is the common case: no newline. */
342 /* Copy non-newline bytes into BUF. */
349 ctx->buf[ctx->i++] = c;
356 *n_non_newline = ctx->i;
361 #define return_false \
369 /* Decode up to four bytes of base64-encoded data, IN, of length INLEN
370 into the output buffer, *OUT, of size *OUTLEN bytes. Return true if
371 decoding is successful, false otherwise. If *OUTLEN is too small,
372 as many bytes as possible are written to *OUT. On return, advance
373 *OUT to point to the byte after the last one written, and decrement
374 *OUTLEN to reflect the number of bytes remaining in *OUT. */
376 decode_4 (char const *restrict in, size_t inlen,
377 char *restrict *outp, size_t *outleft)
383 if (!isbase64 (in[0]) || !isbase64 (in[1]))
388 *out++ = ((b64[to_uchar (in[0])] << 2)
389 | (b64[to_uchar (in[1])] >> 4));
406 if (!isbase64 (in[2]))
411 *out++ = (((b64[to_uchar (in[1])] << 4) & 0xf0)
412 | (b64[to_uchar (in[2])] >> 2));
426 if (!isbase64 (in[3]))
431 *out++ = (((b64[to_uchar (in[2])] << 6) & 0xc0)
432 | b64[to_uchar (in[3])]);
442 /* Decode base64-encoded input array IN of length INLEN to output array
443 OUT that can hold *OUTLEN bytes. The input data may be interspersed
444 with newlines. Return true if decoding was successful, i.e. if the
445 input was valid base64 data, false otherwise. If *OUTLEN is too
446 small, as many bytes as possible will be written to OUT. On return,
447 *OUTLEN holds the length of decoded bytes in OUT. Note that as soon
448 as any non-alphabet, non-newline character is encountered, decoding
449 is stopped and false is returned. If INLEN is zero, then process
450 only whatever data is stored in CTX.
452 Initially, CTX must have been initialized via base64_decode_ctx_init.
453 Subsequent calls to this function must reuse whatever state is recorded
454 in that buffer. It is necessary for when a quadruple of base64 input
455 bytes spans two input buffers. */
458 base64_decode (struct base64_decode_context *ctx,
459 const char *restrict in, size_t inlen,
460 char *restrict out, size_t *outlen)
462 size_t outleft = *outlen;
463 bool flush_ctx = inlen == 0;
467 size_t outleft_save = outleft;
468 if (ctx->i == 0 && !flush_ctx)
472 /* Save a copy of outleft, in case we need to re-parse this
473 block of four bytes. */
474 outleft_save = outleft;
475 if (!decode_4 (in, inlen, &out, &outleft))
483 if (inlen == 0 && !flush_ctx)
486 /* Handle the common case of 72-byte wrapped lines.
487 This also handles any other multiple-of-4-byte wrapping. */
488 if (inlen && *in == '\n')
495 /* Restore OUT and OUTLEFT. */
496 out -= outleft_save - outleft;
497 outleft = outleft_save;
500 char const *in_end = in + inlen;
501 char const *non_nl = get_4 (ctx, &in, in_end, &inlen);
503 /* If the input is empty or consists solely of newlines (0 non-newlines),
504 then we're done. Likewise if there are fewer than 4 bytes when not
506 if (inlen == 0 || (inlen < 4 && !flush_ctx))
511 if (!decode_4 (non_nl, inlen, &out, &outleft))
523 /* Allocate an output buffer in *OUT, and decode the base64 encoded
524 data stored in IN of size INLEN to the *OUT buffer. On return, the
525 size of the decoded data is stored in *OUTLEN. OUTLEN may be NULL,
526 if the caller is not interested in the decoded length. *OUT may be
527 NULL to indicate an out of memory error, in which case *OUTLEN
528 contains the size of the memory block needed. The function returns
529 true on successful decoding and memory allocation errors. (Use the
530 *OUT and *OUTLEN parameters to differentiate between successful
531 decoding and memory error.) The function returns false if the
532 input was invalid, in which case *OUT is NULL and *OUTLEN is
535 base64_decode_alloc (struct base64_decode_context *ctx,
536 const char *in, size_t inlen, char **out,
539 /* This may allocate a few bytes too many, depending on input,
540 but it's not worth the extra CPU time to compute the exact size.
541 The exact size is 3 * inlen / 4, minus 1 if the input ends
542 with "=" and minus another 1 if the input ends with "==".
543 Dividing before multiplying avoids the possibility of overflow. */
544 size_t needlen = 3 * (inlen / 4) + 2;
546 *out = malloc (needlen);
550 if (!base64_decode (ctx, in, inlen, *out, &needlen))