Mercurial > hg > octave-shane > gnulib-hg
annotate lib/base64.c @ 6226:5ddf33c5823b
2005-09-12 Ralf Wildenhues <Ralf.Wildenhues@gmx.de> (tiny change)
* lib/base64.c: Typo.
(base64_encode): Put b64str in initialized data section.
author | Simon Josefsson <simon@josefsson.org> |
---|---|
date | Tue, 13 Sep 2005 08:04:11 +0000 |
parents | c1d164e8c502 |
children | 99e42c0a09e1 |
rev | line source |
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5498 | 1 /* base64.c -- Encode binary data using printable characters. |
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2 Copyright (C) 1999, 2000, 2001, 2004, 2005 Free Software Foundation, Inc. |
5498 | 3 |
4 This program is free software; you can redistribute it and/or modify | |
5 it under the terms of the GNU General Public License as published by | |
6 the Free Software Foundation; either version 2, or (at your option) | |
7 any later version. | |
8 | |
9 This program is distributed in the hope that it will be useful, | |
10 but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 GNU General Public License for more details. | |
13 | |
14 You should have received a copy of the GNU General Public License | |
15 along with this program; if not, write to the Free Software Foundation, | |
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16 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ |
5498 | 17 |
18 /* Written by Simon Josefsson. Partially adapted from GNU MailUtils | |
19 * (mailbox/filter_trans.c, as of 2004-11-28). Improved by review | |
20 * from Paul Eggert, Bruno Haible, and Stepan Kasal. | |
21 * | |
22 * See also RFC 3548 <http://www.ietf.org/rfc/rfc3548.txt>. | |
23 * | |
24 * Be careful with error checking. Here is how you would typically | |
25 * use these functions: | |
26 * | |
27 * bool ok = base64_decode_alloc (in, inlen, &out, &outlen); | |
28 * if (!ok) | |
29 * FAIL: input was not valid base64 | |
30 * if (out == NULL) | |
31 * FAIL: memory allocation error | |
32 * OK: data in OUT/OUTLEN | |
33 * | |
34 * size_t outlen = base64_encode_alloc (in, inlen, &out); | |
35 * if (out == NULL && outlen == 0 && inlen != 0) | |
36 * FAIL: input too long | |
37 * if (out == NULL) | |
38 * FAIL: memory allocation error | |
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39 * OK: data in OUT/OUTLEN. |
5498 | 40 * |
41 */ | |
42 | |
43 #ifdef HAVE_CONFIG_H | |
44 # include <config.h> | |
45 #endif | |
46 | |
47 /* Get prototype. */ | |
48 #include "base64.h" | |
49 | |
50 /* Get malloc. */ | |
51 #include <stdlib.h> | |
52 | |
53 /* C89 compliant way to cast 'char' to 'unsigned char'. */ | |
54 static inline unsigned char | |
55 to_uchar (char ch) | |
56 { | |
57 return ch; | |
58 } | |
59 | |
60 /* Base64 encode IN array of size INLEN into OUT array of size OUTLEN. | |
61 If OUTLEN is less than BASE64_LENGTH(INLEN), write as many bytes as | |
62 possible. If OUTLEN is larger than BASE64_LENGTH(INLEN), also zero | |
63 terminate the output buffer. */ | |
64 void | |
65 base64_encode (const char *restrict in, size_t inlen, | |
66 char *restrict out, size_t outlen) | |
67 { | |
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68 static const char b64str[64] = |
5498 | 69 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; |
70 | |
71 while (inlen && outlen) | |
72 { | |
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73 *out++ = b64str[to_uchar (in[0]) >> 2]; |
5498 | 74 if (!--outlen) |
75 break; | |
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76 *out++ = b64str[((to_uchar (in[0]) << 4) |
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77 + (--inlen ? to_uchar (in[1]) >> 4 : 0)) |
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78 & 0x3f]; |
5498 | 79 if (!--outlen) |
80 break; | |
81 *out++ = | |
82 (inlen | |
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83 ? b64str[((to_uchar (in[1]) << 2) |
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84 + (--inlen ? to_uchar (in[2]) >> 6 : 0)) |
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85 & 0x3f] |
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86 : '='); |
5498 | 87 if (!--outlen) |
88 break; | |
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89 *out++ = inlen ? b64str[to_uchar (in[2]) & 0x3f] : '='; |
5498 | 90 if (!--outlen) |
91 break; | |
92 if (inlen) | |
93 inlen--; | |
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94 if (inlen) |
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95 in += 3; |
5498 | 96 } |
97 | |
98 if (outlen) | |
99 *out = '\0'; | |
100 } | |
101 | |
102 /* Allocate a buffer and store zero terminated base64 encoded data | |
103 from array IN of size INLEN, returning BASE64_LENGTH(INLEN), i.e., | |
104 the length of the encoded data, excluding the terminating zero. On | |
105 return, the OUT variable will hold a pointer to newly allocated | |
106 memory that must be deallocated by the caller. If output string | |
107 length would overflow, 0 is returned and OUT is set to NULL. If | |
108 memory allocation fail, OUT is set to NULL, and the return value | |
109 indicate length of the requested memory block, i.e., | |
110 BASE64_LENGTH(inlen) + 1. */ | |
111 size_t | |
112 base64_encode_alloc (const char *in, size_t inlen, char **out) | |
113 { | |
114 size_t outlen = 1 + BASE64_LENGTH (inlen); | |
115 | |
116 /* Check for overflow in outlen computation. | |
117 * | |
118 * If there is no overflow, outlen >= inlen. | |
119 * | |
120 * If the operation (inlen + 2) overflows then it yields at most +1, so | |
121 * outlen is 0. | |
122 * | |
123 * If the multiplication overflows, we lose at least half of the | |
124 * correct value, so the result is < ((inlen + 2) / 3) * 2, which is | |
125 * less than (inlen + 2) * 0.66667, which is less than inlen as soon as | |
126 * (inlen > 4). | |
127 */ | |
128 if (inlen > outlen) | |
129 { | |
130 *out = NULL; | |
131 return 0; | |
132 } | |
133 | |
134 *out = malloc (outlen); | |
135 if (*out) | |
136 base64_encode (in, inlen, *out, outlen); | |
137 | |
138 return outlen - 1; | |
139 } | |
140 | |
141 /* With this approach this file works independent of the charset used | |
142 (think EBCDIC). However, it does assume that the characters in the | |
143 Base64 alphabet (A-Za-z0-9+/) are encoded in 0..255. POSIX | |
144 1003.1-2001 require that char and unsigned char are 8-bit | |
145 quantities, though, taking care of that problem. But this may be a | |
146 potential problem on non-POSIX C99 platforms. */ | |
147 #define B64(x) \ | |
148 ((x) == 'A' ? 0 \ | |
149 : (x) == 'B' ? 1 \ | |
150 : (x) == 'C' ? 2 \ | |
151 : (x) == 'D' ? 3 \ | |
152 : (x) == 'E' ? 4 \ | |
153 : (x) == 'F' ? 5 \ | |
154 : (x) == 'G' ? 6 \ | |
155 : (x) == 'H' ? 7 \ | |
156 : (x) == 'I' ? 8 \ | |
157 : (x) == 'J' ? 9 \ | |
158 : (x) == 'K' ? 10 \ | |
159 : (x) == 'L' ? 11 \ | |
160 : (x) == 'M' ? 12 \ | |
161 : (x) == 'N' ? 13 \ | |
162 : (x) == 'O' ? 14 \ | |
163 : (x) == 'P' ? 15 \ | |
164 : (x) == 'Q' ? 16 \ | |
165 : (x) == 'R' ? 17 \ | |
166 : (x) == 'S' ? 18 \ | |
167 : (x) == 'T' ? 19 \ | |
168 : (x) == 'U' ? 20 \ | |
169 : (x) == 'V' ? 21 \ | |
170 : (x) == 'W' ? 22 \ | |
171 : (x) == 'X' ? 23 \ | |
172 : (x) == 'Y' ? 24 \ | |
173 : (x) == 'Z' ? 25 \ | |
174 : (x) == 'a' ? 26 \ | |
175 : (x) == 'b' ? 27 \ | |
176 : (x) == 'c' ? 28 \ | |
177 : (x) == 'd' ? 29 \ | |
178 : (x) == 'e' ? 30 \ | |
179 : (x) == 'f' ? 31 \ | |
180 : (x) == 'g' ? 32 \ | |
181 : (x) == 'h' ? 33 \ | |
182 : (x) == 'i' ? 34 \ | |
183 : (x) == 'j' ? 35 \ | |
184 : (x) == 'k' ? 36 \ | |
185 : (x) == 'l' ? 37 \ | |
186 : (x) == 'm' ? 38 \ | |
187 : (x) == 'n' ? 39 \ | |
188 : (x) == 'o' ? 40 \ | |
189 : (x) == 'p' ? 41 \ | |
190 : (x) == 'q' ? 42 \ | |
191 : (x) == 'r' ? 43 \ | |
192 : (x) == 's' ? 44 \ | |
193 : (x) == 't' ? 45 \ | |
194 : (x) == 'u' ? 46 \ | |
195 : (x) == 'v' ? 47 \ | |
196 : (x) == 'w' ? 48 \ | |
197 : (x) == 'x' ? 49 \ | |
198 : (x) == 'y' ? 50 \ | |
199 : (x) == 'z' ? 51 \ | |
200 : (x) == '0' ? 52 \ | |
201 : (x) == '1' ? 53 \ | |
202 : (x) == '2' ? 54 \ | |
203 : (x) == '3' ? 55 \ | |
204 : (x) == '4' ? 56 \ | |
205 : (x) == '5' ? 57 \ | |
206 : (x) == '6' ? 58 \ | |
207 : (x) == '7' ? 59 \ | |
208 : (x) == '8' ? 60 \ | |
209 : (x) == '9' ? 61 \ | |
210 : (x) == '+' ? 62 \ | |
211 : (x) == '/' ? 63 \ | |
212 : -1) | |
213 | |
214 static const signed char b64[0x100] = { | |
215 B64 (0), B64 (1), B64 (2), B64 (3), | |
216 B64 (4), B64 (5), B64 (6), B64 (7), | |
217 B64 (8), B64 (9), B64 (10), B64 (11), | |
218 B64 (12), B64 (13), B64 (14), B64 (15), | |
219 B64 (16), B64 (17), B64 (18), B64 (19), | |
220 B64 (20), B64 (21), B64 (22), B64 (23), | |
221 B64 (24), B64 (25), B64 (26), B64 (27), | |
222 B64 (28), B64 (29), B64 (30), B64 (31), | |
223 B64 (32), B64 (33), B64 (34), B64 (35), | |
224 B64 (36), B64 (37), B64 (38), B64 (39), | |
225 B64 (40), B64 (41), B64 (42), B64 (43), | |
226 B64 (44), B64 (45), B64 (46), B64 (47), | |
227 B64 (48), B64 (49), B64 (50), B64 (51), | |
228 B64 (52), B64 (53), B64 (54), B64 (55), | |
229 B64 (56), B64 (57), B64 (58), B64 (59), | |
230 B64 (60), B64 (61), B64 (62), B64 (63), | |
231 B64 (64), B64 (65), B64 (66), B64 (67), | |
232 B64 (68), B64 (69), B64 (70), B64 (71), | |
233 B64 (72), B64 (73), B64 (74), B64 (75), | |
234 B64 (76), B64 (77), B64 (78), B64 (79), | |
235 B64 (80), B64 (81), B64 (82), B64 (83), | |
236 B64 (84), B64 (85), B64 (86), B64 (87), | |
237 B64 (88), B64 (89), B64 (90), B64 (91), | |
238 B64 (92), B64 (93), B64 (94), B64 (95), | |
239 B64 (96), B64 (97), B64 (98), B64 (99), | |
240 B64 (100), B64 (101), B64 (102), B64 (103), | |
241 B64 (104), B64 (105), B64 (106), B64 (107), | |
242 B64 (108), B64 (109), B64 (110), B64 (111), | |
243 B64 (112), B64 (113), B64 (114), B64 (115), | |
244 B64 (116), B64 (117), B64 (118), B64 (119), | |
245 B64 (120), B64 (121), B64 (122), B64 (123), | |
246 B64 (124), B64 (125), B64 (126), B64 (127), | |
247 B64 (128), B64 (129), B64 (130), B64 (131), | |
248 B64 (132), B64 (133), B64 (134), B64 (135), | |
249 B64 (136), B64 (137), B64 (138), B64 (139), | |
250 B64 (140), B64 (141), B64 (142), B64 (143), | |
251 B64 (144), B64 (145), B64 (146), B64 (147), | |
252 B64 (148), B64 (149), B64 (150), B64 (151), | |
253 B64 (152), B64 (153), B64 (154), B64 (155), | |
254 B64 (156), B64 (157), B64 (158), B64 (159), | |
255 B64 (160), B64 (161), B64 (162), B64 (163), | |
256 B64 (164), B64 (165), B64 (166), B64 (167), | |
257 B64 (168), B64 (169), B64 (170), B64 (171), | |
258 B64 (172), B64 (173), B64 (174), B64 (175), | |
259 B64 (176), B64 (177), B64 (178), B64 (179), | |
260 B64 (180), B64 (181), B64 (182), B64 (183), | |
261 B64 (184), B64 (185), B64 (186), B64 (187), | |
262 B64 (188), B64 (189), B64 (190), B64 (191), | |
263 B64 (192), B64 (193), B64 (194), B64 (195), | |
264 B64 (196), B64 (197), B64 (198), B64 (199), | |
265 B64 (200), B64 (201), B64 (202), B64 (203), | |
266 B64 (204), B64 (205), B64 (206), B64 (207), | |
267 B64 (208), B64 (209), B64 (210), B64 (211), | |
268 B64 (212), B64 (213), B64 (214), B64 (215), | |
269 B64 (216), B64 (217), B64 (218), B64 (219), | |
270 B64 (220), B64 (221), B64 (222), B64 (223), | |
271 B64 (224), B64 (225), B64 (226), B64 (227), | |
272 B64 (228), B64 (229), B64 (230), B64 (231), | |
273 B64 (232), B64 (233), B64 (234), B64 (235), | |
274 B64 (236), B64 (237), B64 (238), B64 (239), | |
275 B64 (240), B64 (241), B64 (242), B64 (243), | |
276 B64 (244), B64 (245), B64 (246), B64 (247), | |
277 B64 (248), B64 (249), B64 (250), B64 (251), | |
278 B64 (252), B64 (253), B64 (254), B64 (255) | |
279 }; | |
280 | |
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281 bool |
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* base64.h (isbase64): Add.
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282 isbase64 (char ch) |
5498 | 283 { |
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284 return to_uchar (ch) <= 255 && 0 <= b64[to_uchar (ch)]; |
5498 | 285 } |
286 | |
287 /* Decode base64 encoded input array IN of length INLEN to output | |
288 array OUT that can hold *OUTLEN bytes. Return true if decoding was | |
289 successful, i.e. if the input was valid base64 data, false | |
290 otherwise. If *OUTLEN is too small, as many bytes as possible will | |
291 be written to OUT. On return, *OUTLEN holds the length of decoded | |
292 bytes in OUT. Note that as soon as any non-alphabet characters are | |
293 encountered, decoding is stopped and false is returned. */ | |
294 bool | |
295 base64_decode (const char *restrict in, size_t inlen, | |
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296 char *restrict out, size_t *outlen) |
5498 | 297 { |
298 size_t outleft = *outlen; | |
299 | |
300 while (inlen >= 2) | |
301 { | |
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302 if (!isbase64 (in[0]) || !isbase64 (in[1])) |
5498 | 303 break; |
304 | |
305 if (outleft) | |
306 { | |
307 *out++ = ((b64[to_uchar (in[0])] << 2) | |
308 | (b64[to_uchar (in[1])] >> 4)); | |
309 outleft--; | |
310 } | |
311 | |
312 if (inlen == 2) | |
313 break; | |
314 | |
315 if (in[2] == '=') | |
316 { | |
317 if (inlen != 4) | |
318 break; | |
319 | |
320 if (in[3] != '=') | |
321 break; | |
322 | |
323 } | |
324 else | |
325 { | |
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326 if (!isbase64 (in[2])) |
5498 | 327 break; |
328 | |
329 if (outleft) | |
330 { | |
331 *out++ = (((b64[to_uchar (in[1])] << 4) & 0xf0) | |
332 | (b64[to_uchar (in[2])] >> 2)); | |
333 outleft--; | |
334 } | |
335 | |
336 if (inlen == 3) | |
337 break; | |
338 | |
339 if (in[3] == '=') | |
340 { | |
341 if (inlen != 4) | |
342 break; | |
343 } | |
344 else | |
345 { | |
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346 if (!isbase64 (in[3])) |
5498 | 347 break; |
348 | |
349 if (outleft) | |
350 { | |
351 *out++ = (((b64[to_uchar (in[2])] << 6) & 0xc0) | |
352 | b64[to_uchar (in[3])]); | |
353 outleft--; | |
354 } | |
355 } | |
356 } | |
357 | |
358 in += 4; | |
359 inlen -= 4; | |
360 } | |
361 | |
362 *outlen -= outleft; | |
363 | |
364 if (inlen != 0) | |
365 return false; | |
366 | |
367 return true; | |
368 } | |
369 | |
370 /* Allocate an output buffer in *OUT, and decode the base64 encoded | |
371 data stored in IN of size INLEN to the *OUT buffer. On return, the | |
372 size of the decoded data is stored in *OUTLEN. OUTLEN may be NULL, | |
373 if the caller is not interested in the decoded length. *OUT may be | |
374 NULL to indicate an out of memory error, in which case *OUTLEN | |
375 contain the size of the memory block needed. The function return | |
376 true on successful decoding and memory allocation errors. (Use the | |
377 *OUT and *OUTLEN parameters to differentiate between successful | |
378 decoding and memory error.) The function return false if the input | |
379 was invalid, in which case *OUT is NULL and *OUTLEN is | |
380 undefined. */ | |
381 bool | |
382 base64_decode_alloc (const char *in, size_t inlen, char **out, | |
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383 size_t *outlen) |
5498 | 384 { |
385 /* This may allocate a few bytes too much, depending on input, | |
386 but it's not worth the extra CPU time to compute the exact amount. | |
387 The exact amount is 3 * inlen / 4, minus 1 if the input ends | |
388 with "=" and minus another 1 if the input ends with "==". | |
389 Dividing before multiplying avoids the possibility of overflow. */ | |
390 size_t needlen = 3 * (inlen / 4) + 2; | |
391 | |
392 *out = malloc (needlen); | |
393 if (!*out) | |
394 return true; | |
395 | |
396 if (!base64_decode (in, inlen, *out, &needlen)) | |
397 { | |
398 free (*out); | |
399 *out = NULL; | |
400 return false; | |
401 } | |
402 | |
403 if (outlen) | |
404 *outlen = needlen; | |
405 | |
406 return true; | |
407 } |