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base64.c
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1 /*
2  * Copyright (c) 2006 Ryan Martell. (rdm4@martellventures.com)
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 /**
22  * @file
23  * @brief Base64 encode/decode
24  * @author Ryan Martell <rdm4@martellventures.com> (with lots of Michael)
25  */
26 
27 #include "common.h"
28 #include "base64.h"
29 #include "intreadwrite.h"
30 
31 /* ---------------- private code */
32 static const uint8_t map2[256] =
33 {
34  0xfe, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
35  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
36  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
37  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
38  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
39  0xff, 0xff, 0xff,
40 
41  0x3e, 0xff, 0xff, 0xff, 0x3f, 0x34, 0x35, 0x36,
42  0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0xff,
43  0xff, 0xff, 0xfe, 0xff, 0xff, 0xff, 0x00, 0x01,
44  0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
45  0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11,
46  0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19,
47  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x1a, 0x1b,
48  0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23,
49  0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b,
50  0x2c, 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33,
51 
52  0xff, 0xff, 0xff, 0xff, 0xff,
53  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
54  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
55  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
56  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
57  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
58  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
59  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
60  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
61  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
62  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
63  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
64  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
65  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
66  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
67  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
68  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
69 };
70 
71 #define BASE64_DEC_STEP(i) do { \
72  bits = map2[in[i]]; \
73  if (bits & 0x80) \
74  goto out ## i; \
75  v = i ? (v << 6) + bits : bits; \
76 } while(0)
77 
78 int av_base64_decode(uint8_t *out, const char *in_str, int out_size)
79 {
80  uint8_t *dst = out;
81  uint8_t *end = out + out_size;
82  // no sign extension
83  const uint8_t *in = in_str;
84  unsigned bits = 0xff;
85  unsigned v;
86 
87  while (end - dst > 3) {
88  BASE64_DEC_STEP(0);
89  BASE64_DEC_STEP(1);
90  BASE64_DEC_STEP(2);
91  BASE64_DEC_STEP(3);
92  // Using AV_WB32 directly confuses compiler
93  v = av_be2ne32(v << 8);
94  AV_WN32(dst, v);
95  dst += 3;
96  in += 4;
97  }
98  if (end - dst) {
99  BASE64_DEC_STEP(0);
100  BASE64_DEC_STEP(1);
101  BASE64_DEC_STEP(2);
102  BASE64_DEC_STEP(3);
103  *dst++ = v >> 16;
104  if (end - dst)
105  *dst++ = v >> 8;
106  if (end - dst)
107  *dst++ = v;
108  in += 4;
109  }
110  while (1) {
111  BASE64_DEC_STEP(0);
112  in++;
113  BASE64_DEC_STEP(0);
114  in++;
115  BASE64_DEC_STEP(0);
116  in++;
117  BASE64_DEC_STEP(0);
118  in++;
119  }
120 
121 out3:
122  *dst++ = v >> 10;
123  v <<= 2;
124 out2:
125  *dst++ = v >> 4;
126 out1:
127 out0:
128  return bits & 1 ? AVERROR_INVALIDDATA : dst - out;
129 }
130 
131 /*****************************************************************************
132 * b64_encode: Stolen from VLC's http.c.
133 * Simplified by Michael.
134 * Fixed edge cases and made it work from data (vs. strings) by Ryan.
135 *****************************************************************************/
136 
137 char *av_base64_encode(char *out, int out_size, const uint8_t *in, int in_size)
138 {
139  static const char b64[] =
140  "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
141  char *ret, *dst;
142  unsigned i_bits = 0;
143  int i_shift = 0;
144  int bytes_remaining = in_size;
145 
146  if (in_size >= UINT_MAX / 4 ||
147  out_size < AV_BASE64_SIZE(in_size))
148  return NULL;
149  ret = dst = out;
150  while (bytes_remaining > 3) {
151  i_bits = AV_RB32(in);
152  in += 3; bytes_remaining -= 3;
153  *dst++ = b64[ i_bits>>26 ];
154  *dst++ = b64[(i_bits>>20) & 0x3F];
155  *dst++ = b64[(i_bits>>14) & 0x3F];
156  *dst++ = b64[(i_bits>>8 ) & 0x3F];
157  }
158  i_bits = 0;
159  while (bytes_remaining) {
160  i_bits = (i_bits << 8) + *in++;
161  bytes_remaining--;
162  i_shift += 8;
163  }
164  while (i_shift > 0) {
165  *dst++ = b64[(i_bits << 6 >> i_shift) & 0x3f];
166  i_shift -= 6;
167  }
168  while ((dst - ret) & 3)
169  *dst++ = '=';
170  *dst = '\0';
171 
172  return ret;
173 }
174 
175 #ifdef TEST
176 // LCOV_EXCL_START
177 
178 #define MAX_DATA_SIZE 1024
179 #define MAX_ENCODED_SIZE 2048
180 
181 static int test_encode_decode(const uint8_t *data, unsigned int data_size,
182  const char *encoded_ref)
183 {
184  char encoded[MAX_ENCODED_SIZE];
185  uint8_t data2[MAX_DATA_SIZE];
186  int data2_size, max_data2_size = MAX_DATA_SIZE;
187 
188  if (!av_base64_encode(encoded, MAX_ENCODED_SIZE, data, data_size)) {
189  printf("Failed: cannot encode the input data\n");
190  return 1;
191  }
192  if (encoded_ref && strcmp(encoded, encoded_ref)) {
193  printf("Failed: encoded string differs from reference\n"
194  "Encoded:\n%s\nReference:\n%s\n", encoded, encoded_ref);
195  return 1;
196  }
197 
198  if ((data2_size = av_base64_decode(data2, encoded, max_data2_size)) != data_size) {
199  printf("Failed: cannot decode the encoded string\n"
200  "Encoded:\n%s\n", encoded);
201  return 1;
202  }
203  if ((data2_size = av_base64_decode(data2, encoded, data_size)) != data_size) {
204  printf("Failed: cannot decode with minimal buffer\n"
205  "Encoded:\n%s\n", encoded);
206  return 1;
207  }
208  if (memcmp(data2, data, data_size)) {
209  printf("Failed: encoded/decoded data differs from original data\n");
210  return 1;
211  }
212  if (av_base64_decode(NULL, encoded, 0) != 0) {
213  printf("Failed: decode to NULL buffer\n");
214  return 1;
215  }
216  if (strlen(encoded)) {
217  char *end = strchr(encoded, '=');
218  if (!end)
219  end = encoded + strlen(encoded) - 1;
220  *end = '%';
221  if (av_base64_decode(NULL, encoded, 0) >= 0) {
222  printf("Failed: error detection\n");
223  return 1;
224  }
225  }
226 
227  printf("Passed!\n");
228  return 0;
229 }
230 
231 int main(int argc, char ** argv)
232 {
233  int i, error_count = 0;
234  struct test {
235  const uint8_t *data;
236  const char *encoded_ref;
237  } tests[] = {
238  { "", ""},
239  { "1", "MQ=="},
240  { "22", "MjI="},
241  { "333", "MzMz"},
242  { "4444", "NDQ0NA=="},
243  { "55555", "NTU1NTU="},
244  { "666666", "NjY2NjY2"},
245  { "abc:def", "YWJjOmRlZg=="},
246  };
247  char in[1024], out[2048];
248 
249  printf("Encoding/decoding tests\n");
250  for (i = 0; i < FF_ARRAY_ELEMS(tests); i++)
251  error_count += test_encode_decode(tests[i].data, strlen(tests[i].data), tests[i].encoded_ref);
252 
253  if (argc>1 && !strcmp(argv[1], "-t")) {
254  memset(in, 123, sizeof(in));
255  for(i=0; i<10000; i++){
256  START_TIMER
257  av_base64_encode(out, sizeof(out), in, sizeof(in));
258  STOP_TIMER("encode")
259  }
260  for(i=0; i<10000; i++){
261  START_TIMER
262  av_base64_decode(in, out, sizeof(in));
263  STOP_TIMER("decode")
264  }
265 
266  for(i=0; i<10000; i++){
267  START_TIMER
268  av_base64_decode(NULL, out, 0);
269  STOP_TIMER("syntax check")
270  }
271  }
272 
273  return error_count;
274 }
275 
276 // LCOV_EXCL_STOP
277 #endif
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