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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 #include "timer.h"
31 
32 /* ---------------- private code */
33 static const uint8_t map2[256] =
34 {
35  0xfe, 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, 0xff, 0xff, 0xff, 0xff, 0xff,
40  0xff, 0xff, 0xff,
41 
42  0x3e, 0xff, 0xff, 0xff, 0x3f, 0x34, 0x35, 0x36,
43  0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0xff,
44  0xff, 0xff, 0xfe, 0xff, 0xff, 0xff, 0x00, 0x01,
45  0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
46  0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11,
47  0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19,
48  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x1a, 0x1b,
49  0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23,
50  0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b,
51  0x2c, 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33,
52 
53  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  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
70 };
71 
72 #define BASE64_DEC_STEP(i) do { \
73  bits = map2[in[i]]; \
74  if (bits & 0x80) \
75  goto out ## i; \
76  v = i ? (v << 6) + bits : bits; \
77 } while(0)
78 
79 int av_base64_decode(uint8_t *out, const char *in_str, int out_size)
80 {
81  uint8_t *dst = out;
82  uint8_t *end = out + out_size;
83  // no sign extension
84  const uint8_t *in = in_str;
85  unsigned bits = 0xff;
86  unsigned v;
87 
88  while (end - dst > 3) {
89  BASE64_DEC_STEP(0);
90  BASE64_DEC_STEP(1);
91  BASE64_DEC_STEP(2);
92  BASE64_DEC_STEP(3);
93  // Using AV_WB32 directly confuses compiler
94  v = av_be2ne32(v << 8);
95  AV_WN32(dst, v);
96  dst += 3;
97  in += 4;
98  }
99  if (end - dst) {
100  BASE64_DEC_STEP(0);
101  BASE64_DEC_STEP(1);
102  BASE64_DEC_STEP(2);
103  BASE64_DEC_STEP(3);
104  *dst++ = v >> 16;
105  if (end - dst)
106  *dst++ = v >> 8;
107  if (end - dst)
108  *dst++ = v;
109  in += 4;
110  }
111  while (1) {
112  BASE64_DEC_STEP(0);
113  in++;
114  BASE64_DEC_STEP(0);
115  in++;
116  BASE64_DEC_STEP(0);
117  in++;
118  BASE64_DEC_STEP(0);
119  in++;
120  }
121 
122 out3:
123  *dst++ = v >> 10;
124  v <<= 2;
125 out2:
126  *dst++ = v >> 4;
127 out1:
128 out0:
129  return bits & 1 ? AVERROR_INVALIDDATA : dst - out;
130 }
131 
132 /*****************************************************************************
133 * b64_encode: Stolen from VLC's http.c.
134 * Simplified by Michael.
135 * Fixed edge cases and made it work from data (vs. strings) by Ryan.
136 *****************************************************************************/
137 
138 char *av_base64_encode(char *out, int out_size, const uint8_t *in, int in_size)
139 {
140  static const char b64[] =
141  "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
142  char *ret, *dst;
143  unsigned i_bits = 0;
144  int i_shift = 0;
145  int bytes_remaining = in_size;
146 
147  if (in_size >= UINT_MAX / 4 ||
148  out_size < AV_BASE64_SIZE(in_size))
149  return NULL;
150  ret = dst = out;
151  while (bytes_remaining > 3) {
152  i_bits = AV_RB32(in);
153  in += 3; bytes_remaining -= 3;
154  *dst++ = b64[ i_bits>>26 ];
155  *dst++ = b64[(i_bits>>20) & 0x3F];
156  *dst++ = b64[(i_bits>>14) & 0x3F];
157  *dst++ = b64[(i_bits>>8 ) & 0x3F];
158  }
159  i_bits = 0;
160  while (bytes_remaining) {
161  i_bits = (i_bits << 8) + *in++;
162  bytes_remaining--;
163  i_shift += 8;
164  }
165  while (i_shift > 0) {
166  *dst++ = b64[(i_bits << 6 >> i_shift) & 0x3f];
167  i_shift -= 6;
168  }
169  while ((dst - ret) & 3)
170  *dst++ = '=';
171  *dst = '\0';
172 
173  return ret;
174 }
175 
176 #ifdef TEST
177 // LCOV_EXCL_START
178 
179 #define MAX_DATA_SIZE 1024
180 #define MAX_ENCODED_SIZE 2048
181 
182 static int test_encode_decode(const uint8_t *data, unsigned int data_size,
183  const char *encoded_ref)
184 {
185  char encoded[MAX_ENCODED_SIZE];
186  uint8_t data2[MAX_DATA_SIZE];
187  int data2_size, max_data2_size = MAX_DATA_SIZE;
188 
189  if (!av_base64_encode(encoded, MAX_ENCODED_SIZE, data, data_size)) {
190  printf("Failed: cannot encode the input data\n");
191  return 1;
192  }
193  if (encoded_ref && strcmp(encoded, encoded_ref)) {
194  printf("Failed: encoded string differs from reference\n"
195  "Encoded:\n%s\nReference:\n%s\n", encoded, encoded_ref);
196  return 1;
197  }
198 
199  if ((data2_size = av_base64_decode(data2, encoded, max_data2_size)) != data_size) {
200  printf("Failed: cannot decode the encoded string\n"
201  "Encoded:\n%s\n", encoded);
202  return 1;
203  }
204  if ((data2_size = av_base64_decode(data2, encoded, data_size)) != data_size) {
205  printf("Failed: cannot decode with minimal buffer\n"
206  "Encoded:\n%s\n", encoded);
207  return 1;
208  }
209  if (memcmp(data2, data, data_size)) {
210  printf("Failed: encoded/decoded data differs from original data\n");
211  return 1;
212  }
213  if (av_base64_decode(NULL, encoded, 0) != 0) {
214  printf("Failed: decode to NULL buffer\n");
215  return 1;
216  }
217  if (strlen(encoded)) {
218  char *end = strchr(encoded, '=');
219  if (!end)
220  end = encoded + strlen(encoded) - 1;
221  *end = '%';
222  if (av_base64_decode(NULL, encoded, 0) >= 0) {
223  printf("Failed: error detection\n");
224  return 1;
225  }
226  }
227 
228  printf("Passed!\n");
229  return 0;
230 }
231 
232 int main(int argc, char ** argv)
233 {
234  int i, error_count = 0;
235  struct test {
236  const uint8_t *data;
237  const char *encoded_ref;
238  } tests[] = {
239  { "", ""},
240  { "1", "MQ=="},
241  { "22", "MjI="},
242  { "333", "MzMz"},
243  { "4444", "NDQ0NA=="},
244  { "55555", "NTU1NTU="},
245  { "666666", "NjY2NjY2"},
246  { "abc:def", "YWJjOmRlZg=="},
247  };
248  char in[1024], out[2048];
249 
250  printf("Encoding/decoding tests\n");
251  for (i = 0; i < FF_ARRAY_ELEMS(tests); i++)
252  error_count += test_encode_decode(tests[i].data, strlen(tests[i].data), tests[i].encoded_ref);
253 
254  if (argc>1 && !strcmp(argv[1], "-t")) {
255  memset(in, 123, sizeof(in));
256  for(i=0; i<10000; i++){
257  START_TIMER
258  av_base64_encode(out, sizeof(out), in, sizeof(in));
259  STOP_TIMER("encode")
260  }
261  for(i=0; i<10000; i++){
262  START_TIMER
263  av_base64_decode(in, out, sizeof(in));
264  STOP_TIMER("decode")
265  }
266 
267  for(i=0; i<10000; i++){
268  START_TIMER
269  av_base64_decode(NULL, out, 0);
270  STOP_TIMER("syntax check")
271  }
272  }
273 
274  if (error_count)
275  printf("Error Count: %d.\n", error_count);
276 
277  return !!error_count;
278 }
279 
280 // LCOV_EXCL_STOP
281 #endif
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