base64.c
Go to the documentation of this file.
1 /*
2  * Copyright (c) 2006 Ryan Martell. (rdm4@martellventures.com)
3  *
4  * This file is part of Libav.
5  *
6  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
27 #include "common.h"
28 #include "base64.h"
29 
30 /* ---------------- private code */
31 static const uint8_t map2[] =
32 {
33  0x3e, 0xff, 0xff, 0xff, 0x3f, 0x34, 0x35, 0x36,
34  0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0xff,
35  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x01,
36  0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
37  0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11,
38  0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19,
39  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x1a, 0x1b,
40  0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23,
41  0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b,
42  0x2c, 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33
43 };
44 
45 int av_base64_decode(uint8_t *out, const char *in, int out_size)
46 {
47  int i;
48  unsigned v = 0;
49  uint8_t *dst = out;
50 
51  for (i = 0; in[i] && in[i] != '='; i++) {
52  unsigned int index= in[i]-43;
53  if (index>=FF_ARRAY_ELEMS(map2) || map2[index] == 0xff)
54  return -1;
55  v = (v << 6) + map2[index];
56  if (i & 3) {
57  if (dst - out < out_size) {
58  *dst++ = v >> (6 - 2 * (i & 3));
59  }
60  }
61  }
62 
63  return dst - out;
64 }
65 
66 /*****************************************************************************
67 * b64_encode: Stolen from VLC's http.c.
68 * Simplified by Michael.
69 * Fixed edge cases and made it work from data (vs. strings) by Ryan.
70 *****************************************************************************/
71 
72 char *av_base64_encode(char *out, int out_size, const uint8_t *in, int in_size)
73 {
74  static const char b64[] =
75  "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
76  char *ret, *dst;
77  unsigned i_bits = 0;
78  int i_shift = 0;
79  int bytes_remaining = in_size;
80 
81  if (in_size >= UINT_MAX / 4 ||
82  out_size < AV_BASE64_SIZE(in_size))
83  return NULL;
84  ret = dst = out;
85  while (bytes_remaining) {
86  i_bits = (i_bits << 8) + *in++;
87  bytes_remaining--;
88  i_shift += 8;
89 
90  do {
91  *dst++ = b64[(i_bits << 6 >> i_shift) & 0x3f];
92  i_shift -= 6;
93  } while (i_shift > 6 || (bytes_remaining == 0 && i_shift > 0));
94  }
95  while ((dst - ret) & 3)
96  *dst++ = '=';
97  *dst = '\0';
98 
99  return ret;
100 }
101 
102 #ifdef TEST
103 
104 #define MAX_DATA_SIZE 1024
105 #define MAX_ENCODED_SIZE 2048
106 
107 static int test_encode_decode(const uint8_t *data, unsigned int data_size,
108  const char *encoded_ref)
109 {
110  char encoded[MAX_ENCODED_SIZE];
111  uint8_t data2[MAX_DATA_SIZE];
112  int data2_size, max_data2_size = MAX_DATA_SIZE;
113 
114  if (!av_base64_encode(encoded, MAX_ENCODED_SIZE, data, data_size)) {
115  printf("Failed: cannot encode the input data\n");
116  return 1;
117  }
118  if (encoded_ref && strcmp(encoded, encoded_ref)) {
119  printf("Failed: encoded string differs from reference\n"
120  "Encoded:\n%s\nReference:\n%s\n", encoded, encoded_ref);
121  return 1;
122  }
123 
124  if ((data2_size = av_base64_decode(data2, encoded, max_data2_size)) < 0) {
125  printf("Failed: cannot decode the encoded string\n"
126  "Encoded:\n%s\n", encoded);
127  return 1;
128  }
129  if (memcmp(data2, data, data_size)) {
130  printf("Failed: encoded/decoded data differs from original data\n");
131  return 1;
132  }
133 
134  printf("Passed!\n");
135  return 0;
136 }
137 
138 int main(void)
139 {
140  int i, error_count = 0;
141  struct test {
142  const uint8_t *data;
143  const char *encoded_ref;
144  } tests[] = {
145  { "", ""},
146  { "1", "MQ=="},
147  { "22", "MjI="},
148  { "333", "MzMz"},
149  { "4444", "NDQ0NA=="},
150  { "55555", "NTU1NTU="},
151  { "666666", "NjY2NjY2"},
152  { "abc:def", "YWJjOmRlZg=="},
153  };
154 
155  printf("Encoding/decoding tests\n");
156  for (i = 0; i < FF_ARRAY_ELEMS(tests); i++)
157  error_count += test_encode_decode(tests[i].data, strlen(tests[i].data), tests[i].encoded_ref);
158 
159  return error_count;
160 }
161 
162 #endif