1 /*
2 * This code implements the BASE64 algorithm.
3 * This code is in the public domain; do with it what you wish.
4 *
5 * @file base64.c
6 * @brief This code implements the BASE64 algorithm
7 * @author Matthieu Speder
8 */
9 #include "base64.h"
10
11 static const char base64_digits[] =
12 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
13 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
14 0, 0, 0, 0, 0, 62, 0, 0, 0, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61,
15 0, 0, 0, -1, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,
16 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 0, 0, 0, 0, 0, 0, 26,
17 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44,
18 45, 46, 47, 48, 49, 50, 51, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
19 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
20 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
21 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
22 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
23 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
24
25
26 char *
BASE64Decode(const char * src)27 BASE64Decode(const char* src)
28 {
29 size_t in_len = strlen (src);
30 char* dest;
31 char* result;
32
33 if (in_len % 4)
34 {
35 /* Wrong base64 string length */
36 return NULL;
37 }
38 result = dest = malloc(in_len / 4 * 3 + 1);
39 if (result == NULL)
40 return NULL; /* out of memory */
41 while (*src) {
42 char a = base64_digits[(unsigned char)*(src++)];
43 char b = base64_digits[(unsigned char)*(src++)];
44 char c = base64_digits[(unsigned char)*(src++)];
45 char d = base64_digits[(unsigned char)*(src++)];
46 *(dest++) = (a << 2) | ((b & 0x30) >> 4);
47 if (c == (char)-1)
48 break;
49 *(dest++) = ((b & 0x0f) << 4) | ((c & 0x3c) >> 2);
50 if (d == (char)-1)
51 break;
52 *(dest++) = ((c & 0x03) << 6) | d;
53 }
54 *dest = 0;
55 return result;
56 }
57
58
59 /* end of base64.c */
60