| 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 <libsaio.h>␊ |
| 10 | ␊ |
| 11 | //static const char base64_chars[] =␊ |
| 12 | //"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";␊ |
| 13 | ␊ |
| 14 | static const char base64_digits[] =␊ |
| 15 | { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,␊ |
| 16 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,␊ |
| 17 | 0, 0, 0, 0, 0, 62, 0, 0, 0, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61,␊ |
| 18 | 0, 0, 0, -1, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,␊ |
| 19 | 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 0, 0, 0, 0, 0, 0, 26,␊ |
| 20 | 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44,␊ |
| 21 | 45, 46, 47, 48, 49, 50, 51, 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, 0, 0,␊ |
| 24 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,␊ |
| 25 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,␊ |
| 26 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };␊ |
| 27 | ␊ |
| 28 | ␊ |
| 29 | char *BASE64Decode(const char* src, int in_len, int* out_len)␊ |
| 30 | {␊ |
| 31 | int endpad = 0;␊ |
| 32 | char* dest;␊ |
| 33 | char* result;␊ |
| 34 | ␊ |
| 35 | if (in_len % 4)␊ |
| 36 | {␊ |
| 37 | /* Wrong base64 string length */␊ |
| 38 | return NULL;␊ |
| 39 | ␊ |
| 40 | } ␊ |
| 41 | result = dest = malloc(in_len / 4 * 3 + 1);␊ |
| 42 | if (result == NULL)␊ |
| 43 | return NULL; /* out of memory */␊ |
| 44 | while (*src) {␊ |
| 45 | char a = base64_digits[(unsigned char)*(src++)];␊ |
| 46 | char b = base64_digits[(unsigned char)*(src++)];␊ |
| 47 | char c = base64_digits[(unsigned char)*(src++)];␊ |
| 48 | char d = base64_digits[(unsigned char)*(src++)];␊ |
| 49 | *(dest++) = (a << 2) | ((b & 0x30) >> 4);␊ |
| 50 | if (c == (char)-1)␊ |
| 51 | {␊ |
| 52 | // padding char.␊ |
| 53 | endpad += 2;␊ |
| 54 | break;␊ |
| 55 | }␊ |
| 56 | *(dest++) = ((b & 0x0f) << 4) | ((c & 0x3c) >> 2);␊ |
| 57 | if (d == (char)-1)␊ |
| 58 | {␊ |
| 59 | // padding char.␊ |
| 60 | endpad += 1;␊ |
| 61 | break;␊ |
| 62 | }␊ |
| 63 | *(dest++) = ((c & 0x03) << 6) | d;␊ |
| 64 | }␊ |
| 65 | *dest = 0;␊ |
| 66 | *out_len = in_len / 4 * 3 - endpad; // not including NULL terminator␊ |
| 67 | return result;␊ |
| 68 | }␊ |
| 69 | ␊ |
| 70 | ␊ |
| 71 | /* end of base64.c */ |
