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00001 /*
00002  * This code implements the BASE64 algorithm.
00003  * This code is in the public domain; do with it what you wish.
00004  *
00005  * @file base64.c
00006  * @brief This code implements the BASE64 algorithm
00007  * @author Matthieu Speder
00008  */
00009 #include "base64.h"
00010 
00011 static const char base64_chars[] =
00012   "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
00013 
00014 static const char base64_digits[] =
00015   { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
00016     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
00017     0, 0, 0, 0, 0, 62, 0, 0, 0, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61,
00018     0, 0, 0, -1, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,
00019     14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 0, 0, 0, 0, 0, 0, 26,
00020     27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44,
00021     45, 46, 47, 48, 49, 50, 51, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
00022     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
00023     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
00024     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
00025     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
00026     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
00027 
00028 
00029 char * 
00030 BASE64Decode(const char* src) 
00031 {
00032   size_t in_len = strlen (src);
00033   char* dest;
00034   char* result;
00035   
00036   if (in_len % 4) 
00037     {
00038       /* Wrong base64 string length */
00039       return NULL;
00040     }
00041   result = dest = malloc(in_len / 4 * 3 + 1);
00042   if (result == NULL)
00043     return NULL; /* out of memory */
00044   while (*src) {
00045     char a = base64_digits[(unsigned char)*(src++)];
00046     char b = base64_digits[(unsigned char)*(src++)];
00047     char c = base64_digits[(unsigned char)*(src++)];
00048     char d = base64_digits[(unsigned char)*(src++)];
00049     *(dest++) = (a << 2) | ((b & 0x30) >> 4);
00050     if (c == (char)-1)
00051       break;
00052     *(dest++) = ((b & 0x0f) << 4) | ((c & 0x3c) >> 2);
00053     if (d == (char)-1)
00054       break;
00055     *(dest++) = ((c & 0x03) << 6) | d;
00056   }
00057   *dest = 0;
00058   return result;
00059 }
00060 
00061 
00062 /* end of base64.c */