silentbob/silentbob-1.4/gclib/gclib_c/base64.c

   1 /*
   2  * (c) Oleg Puchinin 2006
   3  * graycardinalster@gmail.com
   4  *
   5  */
   6
   7 #include <string.h>
   8 #define __export
   9
  10 const static char base64ABC[] =
  11 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  12 typedef unsigned char uchar_t;
  13
  14 #define S_(a) S[n * 3 + a]
  15 #define S__(a,b) (S[n * 3 + a] & b)
  16 #define S__l(a,b,c) ((S[n * 3 + a] & b) << c)
  17
  18 #define B1 buf[(n<<2)] = base64ABC[ (S_(0) >> 2) ];
  19 #define B2 buf[(n<<2) + 1] = base64ABC [ (S__l(0,0x3,4)) | S_(1) >> 4 ];
  20 #define B3 buf[(n<<2) + 2] = base64ABC [ S__l(1,0x0F,2) | S_(2) >> 6];
  21 #define B4 buf[(n<<2) + 3] = base64ABC [ S__(2,0x3F) ];
  22
  23 __export uchar_t * base64_code (unsigned char * S, int SIZE)
  24 {
  25     uchar_t c, *buf;
  26     int n;
  27
  28     c = (SIZE == 0) ? strlen ((const char *) S) % 3 : SIZE % 3;
  29     SIZE = (SIZE == 0) ? strlen ((const char *) S) / 3 : SIZE / 3;
  30
  31     buf = (uchar_t *) malloc (SIZE * 4 + 5);
  32
  33     for (n = 0; n < SIZE; ++n) {
  34             B1; B2; B3; B4;
  35     }
  36
  37     switch (c) {
  38     case 1:
  39         B1; B2;
  40         buf[(n<<2) + 2] = '=';
  41         buf[(n<<2) + 3] = '=';
  42         ++n;
  43         break;
  44     case 2:
  45         B1; B2; B3;
  46         buf[(n<<2) + 3] = '=';
  47         ++n;
  48         break;
  49     }
  50     buf[(n<<2)] = 0;
  51     return buf;
  52 }
  53
  54 #define BASE64(a) ((unsigned char) (strchr (base64ABC, S[(n<<2) + a]) - base64ABC))
  55
  56 __export uchar_t * base64_decode (unsigned char * S, int SIZE)
  57 {
  58     unsigned char * ptr;
  59     int n;
  60
  61     if (SIZE % 4)
  62         return NULL;
  63
  64     SIZE = SIZE ? SIZE / 4 : strlen ((const char *) S) / 4;
  65     ptr = (uchar_t *) malloc (SIZE * 4 + 5);
  66
  67     for (n = 0; n < SIZE; n++) {
  68         ptr[n * 3] = (BASE64(0) << 2) | ( BASE64(1) >> 4);
  69         if (S[(n<<2) + 2] != '=') {
  70             ptr[n * 3 + 1] = ((BASE64(1) & 0x0F) << 4) | (BASE64(2) >> 2);
  71             if (S[(n<<2) + 3] != '=')
  72                 ptr[n * 3 + 2] = ((BASE64(2) & 0x03) << 6) | BASE64(3);
  73             else
  74                 ptr[n * 3 + 2] = 0;
  75         } else
  76             ptr[n * 3 +1] = 0;
  77     }
  78
  79     ++n;
  80     ptr [n * 3] = 0;
  81     return ptr;
  82 }
  83