WDL/base64encdec.h

   1 #ifndef _BASE64ENCDEC_H_
   2 #define _BASE64ENCDEC_H_
   3
   4 static void base64encode(const unsigned char *in, char *out, int len)
   5 {
   6   char alphabet[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
   7   int shift = 0;
   8   int accum = 0;
   9
  10   while (len>0)
  11   {
  12     len--;
  13     accum <<= 8;
  14     shift += 8;
  15     accum |= *in++;
  16     while ( shift >= 6 )
  17     {
  18       shift -= 6;
  19       *out++ = alphabet[(accum >> shift) & 0x3F];
  20     }
  21   }
  22   if (shift == 4)
  23   {
  24     *out++ = alphabet[(accum & 0xF)<<2];
  25     *out++='=';
  26   }
  27   else if (shift == 2)
  28   {
  29     *out++ = alphabet[(accum & 0x3)<<4];
  30     *out++='=';
  31     *out++='=';
  32   }
  33
  34   *out++=0;
  35 }
  36
  37 static int base64decode(const char *src, unsigned char *dest, int destsize)
  38 {
  39   unsigned char *olddest=dest;
  40
  41   int accum=0;
  42   int nbits=0;
  43   while (*src)
  44   {
  45     int x=0;
  46     char c=*src++;
  47     if (c >= 'A' && c <= 'Z') x=c-'A';
  48     else if (c >= 'a' && c <= 'z') x=c-'a' + 26;
  49     else if (c >= '0' && c <= '9') x=c-'0' + 52;
  50     else if (c == '+') x=62;
  51     else if (c == '/') x=63;
  52     else break;
  53
  54     accum <<= 6;
  55     accum |= x;
  56     nbits += 6;
  57
  58     while (nbits >= 8)
  59     {
  60       if (--destsize<0) break;
  61       nbits-=8;
  62       *dest++ = (char)((accum>>nbits)&0xff);
  63     }
  64
  65   }
  66   return dest-olddest;
  67 }
  68
  69 #endif // _BASE64ENCDEC_H_