WDL/wdl_base64.h

   1 #ifndef _WDL_BASE64_H_
   2 #define _WDL_BASE64_H_
   3
   4 #ifndef WDL_BASE64_FUNCDECL
   5 #define WDL_BASE64_FUNCDECL static
   6 #endif
   7
   8 static const char wdl_base64_alphabet[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
   9 WDL_BASE64_FUNCDECL void wdl_base64encode(const unsigned char *in, char *out, int len)
  10 {
  11   while (len >= 6)
  12   {
  13     const int accum = (in[0] << 16) + (in[1] << 8) + in[2];
  14     const int accum2 = (in[3] << 16) + (in[4] << 8) + in[5];
  15     out[0] = wdl_base64_alphabet[(accum >> 18) & 0x3F];
  16     out[1] = wdl_base64_alphabet[(accum >> 12) & 0x3F];
  17     out[2] = wdl_base64_alphabet[(accum >> 6) & 0x3F];
  18     out[3] = wdl_base64_alphabet[accum & 0x3F];
  19     out[4] = wdl_base64_alphabet[(accum2 >> 18) & 0x3F];
  20     out[5] = wdl_base64_alphabet[(accum2 >> 12) & 0x3F];
  21     out[6] = wdl_base64_alphabet[(accum2 >> 6) & 0x3F];
  22     out[7] = wdl_base64_alphabet[accum2 & 0x3F];
  23     out+=8;
  24     in+=6;
  25     len-=6;
  26   }
  27
  28   if (len >= 3)
  29   {
  30     const int accum = (in[0]<<16)|(in[1]<<8)|in[2];
  31     out[0] = wdl_base64_alphabet[(accum >> 18) & 0x3F];
  32     out[1] = wdl_base64_alphabet[(accum >> 12) & 0x3F];
  33     out[2] = wdl_base64_alphabet[(accum >> 6) & 0x3F];
  34     out[3] = wdl_base64_alphabet[accum & 0x3F];
  35     in+=3;
  36     len-=3;
  37     out+=4;
  38   }
  39
  40   if (len>0)
  41   {
  42     if (len == 2)
  43     {
  44       const int accum = (in[0] << 8) | in[1];
  45       out[0] = wdl_base64_alphabet[(accum >> 10) & 0x3F];
  46       out[1] = wdl_base64_alphabet[(accum >> 4) & 0x3F];
  47       out[2] = wdl_base64_alphabet[(accum & 0xF)<<2];
  48     }
  49     else
  50     {
  51       const int accum = in[0];
  52       out[0] = wdl_base64_alphabet[(accum >> 2) & 0x3F];
  53       out[1] = wdl_base64_alphabet[(accum & 0x3)<<4];
  54       out[2]='=';
  55     }
  56     out[3]='=';
  57     out+=4;
  58   }
  59
  60   out[0]=0;
  61 }
  62
  63 WDL_BASE64_FUNCDECL int wdl_base64decode(const char *src, unsigned char *dest, int destsize)
  64 {
  65   static const char *tab = // poolable string
  66     "\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff"
  67     "\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff"
  68     "\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\x3e\xff\xff\xff\x3f"
  69     "\x34\x35\x36\x37\x38\x39\x3a\x3b\x3c\x3d\xff\xff\xff\xff\xff\xff"
  70     "\xff\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e"
  71     "\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\xff\xff\xff\xff\xff"
  72     "\xff\x1a\x1b\x1c\x1d\x1e\x1f\x20\x21\x22\x23\x24\x25\x26\x27\x28"
  73     "\x29\x2a\x2b\x2c\x2d\x2e\x2f\x30\x31\x32\x33\xff\xff\xff\xff\xff"
  74     "\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff"
  75     "\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff"
  76     "\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff"
  77     "\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff"
  78     "\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff"
  79     "\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff"
  80     "\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff"
  81     "\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff";
  82
  83
  84   unsigned int accum=0;
  85   int nbits=0, wpos=0;
  86
  87   if (destsize <= 0) return 0;
  88
  89   for (;;)
  90   {
  91     const int v=(int)tab[*(unsigned char *)src++];
  92     if (v<0) return wpos;
  93
  94     accum += v;
  95     nbits += 6;
  96
  97     if (nbits >= 8)
  98     {
  99       nbits-=8;
 100       dest[wpos] = (accum>>nbits)&0xff;
 101       if (++wpos >= destsize) return wpos;
 102     }
 103     accum <<= 6;
 104   }
 105 }
 106
 107
 108 #endif