authsaslfrombase64.c

   1 /*
   2 ** Copyright 1998 - 2008 Double Precision, Inc.
   3 ** See COPYING for distribution information.
   4 */
   5
   6 #include        <stdlib.h>
   7
   8 static const char decode64tab[256]= {
   9         100, 100, 100, 100, 100, 100, 100, 100,
  10         100, 100, 100, 100, 100, 100, 100, 100,
  11         100, 100, 100, 100, 100, 100, 100, 100,
  12         100, 100, 100, 100, 100, 100, 100, 100,
  13         100, 100, 100, 100, 100, 100, 100, 100,
  14         100, 100, 100,  62, 100, 100, 100,  63,
  15          52,  53,  54,  55,  56,  57,  58,  59,
  16          60,  61, 100, 100, 100, 100, 100, 100,
  17         100,   0,   1,   2,   3,   4,   5,   6,
  18           7,   8,   9,  10,  11,  12,  13,  14,
  19          15,  16,  17,  18,  19,  20,  21,  22,
  20          23,  24,  25, 100, 100, 100, 100, 100,
  21         100,  26,  27,  28,  29,  30,  31,  32,
  22          33,  34,  35,  36,  37,  38,  39,  40,
  23          41,  42,  43,  44,  45,  46,  47,  48,
  24          49,  50,  51, 100, 100, 100, 100, 100,
  25         100, 100, 100, 100, 100, 100, 100, 100,
  26         100, 100, 100, 100, 100, 100, 100, 100,
  27         100, 100, 100, 100, 100, 100, 100, 100,
  28         100, 100, 100, 100, 100, 100, 100, 100,
  29         100, 100, 100, 100, 100, 100, 100, 100,
  30         100, 100, 100, 100, 100, 100, 100, 100,
  31         100, 100, 100, 100, 100, 100, 100, 100,
  32         100, 100, 100, 100, 100, 100, 100, 100,
  33         100, 100, 100, 100, 100, 100, 100, 100,
  34         100, 100, 100, 100, 100, 100, 100, 100,
  35         100, 100, 100, 100, 100, 100, 100, 100,
  36         100, 100, 100, 100, 100, 100, 100, 100,
  37         100, 100, 100, 100, 100, 100, 100, 100,
  38         100, 100, 100, 100, 100, 100, 100, 100,
  39         100, 100, 100, 100, 100, 100, 100, 100,
  40         100, 100, 100, 100, 100, 100, 100, 100};
  41
  42 int authsasl_frombase64(char *base64buf)
  43 {
  44         int     i, j, k;
  45
  46         for (j=0; base64buf[j]; j++)
  47                 if (decode64tab[(unsigned char)base64buf[j]] >= 100)
  48                         break;
  49
  50         if (base64buf[j] && base64buf[j+1] && base64buf[j+2])
  51                 return (-1);
  52         while (base64buf[j] == '=')     ++j;
  53         if (j % 4)      return (-1);
  54
  55         i=j;
  56         k=0;
  57         for (j=0; j<i; j += 4)
  58         {
  59         int     w=decode64tab[(int)(unsigned char)base64buf[j]];
  60         int     x=decode64tab[(int)(unsigned char)base64buf[j+1]];
  61         int     y=decode64tab[(int)(unsigned char)base64buf[j+2]];
  62         int     z=decode64tab[(int)(unsigned char)base64buf[j+3]];
  63         int     a,b,c;
  64
  65                 a= (w << 2) | (x >> 4);
  66                 b= (x << 4) | (y >> 2);
  67                 c= (y << 6) | z;
  68                 base64buf[k++]=a;
  69                 if ( base64buf[j+2] != '=')
  70                         base64buf[k++]=b;
  71                 if ( base64buf[j+3] != '=')
  72                         base64buf[k++]=c;
  73         }
  74         return (k);
  75 }