| 1 | #include <stdlib.h> |
| 2 | |
| 3 | static int decode64tab_init=0; |
| 4 | static char decode64tab[256]; |
| 5 | |
| 6 | /* |
| 7 | ** Copyright 1998 - 1999 Double Precision, Inc. |
| 8 | ** See COPYING for distribution information. |
| 9 | */ |
| 10 | |
| 11 | int authsasl_frombase64(char *base64buf) |
| 12 | { |
| 13 | int i, j, k; |
| 14 | |
| 15 | if (!decode64tab_init) |
| 16 | { |
| 17 | for (i=0; i<256; i++) decode64tab[i]=100; |
| 18 | for (i=0; i<64; i++) |
| 19 | decode64tab[ (int) |
| 20 | ("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"[i]) ]=i; |
| 21 | decode64tab_init=1; |
| 22 | } |
| 23 | |
| 24 | for (j=0; base64buf[j]; j++) |
| 25 | if (decode64tab[(unsigned char)base64buf[j]] >= 100) |
| 26 | break; |
| 27 | |
| 28 | if (base64buf[j] && base64buf[j+1] && base64buf[j+2]) |
| 29 | return (-1); |
| 30 | while (base64buf[j] == '=') ++j; |
| 31 | if (j % 4) return (-1); |
| 32 | |
| 33 | i=j; |
| 34 | k=0; |
| 35 | for (j=0; j<i; j += 4) |
| 36 | { |
| 37 | int w=decode64tab[(int)(unsigned char)base64buf[j]]; |
| 38 | int x=decode64tab[(int)(unsigned char)base64buf[j+1]]; |
| 39 | int y=decode64tab[(int)(unsigned char)base64buf[j+2]]; |
| 40 | int z=decode64tab[(int)(unsigned char)base64buf[j+3]]; |
| 41 | int a,b,c; |
| 42 | |
| 43 | a= (w << 2) | (x >> 4); |
| 44 | b= (x << 4) | (y >> 2); |
| 45 | c= (y << 6) | z; |
| 46 | base64buf[k++]=a; |
| 47 | if ( base64buf[j+2] != '=') |
| 48 | base64buf[k++]=b; |
| 49 | if ( base64buf[j+3] != '=') |
| 50 | base64buf[k++]=c; |
| 51 | } |
| 52 | return (k); |
| 53 | } |