code.delx.au - pulseaudio/blob - src/modules/raop/base64.c

   1 /***
   2   This file is part of PulseAudio.
   3
   4   Copyright 2008 Colin Guthrie
   5
   6   PulseAudio is free software; you can redistribute it and/or modify
   7   it under the terms of the GNU Lesser General Public License as published
   8   by the Free Software Foundation; either version 2.1 of the License,
   9   or (at your option) any later version.
  10
  11   PulseAudio is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with PulseAudio; if not, write to the Free Software
  18   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  19   USA.
  20 ***/
  21
  22 /*
  23   This file was originally inspired by a file developed by
  24     Kungliga Tekniska H�gskolan
  25 */
  26
  27 #ifdef HAVE_CONFIG_H
  28 #include <config.h>
  29 #endif
  30
  31 #include <stdlib.h>
  32 #include <string.h>
  33
  34 #include <pulse/xmalloc.h>
  35
  36 #include "base64.h"
  37
  38 static const char base64_chars[] =
  39     "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  40
  41 static int pos(char c)
  42 {
  43     if (c >= 'A' && c <= 'Z') return c - 'A' + 0;
  44     if (c >= 'a' && c <= 'z') return c - 'a' + 26;
  45     if (c >= '0' && c <= '9') return c - '0' + 52;
  46     if (c == '+') return 62;
  47     if (c == '/') return 63;
  48     return -1;
  49 }
  50
  51 int pa_base64_encode(const void *data, int size, char **str)
  52 {
  53     char *s, *p;
  54     int i;
  55     int c;
  56     const unsigned char *q;
  57
  58     p = s = pa_xnew(char, size * 4 / 3 + 4);
  59     q = (const unsigned char *) data;
  60     for (i = 0; i < size;) {
  61         c = q[i++];
  62         c *= 256;
  63         if (i < size)
  64             c += q[i];
  65         i++;
  66         c *= 256;
  67         if (i < size)
  68             c += q[i];
  69         i++;
  70         p[0] = base64_chars[(c & 0x00fc0000) >> 18];
  71         p[1] = base64_chars[(c & 0x0003f000) >> 12];
  72         p[2] = base64_chars[(c & 0x00000fc0) >> 6];
  73         p[3] = base64_chars[(c & 0x0000003f) >> 0];
  74         if (i > size)
  75             p[3] = '=';
  76         if (i > size + 1)
  77             p[2] = '=';
  78         p += 4;
  79     }
  80     *p = 0;
  81     *str = s;
  82     return strlen(s);
  83 }
  84
  85 #define DECODE_ERROR 0xffffffff
  86
  87 static unsigned int token_decode(const char *token)
  88 {
  89     int i;
  90     unsigned int val = 0;
  91     int marker = 0;
  92     if (strlen(token) < 4)
  93         return DECODE_ERROR;
  94     for (i = 0; i < 4; i++) {
  95         val *= 64;
  96         if (token[i] == '=')
  97             marker++;
  98         else if (marker > 0)
  99             return DECODE_ERROR;
 100         else {
 101             int lpos = pos(token[i]);
 102             if (lpos < 0)
 103                 return DECODE_ERROR;
 104             val += lpos;
 105         }
 106     }
 107     if (marker > 2)
 108         return DECODE_ERROR;
 109     return (marker << 24) | val;
 110 }
 111
 112 int pa_base64_decode(const char *str, void *data)
 113 {
 114     const char *p;
 115     unsigned char *q;
 116
 117     q = data;
 118     for (p = str; *p && (*p == '=' || strchr(base64_chars, *p)); p += 4) {
 119         unsigned int val = token_decode(p);
 120         unsigned int marker = (val >> 24) & 0xff;
 121         if (val == DECODE_ERROR)
 122             return -1;
 123         *q++ = (val >> 16) & 0xff;
 124         if (marker < 2)
 125             *q++ = (val >> 8) & 0xff;
 126         if (marker < 1)
 127             *q++ = val & 0xff;
 128     }
 129     return q - (unsigned char *) data;
 130 }