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 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     i = 0;
  61     for (i = 0; i < size;) {
  62         c = q[i++];
  63         c *= 256;
  64         if (i < size)
  65             c += q[i];
  66         i++;
  67         c *= 256;
  68         if (i < size)
  69             c += q[i];
  70         i++;
  71         p[0] = base64_chars[(c & 0x00fc0000) >> 18];
  72         p[1] = base64_chars[(c & 0x0003f000) >> 12];
  73         p[2] = base64_chars[(c & 0x00000fc0) >> 6];
  74         p[3] = base64_chars[(c & 0x0000003f) >> 0];
  75         if (i > size)
  76             p[3] = '=';
  77         if (i > size + 1)
  78             p[2] = '=';
  79         p += 4;
  80     }
  81     *p = 0;
  82     *str = s;
  83     return strlen(s);
  84 }
  85
  86 #define DECODE_ERROR 0xffffffff
  87
  88 static unsigned int token_decode(const char *token)
  89 {
  90     int i;
  91     unsigned int val = 0;
  92     int marker = 0;
  93     if (strlen(token) < 4)
  94         return DECODE_ERROR;
  95     for (i = 0; i < 4; i++) {
  96         val *= 64;
  97         if (token[i] == '=')
  98             marker++;
  99         else if (marker > 0)
 100             return DECODE_ERROR;
 101         else {
 102             int lpos = pos(token[i]);
 103             if (lpos < 0)
 104                 return DECODE_ERROR;
 105             val += lpos;
 106         }
 107     }
 108     if (marker > 2)
 109         return DECODE_ERROR;
 110     return (marker << 24) | val;
 111 }
 112
 113 int pa_base64_decode(const char *str, void *data)
 114 {
 115     const char *p;
 116     unsigned char *q;
 117
 118     q = data;
 119     for (p = str; *p && (*p == '=' || strchr(base64_chars, *p)); p += 4) {
 120         unsigned int val = token_decode(p);
 121         unsigned int marker = (val >> 24) & 0xff;
 122         if (val == DECODE_ERROR)
 123             return -1;
 124         *q++ = (val >> 16) & 0xff;
 125         if (marker < 2)
 126             *q++ = (val >> 8) & 0xff;
 127         if (marker < 1)
 128             *q++ = val & 0xff;
 129     }
 130     return q - (unsigned char *) data;
 131 }