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

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