mdw@git.distorted.org.uk Git - disorder/blob - lib/mixer.c

   1 /*
   2  * This file is part of DisOrder
   3  * Copyright (C) 2004 Richard Kettlewell
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  18  * USA
  19  */
  20
  21 #include <config.h>
  22
  23 #include <stdio.h>
  24 #include <string.h>
  25 #include <fcntl.h>
  26 #include <unistd.h>
  27 #include <stdlib.h>
  28 #include <errno.h>
  29 #include <stddef.h>
  30 #include <sys/ioctl.h>
  31
  32 #include "configuration.h"
  33 #include "mixer.h"
  34 #include "log.h"
  35 #include "syscalls.h"
  36
  37 #if HAVE_SYS_SOUNDCARD_H
  38 #include <sys/soundcard.h>
  39
  40 /* documentation does not match implementation! */
  41 #ifndef SOUND_MIXER_READ
  42 # define SOUND_MIXER_READ(x) MIXER_READ(x)
  43 #endif
  44 #ifndef SOUND_MIXER_WRITE
  45 # define SOUND_MIXER_WRITE(x) MIXER_WRITE(x)
  46 #endif
  47
  48 static const char *channels[] = SOUND_DEVICE_NAMES;
  49
  50 int mixer_channel(const char *c) {
  51   unsigned n;
  52
  53   if(!c[strspn(c, "0123456789")])
  54     return atoi(c);
  55   else {
  56     for(n = 0; n < sizeof channels / sizeof *channels; ++n)
  57       if(!strcmp(channels[n], c))
  58         return n;
  59     return -1;
  60   }
  61 }
  62
  63 int mixer_control(int *left, int *right, int set) {
  64   int fd, ch, r;
  65
  66   if(config->mixer
  67      && config->channel
  68      && (ch = mixer_channel(config->channel)) != -1) {
  69     if((fd = open(config->mixer, O_RDWR, 0)) < 0) {
  70       error(errno, "error opening %s", config->mixer);
  71       return -1;
  72     }
  73     if(set) {
  74       r = (*left & 0xff) + (*right & 0xff) * 256;
  75       if(ioctl(fd, SOUND_MIXER_WRITE(ch), &r) == -1) {
  76         error(errno, "error changing %s channel %s",
  77               config->mixer, config->channel);
  78         xclose(fd);
  79         return -1;
  80       }
  81     }
  82     if(ioctl(fd, SOUND_MIXER_READ(ch), &r) == -1) {
  83       error(errno, "error reading %s channel %s",
  84             config->mixer, config->channel);
  85       xclose(fd);
  86       return -1;
  87     }
  88     *left = r & 0xff;
  89     *right = (r >> 8) & 0xff;
  90     xclose(fd);
  91     return 0;
  92   } else
  93     return -1;
  94 }
  95 #else
  96 int mixer_channel(const char attribute((unused)) *c) {
  97   return 0;
  98 }
  99
 100 int mixer_control(int attribute((unused)) *left,
 101                   int attribute((unused)) *right,
 102                   int attribute((unused)) set) {
 103   error(0, "don't know how to set volume on this platform");
 104   return -1;
 105 }
 106 #endif
 107
 108 /*
 109 Local Variables:
 110 c-basic-offset:2
 111 comment-column:40
 112 End:
 113 */
 114 /* arch-tag:2c047b85dbe68f45f2ebfc8c051ba967 */