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 #include "types.h"
  23
  24 #include <stdio.h>
  25 #include <string.h>
  26 #include <fcntl.h>
  27 #include <unistd.h>
  28 #include <stdlib.h>
  29 #include <errno.h>
  30 #include <stddef.h>
  31 #include <sys/ioctl.h>
  32
  33 #include "configuration.h"
  34 #include "mixer.h"
  35 #include "log.h"
  36 #include "syscalls.h"
  37
  38 #if HAVE_SYS_SOUNDCARD_H
  39 #include <sys/soundcard.h>
  40
  41 /* documentation does not match implementation! */
  42 #ifndef SOUND_MIXER_READ
  43 # define SOUND_MIXER_READ(x) MIXER_READ(x)
  44 #endif
  45 #ifndef SOUND_MIXER_WRITE
  46 # define SOUND_MIXER_WRITE(x) MIXER_WRITE(x)
  47 #endif
  48
  49 static const char *channels[] = SOUND_DEVICE_NAMES;
  50
  51 int mixer_channel(const char *c) {
  52   unsigned n;
  53
  54   if(!c[strspn(c, "0123456789")])
  55     return atoi(c);
  56   else {
  57     for(n = 0; n < sizeof channels / sizeof *channels; ++n)
  58       if(!strcmp(channels[n], c))
  59         return n;
  60     return -1;
  61   }
  62 }
  63
  64 int mixer_control(int *left, int *right, int set) {
  65   int fd, ch, r;
  66
  67   if(config->mixer
  68      && config->channel
  69      && (ch = mixer_channel(config->channel)) != -1) {
  70     if((fd = open(config->mixer, O_RDWR, 0)) < 0) {
  71       error(errno, "error opening %s", config->mixer);
  72       return -1;
  73     }
  74     if(set) {
  75       r = (*left & 0xff) + (*right & 0xff) * 256;
  76       if(ioctl(fd, SOUND_MIXER_WRITE(ch), &r) == -1) {
  77         error(errno, "error changing %s channel %s",
  78               config->mixer, config->channel);
  79         xclose(fd);
  80         return -1;
  81       }
  82     }
  83     if(ioctl(fd, SOUND_MIXER_READ(ch), &r) == -1) {
  84       error(errno, "error reading %s channel %s",
  85             config->mixer, config->channel);
  86       xclose(fd);
  87       return -1;
  88     }
  89     *left = r & 0xff;
  90     *right = (r >> 8) & 0xff;
  91     xclose(fd);
  92     return 0;
  93   } else
  94     return -1;
  95 }
  96 #else
  97 int mixer_channel(const char attribute((unused)) *c) {
  98   return 0;
  99 }
 100
 101 int mixer_control(int attribute((unused)) *left,
 102                   int attribute((unused)) *right,
 103                   int attribute((unused)) set) {
 104   static int reported;
 105
 106   if(!reported) {
 107     error(0, "don't know how to set volume on this platform");
 108     reported = 1;
 109   }
 110   return -1;
 111 }
 112 #endif
 113
 114 /*
 115 Local Variables:
 116 c-basic-offset:2
 117 comment-column:40
 118 End:
 119 */