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

   1 /*
   2  * This file is part of DisOrder
   3  * Copyright (C) 2004, 2007, 2008 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 /** @file lib/mixer-oss.c
  21  * @brief OSS mixer support
  22  *
  23  * Mono output devices aren't explicitly supported (but may work
  24  * nonetheless).
  25  */
  26
  27 #include "common.h"
  28
  29 #if HAVE_SYS_SOUNDCARD_H
  30
  31 #include <fcntl.h>
  32 #include <unistd.h>
  33 #include <errno.h>
  34 #include <stddef.h>
  35 #include <sys/ioctl.h>
  36 #include <sys/soundcard.h>
  37
  38 #include "configuration.h"
  39 #include "mixer.h"
  40 #include "log.h"
  41 #include "syscalls.h"
  42 #include "mem.h"
  43
  44 /* documentation does not match implementation! */
  45 #ifndef SOUND_MIXER_READ
  46 # define SOUND_MIXER_READ(x) MIXER_READ(x)
  47 #endif
  48 #ifndef SOUND_MIXER_WRITE
  49 # define SOUND_MIXER_WRITE(x) MIXER_WRITE(x)
  50 #endif
  51
  52 /** @brief Channel names */
  53 static const char *channels[] = SOUND_DEVICE_NAMES;
  54
  55 /** @brief Convert channel name to number */
  56 static int mixer_channel(const char *c) {
  57   unsigned n;
  58
  59   if(!c[strspn(c, "0123456789")])
  60     return atoi(c);
  61   else {
  62     for(n = 0; n < sizeof channels / sizeof *channels; ++n)
  63       if(!strcmp(channels[n], c))
  64         return n;
  65     return -1;
  66   }
  67 }
  68
  69 /** @brief Open the OSS mixer device and return its fd */
  70 static int oss_do_open(void) {
  71   int fd;
  72
  73   if((fd = open(config->mixer, O_RDWR, 0)) < 0) {
  74     static char *reported;
  75
  76     if(!reported || strcmp(reported, config->mixer)) {
  77       if(reported)
  78         xfree(reported);
  79       reported = xstrdup(config->mixer);
  80       error(errno, "error opening %s", config->mixer);
  81     }
  82   }
  83   return fd;
  84 }
  85
  86 /** @brief Get the OSS mixer setting */
  87 static int oss_do_get(int *left, int *right, int fd, int ch) {
  88   int r;
  89
  90   if(ioctl(fd, SOUND_MIXER_READ(ch), &r) == -1) {
  91     error(errno, "error reading %s channel %s",
  92           config->mixer, config->channel);
  93     return -1;
  94   }
  95   *left = r & 0xff;
  96   *right = (r >> 8) & 0xff;
  97   return 0;
  98 }
  99
 100 /** @brief Get OSS volume */
 101 static int oss_get(int *left, int *right) {
 102   int ch, fd;
 103
 104   if(config->mixer
 105      && config->channel
 106      && (ch = mixer_channel(config->channel)) != -1) {
 107     if((fd = oss_do_open()) < 0)
 108       return -1;
 109     if(oss_do_get(left, right, fd, ch) < 0) {
 110       xclose(fd);
 111       return -1;
 112     }
 113     xclose(fd);
 114     return 0;
 115   } else
 116     return -1;
 117 }
 118
 119 /** @brief Set OSS volume */
 120 static int oss_set(int *left, int *right) {
 121   int ch, fd, r;
 122
 123   if(config->mixer
 124      && config->channel
 125      && (ch = mixer_channel(config->channel)) != -1) {
 126     if((fd = oss_do_open()) < 0)
 127       return -1;
 128     r = (*left & 0xff) + (*right & 0xff) * 256;
 129     if(ioctl(fd, SOUND_MIXER_WRITE(ch), &r) == -1) {
 130       error(errno, "error changing %s channel %s",
 131             config->mixer, config->channel);
 132       xclose(fd);
 133       return -1;
 134     }
 135     if(oss_do_get(left, right, fd, ch) < 0) {
 136       xclose(fd);
 137       return -1;
 138     }
 139     xclose(fd);
 140     return 0;
 141   } else
 142     return -1;
 143 }
 144
 145 /** @brief OSS mixer vtable */
 146 const struct mixer mixer_oss = {
 147   BACKEND_OSS,
 148   oss_get,
 149   oss_set,
 150   "/dev/mixer",
 151   "pcm"
 152 };
 153 #endif
 154
 155 /*
 156 Local Variables:
 157 c-basic-offset:2
 158 comment-column:40
 159 End:
 160 */