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 3 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,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU 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, see <http://www.gnu.org/licenses/>.
  17  */
  18 /** @file lib/mixer-oss.c
  19  * @brief OSS mixer support
  20  *
  21  * Mono output devices aren't explicitly supported (but may work
  22  * nonetheless).
  23  */
  24
  25 #include "common.h"
  26
  27 #if HAVE_SYS_SOUNDCARD_H
  28
  29 #include <fcntl.h>
  30 #include <unistd.h>
  31 #include <errno.h>
  32 #include <stddef.h>
  33 #include <sys/ioctl.h>
  34 #include <sys/soundcard.h>
  35
  36 #include "configuration.h"
  37 #include "mixer.h"
  38 #include "log.h"
  39 #include "syscalls.h"
  40 #include "mem.h"
  41
  42 /* documentation does not match implementation! */
  43 #ifndef SOUND_MIXER_READ
  44 # define SOUND_MIXER_READ(x) MIXER_READ(x)
  45 #endif
  46 #ifndef SOUND_MIXER_WRITE
  47 # define SOUND_MIXER_WRITE(x) MIXER_WRITE(x)
  48 #endif
  49
  50 /** @brief Channel names */
  51 static const char *channels[] = SOUND_DEVICE_NAMES;
  52
  53 /** @brief Convert channel name to number */
  54 static int mixer_channel(const char *c) {
  55   unsigned n;
  56
  57   if(!c[strspn(c, "0123456789")])
  58     return atoi(c);
  59   else {
  60     for(n = 0; n < sizeof channels / sizeof *channels; ++n)
  61       if(!strcmp(channels[n], c))
  62         return n;
  63     return -1;
  64   }
  65 }
  66
  67 /** @brief Open the OSS mixer device and return its fd */
  68 static int oss_do_open(void) {
  69   int fd;
  70
  71   if((fd = open(config->mixer, O_RDWR, 0)) < 0) {
  72     static char *reported;
  73
  74     if(!reported || strcmp(reported, config->mixer)) {
  75       if(reported)
  76         xfree(reported);
  77       reported = xstrdup(config->mixer);
  78       error(errno, "error opening %s", config->mixer);
  79     }
  80   }
  81   return fd;
  82 }
  83
  84 /** @brief Get the OSS mixer setting */
  85 static int oss_do_get(int *left, int *right, int fd, int ch) {
  86   int r;
  87
  88   if(ioctl(fd, SOUND_MIXER_READ(ch), &r) == -1) {
  89     error(errno, "error reading %s channel %s",
  90           config->mixer, config->channel);
  91     return -1;
  92   }
  93   *left = r & 0xff;
  94   *right = (r >> 8) & 0xff;
  95   return 0;
  96 }
  97
  98 /** @brief Get OSS volume */
  99 static int oss_get(int *left, int *right) {
 100   int ch, fd;
 101
 102   if(config->mixer
 103      && config->channel
 104      && (ch = mixer_channel(config->channel)) != -1) {
 105     if((fd = oss_do_open()) < 0)
 106       return -1;
 107     if(oss_do_get(left, right, fd, ch) < 0) {
 108       xclose(fd);
 109       return -1;
 110     }
 111     xclose(fd);
 112     return 0;
 113   } else
 114     return -1;
 115 }
 116
 117 /** @brief Set OSS volume */
 118 static int oss_set(int *left, int *right) {
 119   int ch, fd, r;
 120
 121   if(config->mixer
 122      && config->channel
 123      && (ch = mixer_channel(config->channel)) != -1) {
 124     if((fd = oss_do_open()) < 0)
 125       return -1;
 126     r = (*left & 0xff) + (*right & 0xff) * 256;
 127     if(ioctl(fd, SOUND_MIXER_WRITE(ch), &r) == -1) {
 128       error(errno, "error changing %s channel %s",
 129             config->mixer, config->channel);
 130       xclose(fd);
 131       return -1;
 132     }
 133     if(oss_do_get(left, right, fd, ch) < 0) {
 134       xclose(fd);
 135       return -1;
 136     }
 137     xclose(fd);
 138     return 0;
 139   } else
 140     return -1;
 141 }
 142
 143 /** @brief OSS mixer vtable */
 144 const struct mixer mixer_oss = {
 145   BACKEND_OSS,
 146   oss_get,
 147   oss_set,
 148   "/dev/mixer",
 149   "pcm"
 150 };
 151 #endif
 152
 153 /*
 154 Local Variables:
 155 c-basic-offset:2
 156 comment-column:40
 157 End:
 158 */