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 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 static 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 static int oss_validate_channel(const char *c) {
  65   if(mixer_channel(c) != -1)
  66     return 1;
  67   else
  68     return 0;
  69 }
  70
  71 static int oss_validate_device(const char *d) {
  72   struct stat sb;
  73
  74   if(stat(d, &sb) < 0) {
  75     error(errno, "%s", d);
  76     return 0;
  77   }
  78   if(!S_ISCHR(sb.st_mode)) {
  79     error(0, "%s: not a character device", d);
  80     return 0;
  81   }
  82   return 1;
  83 }
  84
  85 static int oss_do_open(void) {
  86   int fd;
  87
  88   if((fd = open(config->mixer, O_RDWR, 0)) < 0)
  89     error(errno, "error opening %s", config->mixer);
  90   return fd;
  91 }
  92
  93 static int oss_do_get(int *left, int *right, int fd, int ch) {
  94   int r;
  95
  96   if(ioctl(fd, SOUND_MIXER_READ(ch), &r) == -1) {
  97     error(errno, "error reading %s channel %s",
  98           config->mixer, config->channel);
  99     return -1;
 100   }
 101   *left = r & 0xff;
 102   *right = (r >> 8) & 0xff;
 103   return 0;
 104 }
 105
 106 static int oss_get(int *left, int *right) {
 107   int ch, fd;
 108
 109   if(config->mixer
 110      && config->channel
 111      && (ch = mixer_channel(config->channel)) != -1) {
 112     if((fd = oss_do_open()) < 0)
 113       return -1;
 114     if(oss_do_get(left, right, fd, ch) < 0) {
 115       xclose(fd);
 116       return -1;
 117     }
 118     xclose(fd);
 119     return 0;
 120   } else
 121     return -1;
 122 }
 123
 124 static int oss_set(int *left, int *right) {
 125   int ch, fd, r;
 126
 127   if(config->mixer
 128      && config->channel
 129      && (ch = mixer_channel(config->channel)) != -1) {
 130     if((fd = oss_do_open()) < 0)
 131       return -1;
 132     r = (*left & 0xff) + (*right & 0xff) * 256;
 133     if(ioctl(fd, SOUND_MIXER_WRITE(ch), &r) == -1) {
 134       error(errno, "error changing %s channel %s",
 135             config->mixer, config->channel);
 136       xclose(fd);
 137       return -1;
 138     }
 139     if(oss_do_get(left, right, fd, ch) < 0) {
 140       xclose(fd);
 141       return -1;
 142     }
 143     xclose(fd);
 144     return 0;
 145   } else
 146     return -1;
 147 }
 148
 149 const struct mixer mixer_oss = {
 150   BACKEND_OSS,
 151   oss_validate_device,
 152   oss_validate_channel,
 153   oss_get,
 154   oss_set,
 155   "/dev/mixer",
 156   "pcm"
 157 };
 158 #endif
 159
 160 /*
 161 Local Variables:
 162 c-basic-offset:2
 163 comment-column:40
 164 End:
 165 */