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

   1 /*
   2  * This file is part of DisOrder
   3  * Copyright (C) 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 /** @file lib/mixer.c
  21  * @brief Mixer support
  22  */
  23
  24 #include <config.h>
  25 #include "types.h"
  26
  27 #include "configuration.h"
  28 #include "mixer.h"
  29 #include "log.h"
  30 #include "mem.h"
  31
  32 /** @brief Whether lack of volume support has been reported yet */
  33 static int none_reported;
  34
  35 /** @brief Get/set volume stub if volume control is not supported */
  36 static int none_get_set(int attribute((unused)) *left,
  37                         int attribute((unused)) *right) {
  38   if(!none_reported) {
  39     error(0, "don't know how to get/set volume with this api");
  40     none_reported = 1;
  41   }
  42   return -1;
  43 }
  44
  45 /** @brief Stub mixer control */
  46 static const struct mixer mixer_none = {
  47   -1,
  48   none_get_set,
  49   none_get_set,
  50   "",
  51   ""
  52 };
  53
  54 /** @brief Table of mixer definitions */
  55 static const struct mixer *mixers[] = {
  56 #if HAVE_SYS_SOUNDCARD_H
  57   &mixer_oss,
  58 #endif
  59 #if HAVE_ALSA_ASOUNDLIB_H
  60   &mixer_alsa,
  61 #endif
  62   &mixer_none                           /* make sure array is never empty */
  63 };
  64
  65 /** @brief Number of mixer definitions */
  66 #define NMIXERS (sizeof mixers / sizeof *mixers)
  67
  68 /** @brief Find the mixer definition */
  69 static const struct mixer *find_mixer(int api) {
  70   size_t n;
  71
  72   for(n = 0; n < NMIXERS; ++n)
  73     if(mixers[n]->api == api)
  74       return mixers[n];
  75   return &mixer_none;
  76 }
  77
  78 /** @brief Get/set volume
  79  * @param left Left channel level, 0-100
  80  * @param right Right channel level, 0-100
  81  * @param set Set volume if non-0
  82  * @return 0 on success, non-0 on error
  83  *
  84  * If getting the volume then @p left and @p right are filled in.
  85  *
  86  * If setting the volume then the target levels are read from @p left and
  87  * @p right, and the actual level set is stored in them.
  88  */
  89 int mixer_control(int *left, int *right, int set) {
  90   const struct mixer *const m = find_mixer(config->api);
  91
  92   /* We impose defaults bizarrely late, but this has the advantage of
  93    * not making everything depend on sound libraries */
  94   if(!config->mixer)
  95     config->mixer = xstrdup(m->device);
  96   if(!config->channel)
  97     config->channel = xstrdup(m->channel);
  98   if(set)
  99     return m->set(left, right);
 100   else
 101     return m->get(left, right);
 102 }
 103
 104 /*
 105 Local Variables:
 106 c-basic-offset:2
 107 comment-column:40
 108 End:
 109 */