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 "common.h"
  25
  26 #include "configuration.h"
  27 #include "mixer.h"
  28 #include "log.h"
  29 #include "mem.h"
  30
  31 /** @brief Whether lack of volume support has been reported yet */
  32 static int none_reported;
  33
  34 /** @brief Get/set volume stub if volume control is not supported */
  35 static int none_get_set(int attribute((unused)) *left,
  36                         int attribute((unused)) *right) {
  37   if(!none_reported) {
  38     error(0, "don't know how to get/set volume with this api");
  39     none_reported = 1;
  40   }
  41   return -1;
  42 }
  43
  44 /** @brief Stub mixer control */
  45 static const struct mixer mixer_none = {
  46   -1,
  47   none_get_set,
  48   none_get_set,
  49   "",
  50   ""
  51 };
  52
  53 /** @brief Table of mixer definitions */
  54 static const struct mixer *mixers[] = {
  55 #if HAVE_SYS_SOUNDCARD_H
  56   &mixer_oss,
  57 #endif
  58 #if HAVE_ALSA_ASOUNDLIB_H
  59   &mixer_alsa,
  60 #endif
  61   &mixer_none                           /* make sure array is never empty */
  62 };
  63
  64 /** @brief Number of mixer definitions */
  65 #define NMIXERS (sizeof mixers / sizeof *mixers)
  66
  67 /** @brief Find the mixer definition */
  68 static const struct mixer *find_mixer(int api) {
  69   size_t n;
  70
  71   if(api == -1)
  72     api = config->api;
  73   for(n = 0; n < NMIXERS; ++n)
  74     if(mixers[n]->api == api)
  75       return mixers[n];
  76   return &mixer_none;
  77 }
  78
  79 /** @brief Return true if we know how to drive the mixer
  80  * @param api Sound api or -1 for default
  81  * @return true if suppored, false otherwise
  82  */
  83 int mixer_supported(int api) {
  84   const struct mixer *const m = find_mixer(api);
  85   return m != &mixer_none;
  86 }
  87
  88 /** @brief Get/set volume
  89  * @param api Sound api or -1 for default
  90  * @param left Left channel level, 0-100
  91  * @param right Right channel level, 0-100
  92  * @param set Set volume if non-0
  93  * @return 0 on success, non-0 on error
  94  *
  95  * If getting the volume then @p left and @p right are filled in.
  96  *
  97  * If setting the volume then the target levels are read from @p left and
  98  * @p right, and the actual level set is stored in them.
  99  */
 100 int mixer_control(int api, int *left, int *right, int set) {
 101   const struct mixer *const m = find_mixer(api);
 102
 103   /* We impose defaults bizarrely late, but this has the advantage of
 104    * not making everything depend on sound libraries */
 105   if(!config->mixer)
 106     config->mixer = xstrdup(m->device);
 107   if(!config->channel)
 108     config->channel = xstrdup(m->channel);
 109   if(set)
 110     return m->set(left, right);
 111   else
 112     return m->get(left, right);
 113 }
 114
 115 /*
 116 Local Variables:
 117 c-basic-offset:2
 118 comment-column:40
 119 End:
 120 */