path: root/src/mixer.cc

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set et sw=2 ts=2: */
/***************************************************************************
 *            mixer.cc
 *
 *  Tue Sep 23 14:38:54 CEST 2014
 *  Copyright 2014 Bent Bisballe Nyeng
 *  deva@aasimon.org
 ****************************************************************************/

/*
 *  This file is part of LibAudioIO.
 *
 *  LibAudioIO is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *  
 *  LibAudioIO is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *  
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with LibAudioIO; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */
#include "mixer.h"

#include <string>
#include <stdlib.h>

#define fERROR (strtof("-INF", NULL))

Mixer::Mixer(snd_mixer_t *handle, snd_mixer_elem_t *elem)
{
  this->handle = handle;
  this->elem = elem;
}

Mixer::~Mixer()
{
  if(handle) snd_mixer_close(handle);
}

snd_mixer_selem_channel_id_t Mixer::chanId(int idx)
{
  int num = 0;

  for(int ichn = 0; ichn <= (int)SND_MIXER_SCHN_LAST; ichn++) {
    snd_mixer_selem_channel_id_t chn = (snd_mixer_selem_channel_id_t)ichn;
    if(!snd_mixer_selem_has_capture_channel(elem, chn) &&
       !snd_mixer_selem_has_playback_channel(elem, chn)) continue;
    if(idx == num) return chn;
    num++;
  }

  return SND_MIXER_SCHN_UNKNOWN;
}

int Mixer::numberOfChannels()
{
  int num = 0;
  for(int ichn = 0; ichn <= (int)SND_MIXER_SCHN_LAST; ichn++) {
    snd_mixer_selem_channel_id_t chn = (snd_mixer_selem_channel_id_t)ichn;
    if(!snd_mixer_selem_has_capture_channel(elem, chn) &&
       !snd_mixer_selem_has_playback_channel(elem, chn)) continue;
    num++;
  }

  return num;
}

bool Mixer::isCapture()
{
  return snd_mixer_selem_has_capture_volume(elem) ||
    snd_mixer_selem_has_capture_switch(elem);
}

bool Mixer::isPlayback()
{
  return snd_mixer_selem_has_playback_volume(elem);
}

bool Mixer::isEnum()
{
  return snd_mixer_selem_is_enumerated(elem);
}

void Mixer::setEnumValue(std::string value)
{
  if(!isEnum()) return;

  int i, items;
  char itemname[40];

  // TODO: Always MONO for enums?
  snd_mixer_selem_channel_id_t channel_id =  SND_MIXER_SCHN_MONO;

  items = snd_mixer_selem_get_enum_items(elem);
  for (i = 0; i < items; i++) {
    snd_mixer_selem_get_enum_item_name(elem, i, sizeof(itemname) - 1, itemname);
    if(value == itemname) {
      snd_mixer_selem_set_enum_item(elem, channel_id, i);
      return;
    }
  }
}

std::string Mixer::enumValue()
{
  if(!isEnum()) return "";

  unsigned int idx;
  char itemname[40];

  // TODO: Always MONO for enums?
  snd_mixer_selem_channel_id_t channel_id = SND_MIXER_SCHN_MONO;

  if(!snd_mixer_selem_get_enum_item(elem, channel_id, &idx)) {
    snd_mixer_selem_get_enum_item_name(elem, idx,
                                       sizeof(itemname) - 1, itemname);
    return itemname;
  }

  return "";
}

std::vector<std::string> Mixer::enumValues()
{
  std::vector<std::string> values;
  if(!isEnum()) return values;

  int i, items;
  char itemname[40];
  items = snd_mixer_selem_get_enum_items(elem);
  for (i = 0; i < items; i++) {
    snd_mixer_selem_get_enum_item_name(elem, i, sizeof(itemname) - 1, itemname);
    values.push_back(itemname);
  }

  return values;
}

int Mixer::setLevel(int channel, float level)
{
  int err;
  long int value = level * 100;
  // dir: -1 := exact or first below
  //       0 := exact (error if not?)
  //       1 := exact or first above
  int dir = 1;

  if(isCapture()) {
    err = snd_mixer_selem_set_capture_dB(elem, chanId(channel), value, dir);	
    if(err) {
      printf("snd_mixer_selem_set_capture_dB: %s, %d\n",
             snd_strerror(err), err);
      return 1;
    }
  }

  if(isPlayback()) {
    err = snd_mixer_selem_set_playback_dB(elem, chanId(channel), value, dir);	
    if(err) {
      printf("snd_mixer_selem_set_playback_dB: %s, %d\n",
             snd_strerror(err), err);
      return 1;
    }
  }

  return 0;
}

float Mixer::level(int channel)
{
  int err;
  long int value;

  if(isCapture()) {
    err = snd_mixer_selem_get_capture_dB(elem, chanId(channel), &value);	
    if(err) {
      printf("snd_mixer_selem_get_capture_dB: %s, %d\n",
             snd_strerror(err), err);
      return fERROR;
    }
  } else if(isPlayback()) {
    err = snd_mixer_selem_get_playback_dB(elem, chanId(channel), &value);	
    if(err) {
      printf("snd_mixer_selem_get_playback_dB: %s, %d\n",
             snd_strerror(err), err);
      return fERROR;
    }
  } else {
    return fERROR;
  }

  return (float)value / 100.0;
}

Mixer::range_t Mixer::range()
{
  Mixer::range_t range;

  int err;
  long int lvl_min, lvl_max;

  if(isCapture()) {
    err = snd_mixer_selem_get_capture_dB_range(elem, &lvl_min, &lvl_max);

    if(err) {
      printf("snd_mixer_selem_get_capture_dB_range: %s, %d\n",
             snd_strerror(err), err);
    }
  } else if(isPlayback()) {
    err = snd_mixer_selem_get_playback_dB_range(elem, &lvl_min, &lvl_max);

    if(err) {
      printf("snd_mixer_selem_get_playback_dB_range: %s, %d\n",
             snd_strerror(err), err);
    }
  } else {
    range.min = fERROR;
    range.max = fERROR;
    return range;
  }

  range.min = (float)lvl_min / 100.0;
  range.max = (float)lvl_max / 100.0;

  return range;
}

void Mixer::setCapture(bool capture)
{
  if(!isCapture()) return;
  int c = capture?1:0;
  int err;
  err = snd_mixer_selem_set_capture_switch_all(elem, c);
  if(err) {
    printf("snd_mixer_selem_set_capture_switch_all: %s, %d\n",
           snd_strerror(err), err);
  }
}

bool Mixer::capture()
{
  if(!isCapture()) return false;

  int err;
  
  int num = numberOfChannels();
  for(int idx = 0; idx < num; idx++) {
    int value;
    err = snd_mixer_selem_get_capture_switch(elem, chanId(idx), &value);
    if(err) {
      printf(" snd_mixer_selem_get_capture_switch: %s, %d\n",
             snd_strerror(err), err);
      return false;
    }
    if(value == 0) return false;
 }

  return true;
}

void Mixer::setMuted(bool muted)
{
  if(!isPlayback()) return;
  int p = muted?0:1;
  int err;
  err = snd_mixer_selem_set_playback_switch_all(elem, p);
  if(err) {
    printf("snd_mixer_selem_set_playback_switch_all: %s, %d\n",
           snd_strerror(err), err);
  }
}

bool Mixer::muted()
{
  if(!isPlayback()) return false;

  int err;
  
  int num = numberOfChannels();
  for(int idx = 0; idx < num; idx++) {
    int value;
    err = snd_mixer_selem_get_playback_switch(elem, chanId(idx), &value);
    if(err) {
      printf(" snd_mixer_selem_get_playback_switch: %s, %d\n",
             snd_strerror(err), err);
      return true;
    }
    if(value == 0) return true;
 }

  return false;
}