/*
* Copyright (C) 2003-2013 The Music Player Daemon Project
* http://www.musicpd.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/** \file
*
* This header declares the mixer_plugin class. It should not be
* included directly; use MixerInternal.hxx instead in mixer
* implementations.
*/
#ifndef MPD_MIXER_PLUGIN_HXX
#define MPD_MIXER_PLUGIN_HXX
struct config_param;
class Mixer;
class Error;
struct mixer_plugin {
/**
* Alocates and configures a mixer device.
*
* @param ao the pointer returned by audio_output_plugin.init
* @param param the configuration section
* @param error_r location to store the error occurring, or
* NULL to ignore errors
* @return a mixer object, or NULL on error
*/
Mixer *(*init)(void *ao, const config_param ¶m,
Error &error);
/**
* Finish and free mixer data
*/
void (*finish)(Mixer *data);
/**
* Open mixer device
*
* @param error_r location to store the error occurring, or
* NULL to ignore errors
* @return true on success, false on error
*/
bool (*open)(Mixer *data, Error &error);
/**
* Close mixer device
*/
void (*close)(Mixer *data);
/**
* Reads the current volume.
*
* @param error_r location to store the error occurring, or
* NULL to ignore errors
* @return the current volume (0..100 including) or -1 if
* unavailable or on error (error set, mixer will be closed)
*/
int (*get_volume)(Mixer *mixer, Error &error);
/**
* Sets the volume.
*
* @param error_r location to store the error occurring, or
* NULL to ignore errors
* @param volume the new volume (0..100 including)
* @return true on success, false on error
*/
bool (*set_volume)(Mixer *mixer, unsigned volume,
Error &error);
/**
* If true, then the mixer is automatically opened, even if
* its audio output is not open. If false, then the mixer is
* disabled as long as its audio output is closed.
*/
bool global;
};
#endif
