134 lines
3.5 KiB
C
134 lines
3.5 KiB
C
/* the Music Player Daemon (MPD)
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* Copyright (C) 2003-2007 by Warren Dukes (warren.dukes@gmail.com)
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* Copyright (C) 2008 Max Kellermann <max@duempel.org>
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* This project's homepage is: http://www.musicpd.org
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef OUTPUT_API_H
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#define OUTPUT_API_H
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#include "../config.h"
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#include "audio_format.h"
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#include "tag.h"
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#include "conf.h"
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#include "log.h"
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#include <stdbool.h>
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#define DISABLED_AUDIO_OUTPUT_PLUGIN(plugin) const struct audio_output_plugin plugin;
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struct audio_output;
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/**
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* A plugin which controls an audio output device.
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*/
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struct audio_output_plugin {
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/**
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* the plugin's name
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*/
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const char *name;
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/**
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* Test if this plugin can provide a default output, in case
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* none has been configured. This method is optional.
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*/
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int (*test_default_device)(void);
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/**
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* Configure and initialize the device, but do not open it
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* yet.
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*
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* @param ao an opaque pointer to the audio_output structure
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* @param audio_format the configured audio format, or NULL if
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* none is configured
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* @param param the configuration section, or NULL if there is
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* no configuration
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* @return NULL on error, or an opaque pointer to the plugin's
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* data
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*/
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void *(*init)(struct audio_output *ao,
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const struct audio_format *audio_format,
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ConfigParam *param);
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/**
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* Free resources allocated by this device.
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*/
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void (*finish)(void *data);
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/**
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* Really open the device.
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* @param audio_format the audio format in which data is going
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* to be delivered; may be modified by the plugin
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*/
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int (*open)(void *data, struct audio_format *audio_format);
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/**
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* Play a chunk of audio data.
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*/
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int (*play)(void *data, const char *playChunk, size_t size);
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/**
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* Pause the device. If supported, it may perform a special
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* action, which keeps the device open, but does not play
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* anything. Output plugins like "shout" might want to play
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* silence during pause, so their clients won't be
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* disconnected. Plugins which do not support pausing will
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* simply be closed, and have to be reopened when unpaused.
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*/
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void (*pause)(void *data);
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/**
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* Try to cancel data which may still be in the device's
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* buffers.
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*/
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void (*cancel)(void *data);
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/**
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* Close the device.
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*/
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void (*close)(void *data);
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/**
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* Display metadata for the next chunk. Optional method,
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* because not all devices can display metadata.
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*/
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void (*send_tag)(void *data, const struct tag *tag);
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};
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enum audio_output_command {
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AO_COMMAND_NONE = 0,
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AO_COMMAND_OPEN,
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AO_COMMAND_CLOSE,
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AO_COMMAND_PLAY,
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AO_COMMAND_PAUSE,
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AO_COMMAND_CANCEL,
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AO_COMMAND_SEND_TAG,
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AO_COMMAND_KILL
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};
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struct audio_output;
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const char *audio_output_get_name(const struct audio_output *ao);
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void audio_output_closed(struct audio_output *ao);
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/**
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* Returns true if there is a command pending.
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*/
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bool audio_output_is_pending(const struct audio_output *ao);
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#endif
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