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akode/akode/lib/sink.h

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/* aKode: Sink abstract-type
Copyright (C) 2004 Allan Sandfeld Jensen <kde@carewolf.com>
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with this library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 51 Franklin Steet, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
#ifndef _AKODE_SINK_H
#define _AKODE_SINK_H
#include "pluginhandler.h"
#include "akode_export.h"
namespace aKode {
class AudioFrame;
class AudioBuffer;
class AudioConfiguration;
//! A generic interface for all sinks
/*!
* Sinks are where an audiostream goes. It can in aKodeLib be either an
* encoder or an audio-output such as ALSA or OSS.
*/
class AKODE_EXPORT Sink {
public:
virtual ~Sink() {};
/*!
* Opens the sink for playing and returns true if succesfull.
*/
virtual bool open() = 0;
/*!
* Closes the sink and releases any held resources or processes.
*/
virtual void close() {};
/*!
* Tries to configure the sink for the configuration \a config.
* Returns 0 if a perfect match was possible, positive if a close
* match was possible, and negative to indicate complete failure.
*/
virtual int setAudioConfiguration(const AudioConfiguration* config) = 0;
/*!
* Returns the configuration the sink currently expects.
*/
virtual const AudioConfiguration* audioConfiguration() const = 0;
/*!
* Writes one frame to the sink. If the frame has a different configuration
* than the sink expects, the result is undefined.
*
* Some sinks might handle automatic reconfiguration gracefully, but this
* will be plugin-specific and cannot be generally relied upon.
*/
virtual bool writeFrame(AudioFrame* frame) = 0;
/*!
* Pauses buffer-playback in the sink in case it has a buffer of significance.
* Notice that not all sinks are capable of precise pausing.
*/
virtual void pause() {};
/*!
* Resume from a paused state
*/
virtual void resume() {};
};
class SinkPlugin {
public:
/*!
* Asks the plugin to open a Sink, returns 0 if the
* plugin could not.
*/
virtual Sink* openSink() = 0;
};
class AKODE_EXPORT SinkPluginHandler : public PluginHandler, public SinkPlugin {
public:
static list<string> listSinkPlugins();
SinkPluginHandler() : sink_plugin(0) {};
SinkPluginHandler(const string name);
Sink* openSink();
/*!
* Loads the sink-plugin named \a name (alsa,oss..)
*/
virtual bool load(const string name);
virtual void unload();
bool isLoaded() { return sink_plugin != 0; };
protected:
SinkPlugin* sink_plugin;
};
} // namespace
#endif