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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef MEDIA_AUDIO_SNDIO_SNDIO_OUTPUT_H_
#define MEDIA_AUDIO_SNDIO_SNDIO_OUTPUT_H_
#include <pthread.h>
#include <sndio.h>
#include "base/time/tick_clock.h"
#include "base/time/time.h"
#include "media/audio/audio_io.h"
namespace media {
class AudioParameters;
class AudioManagerBase;
// call-backs invoked from C libraries, thus requiring C linkage
extern "C" {
// Invoked (on the real-time thread) at each sound card clock tick
void sndio_onmove(void *arg, int delta);
// Invoked (on the real-time thread) whenever the volume changes
void sndio_onvol(void *arg, unsigned int vol);
// Real-time thread entry point
void *sndio_threadstart(void *arg);
}
// Implementation of AudioOutputStream using sndio(7)
class SndioAudioOutputStream : public AudioOutputStream {
public:
// The manager is creating this object
SndioAudioOutputStream(const AudioParameters& params,
AudioManagerBase* manager);
virtual ~SndioAudioOutputStream();
// Implementation of AudioOutputStream.
virtual bool Open() override;
virtual void Close() override;
virtual void Start(AudioSourceCallback* callback) override;
virtual void Stop() override;
virtual void SetVolume(double volume) override;
virtual void GetVolume(double* volume) override;
// C-linkage call-backs are friends to access private data
friend void sndio_onmove(void *arg, int delta);
friend void sndio_onvol(void *arg, unsigned int vol);
friend void *sndio_threadstart(void *arg);
private:
enum StreamState {
kClosed, // Not opened yet
kStopped, // Device opened, but not started yet
kRunning, // Started, device playing
kStopWait // Stopping, waiting for the real-time thread to exit
};
// Continuously moves data from the audio bus to the device
void RealTimeThread(void);
// Our creator, the audio manager needs to be notified when we close.
AudioManagerBase* manager;
// Parameters of the source
AudioParameters params;
// Source stores data here
std::unique_ptr<AudioBus> audio_bus;
int bytes_per_frame;
// Call-back that produces data to play
AudioSourceCallback* source;
// Handle of the audio device
struct sio_hdl* hdl;
// Current state of the stream
enum StreamState state;
// High priority thread running RealTimeThread()
pthread_t thread;
// Protects vol, volpending and hw_delay
pthread_mutex_t mutex;
// Current volume in the 0..SIO_MAXVOL range
int vol;
// Set to 1 if volumes must be refreshed in the realtime thread
int volpending;
// Number of bytes buffered in the hardware
int hw_delay;
// Temporary buffer where data is stored sndio-compatible format
char* buffer;
DISALLOW_COPY_AND_ASSIGN(SndioAudioOutputStream);
};
} // namespace media
#endif // MEDIA_AUDIO_SNDIO_SNDIO_OUTPUT_H_
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