/*
* Copyright (C) 2012 Google Inc. All rights reserved.
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* 1. Redistributions of source code must retain the above copyright
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*
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#ifndef AudioPullFIFO_h
#define AudioPullFIFO_h
#include "platform/audio/AudioBus.h"
#include "platform/audio/AudioFIFO.h"
#include "platform/audio/AudioSourceProvider.h"
namespace WebCore {
// A FIFO (First In First Out) buffer to handle mismatches in buffer sizes between a provider and
// receiver. The receiver will "pull" data from this FIFO. If data is already available in the
// FIFO, it is provided to the receiver. If insufficient data is available to satisfy the request,
// the FIFO will ask the provider for more data when necessary to fulfill a request. Contrast this
// with a "push" FIFO, where the sender pushes data to the FIFO which will itself push the data to
// the receiver when the FIFO is full.
class PLATFORM_EXPORT AudioPullFIFO {
public:
// Create a FIFO that gets data from |provider|. The FIFO will be large enough to hold
// |fifoLength| frames of data of |numberOfChannels| channels. The AudioSourceProvider will be
// asked to produce |providerSize| frames when the FIFO needs more data.
AudioPullFIFO(AudioSourceProvider& audioProvider, unsigned numberOfChannels, size_t fifoLength, size_t providerSize);
// Read |framesToConsume| frames from the FIFO into the destination. If the FIFO does not have
// enough data, we ask the |provider| to get more data to fulfill the request.
void consume(AudioBus* destination, size_t framesToConsume);
private:
// Fill the FIFO buffer with at least |numberOfFrames| more data.
void fillBuffer(size_t numberOfFrames);
// The provider of the data in our FIFO.
AudioSourceProvider& m_provider;
// The actual FIFO
AudioFIFO m_fifo;
// Number of frames of data that the provider will produce per call.
unsigned m_providerSize;
// Temporary workspace to hold the data from the provider.
RefPtr<AudioBus> m_tempBus;
};
} // namespace WebCore
#endif // AudioPullFIFO.h