/*
* Copyright (C) 2012 Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef AudioFIFO_h
#define AudioFIFO_h
#include "platform/audio/AudioBus.h"
namespace WebCore {
class AudioFIFO {
public:
// Create a FIFO large enough to hold |fifoLength| frames of data of |numberOfChannels| channels.
AudioFIFO(unsigned numberOfChannels, size_t fifoLength);
// Push the data from the bus into the FIFO.
void push(const AudioBus*);
// Consume |framesToConsume| frames of data from the FIFO and put them in |destination|. The
// corresponding frames are removed from the FIFO.
void consume(AudioBus* destination, size_t framesToConsume);
// Number of frames of data that are currently in the FIFO.
size_t framesInFifo() const { return m_framesInFifo; }
private:
// Update the FIFO index by the step, with appropriate wrapping around the endpoint.
int updateIndex(int index, int step) { return (index + step) % m_fifoLength; }
void findWrapLengths(size_t index, size_t providerSize, size_t& part1Length, size_t& part2Length);
// The FIFO itself. In reality, the FIFO is a circular buffer.
RefPtr<AudioBus> m_fifoAudioBus;
// The total available space in the FIFO.
size_t m_fifoLength;
// The number of actual elements in the FIFO
size_t m_framesInFifo;
// Where to start reading from the FIFO.
size_t m_readIndex;
// Where to start writing to the FIFO.
size_t m_writeIndex;
};
} // namespace WebCore
#endif // AudioFIFO.h