/*

 * Copyright (C) 2010 Google Inc. All rights reserved.

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 * 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

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 * 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

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 */

#ifndef ReverbAccumulationBuffer_h

#define ReverbAccumulationBuffer_h

#include "AlignedTArray.h"

#include "mozilla/MemoryReporting.h"

namespace WebCore {

// ReverbAccumulationBuffer is a circular delay buffer with one client reading from it and multiple clients

// writing/accumulating to it at different delay offsets from the read position.  The read operation will zero the memory

// just read from the buffer, so it will be ready for accumulation the next time around.

class ReverbAccumulationBuffer {

public:

    explicit ReverbAccumulationBuffer(size_t length);

    // This will read from, then clear-out numberOfFrames

    void readAndClear(float* destination, size_t numberOfFrames);

    // Each ReverbConvolverStage will accumulate its output at the appropriate delay from the read position.

    // We need to pass in and update readIndex here, since each ReverbConvolverStage may be running in

    // a different thread than the realtime thread calling ReadAndClear() and maintaining m_readIndex

    // Returns the writeIndex where the accumulation took place

    int accumulate(const float* source, size_t numberOfFrames, int* readIndex, size_t delayFrames);

    size_t readIndex() const { return m_readIndex; }

    void updateReadIndex(int* readIndex, size_t numberOfFrames) const;

    size_t readTimeFrame() const { return m_readTimeFrame; }

    void reset();

    size_t sizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const

    {

        return m_buffer.ShallowSizeOfExcludingThis(aMallocSizeOf);

    }

private:

    AlignedTArray<float, 16> m_buffer;

    size_t m_readIndex;

    size_t m_readTimeFrame; // for debugging (frame on continuous timeline)

};

} // namespace WebCore

#endif // ReverbAccumulationBuffer_h