/*

 * Copyright (C) 2010 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;

 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND

 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#include "ReverbAccumulationBuffer.h"

#include "AudioNodeEngine.h"

#include "mozilla/PodOperations.h"

#include <algorithm>

using namespace mozilla;

namespace WebCore {

ReverbAccumulationBuffer::ReverbAccumulationBuffer(size_t length)

    : m_readIndex(0)

    , m_readTimeFrame(0)

{

  m_buffer.SetLength(length);

  PodZero(m_buffer.Elements(), length);

}

void ReverbAccumulationBuffer::readAndClear(float* destination, size_t numberOfFrames)

{

    size_t bufferLength = m_buffer.Length();

    bool isCopySafe = m_readIndex <= bufferLength && numberOfFrames <= bufferLength;

    MOZ_ASSERT(isCopySafe);

    if (!isCopySafe)

        return;

    size_t framesAvailable = bufferLength - m_readIndex;

    size_t numberOfFrames1 = std::min(numberOfFrames, framesAvailable);

    size_t numberOfFrames2 = numberOfFrames - numberOfFrames1;

    float* source = m_buffer.Elements();

    memcpy(destination, source + m_readIndex, sizeof(float) * numberOfFrames1);

    memset(source + m_readIndex, 0, sizeof(float) * numberOfFrames1);

    // Handle wrap-around if necessary

    if (numberOfFrames2 > 0) {

        memcpy(destination + numberOfFrames1, source, sizeof(float) * numberOfFrames2);

        memset(source, 0, sizeof(float) * numberOfFrames2);

    }

    m_readIndex = (m_readIndex + numberOfFrames) % bufferLength;

    m_readTimeFrame += numberOfFrames;

}

void ReverbAccumulationBuffer::updateReadIndex(int* readIndex, size_t numberOfFrames) const

{

    // Update caller's readIndex

    *readIndex = (*readIndex + numberOfFrames) % m_buffer.Length();

}

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

{

    size_t bufferLength = m_buffer.Length();

    size_t writeIndex = (*readIndex + delayFrames) % bufferLength;

    // Update caller's readIndex

    *readIndex = (*readIndex + numberOfFrames) % bufferLength;

    size_t framesAvailable = bufferLength - writeIndex;

    size_t numberOfFrames1 = std::min(numberOfFrames, framesAvailable);

    size_t numberOfFrames2 = numberOfFrames - numberOfFrames1;

    float* destination = m_buffer.Elements();

    bool isSafe = writeIndex <= bufferLength && numberOfFrames1 + writeIndex <= bufferLength && numberOfFrames2 <= bufferLength;

    MOZ_ASSERT(isSafe);

    if (!isSafe)

        return 0;

    AudioBufferAddWithScale(source, 1.0f, destination + writeIndex, numberOfFrames1);

    if (numberOfFrames2 > 0) {

        AudioBufferAddWithScale(source + numberOfFrames1, 1.0f, destination, numberOfFrames2);

    }

    return writeIndex;

}

void ReverbAccumulationBuffer::reset()

{

    PodZero(m_buffer.Elements(), m_buffer.Length());

    m_readIndex = 0;

    m_readTimeFrame = 0;

}

} // namespace WebCore