/*

 * 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 "ReverbInputBuffer.h"

#include "mozilla/PodOperations.h"

using namespace mozilla;

namespace WebCore {

ReverbInputBuffer::ReverbInputBuffer(size_t length)

    : m_writeIndex(0)

{

  m_buffer.SetLength(length);

  PodZero(m_buffer.Elements(), length);

}

void ReverbInputBuffer::write(const float* sourceP, size_t numberOfFrames)

{

    size_t bufferLength = m_buffer.Length();

    bool isCopySafe = m_writeIndex + numberOfFrames <= bufferLength;

    MOZ_ASSERT(isCopySafe);

    if (!isCopySafe)

        return;

    memcpy(m_buffer.Elements() + m_writeIndex, sourceP, sizeof(float) * numberOfFrames);

    m_writeIndex += numberOfFrames;

    MOZ_ASSERT(m_writeIndex <= bufferLength);

    if (m_writeIndex >= bufferLength)

        m_writeIndex = 0;

}

float* ReverbInputBuffer::directReadFrom(int* readIndex, size_t numberOfFrames)

{

    size_t bufferLength = m_buffer.Length();

    bool isPointerGood = readIndex && *readIndex >= 0 && *readIndex + numberOfFrames <= bufferLength;

    MOZ_ASSERT(isPointerGood);

    if (!isPointerGood) {

        // Should never happen in practice but return pointer to start of buffer (avoid crash)

        if (readIndex)

            *readIndex = 0;

        return m_buffer.Elements();

    }

    float* sourceP = m_buffer.Elements();

    float* p = sourceP + *readIndex;

    // Update readIndex

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

    return p;

}

void ReverbInputBuffer::reset()

{

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

    m_writeIndex = 0;

}

} // namespace WebCore