michael@0: /*
michael@0:  * Copyright (C) 2010 Google Inc. All rights reserved.
michael@0:  *
michael@0:  * Redistribution and use in source and binary forms, with or without
michael@0:  * modification, are permitted provided that the following conditions
michael@0:  * are met:
michael@0:  *
michael@0:  * 1.  Redistributions of source code must retain the above copyright
michael@0:  *     notice, this list of conditions and the following disclaimer.
michael@0:  * 2.  Redistributions in binary form must reproduce the above copyright
michael@0:  *     notice, this list of conditions and the following disclaimer in the
michael@0:  *     documentation and/or other materials provided with the distribution.
michael@0:  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
michael@0:  *     its contributors may be used to endorse or promote products derived
michael@0:  *     from this software without specific prior written permission.
michael@0:  *
michael@0:  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
michael@0:  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
michael@0:  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
michael@0:  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
michael@0:  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
michael@0:  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
michael@0:  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
michael@0:  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
michael@0:  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
michael@0:  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
michael@0:  */
michael@0: 
michael@0: #include "ReverbAccumulationBuffer.h"
michael@0: #include "AudioNodeEngine.h"
michael@0: #include "mozilla/PodOperations.h"
michael@0: #include <algorithm>
michael@0: 
michael@0: using namespace mozilla;
michael@0: 
michael@0: namespace WebCore {
michael@0: 
michael@0: ReverbAccumulationBuffer::ReverbAccumulationBuffer(size_t length)
michael@0:     : m_readIndex(0)
michael@0:     , m_readTimeFrame(0)
michael@0: {
michael@0:   m_buffer.SetLength(length);
michael@0:   PodZero(m_buffer.Elements(), length);
michael@0: }
michael@0: 
michael@0: void ReverbAccumulationBuffer::readAndClear(float* destination, size_t numberOfFrames)
michael@0: {
michael@0:     size_t bufferLength = m_buffer.Length();
michael@0:     bool isCopySafe = m_readIndex <= bufferLength && numberOfFrames <= bufferLength;
michael@0: 
michael@0:     MOZ_ASSERT(isCopySafe);
michael@0:     if (!isCopySafe)
michael@0:         return;
michael@0: 
michael@0:     size_t framesAvailable = bufferLength - m_readIndex;
michael@0:     size_t numberOfFrames1 = std::min(numberOfFrames, framesAvailable);
michael@0:     size_t numberOfFrames2 = numberOfFrames - numberOfFrames1;
michael@0: 
michael@0:     float* source = m_buffer.Elements();
michael@0:     memcpy(destination, source + m_readIndex, sizeof(float) * numberOfFrames1);
michael@0:     memset(source + m_readIndex, 0, sizeof(float) * numberOfFrames1);
michael@0: 
michael@0:     // Handle wrap-around if necessary
michael@0:     if (numberOfFrames2 > 0) {
michael@0:         memcpy(destination + numberOfFrames1, source, sizeof(float) * numberOfFrames2);
michael@0:         memset(source, 0, sizeof(float) * numberOfFrames2);
michael@0:     }
michael@0: 
michael@0:     m_readIndex = (m_readIndex + numberOfFrames) % bufferLength;
michael@0:     m_readTimeFrame += numberOfFrames;
michael@0: }
michael@0: 
michael@0: void ReverbAccumulationBuffer::updateReadIndex(int* readIndex, size_t numberOfFrames) const
michael@0: {
michael@0:     // Update caller's readIndex
michael@0:     *readIndex = (*readIndex + numberOfFrames) % m_buffer.Length();
michael@0: }
michael@0: 
michael@0: int ReverbAccumulationBuffer::accumulate(float* source, size_t numberOfFrames, int* readIndex, size_t delayFrames)
michael@0: {
michael@0:     size_t bufferLength = m_buffer.Length();
michael@0: 
michael@0:     size_t writeIndex = (*readIndex + delayFrames) % bufferLength;
michael@0: 
michael@0:     // Update caller's readIndex
michael@0:     *readIndex = (*readIndex + numberOfFrames) % bufferLength;
michael@0: 
michael@0:     size_t framesAvailable = bufferLength - writeIndex;
michael@0:     size_t numberOfFrames1 = std::min(numberOfFrames, framesAvailable);
michael@0:     size_t numberOfFrames2 = numberOfFrames - numberOfFrames1;
michael@0: 
michael@0:     float* destination = m_buffer.Elements();
michael@0: 
michael@0:     bool isSafe = writeIndex <= bufferLength && numberOfFrames1 + writeIndex <= bufferLength && numberOfFrames2 <= bufferLength;
michael@0:     MOZ_ASSERT(isSafe);
michael@0:     if (!isSafe)
michael@0:         return 0;
michael@0: 
michael@0:     AudioBufferAddWithScale(source, 1.0f, destination + writeIndex, numberOfFrames1);
michael@0: 
michael@0:     // Handle wrap-around if necessary
michael@0:     if (numberOfFrames2 > 0) {
michael@0:         AudioBufferAddWithScale(source + numberOfFrames1, 1.0f, destination, numberOfFrames2);
michael@0:     }
michael@0: 
michael@0:     return writeIndex;
michael@0: }
michael@0: 
michael@0: void ReverbAccumulationBuffer::reset()
michael@0: {
michael@0:     PodZero(m_buffer.Elements(), m_buffer.Length());
michael@0:     m_readIndex = 0;
michael@0:     m_readTimeFrame = 0;
michael@0: }
michael@0: 
michael@0: } // namespace WebCore