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 "ReverbInputBuffer.h"
michael@0: #include "mozilla/PodOperations.h"
michael@0: 
michael@0: using namespace mozilla;
michael@0: 
michael@0: namespace WebCore {
michael@0: 
michael@0: ReverbInputBuffer::ReverbInputBuffer(size_t length)
michael@0:     : m_writeIndex(0)
michael@0: {
michael@0:   m_buffer.SetLength(length);
michael@0:   PodZero(m_buffer.Elements(), length);
michael@0: }
michael@0: 
michael@0: void ReverbInputBuffer::write(const float* sourceP, size_t numberOfFrames)
michael@0: {
michael@0:     size_t bufferLength = m_buffer.Length();
michael@0:     bool isCopySafe = m_writeIndex + numberOfFrames <= bufferLength;
michael@0:     MOZ_ASSERT(isCopySafe);
michael@0:     if (!isCopySafe)
michael@0:         return;
michael@0: 
michael@0:     memcpy(m_buffer.Elements() + m_writeIndex, sourceP, sizeof(float) * numberOfFrames);
michael@0: 
michael@0:     m_writeIndex += numberOfFrames;
michael@0:     MOZ_ASSERT(m_writeIndex <= bufferLength);
michael@0: 
michael@0:     if (m_writeIndex >= bufferLength)
michael@0:         m_writeIndex = 0;
michael@0: }
michael@0: 
michael@0: float* ReverbInputBuffer::directReadFrom(int* readIndex, size_t numberOfFrames)
michael@0: {
michael@0:     size_t bufferLength = m_buffer.Length();
michael@0:     bool isPointerGood = readIndex && *readIndex >= 0 && *readIndex + numberOfFrames <= bufferLength;
michael@0:     MOZ_ASSERT(isPointerGood);
michael@0:     if (!isPointerGood) {
michael@0:         // Should never happen in practice but return pointer to start of buffer (avoid crash)
michael@0:         if (readIndex)
michael@0:             *readIndex = 0;
michael@0:         return m_buffer.Elements();
michael@0:     }
michael@0: 
michael@0:     float* sourceP = m_buffer.Elements();
michael@0:     float* p = sourceP + *readIndex;
michael@0: 
michael@0:     // Update readIndex
michael@0:     *readIndex = (*readIndex + numberOfFrames) % bufferLength;
michael@0: 
michael@0:     return p;
michael@0: }
michael@0: 
michael@0: void ReverbInputBuffer::reset()
michael@0: {
michael@0:     PodZero(m_buffer.Elements(), m_buffer.Length());
michael@0:     m_writeIndex = 0;
michael@0: }
michael@0: 
michael@0: } // namespace WebCore