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 "FFTConvolver.h"
michael@0: #include "mozilla/PodOperations.h"
michael@0: 
michael@0: using namespace mozilla;
michael@0: 
michael@0: namespace WebCore {
michael@0: 
michael@0: FFTConvolver::FFTConvolver(size_t fftSize)
michael@0:     : m_frame(fftSize)
michael@0:     , m_readWriteIndex(0)
michael@0: {
michael@0:   m_inputBuffer.SetLength(fftSize);
michael@0:   PodZero(m_inputBuffer.Elements(), fftSize);
michael@0:   m_outputBuffer.SetLength(fftSize);
michael@0:   PodZero(m_outputBuffer.Elements(), fftSize);
michael@0:   m_lastOverlapBuffer.SetLength(fftSize / 2);
michael@0:   PodZero(m_lastOverlapBuffer.Elements(), fftSize / 2);
michael@0: }
michael@0: 
michael@0: size_t FFTConvolver::sizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
michael@0: {
michael@0:     size_t amount = 0;
michael@0:     amount += m_frame.SizeOfExcludingThis(aMallocSizeOf);
michael@0:     amount += m_inputBuffer.SizeOfExcludingThis(aMallocSizeOf);
michael@0:     amount += m_outputBuffer.SizeOfExcludingThis(aMallocSizeOf);
michael@0:     amount += m_lastOverlapBuffer.SizeOfExcludingThis(aMallocSizeOf);
michael@0:     return amount;
michael@0: }
michael@0: 
michael@0: size_t FFTConvolver::sizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
michael@0: {
michael@0:   return aMallocSizeOf(this) + sizeOfExcludingThis(aMallocSizeOf);
michael@0: }
michael@0: 
michael@0: void FFTConvolver::process(FFTBlock* fftKernel, const float* sourceP, float* destP, size_t framesToProcess)
michael@0: {
michael@0:     size_t halfSize = fftSize() / 2;
michael@0: 
michael@0:     // framesToProcess must be an exact multiple of halfSize,
michael@0:     // or halfSize is a multiple of framesToProcess when halfSize > framesToProcess.
michael@0:     bool isGood = !(halfSize % framesToProcess && framesToProcess % halfSize);
michael@0:     MOZ_ASSERT(isGood);
michael@0:     if (!isGood)
michael@0:         return;
michael@0: 
michael@0:     size_t numberOfDivisions = halfSize <= framesToProcess ? (framesToProcess / halfSize) : 1;
michael@0:     size_t divisionSize = numberOfDivisions == 1 ? framesToProcess : halfSize;
michael@0: 
michael@0:     for (size_t i = 0; i < numberOfDivisions; ++i, sourceP += divisionSize, destP += divisionSize) {
michael@0:         // Copy samples to input buffer (note contraint above!)
michael@0:         float* inputP = m_inputBuffer.Elements();
michael@0: 
michael@0:         // Sanity check
michael@0:         bool isCopyGood1 = sourceP && inputP && m_readWriteIndex + divisionSize <= m_inputBuffer.Length();
michael@0:         MOZ_ASSERT(isCopyGood1);
michael@0:         if (!isCopyGood1)
michael@0:             return;
michael@0: 
michael@0:         memcpy(inputP + m_readWriteIndex, sourceP, sizeof(float) * divisionSize);
michael@0: 
michael@0:         // Copy samples from output buffer
michael@0:         float* outputP = m_outputBuffer.Elements();
michael@0: 
michael@0:         // Sanity check
michael@0:         bool isCopyGood2 = destP && outputP && m_readWriteIndex + divisionSize <= m_outputBuffer.Length();
michael@0:         MOZ_ASSERT(isCopyGood2);
michael@0:         if (!isCopyGood2)
michael@0:             return;
michael@0: 
michael@0:         memcpy(destP, outputP + m_readWriteIndex, sizeof(float) * divisionSize);
michael@0:         m_readWriteIndex += divisionSize;
michael@0: 
michael@0:         // Check if it's time to perform the next FFT
michael@0:         if (m_readWriteIndex == halfSize) {
michael@0:             // The input buffer is now filled (get frequency-domain version)
michael@0:             m_frame.PerformFFT(m_inputBuffer.Elements());
michael@0:             m_frame.Multiply(*fftKernel);
michael@0:             m_frame.GetInverseWithoutScaling(m_outputBuffer.Elements());
michael@0: 
michael@0:             // Overlap-add 1st half from previous time
michael@0:             AudioBufferAddWithScale(m_lastOverlapBuffer.Elements(), 1.0f,
michael@0:                                     m_outputBuffer.Elements(), halfSize);
michael@0: 
michael@0:             // Finally, save 2nd half of result
michael@0:             bool isCopyGood3 = m_outputBuffer.Length() == 2 * halfSize && m_lastOverlapBuffer.Length() == halfSize;
michael@0:             MOZ_ASSERT(isCopyGood3);
michael@0:             if (!isCopyGood3)
michael@0:                 return;
michael@0: 
michael@0:             memcpy(m_lastOverlapBuffer.Elements(), m_outputBuffer.Elements() + halfSize, sizeof(float) * halfSize);
michael@0: 
michael@0:             // Reset index back to start for next time
michael@0:             m_readWriteIndex = 0;
michael@0:         }
michael@0:     }
michael@0: }
michael@0: 
michael@0: void FFTConvolver::reset()
michael@0: {
michael@0:     PodZero(m_lastOverlapBuffer.Elements(), m_lastOverlapBuffer.Length());
michael@0:     m_readWriteIndex = 0;
michael@0: }
michael@0: 
michael@0: } // namespace WebCore