/*
 * Copyright (C) 2010 Google Inc. All rights reserved.
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 * 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.
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 *     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
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#include "ReverbConvolverStage.h"

#include "ReverbAccumulationBuffer.h"
#include "ReverbConvolver.h"
#include "ReverbInputBuffer.h"
#include "mozilla/PodOperations.h"

using namespace mozilla;

namespace WebCore {

ReverbConvolverStage::ReverbConvolverStage(
    const float* impulseResponse, size_t, size_t reverbTotalLatency,
    size_t stageOffset, size_t stageLength, size_t fftSize, size_t renderPhase,
    ReverbAccumulationBuffer* accumulationBuffer)
    : m_accumulationBuffer(accumulationBuffer),
      m_accumulationReadIndex(0),
      m_inputReadIndex(0) {
  MOZ_ASSERT(impulseResponse);
  MOZ_ASSERT(accumulationBuffer);

  m_fftKernel = MakeUnique<FFTBlock>(fftSize);
  m_fftKernel->PadAndMakeScaledDFT(impulseResponse + stageOffset, stageLength);
  m_fftConvolver = MakeUnique<FFTConvolver>(fftSize, renderPhase);

  // The convolution stage at offset stageOffset needs to have a corresponding
  // delay to cancel out the offset.
  size_t totalDelay = stageOffset + reverbTotalLatency;

  // But, the FFT convolution itself incurs latency, so subtract this out...
  size_t fftLatency = m_fftConvolver->latencyFrames();
  MOZ_ASSERT(totalDelay >= fftLatency);
  totalDelay -= fftLatency;

  m_postDelayLength = totalDelay;
}

size_t ReverbConvolverStage::sizeOfIncludingThis(
    mozilla::MallocSizeOf aMallocSizeOf) const {
  size_t amount = aMallocSizeOf(this);

  if (m_fftKernel) {
    amount += m_fftKernel->SizeOfIncludingThis(aMallocSizeOf);
  }

  if (m_fftConvolver) {
    amount += m_fftConvolver->sizeOfIncludingThis(aMallocSizeOf);
  }

  return amount;
}

void ReverbConvolverStage::processInBackground(ReverbConvolver* convolver) {
  ReverbInputBuffer* inputBuffer = convolver->inputBuffer();
  float* source =
      inputBuffer->directReadFrom(&m_inputReadIndex, WEBAUDIO_BLOCK_SIZE);
  process(source);
}

void ReverbConvolverStage::process(const float* source) {
  MOZ_ASSERT(source);
  if (!source) return;

  // Now, run the convolution (into the delay buffer).
  // An expensive FFT will happen every fftSize / 2 frames.
  const float* output = m_fftConvolver->process(m_fftKernel.get(), source);

  // Now accumulate into reverb's accumulation buffer.
  m_accumulationBuffer->accumulate(output, WEBAUDIO_BLOCK_SIZE,
                                   &m_accumulationReadIndex, m_postDelayLength);
}

}  // namespace WebCore