third_party/WebKit/Source/modules/webaudio/DelayDSPKernel.cpp

/*
 * Copyright (C) 2010, Google Inc. All rights reserved.
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#include "modules/webaudio/DelayDSPKernel.h"
#include "platform/audio/AudioUtilities.h"
#include "wtf/MathExtras.h"
#include <algorithm>

namespace blink {

const float SmoothingTimeConstant = 0.020f;  // 20ms

DelayDSPKernel::DelayDSPKernel(DelayProcessor* processor)
    : AudioDelayDSPKernel(processor, AudioHandler::ProcessingSizeInFrames) {
  DCHECK(processor);
  DCHECK_GT(processor->sampleRate(), 0);
  if (!(processor && processor->sampleRate() > 0))
    return;

  m_maxDelayTime = processor->maxDelayTime();
  DCHECK_GE(m_maxDelayTime, 0);
  DCHECK(!std::isnan(m_maxDelayTime));
  if (m_maxDelayTime < 0 || std::isnan(m_maxDelayTime))
    return;

  m_buffer.allocate(
      bufferLengthForDelay(m_maxDelayTime, processor->sampleRate()));
  m_buffer.zero();

  m_smoothingRate = AudioUtilities::discreteTimeConstantForSampleRate(
      SmoothingTimeConstant, processor->sampleRate());
}

bool DelayDSPKernel::hasSampleAccurateValues() {
  return getDelayProcessor()->delayTime().hasSampleAccurateValues();
}

void DelayDSPKernel::calculateSampleAccurateValues(float* delayTimes,
                                                   size_t framesToProcess) {
  getDelayProcessor()->delayTime().calculateSampleAccurateValues(
      delayTimes, framesToProcess);
}

double DelayDSPKernel::delayTime(float) {
  return getDelayProcessor()->delayTime().finalValue();
}

}  // namespace blink