Source/modules/webaudio/DelayDSPKernel.cpp

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

#if ENABLE(WEB_AUDIO)

#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, AudioNode::ProcessingSizeInFrames)
{
    ASSERT(processor && processor->sampleRate() > 0);
    if (!(processor && processor->sampleRate() > 0))
        return;

    m_maxDelayTime = processor->maxDelayTime();
    ASSERT(m_maxDelayTime >= 0 && !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 delayProcessor()->delayTime()->hasSampleAccurateValues();
}

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

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

} // namespace blink

#endif // ENABLE(WEB_AUDIO)