Source/WebCore/Modules/webaudio/IIRDSPKernel.cpp

/*
 * Copyright 2016 The Chromium Authors. All rights reserved.
 * Copyright (C) 2020, Apple Inc. All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
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#include "config.h"

#if ENABLE(WEB_AUDIO)
#include "IIRDSPKernel.h"

namespace WebCore {

IIRDSPKernel::IIRDSPKernel(IIRProcessor& processor)
    : AudioDSPKernel(&processor)
    , m_iirFilter(processor.feedforward(), processor.feedback())
    , m_tailTime(m_iirFilter.tailTime(processor.sampleRate(), processor.isFilterStable()))
{
}

void IIRDSPKernel::getFrequencyResponse(unsigned length, const float* frequencyHz, float* magResponse, float* phaseResponse)
{
    ASSERT(frequencyHz);
    ASSERT(magResponse);
    ASSERT(phaseResponse);

    Vector<float> frequency(length);
    double nyquist = this->nyquist();

    // Convert from frequency in Hz to normalized frequency (0 -> 1), with 1 equal to the Nyquist frequency.
    for (unsigned k = 0; k < length; ++k)
        frequency[k] = frequencyHz[k] / nyquist;

    m_iirFilter.getFrequencyResponse(length, frequency.data(), magResponse, phaseResponse);
}

void IIRDSPKernel::process(const float* source, float* destination, size_t framesToProcess)
{
    ASSERT(source);
    ASSERT(destination);

    m_iirFilter.process(source, destination, framesToProcess);
}

void IIRDSPKernel::reset()
{
    m_iirFilter.reset();
}

bool IIRDSPKernel::requiresTailProcessing() const
{
    // Always return true even if the tail time and latency might both be zero.
    return true;
}

} // namespace WebCore

#endif // ENABLE(WEB_AUDIO)