Source/WebCore/Modules/webaudio/DelayDSPKernel.h

/*
 * Copyright (C) 2010, Google Inc. All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
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 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
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#pragma once

#include "AudioArray.h"
#include "AudioDSPKernel.h"
#include "DelayProcessor.h"

namespace WebCore {

class DelayProcessor;
    
class DelayDSPKernel final : public AudioDSPKernel {
public:  
    explicit DelayDSPKernel(DelayProcessor*);
    DelayDSPKernel(double maxDelayTime, float sampleRate);
    
    void process(const float* source, float* destination, size_t framesToProcess) override;
    void processOnlyAudioParams(size_t framesToProcess) final;
    void reset() override;
    
    double maxDelayTime() const { return m_maxDelayTime; }
    
    void setDelayFrames(double numberOfFrames) { m_desiredDelayFrames = numberOfFrames; }

    double tailTime() const override;
    double latencyTime() const override;
    bool requiresTailProcessing() const final;

private:
    void processARate(const float* source, float* destination, size_t framesToProcess);
    void processKRate(const float* source, float* destination, size_t framesToProcess);

    AudioFloatArray m_buffer;
    double m_maxDelayTime;
    size_t m_writeIndex { 0 };
    double m_desiredDelayFrames;

    AudioFloatArray m_delayTimes;
    // Temporary buffer used to hold the second sample for interpolation if needed.
    AudioFloatArray m_tempBuffer;

    DelayProcessor* delayProcessor() { return static_cast<DelayProcessor*>(processor()); }
};

} // namespace WebCore