Source/WebCore/webaudio/RealtimeAnalyserNode.cpp

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

#if ENABLE(WEB_AUDIO)

#include "RealtimeAnalyserNode.h"

#include "AudioNodeInput.h"
#include "AudioNodeOutput.h"

namespace WebCore {

RealtimeAnalyserNode::RealtimeAnalyserNode(AudioContext* context, double sampleRate)
    : AudioNode(context, sampleRate)
{
    addInput(adoptPtr(new AudioNodeInput(this)));
    addOutput(adoptPtr(new AudioNodeOutput(this, 2)));
    
    setType(NodeTypeAnalyser);
    
    initialize();
}

RealtimeAnalyserNode::~RealtimeAnalyserNode()
{
    uninitialize();
}

void RealtimeAnalyserNode::process(size_t framesToProcess)
{
    AudioBus* outputBus = output(0)->bus();

    if (!isInitialized() || !input(0)->isConnected()) {
        outputBus->zero();
        return;
    }

    AudioBus* inputBus = input(0)->bus();
    
    // Give the analyser the audio which is passing through this AudioNode.
    m_analyser.writeInput(inputBus, framesToProcess);

    // For in-place processing, our override of pullInputs() will just pass the audio data through unchanged if the channel count matches from input to output
    // (resulting in inputBus == outputBus).  Otherwise, do an up-mix to stereo.
    if (inputBus != outputBus)
        outputBus->copyFrom(*inputBus);
}

// We override pullInputs() as an optimization allowing this node to take advantage of in-place processing,
// where the input is simply passed through unprocessed to the output.
// Note: this only applies if the input and output channel counts match.
void RealtimeAnalyserNode::pullInputs(size_t framesToProcess)
{
    // Render input stream - try to render directly into output bus for pass-through processing where process() doesn't need to do anything...
    input(0)->pull(output(0)->bus(), framesToProcess);
}

void RealtimeAnalyserNode::reset()
{
    m_analyser.reset();
}

} // namespace WebCore

#endif // ENABLE(WEB_AUDIO)