Source/WebCore/Modules/webaudio/OscillatorNode.cpp - WebKit - Git at Google

 /*
  * Copyright (C) 2012, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1.  Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
  * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 #include "config.h"

 #if ENABLE(WEB_AUDIO)

 #include "OscillatorNode.h"

 #include "AudioNodeOutput.h"
 #include "AudioParam.h"
 #include "PeriodicWave.h"
 #include "VectorMath.h"
 #include <wtf/IsoMallocInlines.h>

 namespace WebCore {

 using namespace VectorMath;

 WTF_MAKE_ISO_ALLOCATED_IMPL(OscillatorNode);

 PeriodicWave* OscillatorNode::s_periodicWaveSine = nullptr;
 PeriodicWave* OscillatorNode::s_periodicWaveSquare = nullptr;
 PeriodicWave* OscillatorNode::s_periodicWaveSawtooth = nullptr;
 PeriodicWave* OscillatorNode::s_periodicWaveTriangle = nullptr;

 Ref<OscillatorNode> OscillatorNode::create(AudioContext& context, float sampleRate)
 {
     return adoptRef(*new OscillatorNode(context, sampleRate));
 }

 OscillatorNode::OscillatorNode(AudioContext& context, float sampleRate)
     : AudioScheduledSourceNode(context, sampleRate)
     , m_firstRender(true)
     , m_virtualReadIndex(0)
     , m_phaseIncrements(AudioNode::ProcessingSizeInFrames)
     , m_detuneValues(AudioNode::ProcessingSizeInFrames)
 {
     setNodeType(NodeTypeOscillator);

     // Use musical pitch standard A440 as a default.
     m_frequency = AudioParam::create(context, "frequency", 440, 0, 100000);
     // Default to no detuning.
     m_detune = AudioParam::create(context, "detune", 0, -4800, 4800);

     // Sets up default wave.
     setType(m_type);

     // An oscillator is always mono.
     addOutput(makeUnique<AudioNodeOutput>(this, 1));

     initialize();
 }

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

 ExceptionOr<void> OscillatorNode::setType(Type type)
 {
     PeriodicWave* periodicWave = nullptr;

     ALWAYS_LOG(LOGIDENTIFIER, type);

     switch (type) {
     case Type::Sine:
         if (!s_periodicWaveSine)
             s_periodicWaveSine = &PeriodicWave::createSine(sampleRate()).leakRef();
         periodicWave = s_periodicWaveSine;
         break;
     case Type::Square:
         if (!s_periodicWaveSquare)
             s_periodicWaveSquare = &PeriodicWave::createSquare(sampleRate()).leakRef();
         periodicWave = s_periodicWaveSquare;
         break;
     case Type::Sawtooth:
         if (!s_periodicWaveSawtooth)
             s_periodicWaveSawtooth = &PeriodicWave::createSawtooth(sampleRate()).leakRef();
         periodicWave = s_periodicWaveSawtooth;
         break;
     case Type::Triangle:
         if (!s_periodicWaveTriangle)
             s_periodicWaveTriangle = &PeriodicWave::createTriangle(sampleRate()).leakRef();
         periodicWave = s_periodicWaveTriangle;
         break;
     case Type::Custom:
         if (m_type != Type::Custom)
             return Exception { InvalidStateError };
         return { };
     }

     setPeriodicWave(periodicWave);
     m_type = type;

     return { };
 }

 bool OscillatorNode::calculateSampleAccuratePhaseIncrements(size_t framesToProcess)
 {
     bool isGood = framesToProcess <= m_phaseIncrements.size() && framesToProcess <= m_detuneValues.size();
     ASSERT(isGood);
     if (!isGood)
         return false;

     if (m_firstRender) {
         m_firstRender = false;
         m_frequency->resetSmoothedValue();
         m_detune->resetSmoothedValue();
     }

     bool hasSampleAccurateValues = false;
     bool hasFrequencyChanges = false;
     float* phaseIncrements = m_phaseIncrements.data();

     float finalScale = m_periodicWave->rateScale();

     if (m_frequency->hasSampleAccurateValues()) {
         hasSampleAccurateValues = true;
         hasFrequencyChanges = true;

         // Get the sample-accurate frequency values and convert to phase increments.
         // They will be converted to phase increments below.
         m_frequency->calculateSampleAccurateValues(phaseIncrements, framesToProcess);
     } else {
         // Handle ordinary parameter smoothing/de-zippering if there are no scheduled changes.
         m_frequency->smooth();
         float frequency = m_frequency->smoothedValue();
         finalScale *= frequency;
     }

     if (m_detune->hasSampleAccurateValues()) {
         hasSampleAccurateValues = true;

         // Get the sample-accurate detune values.
         float* detuneValues = hasFrequencyChanges ? m_detuneValues.data() : phaseIncrements;
         m_detune->calculateSampleAccurateValues(detuneValues, framesToProcess);

         // Convert from cents to rate scalar.
         float k = 1.0 / 1200;
         vsmul(detuneValues, 1, &k, detuneValues, 1, framesToProcess);
         for (unsigned i = 0; i < framesToProcess; ++i)
             detuneValues[i] = powf(2, detuneValues[i]); // FIXME: converting to expf() will be faster.

         if (hasFrequencyChanges) {
             // Multiply frequencies by detune scalings.
             vmul(detuneValues, 1, phaseIncrements, 1, phaseIncrements, 1, framesToProcess);
         }
     } else {
         // Handle ordinary parameter smoothing/de-zippering if there are no scheduled changes.
         m_detune->smooth();
         float detune = m_detune->smoothedValue();
         float detuneScale = powf(2, detune / 1200);
         finalScale *= detuneScale;
     }

     if (hasSampleAccurateValues) {
         // Convert from frequency to wave increment.
         vsmul(phaseIncrements, 1, &finalScale, phaseIncrements, 1, framesToProcess);
     }

     return hasSampleAccurateValues;
 }

 void OscillatorNode::process(size_t framesToProcess)
 {
     auto& outputBus = *output(0)->bus();

     if (!isInitialized() || !outputBus.numberOfChannels()) {
         outputBus.zero();
         return;
     }

     ASSERT(framesToProcess <= m_phaseIncrements.size());
     if (framesToProcess > m_phaseIncrements.size())
         return;

     // The audio thread can't block on this lock, so we use std::try_to_lock instead.
     std::unique_lock<Lock> lock(m_processMutex, std::try_to_lock);
     if (!lock.owns_lock()) {
         // Too bad - the try_lock() failed. We must be in the middle of changing wave-tables.
         outputBus.zero();
         return;
     }

     // We must access m_periodicWave only inside the lock.
     if (!m_periodicWave.get()) {
         outputBus.zero();
         return;
     }

     size_t quantumFrameOffset = 0;
     size_t nonSilentFramesToProcess = 0;
     updateSchedulingInfo(framesToProcess, outputBus, quantumFrameOffset, nonSilentFramesToProcess);

     if (!nonSilentFramesToProcess) {
         outputBus.zero();
         return;
     }

     unsigned periodicWaveSize = m_periodicWave->periodicWaveSize();
     double invPeriodicWaveSize = 1.0 / periodicWaveSize;

     float* destP = outputBus.channel(0)->mutableData();

     ASSERT(quantumFrameOffset <= framesToProcess);

     // We keep virtualReadIndex double-precision since we're accumulating values.
     double virtualReadIndex = m_virtualReadIndex;

     float rateScale = m_periodicWave->rateScale();
     float invRateScale = 1 / rateScale;
     bool hasSampleAccurateValues = calculateSampleAccuratePhaseIncrements(framesToProcess);

     float frequency = 0;
     float* higherWaveData = nullptr;
     float* lowerWaveData = nullptr;
     float tableInterpolationFactor = 0;

     if (!hasSampleAccurateValues) {
         frequency = m_frequency->smoothedValue();
         float detune = m_detune->smoothedValue();
         float detuneScale = powf(2, detune / 1200);
         frequency *= detuneScale;
         m_periodicWave->waveDataForFundamentalFrequency(frequency, lowerWaveData, higherWaveData, tableInterpolationFactor);
     }

     float incr = frequency * rateScale;
     float* phaseIncrements = m_phaseIncrements.data();

     unsigned readIndexMask = periodicWaveSize - 1;

     // Start rendering at the correct offset.
     destP += quantumFrameOffset;
     int n = nonSilentFramesToProcess;

     while (n--) {
         unsigned readIndex = static_cast<unsigned>(virtualReadIndex);
         unsigned readIndex2 = readIndex + 1;

         // Contain within valid range.
         readIndex = readIndex & readIndexMask;
         readIndex2 = readIndex2 & readIndexMask;

         if (hasSampleAccurateValues) {
             incr = *phaseIncrements++;

             frequency = invRateScale * incr;
             m_periodicWave->waveDataForFundamentalFrequency(frequency, lowerWaveData, higherWaveData, tableInterpolationFactor);
         }

         float sample1Lower = lowerWaveData[readIndex];
         float sample2Lower = lowerWaveData[readIndex2];
         float sample1Higher = higherWaveData[readIndex];
         float sample2Higher = higherWaveData[readIndex2];

         // Linearly interpolate within each table (lower and higher).
         float interpolationFactor = static_cast<float>(virtualReadIndex) - readIndex;
         float sampleHigher = (1 - interpolationFactor) * sample1Higher + interpolationFactor * sample2Higher;
         float sampleLower = (1 - interpolationFactor) * sample1Lower + interpolationFactor * sample2Lower;

         // Then interpolate between the two tables.
         float sample = (1 - tableInterpolationFactor) * sampleHigher + tableInterpolationFactor * sampleLower;

         *destP++ = sample;

         // Increment virtual read index and wrap virtualReadIndex into the range 0 -> periodicWaveSize.
         virtualReadIndex += incr;
         virtualReadIndex -= floor(virtualReadIndex * invPeriodicWaveSize) * periodicWaveSize;
     }

     m_virtualReadIndex = virtualReadIndex;

     outputBus.clearSilentFlag();
 }

 void OscillatorNode::reset()
 {
     m_virtualReadIndex = 0;
 }

 void OscillatorNode::setPeriodicWave(PeriodicWave* periodicWave)
 {
     ALWAYS_LOG(LOGIDENTIFIER, "sample rate = ", periodicWave ? periodicWave->sampleRate() : 0, ", wave size = ", periodicWave ? periodicWave->periodicWaveSize() : 0, ", rate scale = ", periodicWave ? periodicWave->rateScale() : 0);
     ASSERT(isMainThread());

     // This synchronizes with process().
     std::lock_guard<Lock> lock(m_processMutex);
     m_periodicWave = periodicWave;
     m_type = Type::Custom;
 }

 bool OscillatorNode::propagatesSilence() const
 {
     return !isPlayingOrScheduled() || hasFinished() || !m_periodicWave.get();
 }

 } // namespace WebCore

 #endif // ENABLE(WEB_AUDIO)
	/*
	* Copyright (C) 2012, Google Inc. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
	* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
	* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
	* DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
	* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
	* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
	* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
	* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
	* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#include "config.h"

	#if ENABLE(WEB_AUDIO)

	#include "OscillatorNode.h"

	#include "AudioNodeOutput.h"
	#include "AudioParam.h"
	#include "PeriodicWave.h"
	#include "VectorMath.h"
	#include <wtf/IsoMallocInlines.h>

	namespace WebCore {

	using namespace VectorMath;

	WTF_MAKE_ISO_ALLOCATED_IMPL(OscillatorNode);

	PeriodicWave* OscillatorNode::s_periodicWaveSine = nullptr;
	PeriodicWave* OscillatorNode::s_periodicWaveSquare = nullptr;
	PeriodicWave* OscillatorNode::s_periodicWaveSawtooth = nullptr;
	PeriodicWave* OscillatorNode::s_periodicWaveTriangle = nullptr;

	Ref<OscillatorNode> OscillatorNode::create(AudioContext& context, float sampleRate)
	{
	return adoptRef(*new OscillatorNode(context, sampleRate));
	}

	OscillatorNode::OscillatorNode(AudioContext& context, float sampleRate)
	: AudioScheduledSourceNode(context, sampleRate)
	, m_firstRender(true)
	, m_virtualReadIndex(0)
	, m_phaseIncrements(AudioNode::ProcessingSizeInFrames)
	, m_detuneValues(AudioNode::ProcessingSizeInFrames)
	{
	setNodeType(NodeTypeOscillator);

	// Use musical pitch standard A440 as a default.
	m_frequency = AudioParam::create(context, "frequency", 440, 0, 100000);
	// Default to no detuning.
	m_detune = AudioParam::create(context, "detune", 0, -4800, 4800);

	// Sets up default wave.
	setType(m_type);

	// An oscillator is always mono.
	addOutput(makeUnique<AudioNodeOutput>(this, 1));

	initialize();
	}

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

	ExceptionOr<void> OscillatorNode::setType(Type type)
	{
	PeriodicWave* periodicWave = nullptr;

	ALWAYS_LOG(LOGIDENTIFIER, type);

	switch (type) {
	case Type::Sine:
	if (!s_periodicWaveSine)
	s_periodicWaveSine = &PeriodicWave::createSine(sampleRate()).leakRef();
	periodicWave = s_periodicWaveSine;
	break;
	case Type::Square:
	if (!s_periodicWaveSquare)
	s_periodicWaveSquare = &PeriodicWave::createSquare(sampleRate()).leakRef();
	periodicWave = s_periodicWaveSquare;
	break;
	case Type::Sawtooth:
	if (!s_periodicWaveSawtooth)
	s_periodicWaveSawtooth = &PeriodicWave::createSawtooth(sampleRate()).leakRef();
	periodicWave = s_periodicWaveSawtooth;
	break;
	case Type::Triangle:
	if (!s_periodicWaveTriangle)
	s_periodicWaveTriangle = &PeriodicWave::createTriangle(sampleRate()).leakRef();
	periodicWave = s_periodicWaveTriangle;
	break;
	case Type::Custom:
	if (m_type != Type::Custom)
	return Exception { InvalidStateError };
	return { };
	}

	setPeriodicWave(periodicWave);
	m_type = type;

	return { };
	}

	bool OscillatorNode::calculateSampleAccuratePhaseIncrements(size_t framesToProcess)
	{
	bool isGood = framesToProcess <= m_phaseIncrements.size() && framesToProcess <= m_detuneValues.size();
	ASSERT(isGood);
	if (!isGood)
	return false;

	if (m_firstRender) {
	m_firstRender = false;
	m_frequency->resetSmoothedValue();
	m_detune->resetSmoothedValue();
	}

	bool hasSampleAccurateValues = false;
	bool hasFrequencyChanges = false;
	float* phaseIncrements = m_phaseIncrements.data();

	float finalScale = m_periodicWave->rateScale();

	if (m_frequency->hasSampleAccurateValues()) {
	hasSampleAccurateValues = true;
	hasFrequencyChanges = true;

	// Get the sample-accurate frequency values and convert to phase increments.
	// They will be converted to phase increments below.
	m_frequency->calculateSampleAccurateValues(phaseIncrements, framesToProcess);
	} else {
	// Handle ordinary parameter smoothing/de-zippering if there are no scheduled changes.
	m_frequency->smooth();
	float frequency = m_frequency->smoothedValue();
	finalScale *= frequency;
	}

	if (m_detune->hasSampleAccurateValues()) {
	hasSampleAccurateValues = true;

	// Get the sample-accurate detune values.
	float* detuneValues = hasFrequencyChanges ? m_detuneValues.data() : phaseIncrements;
	m_detune->calculateSampleAccurateValues(detuneValues, framesToProcess);

	// Convert from cents to rate scalar.
	float k = 1.0 / 1200;
	vsmul(detuneValues, 1, &k, detuneValues, 1, framesToProcess);
	for (unsigned i = 0; i < framesToProcess; ++i)
	detuneValues[i] = powf(2, detuneValues[i]); // FIXME: converting to expf() will be faster.

	if (hasFrequencyChanges) {
	// Multiply frequencies by detune scalings.
	vmul(detuneValues, 1, phaseIncrements, 1, phaseIncrements, 1, framesToProcess);
	}
	} else {
	// Handle ordinary parameter smoothing/de-zippering if there are no scheduled changes.
	m_detune->smooth();
	float detune = m_detune->smoothedValue();
	float detuneScale = powf(2, detune / 1200);
	finalScale *= detuneScale;
	}

	if (hasSampleAccurateValues) {
	// Convert from frequency to wave increment.
	vsmul(phaseIncrements, 1, &finalScale, phaseIncrements, 1, framesToProcess);
	}

	return hasSampleAccurateValues;
	}

	void OscillatorNode::process(size_t framesToProcess)
	{
	auto& outputBus = *output(0)->bus();

	if (!isInitialized() \|\| !outputBus.numberOfChannels()) {
	outputBus.zero();
	return;
	}

	ASSERT(framesToProcess <= m_phaseIncrements.size());
	if (framesToProcess > m_phaseIncrements.size())
	return;

	// The audio thread can't block on this lock, so we use std::try_to_lock instead.
	std::unique_lock<Lock> lock(m_processMutex, std::try_to_lock);
	if (!lock.owns_lock()) {
	// Too bad - the try_lock() failed. We must be in the middle of changing wave-tables.
	outputBus.zero();
	return;
	}

	// We must access m_periodicWave only inside the lock.
	if (!m_periodicWave.get()) {
	outputBus.zero();
	return;
	}

	size_t quantumFrameOffset = 0;
	size_t nonSilentFramesToProcess = 0;
	updateSchedulingInfo(framesToProcess, outputBus, quantumFrameOffset, nonSilentFramesToProcess);

	if (!nonSilentFramesToProcess) {
	outputBus.zero();
	return;
	}

	unsigned periodicWaveSize = m_periodicWave->periodicWaveSize();
	double invPeriodicWaveSize = 1.0 / periodicWaveSize;

	float* destP = outputBus.channel(0)->mutableData();

	ASSERT(quantumFrameOffset <= framesToProcess);

	// We keep virtualReadIndex double-precision since we're accumulating values.
	double virtualReadIndex = m_virtualReadIndex;

	float rateScale = m_periodicWave->rateScale();
	float invRateScale = 1 / rateScale;
	bool hasSampleAccurateValues = calculateSampleAccuratePhaseIncrements(framesToProcess);

	float frequency = 0;
	float* higherWaveData = nullptr;
	float* lowerWaveData = nullptr;
	float tableInterpolationFactor = 0;

	if (!hasSampleAccurateValues) {
	frequency = m_frequency->smoothedValue();
	float detune = m_detune->smoothedValue();
	float detuneScale = powf(2, detune / 1200);
	frequency *= detuneScale;
	m_periodicWave->waveDataForFundamentalFrequency(frequency, lowerWaveData, higherWaveData, tableInterpolationFactor);
	}

	float incr = frequency * rateScale;
	float* phaseIncrements = m_phaseIncrements.data();

	unsigned readIndexMask = periodicWaveSize - 1;

	// Start rendering at the correct offset.
	destP += quantumFrameOffset;
	int n = nonSilentFramesToProcess;

	while (n--) {
	unsigned readIndex = static_cast<unsigned>(virtualReadIndex);
	unsigned readIndex2 = readIndex + 1;

	// Contain within valid range.
	readIndex = readIndex & readIndexMask;
	readIndex2 = readIndex2 & readIndexMask;

	if (hasSampleAccurateValues) {
	incr = *phaseIncrements++;

	frequency = invRateScale * incr;
	m_periodicWave->waveDataForFundamentalFrequency(frequency, lowerWaveData, higherWaveData, tableInterpolationFactor);
	}

	float sample1Lower = lowerWaveData[readIndex];
	float sample2Lower = lowerWaveData[readIndex2];
	float sample1Higher = higherWaveData[readIndex];
	float sample2Higher = higherWaveData[readIndex2];

	// Linearly interpolate within each table (lower and higher).
	float interpolationFactor = static_cast<float>(virtualReadIndex) - readIndex;
	float sampleHigher = (1 - interpolationFactor) * sample1Higher + interpolationFactor * sample2Higher;
	float sampleLower = (1 - interpolationFactor) * sample1Lower + interpolationFactor * sample2Lower;

	// Then interpolate between the two tables.
	float sample = (1 - tableInterpolationFactor) * sampleHigher + tableInterpolationFactor * sampleLower;

	*destP++ = sample;

	// Increment virtual read index and wrap virtualReadIndex into the range 0 -> periodicWaveSize.
	virtualReadIndex += incr;
	virtualReadIndex -= floor(virtualReadIndex * invPeriodicWaveSize) * periodicWaveSize;
	}

	m_virtualReadIndex = virtualReadIndex;

	outputBus.clearSilentFlag();
	}

	void OscillatorNode::reset()
	{
	m_virtualReadIndex = 0;
	}

	void OscillatorNode::setPeriodicWave(PeriodicWave* periodicWave)
	{
	ALWAYS_LOG(LOGIDENTIFIER, "sample rate = ", periodicWave ? periodicWave->sampleRate() : 0, ", wave size = ", periodicWave ? periodicWave->periodicWaveSize() : 0, ", rate scale = ", periodicWave ? periodicWave->rateScale() : 0);
	ASSERT(isMainThread());

	// This synchronizes with process().
	std::lock_guard<Lock> lock(m_processMutex);
	m_periodicWave = periodicWave;
	m_type = Type::Custom;
	}

	bool OscillatorNode::propagatesSilence() const
	{
	return !isPlayingOrScheduled() \|\| hasFinished() \|\| !m_periodicWave.get();
	}

	} // namespace WebCore

	#endif // ENABLE(WEB_AUDIO)