WaveShaperNode.cpp   [plain text]

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#include "config.h"
#include "WaveShaperNode.h"

#if ENABLE(WEB_AUDIO)

#include "AudioContext.h"
#include <JavaScriptCore/JSCInlines.h>
#include <JavaScriptCore/TypedArrayInlines.h>
#include <wtf/IsoMallocInlines.h>
#include <wtf/MainThread.h>

namespace WebCore {

WTF_MAKE_ISO_ALLOCATED_IMPL(WaveShaperNode);

ExceptionOr<Ref<WaveShaperNode>> WaveShaperNode::create(BaseAudioContext& context, const WaveShaperOptions& options)
{
    if (context.isStopped())
        return Exception { InvalidStateError };

    context.lazyInitialize();
    UNUSED_PARAM(options);

    RefPtr<Float32Array> curve;
    if (options.curve) {
        curve = Float32Array::tryCreate(options.curve->data(), options.curve->size());
        if (!curve)
            return Exception { InvalidStateError, "Invalid curve parameter" };
    }

    auto node = adoptRef(*new WaveShaperNode(context));

    auto result = node->handleAudioNodeOptions(options, { 2, ChannelCountMode::Max, ChannelInterpretation::Speakers });
    if (result.hasException())
        return result.releaseException();

    if (curve) {
        result = node->setCurve(WTFMove(curve));
        if (result.hasException())
            return result.releaseException();
    }

    node->setOversample(options.oversample);

    return node;
}

WaveShaperNode::WaveShaperNode(BaseAudioContext& context)
    : AudioBasicProcessorNode(context)
{
    setNodeType(NodeTypeWaveShaper);
    m_processor = makeUnique<WaveShaperProcessor>(context.sampleRate(), 1);

    initialize();
}

ExceptionOr<void> WaveShaperNode::setCurve(RefPtr<Float32Array>&& curve)
{
    ASSERT(isMainThread()); 
    DEBUG_LOG(LOGIDENTIFIER);
    if (curve && curve->length() < 2)
        return Exception { InvalidStateError, "Length of curve array cannot be less than 2" };

    if (curve) {
        // The specification states that we should maintain an internal copy of the curve so that
        // subsequent modifications of the contents of the array have no effect.
        auto clonedCurve = Float32Array::create(curve->data(), curve->length());
        curve = WTFMove(clonedCurve);
    }

    waveShaperProcessor()->setCurve(curve.get());
    return { };
}

Float32Array* WaveShaperNode::curve()
{
    return waveShaperProcessor()->curve();
}

static inline WaveShaperProcessor::OverSampleType processorType(OverSampleType type)
{
    switch (type) {
    case OverSampleType::None:
        return WaveShaperProcessor::OverSampleNone;
    case OverSampleType::_2x:
        return WaveShaperProcessor::OverSample2x;
    case OverSampleType::_4x:
        return WaveShaperProcessor::OverSample4x;
    }
    ASSERT_NOT_REACHED();
    return WaveShaperProcessor::OverSampleNone;
}

void WaveShaperNode::setOversample(OverSampleType type)
{
    ASSERT(isMainThread());
    INFO_LOG(LOGIDENTIFIER, type);

    // Synchronize with any graph changes or changes to channel configuration.
    AudioContext::AutoLocker contextLocker(context());
    waveShaperProcessor()->setOversample(processorType(type));
}

auto WaveShaperNode::oversample() const -> OverSampleType
{
    switch (const_cast<WaveShaperNode*>(this)->waveShaperProcessor()->oversample()) {
    case WaveShaperProcessor::OverSampleNone:
        return OverSampleType::None;
    case WaveShaperProcessor::OverSample2x:
        return OverSampleType::_2x;
    case WaveShaperProcessor::OverSample4x:
        return OverSampleType::_4x;
    }
    ASSERT_NOT_REACHED();
    return OverSampleType::None;
}

bool WaveShaperNode::propagatesSilence() const
{
    auto curve = const_cast<WaveShaperNode*>(this)->curve();
    return !curve || !curve->length();
}

} // namespace WebCore

#endif // ENABLE(WEB_AUDIO)