third_party/WebKit/Source/modules/webaudio/ChannelSplitterNode.cpp

/*
 * Copyright (C) 2010, 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 "modules/webaudio/ChannelSplitterNode.h"
#include "bindings/core/v8/ExceptionMessages.h"
#include "bindings/core/v8/ExceptionState.h"
#include "core/dom/ExceptionCode.h"
#include "modules/webaudio/AbstractAudioContext.h"
#include "modules/webaudio/AudioNodeInput.h"
#include "modules/webaudio/AudioNodeOutput.h"

namespace blink {

ChannelSplitterHandler::ChannelSplitterHandler(AudioNode& node, float sampleRate, unsigned numberOfOutputs)
    : AudioHandler(NodeTypeChannelSplitter, node, sampleRate)
{
    addInput();

    // Create a fixed number of outputs (able to handle the maximum number of channels fed to an input).
    for (unsigned i = 0; i < numberOfOutputs; ++i)
        addOutput(1);

    initialize();
}

PassRefPtr<ChannelSplitterHandler> ChannelSplitterHandler::create(AudioNode& node, float sampleRate, unsigned numberOfOutputs)
{
    return adoptRef(new ChannelSplitterHandler(node, sampleRate, numberOfOutputs));
}

void ChannelSplitterHandler::process(size_t framesToProcess)
{
    AudioBus* source = input(0).bus();
    ASSERT(source);
    ASSERT_UNUSED(framesToProcess, framesToProcess == source->length());

    unsigned numberOfSourceChannels = source->numberOfChannels();

    for (unsigned i = 0; i < numberOfOutputs(); ++i) {
        AudioBus* destination = output(i).bus();
        ASSERT(destination);

        if (i < numberOfSourceChannels) {
            // Split the channel out if it exists in the source.
            // It would be nice to avoid the copy and simply pass along pointers, but this becomes extremely difficult with fanout and fanin.
            destination->channel(0)->copyFrom(source->channel(i));
        } else if (output(i).renderingFanOutCount() > 0) {
            // Only bother zeroing out the destination if it's connected to anything
            destination->zero();
        }
    }
}

// ----------------------------------------------------------------

ChannelSplitterNode::ChannelSplitterNode(AbstractAudioContext& context, unsigned numberOfOutputs)
    : AudioNode(context)
{
    setHandler(ChannelSplitterHandler::create(*this, context.sampleRate(), numberOfOutputs));
}

ChannelSplitterNode* ChannelSplitterNode::create(AbstractAudioContext& context, ExceptionState& exceptionState)
{
    DCHECK(isMainThread());

    // Default number of outputs for the splitter node is 6.
    return create(context, 6, exceptionState);
}

ChannelSplitterNode* ChannelSplitterNode::create(AbstractAudioContext& context, unsigned numberOfOutputs, ExceptionState& exceptionState)
{
    DCHECK(isMainThread());

    if (context.isContextClosed()) {
        context.throwExceptionForClosedState(exceptionState);
        return nullptr;
    }

    if (!numberOfOutputs || numberOfOutputs > AbstractAudioContext::maxNumberOfChannels()) {
        exceptionState.throwDOMException(
            IndexSizeError,
            ExceptionMessages::indexOutsideRange<size_t>(
                "number of outputs",
                numberOfOutputs,
                1,
                ExceptionMessages::InclusiveBound,
                AbstractAudioContext::maxNumberOfChannels(),
                ExceptionMessages::InclusiveBound));
        return nullptr;
    }

    return new ChannelSplitterNode(context, numberOfOutputs);
}

} // namespace blink