1/*
2 * Copyright (C) 2010, Google Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1.  Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2.  Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
15 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
16 * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
17 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
18 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
19 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
20 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
22 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23 */
24
25#include "config.h"
26
27#if ENABLE(WEB_AUDIO)
28
29#include "modules/webaudio/ChannelSplitterNode.h"
30
31#include "modules/webaudio/AudioContext.h"
32#include "modules/webaudio/AudioNodeInput.h"
33#include "modules/webaudio/AudioNodeOutput.h"
34
35namespace blink {
36
37ChannelSplitterNode* ChannelSplitterNode::create(AudioContext* context, float sampleRate, unsigned numberOfOutputs)
38{
39    if (!numberOfOutputs || numberOfOutputs > AudioContext::maxNumberOfChannels())
40        return 0;
41
42    return adoptRefCountedGarbageCollectedWillBeNoop(new ChannelSplitterNode(context, sampleRate, numberOfOutputs));
43}
44
45ChannelSplitterNode::ChannelSplitterNode(AudioContext* context, float sampleRate, unsigned numberOfOutputs)
46    : AudioNode(context, sampleRate)
47{
48    addInput();
49
50    // Create a fixed number of outputs (able to handle the maximum number of channels fed to an input).
51    for (unsigned i = 0; i < numberOfOutputs; ++i)
52        addOutput(AudioNodeOutput::create(this, 1));
53
54    setNodeType(NodeTypeChannelSplitter);
55    initialize();
56}
57
58void ChannelSplitterNode::process(size_t framesToProcess)
59{
60    AudioBus* source = input(0)->bus();
61    ASSERT(source);
62    ASSERT_UNUSED(framesToProcess, framesToProcess == source->length());
63
64    unsigned numberOfSourceChannels = source->numberOfChannels();
65
66    for (unsigned i = 0; i < numberOfOutputs(); ++i) {
67        AudioBus* destination = output(i)->bus();
68        ASSERT(destination);
69
70        if (i < numberOfSourceChannels) {
71            // Split the channel out if it exists in the source.
72            // It would be nice to avoid the copy and simply pass along pointers, but this becomes extremely difficult with fanout and fanin.
73            destination->channel(0)->copyFrom(source->channel(i));
74        } else if (output(i)->renderingFanOutCount() > 0) {
75            // Only bother zeroing out the destination if it's connected to anything
76            destination->zero();
77        }
78    }
79}
80
81} // namespace blink
82
83#endif // ENABLE(WEB_AUDIO)
84