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 *
8 * 1.  Redistributions of source code must retain the above copyright
9 *     notice, this list of conditions and the following disclaimer.
10 * 2.  Redistributions in binary form must reproduce the above copyright
11 *     notice, this list of conditions and the following disclaimer in the
12 *     documentation and/or other materials provided with the distribution.
13 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
14 *     its contributors may be used to endorse or promote products derived
15 *     from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
18 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#include "config.h"
30
31#if ENABLE(WEB_AUDIO)
32
33#include "AudioChannelMerger.h"
34
35#include "AudioNodeInput.h"
36#include "AudioNodeOutput.h"
37
38namespace WebCore {
39
40// This is considering that 5.1 (6 channels) is the largest we'll ever deal with.
41// It can easily be increased to support more if the web audio specification is updated.
42const unsigned NumberOfInputs = 6;
43
44AudioChannelMerger::AudioChannelMerger(AudioContext* context, double sampleRate)
45    : AudioNode(context, sampleRate)
46{
47    // Create a fixed number of inputs (able to handle the maximum number of channels we deal with).
48    for (unsigned i = 0; i < NumberOfInputs; ++i)
49        addInput(adoptPtr(new AudioNodeInput(this)));
50
51    addOutput(adoptPtr(new AudioNodeOutput(this, 1)));
52
53    setType(NodeTypeChannelMerger);
54
55    initialize();
56}
57
58void AudioChannelMerger::process(size_t framesToProcess)
59{
60    AudioNodeOutput* output = this->output(0);
61    ASSERT(output);
62    ASSERT_UNUSED(framesToProcess, framesToProcess == output->bus()->length());
63
64    // Count how many channels we have all together from all of the inputs.
65    unsigned numberOfOutputChannels = 0;
66    for (unsigned i = 0; i < numberOfInputs(); ++i) {
67        AudioNodeInput* input = this->input(i);
68        if (input->isConnected())
69            numberOfOutputChannels += input->bus()->numberOfChannels();
70    }
71
72    // Set the correct number of channels on the output
73    output->setNumberOfChannels(numberOfOutputChannels);
74
75    // Now merge the channels back into one output.
76    unsigned outputChannelIndex = 0;
77    for (unsigned i = 0; i < numberOfInputs(); ++i) {
78        AudioNodeInput* input = this->input(i);
79        if (input->isConnected()) {
80            unsigned numberOfInputChannels = input->bus()->numberOfChannels();
81
82            // Merge channels from this particular input.
83            for (unsigned j = 0; j < numberOfInputChannels; ++j) {
84                AudioChannel* inputChannel = input->bus()->channel(j);
85                AudioChannel* outputChannel = output->bus()->channel(outputChannelIndex);
86                outputChannel->copyFrom(inputChannel);
87
88                ++outputChannelIndex;
89            }
90        }
91    }
92
93    ASSERT(outputChannelIndex == numberOfOutputChannels);
94}
95
96void AudioChannelMerger::reset()
97{
98}
99
100} // namespace WebCore
101
102#endif // ENABLE(WEB_AUDIO)
103