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1 /*
2  * Copyright (C) 2012 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 "platform/audio/AudioPullFIFO.h"
34 
35 namespace blink {
36 
AudioPullFIFO(AudioSourceProvider & audioProvider,unsigned numberOfChannels,size_t fifoLength,size_t providerSize)37 AudioPullFIFO::AudioPullFIFO(AudioSourceProvider& audioProvider, unsigned numberOfChannels, size_t fifoLength, size_t providerSize)
38     : m_provider(audioProvider)
39     , m_fifo(numberOfChannels, fifoLength)
40     , m_providerSize(providerSize)
41     , m_tempBus(AudioBus::create(numberOfChannels, providerSize))
42 {
43 }
44 
consume(AudioBus * destination,size_t framesToConsume)45 void AudioPullFIFO::consume(AudioBus* destination, size_t framesToConsume)
46 {
47     if (!destination)
48         return;
49 
50     if (framesToConsume > m_fifo.framesInFifo()) {
51         // We don't have enough data in the FIFO to fulfill the request. Ask for more data.
52         fillBuffer(framesToConsume - m_fifo.framesInFifo());
53     }
54 
55     m_fifo.consume(destination, framesToConsume);
56 }
57 
fillBuffer(size_t numberOfFrames)58 void AudioPullFIFO::fillBuffer(size_t numberOfFrames)
59 {
60     // Keep asking the provider to give us data until we have received at least |numberOfFrames| of
61     // data. Stuff the data into the FIFO.
62     size_t framesProvided = 0;
63 
64     while (framesProvided < numberOfFrames) {
65         m_provider.provideInput(m_tempBus.get(), m_providerSize);
66 
67         m_fifo.push(m_tempBus.get());
68 
69         framesProvided += m_providerSize;
70     }
71 }
72 
73 } // namespace blink
74 
75 #endif // ENABLE(WEB_AUDIO)
76