Home | History | Annotate | Download | only in audio 
      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 "core/platform/audio/AudioPullFIFO.h"
     34 
     35 namespace WebCore {
     36 
     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 
     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 
     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 WebCore
     74 
     75 #endif // ENABLE(WEB_AUDIO)
     76