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      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 #ifndef AudioBuffer_h
     30 #define AudioBuffer_h
     31 
     32 #include "bindings/v8/ScriptWrappable.h"
     33 #include "wtf/Float32Array.h"
     34 #include "wtf/PassRefPtr.h"
     35 #include "wtf/RefCounted.h"
     36 #include "wtf/RefPtr.h"
     37 #include "wtf/Vector.h"
     38 
     39 namespace WebCore {
     40 
     41 class AudioBus;
     42 class ExceptionState;
     43 
     44 class AudioBuffer : public ScriptWrappable, public RefCounted<AudioBuffer> {
     45 public:
     46     static PassRefPtr<AudioBuffer> create(unsigned numberOfChannels, size_t numberOfFrames, float sampleRate);
     47 
     48     // Returns 0 if data is not a valid audio file.
     49     static PassRefPtr<AudioBuffer> createFromAudioFileData(const void* data, size_t dataSize, bool mixToMono, float sampleRate);
     50 
     51     // Format
     52     size_t length() const { return m_length; }
     53     double duration() const { return length() / sampleRate(); }
     54     float sampleRate() const { return m_sampleRate; }
     55 
     56     // Channel data access
     57     unsigned numberOfChannels() const { return m_channels.size(); }
     58     PassRefPtr<Float32Array> getChannelData(unsigned channelIndex, ExceptionState&);
     59     Float32Array* getChannelData(unsigned channelIndex);
     60     void zero();
     61 
     62     // Scalar gain
     63     double gain() const { return m_gain; }
     64     void setGain(double gain) { m_gain = gain; }
     65 
     66     // Because an AudioBuffer has a JavaScript wrapper, which will be garbage collected, it may take awhile for this object to be deleted.
     67     // releaseMemory() can be called when the AudioContext goes away, so we can release the memory earlier than when the garbage collection happens.
     68     // Careful! Only call this when the page unloads, after the AudioContext is no longer processing.
     69     void releaseMemory();
     70 
     71 protected:
     72     AudioBuffer(unsigned numberOfChannels, size_t numberOfFrames, float sampleRate);
     73     explicit AudioBuffer(AudioBus*);
     74 
     75     double m_gain; // scalar gain
     76     float m_sampleRate;
     77     size_t m_length;
     78 
     79     Vector<RefPtr<Float32Array> > m_channels;
     80 };
     81 
     82 } // namespace WebCore
     83 
     84 #endif // AudioBuffer_h
     85