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