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 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 ReverbAccumulationBuffer_h
30#define ReverbAccumulationBuffer_h
31
32#include "AudioArray.h"
33
34namespace WebCore {
35
36// ReverbAccumulationBuffer is a circular delay buffer with one client reading from it and multiple clients
37// writing/accumulating to it at different delay offsets from the read position. The read operation will zero the memory
38// just read from the buffer, so it will be ready for accumulation the next time around.
39class ReverbAccumulationBuffer {
40public:
41 ReverbAccumulationBuffer(size_t length);
42
43 // This will read from, then clear-out numberOfFrames
44 void readAndClear(float* destination, size_t numberOfFrames);
45
46 // Each ReverbConvolverStage will accumulate its output at the appropriate delay from the read position.
47 // We need to pass in and update readIndex here, since each ReverbConvolverStage may be running in
48 // a different thread than the realtime thread calling ReadAndClear() and maintaining m_readIndex
49 // Returns the writeIndex where the accumulation took place
50 int accumulate(float* source, size_t numberOfFrames, int* readIndex, size_t delayFrames);
51
52 size_t readIndex() const { return m_readIndex; }
53 void updateReadIndex(int* readIndex, size_t numberOfFrames) const;
54
55 size_t readTimeFrame() const { return m_readTimeFrame; }
56
57 void reset();
58
59private:
60 AudioFloatArray m_buffer;
61 size_t m_readIndex;
62 size_t m_readTimeFrame; // for debugging (frame on continuous timeline)
63};
64
65} // namespace WebCore
66
67#endif // ReverbAccumulationBuffer_h
68