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#include "config.h"
30
31#if ENABLE(WEB_AUDIO)
32
33#include "ReverbAccumulationBuffer.h"
34
35#include "VectorMath.h"
36
37namespace WebCore {
38
39using namespace VectorMath;
40
41ReverbAccumulationBuffer::ReverbAccumulationBuffer(size_t length)
42    : m_buffer(length)
43    , m_readIndex(0)
44    , m_readTimeFrame(0)
45{
46}
47
48void ReverbAccumulationBuffer::readAndClear(float* destination, size_t numberOfFrames)
49{
50    size_t bufferLength = m_buffer.size();
51    bool isCopySafe = m_readIndex <= bufferLength && numberOfFrames <= bufferLength;
52
53    ASSERT(isCopySafe);
54    if (!isCopySafe)
55        return;
56
57    size_t framesAvailable = bufferLength - m_readIndex;
58    size_t numberOfFrames1 = std::min(numberOfFrames, framesAvailable);
59    size_t numberOfFrames2 = numberOfFrames - numberOfFrames1;
60
61    float* source = m_buffer.data();
62    memcpy(destination, source + m_readIndex, sizeof(float) * numberOfFrames1);
63    memset(source + m_readIndex, 0, sizeof(float) * numberOfFrames1);
64
65    // Handle wrap-around if necessary
66    if (numberOfFrames2 > 0) {
67        memcpy(destination + numberOfFrames1, source, sizeof(float) * numberOfFrames2);
68        memset(source, 0, sizeof(float) * numberOfFrames2);
69    }
70
71    m_readIndex = (m_readIndex + numberOfFrames) % bufferLength;
72    m_readTimeFrame += numberOfFrames;
73}
74
75void ReverbAccumulationBuffer::updateReadIndex(int* readIndex, size_t numberOfFrames) const
76{
77    // Update caller's readIndex
78    *readIndex = (*readIndex + numberOfFrames) % m_buffer.size();
79}
80
81int ReverbAccumulationBuffer::accumulate(float* source, size_t numberOfFrames, int* readIndex, size_t delayFrames)
82{
83    size_t bufferLength = m_buffer.size();
84
85    size_t writeIndex = (*readIndex + delayFrames) % bufferLength;
86
87    // Update caller's readIndex
88    *readIndex = (*readIndex + numberOfFrames) % bufferLength;
89
90    size_t framesAvailable = bufferLength - writeIndex;
91    size_t numberOfFrames1 = std::min(numberOfFrames, framesAvailable);
92    size_t numberOfFrames2 = numberOfFrames - numberOfFrames1;
93
94    float* destination = m_buffer.data();
95
96    bool isSafe = writeIndex <= bufferLength && numberOfFrames1 + writeIndex <= bufferLength && numberOfFrames2 <= bufferLength;
97    ASSERT(isSafe);
98    if (!isSafe)
99        return 0;
100
101    vadd(source, 1, destination + writeIndex, 1, destination + writeIndex, 1, numberOfFrames1);
102
103    // Handle wrap-around if necessary
104    if (numberOfFrames2 > 0)
105        vadd(source + numberOfFrames1, 1, destination, 1, destination, 1, numberOfFrames2);
106
107    return writeIndex;
108}
109
110void ReverbAccumulationBuffer::reset()
111{
112    m_buffer.zero();
113    m_readIndex = 0;
114    m_readTimeFrame = 0;
115}
116
117} // namespace WebCore
118
119#endif // ENABLE(WEB_AUDIO)
120