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 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 "AudioFIFO.h"
34
35namespace WebCore {
36
37AudioFIFO::AudioFIFO(unsigned numberOfChannels, size_t fifoLength)
38 : m_fifoAudioBus(AudioBus::create(numberOfChannels, fifoLength))
39 , m_fifoLength(fifoLength)
40 , m_framesInFifo(0)
41 , m_readIndex(0)
42 , m_writeIndex(0)
43{
44}
45
46void AudioFIFO::consume(AudioBus* destination, size_t framesToConsume)
47{
48 bool isGood = destination && (framesToConsume <= m_fifoLength) && (framesToConsume <= m_framesInFifo) && (destination->length() >= framesToConsume);
49 ASSERT(isGood);
50 if (!isGood)
51 return;
52
53 // Copy the requested number of samples to the destination.
54
55 size_t part1Length;
56 size_t part2Length;
57 findWrapLengths(m_readIndex, framesToConsume, part1Length, part2Length);
58
59 size_t numberOfChannels = m_fifoAudioBus->numberOfChannels();
60
61 for (size_t channelIndex = 0; channelIndex < numberOfChannels; ++channelIndex) {
62 float* destinationData = destination->channel(channelIndex)->mutableData();
63 const float* sourceData = m_fifoAudioBus->channel(channelIndex)->data();
64
65 bool isCopyGood = ((m_readIndex < m_fifoLength)
66 && (m_readIndex + part1Length) <= m_fifoLength
67 && (part1Length <= destination->length())
68 && (part1Length + part2Length) <= destination->length());
69 ASSERT(isCopyGood);
70 if (!isCopyGood)
71 return;
72
73 memcpy(destinationData, sourceData + m_readIndex, part1Length * sizeof(*sourceData));
74 // Handle wrap around of the FIFO, if needed.
75 if (part2Length)
76 memcpy(destinationData + part1Length, sourceData, part2Length * sizeof(*sourceData));
77 }
78 m_readIndex = updateIndex(m_readIndex, framesToConsume);
79 ASSERT(m_framesInFifo >= framesToConsume);
80 m_framesInFifo -= framesToConsume;
81}
82
83void AudioFIFO::push(const AudioBus* sourceBus)
84{
85 // Copy the sourceBus into the FIFO buffer.
86
87 bool isGood = sourceBus && (m_framesInFifo + sourceBus->length() <= m_fifoLength);
88 if (!isGood)
89 return;
90
91 size_t sourceLength = sourceBus->length();
92 size_t part1Length;
93 size_t part2Length;
94 findWrapLengths(m_writeIndex, sourceLength, part1Length, part2Length);
95
96 size_t numberOfChannels = m_fifoAudioBus->numberOfChannels();
97
98 for (size_t channelIndex = 0; channelIndex < numberOfChannels; ++channelIndex) {
99 float* destination = m_fifoAudioBus->channel(channelIndex)->mutableData();
100 const float* source = sourceBus->channel(channelIndex)->data();
101
102 bool isCopyGood = ((m_writeIndex < m_fifoLength)
103 && (m_writeIndex + part1Length) <= m_fifoLength
104 && part2Length < m_fifoLength
105 && part1Length + part2Length <= sourceLength);
106 ASSERT(isCopyGood);
107 if (!isCopyGood)
108 return;
109
110 memcpy(destination + m_writeIndex, source, part1Length * sizeof(*destination));
111
112 // Handle wrap around of the FIFO, if needed.
113 if (part2Length)
114 memcpy(destination, source + part1Length, part2Length * sizeof(*destination));
115 }
116
117 m_framesInFifo += sourceLength;
118 ASSERT(m_framesInFifo <= m_fifoLength);
119 m_writeIndex = updateIndex(m_writeIndex, sourceLength);
120}
121
122void AudioFIFO::findWrapLengths(size_t index, size_t size, size_t& part1Length, size_t& part2Length)
123{
124 ASSERT_WITH_SECURITY_IMPLICATION(index < m_fifoLength && size <= m_fifoLength);
125 if (index < m_fifoLength && size <= m_fifoLength) {
126 if (index + size > m_fifoLength) {
127 // Need to wrap. Figure out the length of each piece.
128 part1Length = m_fifoLength - index;
129 part2Length = size - part1Length;
130 } else {
131 // No wrap needed.
132 part1Length = size;
133 part2Length = 0;
134 }
135 } else {
136 // Invalid values for index or size. Set the part lengths to zero so nothing is copied.
137 part1Length = 0;
138 part2Length = 0;
139 }
140}
141
142} // namespace WebCore
143
144#endif // ENABLE(WEB_AUDIO)
145