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 are
6 * met:
7 *
8 *     * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 *     * Redistributions in binary form must reproduce the above
11 * copyright notice, this list of conditions and the following disclaimer
12 * in the documentation and/or other materials provided with the
13 * distribution.
14 *     * Neither the name of Google Inc. nor the names of its
15 * contributors may be used to endorse or promote products derived from
16 * this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#ifndef AudioProcessor_h
32#define AudioProcessor_h
33
34namespace WebCore {
35
36class AudioBus;
37
38// AudioProcessor is an abstract base class representing an audio signal processing object with a single input and a single output,
39// where the number of input channels equals the number of output channels.  It can be used as one part of a complex DSP algorithm,
40// or as the processor for a basic (one input - one output) AudioNode.
41
42class AudioProcessor {
43public:
44    AudioProcessor(float sampleRate, unsigned numberOfChannels)
45        : m_initialized(false)
46        , m_numberOfChannels(numberOfChannels)
47        , m_sampleRate(sampleRate)
48    {
49    }
50
51    virtual ~AudioProcessor() { }
52
53    // Full initialization can be done here instead of in the constructor.
54    virtual void initialize() = 0;
55    virtual void uninitialize() = 0;
56
57    // Processes the source to destination bus.  The number of channels must match in source and destination.
58    virtual void process(const AudioBus* source, AudioBus* destination, size_t framesToProcess) = 0;
59
60    // Resets filter state
61    virtual void reset() = 0;
62
63    virtual void setNumberOfChannels(unsigned) = 0;
64    virtual unsigned numberOfChannels() const = 0;
65
66    bool isInitialized() const { return m_initialized; }
67
68    float sampleRate() const { return m_sampleRate; }
69
70    virtual double tailTime() const = 0;
71    virtual double latencyTime() const = 0;
72
73protected:
74    bool m_initialized;
75    unsigned m_numberOfChannels;
76    float m_sampleRate;
77};
78
79} // namespace WebCore
80
81#endif // AudioProcessor_h
82