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 * 1.  Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2.  Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
15 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
16 * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
17 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
18 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
19 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
20 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
22 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23 */
24
25#ifndef BiquadProcessor_h
26#define BiquadProcessor_h
27
28#include "AudioDSPKernel.h"
29#include "AudioDSPKernelProcessor.h"
30#include "AudioNode.h"
31#include "AudioParam.h"
32#include "Biquad.h"
33#include <wtf/RefPtr.h>
34
35namespace WebCore {
36
37// BiquadProcessor is an AudioDSPKernelProcessor which uses Biquad objects to implement several common filters.
38
39class BiquadProcessor : public AudioDSPKernelProcessor {
40public:
41    enum FilterType {
42        LowPass2,
43        HighPass2,
44        Peaking,
45        Allpass,
46        LowShelf,
47        HighShelf
48    };
49
50    BiquadProcessor(FilterType, double sampleRate, size_t numberOfChannels, bool autoInitialize = true);
51    virtual ~BiquadProcessor();
52
53    virtual PassOwnPtr<AudioDSPKernel> createKernel();
54
55    virtual void process(AudioBus* source, AudioBus* destination, size_t framesToProcess);
56
57    bool filterCoefficientsDirty() const { return m_filterCoefficientsDirty; }
58
59    AudioParam* parameter1() { return m_parameter1.get(); }
60    AudioParam* parameter2() { return m_parameter2.get(); }
61    AudioParam* parameter3() { return m_parameter3.get(); }
62
63    FilterType type() const { return m_type; }
64
65private:
66    FilterType m_type;
67
68    RefPtr<AudioParam> m_parameter1;
69    RefPtr<AudioParam> m_parameter2;
70    RefPtr<AudioParam> m_parameter3;
71
72    // so DSP kernels know when to re-compute coefficients
73    bool m_filterCoefficientsDirty;
74};
75
76} // namespace WebCore
77
78#endif // BiquadProcessor_h
79