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 AudioDelayDSPKernel_h
26#define AudioDelayDSPKernel_h
27
28#include "platform/audio/AudioArray.h"
29#include "platform/audio/AudioDSPKernel.h"
30
31namespace blink {
32
33class PLATFORM_EXPORT AudioDelayDSPKernel : public AudioDSPKernel {
34public:
35    AudioDelayDSPKernel(double maxDelayTime, float sampleRate);
36
37    virtual void process(const float* source, float* destination, size_t framesToProcess) OVERRIDE;
38    virtual void reset() OVERRIDE;
39
40    double maxDelayTime() const { return m_maxDelayTime; }
41
42    void setDelayFrames(double numberOfFrames) { m_desiredDelayFrames = numberOfFrames; }
43
44    virtual double tailTime() const OVERRIDE;
45    virtual double latencyTime() const OVERRIDE;
46
47protected:
48    AudioDelayDSPKernel(AudioDSPKernelProcessor*, size_t processingSizeInFrames);
49
50    virtual bool hasSampleAccurateValues();
51    virtual void calculateSampleAccurateValues(float* delayTimes, size_t framesToProcess);
52    virtual double delayTime(float sampleRate);
53
54    AudioFloatArray m_buffer;
55    double m_maxDelayTime;
56    int m_writeIndex;
57    double m_currentDelayTime;
58    double m_smoothingRate;
59    bool m_firstTime;
60    double m_desiredDelayFrames;
61
62    AudioFloatArray m_delayTimes;
63
64    size_t bufferLengthForDelay(double delayTime, double sampleRate) const;
65};
66
67} // namespace blink
68
69#endif // AudioDelayDSPKernel_h
70