third_party/WebKit/Source/platform/audio/AudioDelayDSPKernel.h

/*
 * Copyright (C) 2010, Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
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 *    notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE
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#ifndef AudioDelayDSPKernel_h
#define AudioDelayDSPKernel_h

#include "platform/audio/AudioArray.h"
#include "platform/audio/AudioDSPKernel.h"

namespace blink {

class PLATFORM_EXPORT AudioDelayDSPKernel : public AudioDSPKernel {
 public:
  AudioDelayDSPKernel(double maxDelayTime, float sampleRate);

  void process(const float* source,
               float* destination,
               size_t framesToProcess) override;
  void reset() override;

  double maxDelayTime() const { return m_maxDelayTime; }

  void setDelayFrames(double numberOfFrames) {
    m_desiredDelayFrames = numberOfFrames;
  }

  double tailTime() const override;
  double latencyTime() const override;

 protected:
  AudioDelayDSPKernel(AudioDSPKernelProcessor*, size_t processingSizeInFrames);

  virtual bool hasSampleAccurateValues();
  virtual void calculateSampleAccurateValues(float* delayTimes,
                                             size_t framesToProcess);
  virtual double delayTime(float sampleRate);

  AudioFloatArray m_buffer;
  double m_maxDelayTime;
  int m_writeIndex;
  double m_currentDelayTime;
  double m_smoothingRate;
  bool m_firstTime;
  double m_desiredDelayFrames;

  AudioFloatArray m_delayTimes;

  size_t bufferLengthForDelay(double delayTime, double sampleRate) const;
};

}  // namespace blink

#endif  // AudioDelayDSPKernel_h