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:
 * 1.  Redistributions of source code must retain the above copyright
 *    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 max_delay_time, float sample_rate);

  void Process(const float* source,
               float* destination,
               size_t frames_to_process) override;
  void Reset() override;

  double MaxDelayTime() const { return max_delay_time_; }

  void SetDelayFrames(double number_of_frames) {
    desired_delay_frames_ = number_of_frames;
  }

  double TailTime() const override;
  double LatencyTime() const override;

 protected:
  AudioDelayDSPKernel(AudioDSPKernelProcessor*,
                      size_t processing_size_in_frames);

  virtual bool HasSampleAccurateValues();
  virtual void CalculateSampleAccurateValues(float* delay_times,
                                             size_t frames_to_process);
  virtual double DelayTime(float sample_rate);

  AudioFloatArray buffer_;
  double max_delay_time_;
  int write_index_;
  double current_delay_time_;
  double smoothing_rate_;
  bool first_time_;
  double desired_delay_frames_;

  AudioFloatArray delay_times_;

  size_t BufferLengthForDelay(double delay_time, double sample_rate) const;
};

}  // namespace blink

#endif  // AudioDelayDSPKernel_h