third_party/WebKit/Source/modules/webaudio/AudioParamTimeline.h

/*
 * Copyright (C) 2011 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.
 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
 *     its contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE 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
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 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef AudioParamTimeline_h
#define AudioParamTimeline_h

#include "core/dom/DOMTypedArray.h"
#include "modules/webaudio/AudioDestinationNode.h"
#include "modules/webaudio/BaseAudioContext.h"
#include "wtf/Forward.h"
#include "wtf/Threading.h"
#include "wtf/Vector.h"

namespace blink {

class AudioParamTimeline {
  DISALLOW_NEW();

 public:
  AudioParamTimeline() {}

  void setValueAtTime(float value, double time, ExceptionState&);
  void linearRampToValueAtTime(float value,
                               double time,
                               float initialValue,
                               double callTime,
                               ExceptionState&);
  void exponentialRampToValueAtTime(float value,
                                    double time,
                                    float initialValue,
                                    double callTime,
                                    ExceptionState&);
  void setTargetAtTime(float target,
                       double time,
                       double timeConstant,
                       ExceptionState&);
  void setValueCurveAtTime(DOMFloat32Array* curve,
                           double time,
                           double duration,
                           ExceptionState&);
  void cancelScheduledValues(double startTime, ExceptionState&);

  // hasValue is set to true if a valid timeline value is returned.
  // otherwise defaultValue is returned.
  float valueForContextTime(AudioDestinationHandler&,
                            float defaultValue,
                            bool& hasValue,
                            float minValue,
                            float maxValue);

  // Given the time range in frames, calculates parameter values into the values
  // buffer and returns the last parameter value calculated for "values" or the
  // defaultValue if none were calculated.  controlRate is the rate (number per
  // second) at which parameter values will be calculated.  It should equal
  // sampleRate for sample-accurate parameter changes, and otherwise will
  // usually match the render quantum size such that the parameter value changes
  // once per render quantum.
  float valuesForFrameRange(size_t startFrame,
                            size_t endFrame,
                            float defaultValue,
                            float* values,
                            unsigned numberOfValues,
                            double sampleRate,
                            double controlRate,
                            float minValue,
                            float maxValue);

  // Returns true if this AudioParam has any events on it.
  bool hasValues() const;

  float smoothedValue() { return m_smoothedValue; }
  void setSmoothedValue(float v) { m_smoothedValue = v; }

 private:
  class ParamEvent {
   public:
    enum Type {
      SetValue,
      LinearRampToValue,
      ExponentialRampToValue,
      SetTarget,
      SetValueCurve,
      LastType
    };

    static ParamEvent createLinearRampEvent(float value,
                                            double time,
                                            float initialValue,
                                            double callTime);
    static ParamEvent createExponentialRampEvent(float value,
                                                 double time,
                                                 float initialValue,
                                                 double callTime);
    static ParamEvent createSetValueEvent(float value, double time);
    static ParamEvent createSetTargetEvent(float value,
                                           double time,
                                           double timeConstant);
    static ParamEvent createSetValueCurveEvent(const DOMFloat32Array* curve,
                                               double time,
                                               double duration);

    Type getType() const { return m_type; }
    float value() const { return m_value; }
    double time() const { return m_time; }
    void setTime(double newTime) { m_time = newTime; }
    double timeConstant() const { return m_timeConstant; }
    double duration() const { return m_duration; }
    Vector<float>& curve() { return m_curve; }
    float initialValue() const { return m_initialValue; }
    double callTime() const { return m_callTime; }
    bool needsTimeClampCheck() const { return m_needsTimeClampCheck; }
    void clearTimeClampCheck() { m_needsTimeClampCheck = false; }

   private:
    ParamEvent(Type type,
               float value,
               double time,
               double timeConstant,
               double duration,
               const DOMFloat32Array* curve,
               float initialValue = 0,
               double callTime = 0);

    Type m_type;
    float m_value;
    double m_time;
    // Only used for SetTarget events
    double m_timeConstant;
    // Only used for SetValueCurve events.
    double m_duration;
    Vector<float> m_curve;
    // Initial value and time to use for linear and exponential ramps that don't
    // have a preceding event.
    float m_initialValue;
    double m_callTime;
    // True if the start time needs to be checked against current time
    // to implement clamping.
    bool m_needsTimeClampCheck;
  };

  void insertEvent(const ParamEvent&, ExceptionState&);
  float valuesForFrameRangeImpl(size_t startFrame,
                                size_t endFrame,
                                float defaultValue,
                                float* values,
                                unsigned numberOfValues,
                                double sampleRate,
                                double controlRate);

  // Produce a nice string describing the event in human-readable form.
  String eventToString(const ParamEvent&);
  Vector<ParamEvent> m_events;

  mutable Mutex m_eventsLock;

  // Smoothing (de-zippering)
  float m_smoothedValue;
};

}  // namespace blink

#endif  // AudioParamTimeline_h