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      1 /*
      2  * Copyright (C) 2011 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  *
      8  * 1.  Redistributions of source code must retain the above copyright
      9  *     notice, this list of conditions and the following disclaimer.
     10  * 2.  Redistributions in binary form must reproduce the above copyright
     11  *     notice, this list of conditions and the following disclaimer in the
     12  *     documentation and/or other materials provided with the distribution.
     13  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
     14  *     its contributors may be used to endorse or promote products derived
     15  *     from this software without specific prior written permission.
     16  *
     17  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
     18  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     20  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
     21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     22  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     23  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
     24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27  */
     28 
     29 #ifndef AudioParamTimeline_h
     30 #define AudioParamTimeline_h
     31 
     32 #include "modules/webaudio/AudioContext.h"
     33 #include "wtf/Float32Array.h"
     34 #include "wtf/Forward.h"
     35 #include "wtf/Threading.h"
     36 #include "wtf/Vector.h"
     37 
     38 namespace blink {
     39 
     40 class AudioParamTimeline {
     41 public:
     42     AudioParamTimeline()
     43     {
     44     }
     45 
     46     void setValueAtTime(float value, double time, ExceptionState&);
     47     void linearRampToValueAtTime(float value, double time, ExceptionState&);
     48     void exponentialRampToValueAtTime(float value, double time, ExceptionState&);
     49     void setTargetAtTime(float target, double time, double timeConstant, ExceptionState&);
     50     void setValueCurveAtTime(Float32Array* curve, double time, double duration, ExceptionState&);
     51     void cancelScheduledValues(double startTime, ExceptionState&);
     52 
     53     // hasValue is set to true if a valid timeline value is returned.
     54     // otherwise defaultValue is returned.
     55     float valueForContextTime(AudioContext*, float defaultValue, bool& hasValue);
     56 
     57     // Given the time range, calculates parameter values into the values buffer
     58     // and returns the last parameter value calculated for "values" or the defaultValue if none were calculated.
     59     // controlRate is the rate (number per second) at which parameter values will be calculated.
     60     // It should equal sampleRate for sample-accurate parameter changes, and otherwise will usually match
     61     // the render quantum size such that the parameter value changes once per render quantum.
     62     float valuesForTimeRange(double startTime, double endTime, float defaultValue, float* values, unsigned numberOfValues, double sampleRate, double controlRate);
     63 
     64     bool hasValues() { return m_events.size(); }
     65 
     66 private:
     67     class ParamEvent {
     68     public:
     69         enum Type {
     70             SetValue,
     71             LinearRampToValue,
     72             ExponentialRampToValue,
     73             SetTarget,
     74             SetValueCurve,
     75             LastType
     76         };
     77 
     78         ParamEvent(Type type, float value, double time, double timeConstant, double duration, PassRefPtr<Float32Array> curve)
     79             : m_type(type)
     80             , m_value(value)
     81             , m_time(time)
     82             , m_timeConstant(timeConstant)
     83             , m_duration(duration)
     84             , m_curve(curve)
     85         {
     86         }
     87 
     88         unsigned type() const { return m_type; }
     89         float value() const { return m_value; }
     90         double time() const { return m_time; }
     91         double timeConstant() const { return m_timeConstant; }
     92         double duration() const { return m_duration; }
     93         Float32Array* curve() { return m_curve.get(); }
     94 
     95     private:
     96         unsigned m_type;
     97         float m_value;
     98         double m_time;
     99         double m_timeConstant;
    100         double m_duration;
    101         RefPtr<Float32Array> m_curve;
    102     };
    103 
    104     void insertEvent(const ParamEvent&);
    105     float valuesForTimeRangeImpl(double startTime, double endTime, float defaultValue, float* values, unsigned numberOfValues, double sampleRate, double controlRate);
    106 
    107     Vector<ParamEvent> m_events;
    108 
    109     Mutex m_eventsLock;
    110 };
    111 
    112 } // namespace blink
    113 
    114 #endif // AudioParamTimeline_h
    115