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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/PassRefPtr.h"
     35 #include "wtf/RefCounted.h"
     36 #include "wtf/Threading.h"
     37 #include "wtf/Vector.h"
     38 
     39 namespace WebCore {
     40 
     41 class AudioParamTimeline {
     42 public:
     43     AudioParamTimeline()
     44     {
     45     }
     46 
     47     void setValueAtTime(float value, double time);
     48     void linearRampToValueAtTime(float value, double time);
     49     void exponentialRampToValueAtTime(float value, double time);
     50     void setTargetAtTime(float target, double time, double timeConstant);
     51     void setValueCurveAtTime(Float32Array* curve, double time, double duration);
     52     void cancelScheduledValues(double startTime);
     53 
     54     // hasValue is set to true if a valid timeline value is returned.
     55     // otherwise defaultValue is returned.
     56     float valueForContextTime(AudioContext*, float defaultValue, bool& hasValue);
     57 
     58     // Given the time range, calculates parameter values into the values buffer
     59     // and returns the last parameter value calculated for "values" or the defaultValue if none were calculated.
     60     // controlRate is the rate (number per second) at which parameter values will be calculated.
     61     // It should equal sampleRate for sample-accurate parameter changes, and otherwise will usually match
     62     // the render quantum size such that the parameter value changes once per render quantum.
     63     float valuesForTimeRange(double startTime, double endTime, float defaultValue, float* values, unsigned numberOfValues, double sampleRate, double controlRate);
     64 
     65     bool hasValues() { return m_events.size(); }
     66 
     67 private:
     68     class ParamEvent {
     69     public:
     70         enum Type {
     71             SetValue,
     72             LinearRampToValue,
     73             ExponentialRampToValue,
     74             SetTarget,
     75             SetValueCurve,
     76             LastType
     77         };
     78 
     79         ParamEvent(Type type, float value, double time, double timeConstant, double duration, PassRefPtr<Float32Array> curve)
     80             : m_type(type)
     81             , m_value(value)
     82             , m_time(time)
     83             , m_timeConstant(timeConstant)
     84             , m_duration(duration)
     85             , m_curve(curve)
     86         {
     87         }
     88 
     89         unsigned type() const { return m_type; }
     90         float value() const { return m_value; }
     91         double time() const { return m_time; }
     92         double timeConstant() const { return m_timeConstant; }
     93         double duration() const { return m_duration; }
     94         Float32Array* curve() { return m_curve.get(); }
     95 
     96     private:
     97         unsigned m_type;
     98         float m_value;
     99         double m_time;
    100         double m_timeConstant;
    101         double m_duration;
    102         RefPtr<Float32Array> m_curve;
    103     };
    104 
    105     void insertEvent(const ParamEvent&);
    106     float valuesForTimeRangeImpl(double startTime, double endTime, float defaultValue, float* values, unsigned numberOfValues, double sampleRate, double controlRate);
    107 
    108     Vector<ParamEvent> m_events;
    109 
    110     Mutex m_eventsLock;
    111 };
    112 
    113 } // namespace WebCore
    114 
    115 #endif // AudioParamTimeline_h
    116