/*

     File: AUTimestampGenerator.h 

 Abstract:  Part of CoreAudio Utility Classes  

  Version: 1.0.1 

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*/

#ifndef __AUTimestampGenerator_h__

#define __AUTimestampGenerator_h__

#include <math.h>

#include "CAHostTimeBase.h"

#include <stdio.h>

#define TSGFMT "0x%10qx"

//#define TSGFMT "%10qd"

// This class generates a continuously increasing series of timestamps based

// on a series of potentially discontinuous timestamps (as can be delivered from

// CoreAudio in the event of an overload or major engine change).

// N.B.: "output" = downstream (source) timestamp

//       "input"  = upstream (derived) timestamp

class AUTimestampGenerator {

public:

    AUTimestampGenerator(bool hostTimeDiscontinuityCorrection = false) :

        mStartInputAtZero(true),

        mBypassed(false),

        mHostTimeDiscontinuityCorrection(hostTimeDiscontinuityCorrection)

    {

#if DEBUG

        mVerbosity = 0;

        sprintf(mDebugName, "tsg @ %p", this);

#endif

        // CAHostTimeBase should be used instead of the calls in <CoreAudio/HostTime.h>

        // we make this call here to ensure that this is initialized, otherwise the first time

        // you do actually call CAHostTimeBase to do work, can be on the render thread, and lead to unwanted VM faults

        CAHostTimeBase::GetFrequency();

        Reset();

    }

    void    SetStartInputAtZero(bool b) { mStartInputAtZero = b; }

    bool    GetStartInputAtZero() const { return mStartInputAtZero; }

    // bypassing is intended for a narrow special case. the upstream sample time will always be the same as the downstream time.

    void    SetBypassed(bool b) { mBypassed = b; }

    bool    GetBypassed() const { return mBypassed; }

    // Call this to reset the timeline.

    void    Reset()

    {

        mCurrentInputTime.mSampleTime = 0.;

        mNextInputSampleTime = 0.;

        mCurrentOutputTime.mSampleTime = 0.;

        mNextOutputSampleTime = 0.;

        mLastOutputTime.mFlags = 0;

        mRateScalarAdj = 1.;

        mFirstTime = true;

#if DEBUG

        if (mVerbosity)

            printf("%-20.20s: Reset\n", mDebugName);

#endif

    }

    // Call this once per render cycle with the downstream timestamp.

    // expectedDeltaFrames is the expected difference between the current and NEXT 

    //  downstream timestamps.

    // sampleRate is the OUTPUT sample rate.

    void    AddOutputTime(const AudioTimeStamp &inTimeStamp, Float64 expectedDeltaFrames, double outputSampleRate, double rateScalarAdj=1.0);

    // Call this once per render cycle to obtain the upstream timestamp.

    // framesToAdvance is the number of frames the input timeline is to be

    //  advanced during this render cycle.

    // sampleRate is the INPUT sample rate.

    const AudioTimeStamp &  GenerateInputTime(Float64 framesToAdvance, double inputSampleRate);

    // this can be called to override the setting of the next input sample time in GenerateInputTime

    void                    Advance(Float64 framesToAdvance)

    {

#if DEBUG

        if (mVerbosity > 1)

            printf("%-20.20s:   ADVANCE         in = "TSGFMT"                    advance = "TSGFMT"\n", mDebugName, (SInt64)mCurrentInputTime.mSampleTime, (SInt64)framesToAdvance);

#endif

        mNextInputSampleTime = mCurrentInputTime.mSampleTime + framesToAdvance;

    }

private:

    AudioTimeStamp      mCurrentInputTime;

    Float64             mNextInputSampleTime;

    Float64             mNextOutputSampleTime;

    AudioTimeStamp      mLastOutputTime;

    AudioTimeStamp      mCurrentOutputTime;

    bool                mFirstTime;

    bool                mStartInputAtZero;  // if true, input timeline starts at 0, else it starts

                                            // synced with the output timeline

    bool                mDiscontinuous;

    bool                mBypassed;

    Float64             mDiscontinuityDeltaSamples;

    double              mRateScalarAdj;

    bool                mHostTimeDiscontinuityCorrection; // If true, propagate timestamp discontinuities using host time.

#if DEBUG

public:

    int                 mVerbosity;

    char                mDebugName[64];

#endif

};

#endif // __AUTimestampGenerator_h__