cpuTimePosix.H

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/*---------------------------------------------------------------------------*\
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    Copyright (C) 2018-2024 OpenCFD Ltd.
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License
    This file is part of OpenFOAM.

    OpenFOAM is free software: you can redistribute it and/or modify it
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Class
    Foam::cpuTimePosix

Description
    Starts timing CPU usage and return elapsed time from start.

See also
    clockTime

SourceFiles
    cpuTimePosix.C

\*---------------------------------------------------------------------------*/

#ifndef Foam_cpuTimePosix_H
#define Foam_cpuTimePosix_H

#include <string>
#include <ctime>
#include <sys/times.h>

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namespace Foam
{

/*---------------------------------------------------------------------------*\
                           Class cpuTimePosix Declaration
\*---------------------------------------------------------------------------*/

class cpuTimePosix
{
    //- Time structure used, with additional methods
    struct value_type : tms
    {
        //- Construct with the current clock time
        value_type();

        //- Update with the current clock time
        void update();
    };


    // Private Data

        //- Start time, at the time of construction
        value_type start_;

        //- Last time when elapsedCpuTime or cpuTimeIncrement was called.
        //- Also affected by resetCpuTime and resetCpuTimeIncrement.
        mutable value_type last_;


    // Private Member Functions

        //- Difference between two times (a - b)
        inline static double diff(const value_type& a, const value_type& b);


public:

    // Constructors

        //- Construct with the current clock time
        cpuTimePosix();


    // Member Functions

        //- Reset to use the current time for the start time
        void resetCpuTime();

        //- Reset to use the current time for the increment point
        void resetCpuTimeIncrement() const;

        //- Return CPU time [seconds] from the start
        double elapsedCpuTime() const;

        //- Return CPU time [seconds] since last call to cpuTimeIncrement(),
        //- resetCpuTimeIncrement().
        double cpuTimeIncrement() const;
};


// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

} // End namespace Foam

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

#endif

// ************************************************************************* //