inspiration/ETL/ETL/_clock_gettimeofday.h

/*! ========================================================================
** Extended Template and Library
** gettimeofday() Clock Description Implementation
**
** Copyright (c) 2002 Robert B. Quattlebaum Jr.
**
** This package is free software; you can redistribute it and/or
** modify it under the terms of the GNU General Public License as
** published by the Free Software Foundation; either version 2 of
** the License, or (at your option) any later version.
**
** This package is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
** General Public License for more details.
**
** === N O T E S ===========================================================
**
** This is an internal header file, included by other ETL headers.
** You should not attempt to use it directly.
**
** ========================================================================= */

#ifndef __ETL__CLOCK_GETTIMEOFDAY_H
#define __ETL__CLOCK_GETTIMEOFDAY_H

#include <sys/time.h>
#include <cmath>

_ETL_BEGIN_NAMESPACE

class clock_desc_gettimeofday
{
public:
    typedef double value_type;

    inline static bool realtime()
    {
        return true;
    }

    inline static bool proctime()
    {
        return false;
    }

    inline static value_type
    one_second()
    {
        return 1.0f;
    }

    inline static value_type precision()
    {
        return one_second() / (value_type)1000000.0f;
    }

    inline static const char *description()
    {
        return "UNIX gettimeofday()";
    };

protected:
    class timestamp : public timeval
    {
        timestamp(int sec, int usec)
        {
            tv_sec = sec;
            tv_usec = usec;
        }

        friend class clock_desc_gettimeofday;
    public:
        timestamp() { }

        inline timestamp operator-(const timestamp &rhs)const
        {
            timestamp ret;
            ret.tv_usec = tv_usec - rhs.tv_usec;

            if (ret.tv_usec < 0) {
                ret.tv_sec = tv_sec - rhs.tv_sec - 1;
                ret.tv_usec += 1000000;
            } else {
                ret.tv_sec = tv_sec - rhs.tv_sec;
            }

            return ret;
        }

        inline timestamp operator+(timestamp rhs)const
        {
            rhs.tv_usec += tv_usec;

            if (rhs.tv_usec > 1000000) {
                rhs.tv_sec += tv_sec + 1;
                rhs.tv_usec -= 1000000;
            } else {
                rhs.tv_sec += tv_sec;
            }

            return rhs;
        }

        inline bool operator<(const timestamp &rhs)const
        {
            return tv_sec < rhs.tv_sec || tv_usec < rhs.tv_usec;
        }

        inline bool operator==(const timestamp &rhs)const
        {
            return tv_usec == rhs.tv_usec && tv_sec == rhs.tv_sec;
        }

        inline bool operator!=(const timestamp &rhs)const
        {
            return tv_usec != rhs.tv_usec || tv_sec != rhs.tv_sec;
        }
    };

    static void
    get_current_time(timestamp &x)
    {
        gettimeofday(&x, NULL);
    }

    static timestamp
    get_current_time()
    {
        timestamp ret;
        get_current_time(ret);
        return ret;
    }

    static value_type
    timestamp_to_seconds(const timestamp &x)
    {
        return (value_type)x.tv_sec + precision() * x.tv_usec;
    }

    static timestamp
    seconds_to_timestamp(const value_type &x)
    {
        return timestamp((int)floor(x), (int)((x - floor(x)) / precision() + 0.5));
    }
};

_ETL_END_NAMESPACE

#endif