cvd_timer.cpp

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/*                       
    This file is part of the CVD Library.

    Copyright (C) 2005 The Authors

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library 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
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 
    51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
*/
// 
// A timer class designed for dealing with timestamps
// CK Nov 2002
//

#include "timer.h"
#include <iostream>
#include <sys/time.h>  //gettimeofday

namespace CVD {

unsigned long long get_time_of_day_us()
{
    struct timeval tv;
    gettimeofday(&tv,NULL);
    return (unsigned long long)tv.tv_sec*1000000+tv.tv_usec;
}

cvd_timer::cvd_timer()
{
    startTime = get_time_of_day_us();
}

double cvd_timer::reset() 
{
  unsigned long long temp  = get_time_of_day_us();
  double elapsed =  (temp - startTime) / 1000000.0;
  startTime = temp;
  return elapsed;
}

double cvd_timer::get_time() 
{
  return (get_time_of_day_us()-startTime)/1000000.0;
}

// Conv from units of nanosecs (specifically for v4l2 : kernel 2.4
double cvd_timer::conv_ntime(signed long long time)
{
  time=time/1000;  // now in us

  return (time-startTime)/1000000.0;
}

// Conv from units of nanosecs (specifically for v4l2 : kernel 2.6
// Let the overloading mecnanism sort out the difference in the 
// headers from 2.4 hee, hee, hee
double cvd_timer::conv_ntime(const struct timeval& tv)
{
    double time = tv.tv_sec + tv.tv_usec*1e-6;
    return time-startTime / 1e6;
}

double get_time_of_day() 
{
  return get_time_of_day_us()/1000000.0;
}


cvd_timer timer;

}