timer.cpp

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/*
 * This file: timer.cpp, is part of the Astrog software library
 * that uses the graphics processing unit (GPU) to accelerate
 * astronomy calculations. 
 *
 * Copyright (C) 2007  C. J. Harris
 *
 * 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
 */

#include "libastrog_timer.h"

namespace astrog {

double Timer::grain = 0;

Timer::Timer()
{
    // get grain if it hasn't been determined already
    if (this->get_grain()==0.0) {
        this->set_grain();
    }
    // timer starts off
    this->timer_status = 0;
    // accumulated time is zero
    this->time_elapsed = 0.0;
    // zero start/stops so far
    this->error_grains = 0;
    
    

}

Timer::~Timer()
{
}
        
void Timer::start()
{
    if (this->timer_status == 1) {} // TODO throw error
    this->timer_status = 1;
    this->error_grains += 1;
    ftime(&this->latest_start);  
}

void Timer::stop()
{
    if (this->timer_status == 0) {} // TODO throw error
    this->timer_status = 0;
    this->error_grains += 1;
    ftime(&this->latest_stop);
    time_elapsed += ((double)(latest_stop.time-latest_start.time)
                   +((double)(latest_stop.millitm-latest_start.millitm))/1000.0f);
}

void Timer::reset()
{
    if (this->timer_status == 1) {
      this->stop();
      this->start();
    }
    this->time_elapsed = 0;
}

double Timer::get_time()
{
    if (this->timer_status == 1) {} // TODO Throw error
    return this->time_elapsed;
}

double  Timer::get_error_absolute()
{
    return this->error_grains*Timer::grain;
}

double Timer::get_error_relative()
{
    return (this->get_error_absolute())/(this->get_time());
}

double  Timer::get_error_percentage()
{
    return 100*(this->get_error_relative());
}

double Timer::get_grain ()
{
    return Timer::grain;
}

void Timer::set_grain ()
{
    struct timeb start;
    struct timeb stop;
    ftime(&start);
    ftime(&stop);
    double time = 0;
    while (time<=0) {
      ftime(&stop);
      time = ((double)(stop.time-start.time)+(double)(stop.millitm-start.millitm)/1000.0f);
    }
    Timer::grain = time;
}

} // end namespace

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