// Template Numerical Toolkit (TNT) for Linear Algebra 
//
// R. Pozo
// Applied and Computational Mathematics Division
// National Institute of Standards and Technology


#ifndef STPWATCH_H
#define STPWATCH_H

// for clock() and CLOCKS_PER_SEC
#include <ctime>

namespace TNT
{

/*  Simple stopwatch object:

        void    start()     : start timing
        double  stop()      : stop timing
        void    reset()     : set elapsed time to 0.0
        double  read()      : read elapsed time (in seconds)

*/

inline double seconds(void)
{
    static const double secs_per_tick = 1.0 / CLOCKS_PER_SEC;
    return ( (double) clock() ) * secs_per_tick;
}


class stopwatch {
    private:
        int running;
        double last_time;
        double total;

    public:
        stopwatch() : running(0), last_time(0.0), total(0.0) {}
        void reset() { running = 0; last_time = 0.0; total=0.0; }
        void start() { if (!running) { last_time = seconds(); running = 1;}}
        double stop()  { if (running) 
                            {
                                total += seconds() - last_time; 
                                running = 0;
                             }
                          return total; 
                        }
        double read()   {  if (running) 
                            {
                                total+= seconds() - last_time;
                                last_time = seconds();
                            }
                           return total;
                        }       
                            
};

} // namespace TNT

#endif