/*
*
* Mathematical and Computational Sciences Division
* National Institute of Technology,
* Gaithersburg, MD USA
*
*
* This software was developed at the National Institute of Standards and
* Technology (NIST) by employees of the Federal Government in the course
* of their official duties. Pursuant to title 17 Section 105 of the
* United States Code, this software is not subject to copyright protection
* and is in the public domain.  NIST assumes no responsibility whatsoever for
* its use by other parties, and makes no guarantees, expressed or implied,
* about its quality, reliability, or any other characteristic.
*
*/

#ifndef IMPALGEBRA_TNT_STOPWATCH_H
#define IMPALGEBRA_TNT_STOPWATCH_H

// for clock() and CLOCKS_PER_SEC
#include <IMP/algebra/algebra_config.h>
#include <time.h>


IMPALGEBRA_BEGIN_INTERNAL_NAMESPACE
namespace TNT
{
using namespace std;

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

class Stopwatch {
    private:
        int running_;
        double start_time_;
        double total_;

    public:
        inline Stopwatch();
        inline void start();
        inline double stop();
    inline double read();
    inline void resume();
    inline int running();
};

inline Stopwatch::Stopwatch() : running_(0), start_time_(0.0), total_(0.0) {}

void Stopwatch::start()
{
  running_ = 1;
  total_ = 0.0;
  start_time_ = seconds();
}

double Stopwatch::stop()
{
  if (running_)
  {
         total_ += (seconds() - start_time_);
         running_ = 0;
    }
    return total_;
}

inline void Stopwatch::resume()
{
  if (!running_)
  {
    start_time_ = seconds();
    running_ = 1;
  }
}


inline double Stopwatch::read()
{
  if (running_)
  {
    stop();
    resume();
  }
  return total_;
}


} /* TNT namespace */
IMPALGEBRA_END_INTERNAL_NAMESPACE

#endif /* IMPALGEBRA_TNT_STOPWATCH_H */