#include <sys/timex.h>
#include "atimer.h"

int timeval_subtract (struct timeval *result, struct timeval *x, struct timeval *y)
{
// NOTE: THIS FUNCTION IS GNU CODE AND IS USED UNDER THE GPL.
// Purpose:
// Put the result of subtraction of x & y into result
//
// Arguments:
// result - the container for the result of subtraction
// x - the ending time
// y - the starting time
// 
// Return value:
// NONE
	
  // Perform the carry for the later subtraction by updating y.
  if (x->tv_usec < y->tv_usec) {
    int nsec = (y->tv_usec - x->tv_usec) / 1000000 + 1;
    y->tv_usec -= 1000000 * nsec;
    y->tv_sec += nsec;
  }
  if (x->tv_usec - y->tv_usec > 1000000) {
    int nsec = (x->tv_usec - y->tv_usec) / 1000000;
    y->tv_usec += 1000000 * nsec;
    y->tv_sec -= nsec;
  }

  // Compute the time remaining to wait.
  //    tv_usec is certainly positive.
  result->tv_sec = x->tv_sec - y->tv_sec;
  result->tv_usec = x->tv_usec - y->tv_usec;

  // Return 1 if result is negative. 
  return x->tv_sec < y->tv_sec;
}

void atimer::Start() {
   ntp_gettime(&start_t);
}

void atimer::Stop() {
   ntptimeval result;

   ntp_gettime(&end_t);
   timeval_subtract(&result.time, &end_t.time, &start_t.time);

	myElapsed = (result.time.tv_sec + (result.time.tv_usec / 1000000.0)); // Calculate elapsed time in seconds
   myCumulative += myElapsed;
}

void atimer::Reset() {
   end_t.time.tv_sec = 0;
   end_t.time.tv_usec = 0;
   start_t.time.tv_sec = 0;
   start_t.time.tv_usec = 0;
   myElapsed = 0;
   myCumulative = 0;
}

double atimer::ElapsedTime() {
   return myElapsed;
}

double atimer::CumulativeTime() {
   return myCumulative;
}