#include "Timer.h"

static struct timeval start;

void ResetTimer() {
/* this sets the timer back to zero and returns 0 on success, -1 on failure */
  int failurep;

  failurep=gettimeofday(&start,NULL);
  if (failurep) {
    printf ("ResetTimer failed\n");
  }

} /* ResetTimer() */

double timediff(struct timeval time1, struct timeval time2) {
/* this function returns the difference between 2 struct timevals.  time2
should be the later time */
  double result;
  
  result = time2.tv_sec-time1.tv_sec;
  result += (double)(time2.tv_usec-time1.tv_usec)/1000000;
  return(result);

} /* timediff(time1,time2) */

double CheckTimer() {
/* this returns the time elapsed since ResetTimer() was called 
if gettimeofday fails, -1 is returned */

  struct timeval now;

  if (gettimeofday(&now,NULL))
    printf("CheckTimer failed\n");
  return(timediff(start,now));

} /* CheckTimer() */