source: timer.c @ 27c3a93

#include "owl.h"

#define OWL_TIMER_DIRECTION_COUNTUP    1
#define OWL_TIMER_DIRECTION_COUNTDOWN  2


/* Create a "counting up" timer.  The counter starts running as soon
 * as this is called.  Use owl_timer_reset() to reset it.
 */
void owl_timer_create_countup(owl_timer *t)
{
  t->direction=OWL_TIMER_DIRECTION_COUNTUP;
  t->starttime=time(NULL);
}

/* create a "counting down" timer, which counts down from 'start'
 * seconds.  The counter starts running as soon as this is called.
 * Use owl_timer_reset to reset it.
 */
void owl_timer_create_countdown(owl_timer *t, int start)
{
  t->direction=OWL_TIMER_DIRECTION_COUNTDOWN;
  t->start=start;
  t->starttime=time(NULL);
}

/* Reset the timer.  For a "counting up" timer, it is reset to 0.  For
 * a "counting down" timer it is set to the value initially set with
 * owl_timer_create_countdown() or the last value set with
 * owl_timer_reset_newstart() */
void owl_timer_reset(owl_timer *t)
{
  t->starttime=time(NULL);
}

/* Only for a countdown timer.  Rest the timer, but this time (and on
 * future resets) start with 'start' seconds.
 */
void owl_timer_reset_newstart(owl_timer *t, int start)
{
  t->start=start;
  t->starttime=time(NULL);
}

/* Return the number of seconds elapsed or remaining.  If using a
 * countdown timer, a negative value is never reported.  Once the
 * timer gets to 0 it stays at 0 */
int owl_timer_get_time(owl_timer *t)
{
  time_t now;
  int rem;

  now=time(NULL);

  if (t->direction==OWL_TIMER_DIRECTION_COUNTUP) {
    return(now-t->starttime);
  } else if (t->direction==OWL_TIMER_DIRECTION_COUNTDOWN) {
    rem=t->start-(now-t->starttime);
    if (rem<0) return(0);
    return(rem);
  }

  /* never reached */
  return(0);
}

/* Only for countdown timer.  Return true if time has run out (the
 * timer is at 0 seconds or less
 */
int owl_timer_is_expired(owl_timer *t)
{
  if (owl_timer_get_time(t)==0) return(1);
  return(0);
}