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-rw-r--r--drv_PICGraphic.c2
-rw-r--r--timer.c60
2 files changed, 46 insertions, 16 deletions
diff --git a/drv_PICGraphic.c b/drv_PICGraphic.c
index 8586eb6..c33973d 100644
--- a/drv_PICGraphic.c
+++ b/drv_PICGraphic.c
@@ -203,7 +203,7 @@ static void drv_PICGraphic_blit(const int row, const int col, const int height,
delayDone = 0;
int row8, height8;
row8 = 8 * (row / 8);
- height8 = 8 * (height / 8) + ! !(height % 8);
+ height8 = 8 * (height / 8) + !!(height % 8);
info("sending blit");
cmd[0] = 'b';
cmd[1] = row8;
diff --git a/timer.c b/timer.c
index 5dbb379..bd7eeb0 100644
--- a/timer.c
+++ b/timer.c
@@ -113,27 +113,57 @@ int nTimers = 0;
TIMER *Timers = NULL;
-static void timer_inc(struct timeval *tv, const int interval)
-/* Update a timer's trigger by adding the given interval.
+static void timer_inc(const int timer, struct timeval *now)
+/* Update the time a given timer updates next.
- tv (timeval pointer): struct holding the last time the timer has
- been processed
+ timer (integer): internal ID of timer that is to be updated
- interval (integer): interval in milliseconds to be added to the
- the last time the timer has been processed
+ now (timeval pointer): struct holding the "current" time
return value: void
*/
{
- /* split time interval to be added (given in milliseconds) into
- microseconds and seconds */
- struct timeval diff = {
+ /* calculate the time difference between the last time the given
+ timer has been processed and the current time */
+ struct timeval diff;
+ timersub(now, &Timers[timer].when, &diff);
+
+ /* convert this time difference to fractional seconds */
+ float fDiff = diff.tv_sec + diff.tv_usec / 1000000.0f;
+
+ /* convert time difference to fractional milliseconds */
+ fDiff = fDiff * 1000.0f;
+
+ /* calculate the number of timer intervals that have passed since
+ the last timer the given timer has been processed -- value is
+ truncated (rounded down) to an integer */
+ int number_of_intervals = (int) (fDiff / Timers[timer].interval);
+
+ /* notify the user in case one or more timer intervals have been
+ missed */
+ if (number_of_intervals > 0)
+ info("Timer #%d skipped %d interval(s) or %d ms.", timer, number_of_intervals,
+ number_of_intervals * Timers[timer].interval);
+
+ /* increment the number of passed intervals in order to skip all
+ missed intervals -- thereby avoiding that unprocessed timers
+ stack up, continuously update and are notoriously late (certain
+ railway companies might learn a lesson from us <g>) */
+ number_of_intervals++;
+
+ /* calculate time difference between the last time the timer has
+ been processed and the next time it will be processed */
+ int interval = Timers[timer].interval * number_of_intervals;
+
+ /* convert time difference (in milliseconds) to a "timeval"
+ structure (in seconds and microseconds) */
+ struct timeval tv_interval = {
.tv_sec = interval / 1000,
.tv_usec = (interval % 1000) * 1000
};
- /* add interval to timer and store the result in the timer */
- timeradd(tv, &diff, tv);
+ /* finally, add time difference to the timer's trigger */
+ timeradd(&Timers[timer].when, &tv_interval, &Timers[timer].when);
}
@@ -249,7 +279,7 @@ int timer_add(void (*callback) (void *data), void *data, const int interval, con
/* one-shot timers should NOT fire immediately, so delay them by a
single timer interval */
if (one_shot) {
- timer_inc(&Timers[timer].when, interval);
+ timer_inc(timer, &now);
}
/* signal successful timer creation */
@@ -365,9 +395,9 @@ int timer_process(struct timespec *delay)
been deleted and its allocated memory may be re-used) */
Timers[timer].active = 0;
} else {
- /* otherwise, respawn timer by adding one triggering interval
+ /* otherwise, re-spawn timer by adding one triggering interval
to its triggering time */
- timer_inc(&Timers[timer].when, Timers[timer].interval);
+ timer_inc(timer, &now);
}
}
}
@@ -428,7 +458,7 @@ int timer_process(struct timespec *delay)
timerclear(&diff);
/* display an info message to inform the user */
- info("Oops, clock skewed, update timestamp");
+ info("Oops, clock skewed, update time stamp");
/* update time stamp and timer */
/* FIXME: shouldn't we update *all* timers? */