Function timer_fast_forward

ccan/ccan/timer/timer.c:293–337

Assume no timers before 'time', cascade down and update base time. */

/* Assume no timers before 'time', cascade down and update base time. */
static void timer_fast_forward(struct timers *timers, uint64_t time)
{
	unsigned int level, changed;
	int need_level = -1;
	struct list_head list;
	struct timer *i;

	/* How many bits changed between base and time?
	 * Each time we wrap, we need to empty buckets from above. */
	if (time == timers->base)
		return;

	changed = ilog64_nz(time ^ timers->base);
	level = (changed - 1) / TIMER_LEVEL_BITS;

	/* Buckets always empty downwards, so we could cascade manually,
	 * but it's rarely very many so we just remove and re-add */
	list_head_init(&list);

	do {
		if (!timers->level[level]) {
			/* We need any which belong on this level. */
			timers_far_get(timers, &list,
				       timers->base
				       + (1ULL << ((level+1)*TIMER_LEVEL_BITS))-1);
			need_level = level;
		} else {
			unsigned src;

			/* Get all timers from this bucket. */
			src = (time >> (level * TIMER_LEVEL_BITS)) % PER_LEVEL;
			list_append_list(&list,
					 &timers->level[level]->list[src]);
		}
	} while (level--);

	/* Did we hit the last level?  If so, add. */
	if (need_level != -1)
		add_level(timers, need_level);

	/* Fast-forward the time, and re-add everyone. */
	timers->base = time;
	while ((i = list_pop(&list, struct timer, list)) != NULL)
		timer_add_raw(timers, i);
}

/* Returns an expired timer. */
struct timer *timers_expire(struct timers *timers, struct timemono expire)