#ifndef JEMALLOC_INTERNAL_TICKER_H

#define JEMALLOC_INTERNAL_TICKER_H

#include "jemalloc/internal/util.h"

/**

 * A ticker makes it easy to count-down events until some limit.  You

 * ticker_init the ticker to trigger every nticks events.  You then notify it

 * that an event has occurred with calls to ticker_tick (or that nticks events

 * have occurred with a call to ticker_ticks), which will return true (and reset

 * the counter) if the countdown hit zero.

 */

typedef struct {

	int32_t tick;

	int32_t nticks;

} ticker_t;

static inline void

ticker_init(ticker_t *ticker, int32_t nticks) {

	ticker->tick = nticks;

	ticker->nticks = nticks;

}

static inline void

ticker_copy(ticker_t *ticker, const ticker_t *other) {

	*ticker = *other;

}

static inline int32_t

ticker_read(const ticker_t *ticker) {

	return ticker->tick;

}

/*

 * Not intended to be a public API.  Unfortunately, on x86, neither gcc nor

 * clang seems smart enough to turn

 *   ticker->tick -= nticks;

 *   if (unlikely(ticker->tick < 0)) {

 *     fixup ticker

 *     return true;

 *   }

 *   return false;

 * into

 *   subq %nticks_reg, (%ticker_reg)

 *   js fixup ticker

 *

 * unless we force "fixup ticker" out of line.  In that case, gcc gets it right,

 * but clang now does worse than before.  So, on x86 with gcc, we force it out

 * of line, but otherwise let the inlining occur.  Ordinarily this wouldn't be

 * worth the hassle, but this is on the fast path of both malloc and free (via

 * tcache_event).

 */

#if defined(__GNUC__) && !defined(__clang__)				\

    && (defined(__x86_64__) || defined(__i386__))

JEMALLOC_NOINLINE

#endif

static bool

ticker_fixup(ticker_t *ticker) {

	ticker->tick = ticker->nticks;

	return true;

}

static inline bool

ticker_ticks(ticker_t *ticker, int32_t nticks) {

	ticker->tick -= nticks;

	if (unlikely(ticker->tick < 0)) {

		return ticker_fixup(ticker);

	}

	return false;

}

static inline bool

ticker_tick(ticker_t *ticker) {

	return ticker_ticks(ticker, 1);

}

/*

 * Try to tick.  If ticker would fire, return true, but rely on

 * slowpath to reset ticker.

 */

static inline bool

ticker_trytick(ticker_t *ticker) {

	--ticker->tick;

	if (unlikely(ticker->tick < 0)) {

		return true;

	}

	return false;

}

#endif /* JEMALLOC_INTERNAL_TICKER_H */