timeout.c

/* ==========================================================================
 * timeout.c - Tickless hierarchical timing wheel.
 * --------------------------------------------------------------------------
 * Copyright (c) 2013, 2014  William Ahern
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to permit
 * persons to whom the Software is furnished to do so, subject to the
 * following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
 * NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 * USE OR OTHER DEALINGS IN THE SOFTWARE.
 * ==========================================================================
 */
#ifdef HAVE_CONFIG_H
#include "orconfig.h"
#endif
#include <limits.h>    /* CHAR_BIT */
 
#include <stddef.h>    /* NULL */
#include <stdlib.h>    /* malloc(3) free(3) */
#include <stdio.h>     /* FILE fprintf(3) */
 
#include <inttypes.h>  /* UINT64_C uint64_t */
 
#include <string.h>    /* memset(3) */
 
#include <errno.h>     /* errno */
 
#include "ext/tor_queue.h" /* TAILQ(3) */
 
#include "ext/timeouts/timeout.h"
 
#ifndef TIMEOUT_DEBUG
#define TIMEOUT_DEBUG 0
#endif
 
#if TIMEOUT_DEBUG - 0
#include "ext/timeouts/timeout-debug.h"
#endif
 
#ifdef TIMEOUT_DISABLE_RELATIVE_ACCESS
#define TO_SET_TIMEOUTS(to, T) ((void)0)
#else
#define TO_SET_TIMEOUTS(to, T) ((to)->timeouts = (T))
#endif
 
/*
 * A N C I L L A R Y  R O U T I N E S
 *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 
#define abstime_t timeout_t /* for documentation purposes */
#define reltime_t timeout_t /* "" */
 
#if !defined countof
#define countof(a) (sizeof (a) / sizeof *(a))
#endif
 
#if !defined endof
#define endof(a) (&(a)[countof(a)])
#endif
 
#if !defined MIN
#define MIN(a, b) (((a) < (b))? (a) : (b))
#endif
 
#if !defined MAX
#define MAX(a, b) (((a) > (b))? (a) : (b))
#endif
 
#if !defined TOR_TAILQ_CONCAT
#define TOR_TAILQ_CONCAT(head1, head2, field) do {                      \
        if (!TOR_TAILQ_EMPTY(head2)) {                                  \
                *(head1)->tqh_last = (head2)->tqh_first;                \
                (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \
                (head1)->tqh_last = (head2)->tqh_last;                  \
                TOR_TAILQ_INIT((head2));                                \
        }                                                               \
} while (0)
#endif
 
#if !defined TOR_TAILQ_FOREACH_SAFE
#define TOR_TAILQ_FOREACH_SAFE(var, head, field, tvar)                      \
        for ((var) = TOR_TAILQ_FIRST(head);                                 \
            (var) && ((tvar) = TOR_TAILQ_NEXT(var, field), 1);              \
            (var) = (tvar))
#endif
 
 
/*
 * B I T  M A N I P U L A T I O N  R O U T I N E S
 *
 * The macros and routines below implement wheel parameterization. The
 * inputs are:
 *
 *   WHEEL_BIT - The number of value bits mapped in each wheel. The
 *               lowest-order WHEEL_BIT bits index the lowest-order (highest
 *               resolution) wheel, the next group of WHEEL_BIT bits the
 *               higher wheel, etc.
 *
 *   WHEEL_NUM - The number of wheels. WHEEL_BIT * WHEEL_NUM = the number of
 *               value bits used by all the wheels. For the default of 6 and
 *               4, only the low 24 bits are processed. Any timeout value
 *               larger than this will cycle through again.
 *
 * The implementation uses bit fields to remember which slot in each wheel
 * is populated, and to generate masks of expiring slots according to the
 * current update interval (i.e. the "tickless" aspect). The slots to
 * process in a wheel are (populated-set & interval-mask).
 *
 * WHEEL_BIT cannot be larger than 6 bits because 2^6 -> 64 is the largest
 * number of slots which can be tracked in a uint64_t integer bit field.
 * WHEEL_BIT cannot be smaller than 3 bits because of our rotr and rotl
 * routines, which only operate on all the value bits in an integer, and
 * there's no integer smaller than uint8_t.
 *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 
#if !defined WHEEL_BIT
#define WHEEL_BIT 6
#endif
 
#if !defined WHEEL_NUM
#define WHEEL_NUM 4
#endif
 
#define WHEEL_LEN (1U << WHEEL_BIT)
#define WHEEL_MAX (WHEEL_LEN - 1)
#define WHEEL_MASK (WHEEL_LEN - 1)
#define TIMEOUT_MAX ((TIMEOUT_C(1) << (WHEEL_BIT * WHEEL_NUM)) - 1)
 
#include "ext/timeouts/timeout-bitops.c"
 
#if WHEEL_BIT == 6
#define ctz(n) ctz64(n)
#define clz(n) clz64(n)
#define fls(n) ((int)(64 - clz64(n)))
#else
#define ctz(n) ctz32(n)
#define clz(n) clz32(n)
#define fls(n) ((int)(32 - clz32((uint32_t)n)))
#endif
 
#if WHEEL_BIT == 6
#define WHEEL_C(n) UINT64_C(n)
#define WHEEL_PRIu PRIu64
#define WHEEL_PRIx PRIx64
 
typedef uint64_t wheel_t;
 
#elif WHEEL_BIT == 5
 
#define WHEEL_C(n) UINT32_C(n)
#define WHEEL_PRIu PRIu32
#define WHEEL_PRIx PRIx32
 
typedef uint32_t wheel_t;
 
#elif WHEEL_BIT == 4
 
#define WHEEL_C(n) UINT16_C(n)
#define WHEEL_PRIu PRIu16
#define WHEEL_PRIx PRIx16
 
typedef uint16_t wheel_t;
 
#elif WHEEL_BIT == 3
 
#define WHEEL_C(n) UINT8_C(n)
#define WHEEL_PRIu PRIu8
#define WHEEL_PRIx PRIx8
 
typedef uint8_t wheel_t;
 
#else
#error invalid WHEEL_BIT value
#endif
 
 
static inline wheel_t rotl(const wheel_t v, int c) {
        if (!(c &= (sizeof v * CHAR_BIT - 1)))
                return v;
 
        return (v << c) | (v >> (sizeof v * CHAR_BIT - c));
} /* rotl() */
 
 
static inline wheel_t rotr(const wheel_t v, int c) {
        if (!(c &= (sizeof v * CHAR_BIT - 1)))
                return v;
 
        return (v >> c) | (v << (sizeof v * CHAR_BIT - c));
} /* rotr() */
 
 
/*
 * T I M E R  R O U T I N E S
 *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 
TOR_TAILQ_HEAD(timeout_list, timeout);
 
struct timeouts {
        struct timeout_list wheel[WHEEL_NUM][WHEEL_LEN], expired;
 
        wheel_t pending[WHEEL_NUM];
 
        timeout_t curtime;
        timeout_t hertz;
}; /* struct timeouts */
 
 
static struct timeouts *timeouts_init(struct timeouts *T, timeout_t hz) {
        unsigned i, j;
 
        for (i = 0; i < countof(T->wheel); i++) {
                for (j = 0; j < countof(T->wheel[i]); j++) {
                        TOR_TAILQ_INIT(&T->wheel[i][j]);
                }
        }
 
        TOR_TAILQ_INIT(&T->expired);
 
        for (i = 0; i < countof(T->pending); i++) {
                T->pending[i] = 0;
        }
 
        T->curtime = 0;
        T->hertz = (hz)? hz : TIMEOUT_mHZ;
 
        return T;
} /* timeouts_init() */
 
 
TIMEOUT_PUBLIC struct timeouts *timeouts_open(timeout_t hz, int *error) {
        struct timeouts *T;
 
        if ((T = malloc(sizeof *T)))
                return timeouts_init(T, hz);
 
        *error = errno;
 
        return NULL;
} /* timeouts_open() */
 
 
static void timeouts_reset(struct timeouts *T) {
        struct timeout_list reset;
        struct timeout *to;
        unsigned i, j;
 
        TOR_TAILQ_INIT(&reset);
 
        for (i = 0; i < countof(T->wheel); i++) {
                for (j = 0; j < countof(T->wheel[i]); j++) {
                        TOR_TAILQ_CONCAT(&reset, &T->wheel[i][j], tqe);
                }
        }
 
        TOR_TAILQ_CONCAT(&reset, &T->expired, tqe);
 
        TOR_TAILQ_FOREACH(to, &reset, tqe) {
                to->pending = NULL;
                TO_SET_TIMEOUTS(to, NULL);
        }
} /* timeouts_reset() */
 
 
TIMEOUT_PUBLIC void timeouts_close(struct timeouts *T) {
        /*
         * NOTE: Delete installed timeouts so timeout_pending() and
         * timeout_expired() worked as expected.
         */
        timeouts_reset(T);
 
        free(T);
} /* timeouts_close() */
 
 
TIMEOUT_PUBLIC timeout_t timeouts_hz(struct timeouts *T) {
        return T->hertz;
} /* timeouts_hz() */
 
 
TIMEOUT_PUBLIC void timeouts_del(struct timeouts *T, struct timeout *to) {
        if (to->pending) {
                TOR_TAILQ_REMOVE(to->pending, to, tqe);
 
                if (to->pending != &T->expired && TOR_TAILQ_EMPTY(to->pending)) {
                        ptrdiff_t index_ = to->pending - &T->wheel[0][0];
                        int wheel = (int) (index_ / WHEEL_LEN);
                        int slot = index_ % WHEEL_LEN;
 
                        T->pending[wheel] &= ~(WHEEL_C(1) << slot);
                }
 
                to->pending = NULL;
                TO_SET_TIMEOUTS(to, NULL);
        }
} /* timeouts_del() */
 
 
static inline reltime_t timeout_rem(struct timeouts *T, struct timeout *to) {
        return to->expires - T->curtime;
} /* timeout_rem() */
 
 
static inline int timeout_wheel(timeout_t timeout) {
        /* must be called with timeout != 0, so fls input is nonzero */
        return (fls(MIN(timeout, TIMEOUT_MAX)) - 1) / WHEEL_BIT;
} /* timeout_wheel() */
 
 
static inline int timeout_slot(int wheel, timeout_t expires) {
        return WHEEL_MASK & ((expires >> (wheel * WHEEL_BIT)) - !!wheel);
} /* timeout_slot() */
 
 
static void timeouts_sched(struct timeouts *T, struct timeout *to, timeout_t expires) {
        timeout_t rem;
        int wheel, slot;
 
        timeouts_del(T, to);
 
        to->expires = expires;
 
        TO_SET_TIMEOUTS(to, T);
 
        if (expires > T->curtime) {
                rem = timeout_rem(T, to);
 
                /* rem is nonzero since:
                 *   rem == timeout_rem(T,to),
                 *       == to->expires - T->curtime
                 *   and above we have expires > T->curtime.
                 */
                wheel = timeout_wheel(rem);
                slot = timeout_slot(wheel, to->expires);
 
                to->pending = &T->wheel[wheel][slot];
                TOR_TAILQ_INSERT_TAIL(to->pending, to, tqe);
 
                T->pending[wheel] |= WHEEL_C(1) << slot;
        } else {
                to->pending = &T->expired;
                TOR_TAILQ_INSERT_TAIL(to->pending, to, tqe);
        }
} /* timeouts_sched() */
 
 
#ifndef TIMEOUT_DISABLE_INTERVALS
static void timeouts_readd(struct timeouts *T, struct timeout *to) {
        to->expires += to->interval;
 
        if (to->expires <= T->curtime) {
                /* If we've missed the next firing of this timeout, reschedule
                 * it to occur at the next multiple of its interval after
                 * the last time that it fired.
                 */
                timeout_t n = T->curtime - to->expires;
                timeout_t r = n % to->interval;
                to->expires = T->curtime + (to->interval - r);
        }
 
        timeouts_sched(T, to, to->expires);
} /* timeouts_readd() */
#endif
 
 
TIMEOUT_PUBLIC void timeouts_add(struct timeouts *T, struct timeout *to, timeout_t timeout) {
#ifndef TIMEOUT_DISABLE_INTERVALS
        if (to->flags & TIMEOUT_INT)
                to->interval = MAX(1, timeout);
#endif
 
        if (to->flags & TIMEOUT_ABS)
                timeouts_sched(T, to, timeout);
        else
                timeouts_sched(T, to, T->curtime + timeout);
} /* timeouts_add() */
 
 
TIMEOUT_PUBLIC void timeouts_update(struct timeouts *T, abstime_t curtime) {
        timeout_t elapsed = curtime - T->curtime;
        struct timeout_list todo;
        int wheel;
 
        TOR_TAILQ_INIT(&todo);
 
        /*
         * There's no avoiding looping over every wheel. It's best to keep
         * WHEEL_NUM smallish.
         */
        for (wheel = 0; wheel < WHEEL_NUM; wheel++) {
                wheel_t pending;
 
                /*
                 * Calculate the slots expiring in this wheel
                 *
                 * If the elapsed time is greater than the maximum period of
                 * the wheel, mark every position as expiring.
                 *
                 * Otherwise, to determine the expired slots fill in all the
                 * bits between the last slot processed and the current
                 * slot, inclusive of the last slot. We'll bitwise-AND this
                 * with our pending set below.
                 *
                 * If a wheel rolls over, force a tick of the next higher
                 * wheel.
                 */
                if ((elapsed >> (wheel * WHEEL_BIT)) > WHEEL_MAX) {
                        pending = (wheel_t)~WHEEL_C(0);
                } else {
                        wheel_t _elapsed = WHEEL_MASK & (elapsed >> (wheel * WHEEL_BIT));
                        int oslot, nslot;
 
                        /*
                         * TODO: It's likely that at least one of the
                         * following three bit fill operations is redundant
                         * or can be replaced with a simpler operation.
                         */
                        oslot = WHEEL_MASK & (T->curtime >> (wheel * WHEEL_BIT));
                        pending = rotl(((WHEEL_C(1) << _elapsed) - 1), oslot);
 
                        nslot = WHEEL_MASK & (curtime >> (wheel * WHEEL_BIT));
                        pending |= rotr(rotl(((WHEEL_C(1) << _elapsed) - 1), nslot), (int)_elapsed);
                        pending |= WHEEL_C(1) << nslot;
                }
 
                while (pending & T->pending[wheel]) {
                        /* ctz input cannot be zero: loop condition. */
                        int slot = ctz(pending & T->pending[wheel]);
                        TOR_TAILQ_CONCAT(&todo, &T->wheel[wheel][slot], tqe);
                        T->pending[wheel] &= ~(UINT64_C(1) << slot);
                }
 
                if (!(0x1 & pending))
                        break; /* break if we didn't wrap around end of wheel */
 
                /* if we're continuing, the next wheel must tick at least once */
                elapsed = MAX(elapsed, (WHEEL_LEN << (wheel * WHEEL_BIT)));
        }
 
        T->curtime = curtime;
 
        while (!TOR_TAILQ_EMPTY(&todo)) {
                struct timeout *to = TOR_TAILQ_FIRST(&todo);
 
                TOR_TAILQ_REMOVE(&todo, to, tqe);
                to->pending = NULL;
 
                timeouts_sched(T, to, to->expires);
        }
 
        return;
} /* timeouts_update() */
 
TIMEOUT_PUBLIC timeout_t timeouts_get_curtime(struct timeouts *T) {
        return T->curtime;
} /* timeouts_get_curtime() */
 
TIMEOUT_PUBLIC void timeouts_step(struct timeouts *T, reltime_t elapsed) {
        timeouts_update(T, T->curtime + elapsed);
} /* timeouts_step() */
 
 
TIMEOUT_PUBLIC bool timeouts_pending(struct timeouts *T) {
        wheel_t pending = 0;
        int wheel;
 
        for (wheel = 0; wheel < WHEEL_NUM; wheel++) {
                pending |= T->pending[wheel];
        }
 
        return !!pending;
} /* timeouts_pending() */
 
 
TIMEOUT_PUBLIC bool timeouts_expired(struct timeouts *T) {
        return !TOR_TAILQ_EMPTY(&T->expired);
} /* timeouts_expired() */
 
 
/*
 * Calculate the interval before needing to process any timeouts pending on
 * any wheel.
 *
 * (This is separated from the public API routine so we can evaluate our
 * wheel invariant assertions irrespective of the expired queue.)
 *
 * This might return a timeout value sooner than any installed timeout if
 * only higher-order wheels have timeouts pending. We can only know when to
 * process a wheel, not precisely when a timeout is scheduled. Our timeout
 * accuracy could be off by 2^(N*M)-1 units where N is the wheel number and
 * M is WHEEL_BIT. Only timeouts which have fallen through to wheel 0 can be
 * known exactly.
 *
 * We should never return a timeout larger than the lowest actual timeout.
 */
static timeout_t timeouts_int(struct timeouts *T) {
        timeout_t timeout = ~TIMEOUT_C(0), _timeout;
        timeout_t relmask;
        int wheel, slot;
 
        relmask = 0;
 
        for (wheel = 0; wheel < WHEEL_NUM; wheel++) {
                if (T->pending[wheel]) {
                        slot = WHEEL_MASK & (T->curtime >> (wheel * WHEEL_BIT));
 
                        /* ctz input cannot be zero: T->pending[wheel] is
                         * nonzero, so rotr() is nonzero. */
                        _timeout = (ctz(rotr(T->pending[wheel], slot)) + !!wheel) << (wheel * WHEEL_BIT);
                        /* +1 to higher order wheels as those timeouts are one rotation in the future (otherwise they'd be on a lower wheel or expired) */
 
                        _timeout -= relmask & T->curtime;
                        /* reduce by how much lower wheels have progressed */
 
                        timeout = MIN(_timeout, timeout);
                }
 
                relmask <<= WHEEL_BIT;
                relmask |= WHEEL_MASK;
        }
 
        return timeout;
} /* timeouts_int() */
 
 
/*
 * Calculate the interval our caller can wait before needing to process
 * events.
 */
TIMEOUT_PUBLIC timeout_t timeouts_timeout(struct timeouts *T) {
        if (!TOR_TAILQ_EMPTY(&T->expired))
                return 0;
 
        return timeouts_int(T);
} /* timeouts_timeout() */
 
 
TIMEOUT_PUBLIC struct timeout *timeouts_get(struct timeouts *T) {
        if (!TOR_TAILQ_EMPTY(&T->expired)) {
                struct timeout *to = TOR_TAILQ_FIRST(&T->expired);
 
                TOR_TAILQ_REMOVE(&T->expired, to, tqe);
                to->pending = NULL;
                TO_SET_TIMEOUTS(to, NULL);
 
#ifndef TIMEOUT_DISABLE_INTERVALS
                if ((to->flags & TIMEOUT_INT) && to->interval > 0)
                        timeouts_readd(T, to);
#endif
 
                return to;
        } else {
                return 0;
        }
} /* timeouts_get() */
 
 
/*
 * Use dumb looping to locate the earliest timeout pending on the wheel so
 * our invariant assertions can check the result of our optimized code.
 */
static struct timeout *timeouts_min(struct timeouts *T) {
        struct timeout *to, *min = NULL;
        unsigned i, j;
 
        for (i = 0; i < countof(T->wheel); i++) {
                for (j = 0; j < countof(T->wheel[i]); j++) {
                        TOR_TAILQ_FOREACH(to, &T->wheel[i][j], tqe) {
                                if (!min || to->expires < min->expires)
                                        min = to;
                        }
                }
        }
 
        return min;
} /* timeouts_min() */
 
 
/*
 * Check some basic algorithm invariants. If these invariants fail then
 * something is definitely broken.
 */
#define report(...) do { \
        if ((fp)) \
                fprintf(fp, __VA_ARGS__); \
} while (0)
 
#define check(expr, ...) do { \
        if (!(expr)) { \
                report(__VA_ARGS__); \
                return 0; \
        } \
} while (0)
 
TIMEOUT_PUBLIC bool timeouts_check(struct timeouts *T, FILE *fp) {
        timeout_t timeout;
        struct timeout *to;
 
        if ((to = timeouts_min(T))) {
                check(to->expires > T->curtime, "missed timeout (expires:%" TIMEOUT_PRIu " <= curtime:%" TIMEOUT_PRIu ")\n", to->expires, T->curtime);
 
                timeout = timeouts_int(T);
                check(timeout <= to->expires - T->curtime, "wrong soft timeout (soft:%" TIMEOUT_PRIu " > hard:%" TIMEOUT_PRIu ") (expires:%" TIMEOUT_PRIu "; curtime:%" TIMEOUT_PRIu ")\n", timeout, (to->expires - T->curtime), to->expires, T->curtime);
 
                timeout = timeouts_timeout(T);
                check(timeout <= to->expires - T->curtime, "wrong soft timeout (soft:%" TIMEOUT_PRIu " > hard:%" TIMEOUT_PRIu ") (expires:%" TIMEOUT_PRIu "; curtime:%" TIMEOUT_PRIu ")\n", timeout, (to->expires - T->curtime), to->expires, T->curtime);
        } else {
                timeout = timeouts_timeout(T);
 
                if (!TOR_TAILQ_EMPTY(&T->expired))
                        check(timeout == 0, "wrong soft timeout (soft:%" TIMEOUT_PRIu " != hard:%" TIMEOUT_PRIu ")\n", timeout, TIMEOUT_C(0));
                else
                        check(timeout == ~TIMEOUT_C(0), "wrong soft timeout (soft:%" TIMEOUT_PRIu " != hard:%" TIMEOUT_PRIu ")\n", timeout, ~TIMEOUT_C(0));
        }
 
        return 1;
} /* timeouts_check() */
 
 
#define ENTER                                                           \
        do {                                                            \
        static const int pc0 = __LINE__;                                \
        switch (pc0 + it->pc) {                                         \
        case __LINE__: (void)0
 
#define SAVE_AND_DO(do_statement)                                       \
        do {                                                            \
                it->pc = __LINE__ - pc0;                                \
                do_statement;                                           \
                case __LINE__: (void)0;                                 \
        } while (0)
 
#define YIELD(rv)                                                       \
        SAVE_AND_DO(return (rv))
 
#define LEAVE                                                           \
        SAVE_AND_DO(break);                                             \
        }                                                               \
        } while (0)
 
TIMEOUT_PUBLIC struct timeout *timeouts_next(struct timeouts *T, struct timeouts_it *it) {
        struct timeout *to;
 
        ENTER;
 
        if (it->flags & TIMEOUTS_EXPIRED) {
                if (it->flags & TIMEOUTS_CLEAR) {
                        while ((to = timeouts_get(T))) {
                                YIELD(to);
                        }
                } else {
                        TOR_TAILQ_FOREACH_SAFE(to, &T->expired, tqe, it->to) {
                                YIELD(to);
                        }
                }
        }
 
        if (it->flags & TIMEOUTS_PENDING) {
                for (it->i = 0; it->i < countof(T->wheel); it->i++) {
                        for (it->j = 0; it->j < countof(T->wheel[it->i]); it->j++) {
                                TOR_TAILQ_FOREACH_SAFE(to, &T->wheel[it->i][it->j], tqe, it->to) {
                                        YIELD(to);
                                }
                        }
                }
        }
 
        LEAVE;
 
        return NULL;
} /* timeouts_next */
 
#undef LEAVE
#undef YIELD
#undef SAVE_AND_DO
#undef ENTER
 
 
/*
 * T I M E O U T  R O U T I N E S
 *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 
TIMEOUT_PUBLIC struct timeout *timeout_init(struct timeout *to, int flags) {
        memset(to, 0, sizeof *to);
 
        to->flags = flags;
 
        return to;
} /* timeout_init() */
 
 
#ifndef TIMEOUT_DISABLE_RELATIVE_ACCESS
TIMEOUT_PUBLIC bool timeout_pending(struct timeout *to) {
        return to->pending && to->pending != &to->timeouts->expired;
} /* timeout_pending() */
 
 
TIMEOUT_PUBLIC bool timeout_expired(struct timeout *to) {
        return to->pending && to->pending == &to->timeouts->expired;
} /* timeout_expired() */
 
 
TIMEOUT_PUBLIC void timeout_del(struct timeout *to) {
        timeouts_del(to->timeouts, to);
} /* timeout_del() */
#endif
 
 
/*
 * V E R S I O N  I N T E R F A C E S
 *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 
TIMEOUT_PUBLIC int timeout_version(void) {
        return TIMEOUT_VERSION;
} /* timeout_version() */
 
 
TIMEOUT_PUBLIC const char *timeout_vendor(void) {
        return TIMEOUT_VENDOR;
} /* timeout_version() */
 
 
TIMEOUT_PUBLIC int timeout_v_rel(void) {
        return TIMEOUT_V_REL;
} /* timeout_version() */
 
 
TIMEOUT_PUBLIC int timeout_v_abi(void) {
        return TIMEOUT_V_ABI;
} /* timeout_version() */
 
 
TIMEOUT_PUBLIC int timeout_v_api(void) {
        return TIMEOUT_V_API;
} /* timeout_version() */