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/*************************************************************************
* Copyright (C) 2008 Tavian Barnes <tavianator@gmail.com> *
* *
* This file is part of The Sandglass Library. *
* *
* The Sandglass Library is free software; you can redistribute it *
* and/or modify it under the terms of the GNU Lesser General Public *
* License as published by the Free Software Foundation; either version *
* 3 of the License, or (at your option) any later version. *
* *
* The Sandglass Library is distributed in the hope that it will be *
* useful, but WITHOUT ANY WARRANTY; without even the implied warranty *
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
* Lesser General Public License for more details. *
* *
* You should have received a copy of the GNU Lesser General Public *
* License along with this program. If not, see *
* <http://www.gnu.org/licenses/>. *
*************************************************************************/
#include "sandglass_impl.h"
#include "sandglass.h"
#include <time.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
void
sandglass_get_currtime(struct timespec *ts)
{
static int monotonic = 0;
if (!monotonic) {
monotonic = sysconf(_SC_MONOTONIC_CLOCK);
}
if (monotonic > 0) {
if (clock_gettime(CLOCK_MONOTONIC, ts) != 0) {
fprintf(stderr,
"libsandglass: couldn't get value of clock CLOCK_MONOTONIC\n");
exit(EXIT_FAILURE);
}
} else {
if (clock_gettime(CLOCK_REALTIME, ts) != 0) {
fprintf(stderr,
"libsandglass: couldn't get value of clock CLOCK_REALTIME\n");
exit(EXIT_FAILURE);
}
}
}
void
sandglass_timespec_add(struct timespec *ts, const struct timespec *d)
{
if (d->tv_nsec >= 1000000000L - ts->tv_nsec) {
ts->tv_nsec += d->tv_nsec - 1000000000L;
++ts->tv_sec;
} else {
ts->tv_nsec += d->tv_nsec;
}
ts->tv_sec += d->tv_sec;
}
void
sandglass_timespec_sub(struct timespec *ts, const struct timespec *d)
{
if (d->tv_nsec > ts->tv_nsec) {
ts->tv_nsec -= d->tv_nsec - 1000000000L;
--ts->tv_sec;
} else {
ts->tv_nsec -= d->tv_nsec;
}
ts->tv_sec -= d->tv_sec;
}
int
sandglass_timespec_cmp(const struct timespec *a, const struct timespec *b)
{
if (a->tv_sec > b->tv_sec)
return 1;
else if (a->tv_sec == b->tv_sec) {
if (a->tv_nsec > b->tv_nsec)
return 1;
else if (a->tv_nsec == b->tv_nsec)
return 0;
else
return -1;
}
else
return -1;
}
/* Spins for the time interval specified by ts */
void
sandglass_spin(struct timespec *ts)
{
struct timespec curr, until;
sandglass_get_currtime(&curr);
until = curr;
sandglass_timespec_add(&until, ts);
/* Spin */
do {
sandglass_get_currtime(&curr);
} while (sandglass_timespec_cmp(&curr, &until) < 0);
/* Adjust ts to the time actually waited */
sandglass_timespec_sub(&curr, &until);
sandglass_timespec_add(ts, &curr);
}
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