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/***
This file is part of PulseAudio.
Copyright 2006 Lennart Poettering
PulseAudio 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 2.1 of the License,
or (at your option) any later version.
PulseAudio 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
General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with PulseAudio; if not, see <http://www.gnu.org/licenses/>.
***/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <errno.h>
#include <pthread.h>
#include <semaphore.h>
#include <pulse/xmalloc.h>
#include <pulsecore/macro.h>
#include "semaphore.h"
struct pa_semaphore {
sem_t sem;
};
pa_semaphore* pa_semaphore_new(unsigned value) {
pa_semaphore *s;
s = pa_xnew(pa_semaphore, 1);
pa_assert_se(sem_init(&s->sem, 0, value) == 0);
return s;
}
void pa_semaphore_free(pa_semaphore *s) {
pa_assert(s);
pa_assert_se(sem_destroy(&s->sem) == 0);
pa_xfree(s);
}
void pa_semaphore_post(pa_semaphore *s) {
pa_assert(s);
pa_assert_se(sem_post(&s->sem) == 0);
}
void pa_semaphore_wait(pa_semaphore *s) {
int ret;
pa_assert(s);
do {
ret = sem_wait(&s->sem);
} while (ret < 0 && errno == EINTR);
pa_assert(ret == 0);
}
pa_semaphore* pa_static_semaphore_get(pa_static_semaphore *s, unsigned value) {
pa_semaphore *m;
pa_assert(s);
/* First, check if already initialized and short cut */
if ((m = pa_atomic_ptr_load(&s->ptr)))
return m;
/* OK, not initialized, so let's allocate, and fill in */
m = pa_semaphore_new(value);
if ((pa_atomic_ptr_cmpxchg(&s->ptr, NULL, m)))
return m;
pa_semaphore_free(m);
/* Him, filling in failed, so someone else must have filled in
* already */
pa_assert_se(m = pa_atomic_ptr_load(&s->ptr));
return m;
}
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