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/*
* Copyright (c) 2012 Ronald S. Bultje <rsbultje@gmail.com>
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "atomic.h"
#if !HAVE_MEMORYBARRIER && !HAVE_SYNC_VAL_COMPARE_AND_SWAP && !HAVE_MACHINE_RW_BARRIER
#if HAVE_PTHREADS
#include <pthread.h>
static pthread_mutex_t atomic_lock = PTHREAD_MUTEX_INITIALIZER;
int avpriv_atomic_int_get(volatile int *ptr)
{
int res;
pthread_mutex_lock(&atomic_lock);
res = *ptr;
pthread_mutex_unlock(&atomic_lock);
return res;
}
void avpriv_atomic_int_set(volatile int *ptr, int val)
{
pthread_mutex_lock(&atomic_lock);
*ptr = val;
pthread_mutex_unlock(&atomic_lock);
}
int avpriv_atomic_int_add_and_fetch(volatile int *ptr, int inc)
{
int res;
pthread_mutex_lock(&atomic_lock);
*ptr += inc;
res = *ptr;
pthread_mutex_unlock(&atomic_lock);
return res;
}
void *avpriv_atomic_ptr_cas(void * volatile *ptr, void *oldval, void *newval)
{
void *ret;
pthread_mutex_lock(&atomic_lock);
ret = *ptr;
if (*ptr == oldval)
*ptr = newval;
pthread_mutex_unlock(&atomic_lock);
return ret;
}
#elif !HAVE_THREADS
int avpriv_atomic_int_get(volatile int *ptr)
{
return *ptr;
}
void avpriv_atomic_int_set(volatile int *ptr, int val)
{
*ptr = val;
}
int avpriv_atomic_int_add_and_fetch(volatile int *ptr, int inc)
{
*ptr += inc;
return *ptr;
}
void *avpriv_atomic_ptr_cas(void * volatile *ptr, void *oldval, void *newval)
{
if (*ptr == oldval) {
*ptr = newval;
return oldval;
}
return *ptr;
}
#else
#error "Threading is enabled, but there is no implementation of atomic operations available"
#endif /* HAVE_PTHREADS */
#endif /* !HAVE_MEMORYBARRIER && !HAVE_SYNC_VAL_COMPARE_AND_SWAP && !HAVE_MACHINE_RW_BARRIER */
#ifdef TEST
#include <assert.h>
int main(void)
{
volatile int val = 1;
int res;
res = avpriv_atomic_int_add_and_fetch(&val, 1);
assert(res == 2);
avpriv_atomic_int_set(&val, 3);
res = avpriv_atomic_int_get(&val);
assert(res == 3);
return 0;
}
#endif
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