yading@11: /*
yading@11:  * Copyright (c) 2012 Ronald S. Bultje <rsbultje@gmail.com>
yading@11:  *
yading@11:  * This file is part of FFmpeg.
yading@11:  *
yading@11:  * FFmpeg is free software; you can redistribute it and/or
yading@11:  * modify it under the terms of the GNU Lesser General Public
yading@11:  * License as published by the Free Software Foundation; either
yading@11:  * version 2.1 of the License, or (at your option) any later version.
yading@11:  *
yading@11:  * FFmpeg is distributed in the hope that it will be useful,
yading@11:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@11:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@11:  * Lesser General Public License for more details.
yading@11:  *
yading@11:  * You should have received a copy of the GNU Lesser General Public
yading@11:  * License along with FFmpeg; if not, write to the Free Software
yading@11:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@11:  */
yading@11: 
yading@11: #include "atomic.h"
yading@11: 
yading@11: #if !HAVE_ATOMICS_NATIVE
yading@11: 
yading@11: #if HAVE_PTHREADS
yading@11: 
yading@11: #include <pthread.h>
yading@11: 
yading@11: static pthread_mutex_t atomic_lock = PTHREAD_MUTEX_INITIALIZER;
yading@11: 
yading@11: int avpriv_atomic_int_get(volatile int *ptr)
yading@11: {
yading@11:     int res;
yading@11: 
yading@11:     pthread_mutex_lock(&atomic_lock);
yading@11:     res = *ptr;
yading@11:     pthread_mutex_unlock(&atomic_lock);
yading@11: 
yading@11:     return res;
yading@11: }
yading@11: 
yading@11: void avpriv_atomic_int_set(volatile int *ptr, int val)
yading@11: {
yading@11:     pthread_mutex_lock(&atomic_lock);
yading@11:     *ptr = val;
yading@11:     pthread_mutex_unlock(&atomic_lock);
yading@11: }
yading@11: 
yading@11: int avpriv_atomic_int_add_and_fetch(volatile int *ptr, int inc)
yading@11: {
yading@11:     int res;
yading@11: 
yading@11:     pthread_mutex_lock(&atomic_lock);
yading@11:     *ptr += inc;
yading@11:     res = *ptr;
yading@11:     pthread_mutex_unlock(&atomic_lock);
yading@11: 
yading@11:     return res;
yading@11: }
yading@11: 
yading@11: void *avpriv_atomic_ptr_cas(void * volatile *ptr, void *oldval, void *newval)
yading@11: {
yading@11:     void *ret;
yading@11:     pthread_mutex_lock(&atomic_lock);
yading@11:     ret = *ptr;
yading@11:     if (*ptr == oldval)
yading@11:         *ptr = newval;
yading@11:     pthread_mutex_unlock(&atomic_lock);
yading@11:     return ret;
yading@11: }
yading@11: 
yading@11: #elif !HAVE_THREADS
yading@11: 
yading@11: int avpriv_atomic_int_get(volatile int *ptr)
yading@11: {
yading@11:     return *ptr;
yading@11: }
yading@11: 
yading@11: void avpriv_atomic_int_set(volatile int *ptr, int val)
yading@11: {
yading@11:     *ptr = val;
yading@11: }
yading@11: 
yading@11: int avpriv_atomic_int_add_and_fetch(volatile int *ptr, int inc)
yading@11: {
yading@11:     *ptr += inc;
yading@11:     return *ptr;
yading@11: }
yading@11: 
yading@11: void *avpriv_atomic_ptr_cas(void * volatile *ptr, void *oldval, void *newval)
yading@11: {
yading@11:     if (*ptr == oldval) {
yading@11:         *ptr = newval;
yading@11:         return oldval;
yading@11:     }
yading@11:     return *ptr;
yading@11: }
yading@11: 
yading@11: #else
yading@11: 
yading@11: #error "Threading is enabled, but there is no implementation of atomic operations available"
yading@11: 
yading@11: #endif /* HAVE_PTHREADS */
yading@11: 
yading@11: #endif /* !HAVE_MEMORYBARRIER && !HAVE_SYNC_VAL_COMPARE_AND_SWAP && !HAVE_MACHINE_RW_BARRIER */
yading@11: 
yading@11: #ifdef TEST
yading@11: #include "avassert.h"
yading@11: 
yading@11: int main(void)
yading@11: {
yading@11:     volatile int val = 1;
yading@11:     int res;
yading@11: 
yading@11:     res = avpriv_atomic_int_add_and_fetch(&val, 1);
yading@11:     av_assert0(res == 2);
yading@11:     avpriv_atomic_int_set(&val, 3);
yading@11:     res = avpriv_atomic_int_get(&val);
yading@11:     av_assert0(res == 3);
yading@11: 
yading@11:     return 0;
yading@11: }
yading@11: #endif