/* * Copyright (c) 2012 Ronald S. Bultje <rsbultje@gmail.com> * * This file is part of FFmpeg. * * FFmpeg 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. * * FFmpeg 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 FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include "config.h" #include "atomic.h" #if !HAVE_ATOMICS_NATIVE #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 (ret == 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 /* HAVE_THREADS */ /* This should never trigger, unless a new threading implementation * without correct atomics dependencies in configure or a corresponding * atomics implementation is added. */ #error "Threading is enabled, but there is no implementation of atomic operations available" #endif /* HAVE_PTHREADS */ #endif /* !HAVE_ATOMICS_NATIVE */ #ifdef TEST #include "avassert.h" int main(void) { volatile int val = 1; int res; res = avpriv_atomic_int_add_and_fetch(&val, 1); av_assert0(res == 2); avpriv_atomic_int_set(&val, 3); res = avpriv_atomic_int_get(&val); av_assert0(res == 3); return 0; } #endif