text: /*
   * 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 (*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_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
  