atomic.h

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/*
   Copyright (C) 2011  Equinor ASA, Norway.
 
   The file 'atomic.h' is part of ERT - Ensemble based Reservoir Tool.
 
   ERT is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
 
   ERT 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 at <http://www.gnu.org/licenses/gpl.html>
   for more details.
*/
 
/*
   This whole file was something I found on the internet - it was
   posted as beeing in the public domain. The essential functions
   __sync_add_and_fetch() and do on are (as I understand it) built in
   gcc functions. Only available in reasonably new gcc versions
   (4.1???).
*/
 
#ifndef _ATOMIC_H
#define _ATOMIC_H
 
 
 
typedef struct {
  volatile int counter;
} atomic_t;
 
#define ATOMIC_INIT(i) �{ (i) }
 
#define atomic_read(v) ((v)->counter)
 
#define atomic_set(v,i) (((v)->counter) = (i))
 
static inline void atomic_add( int i, atomic_t *v )
{
  (void)__sync_add_and_fetch(&v->counter, i);
}
 
static inline void atomic_sub( int i, atomic_t *v )
{
  (void)__sync_sub_and_fetch(&v->counter, i);
}
 
static inline int atomic_sub_and_test( int i, atomic_t *v )
{
  return !(__sync_sub_and_fetch(&v->counter, i));
}
 
static inline void atomic_inc( atomic_t *v )
{
  (void)__sync_fetch_and_add(&v->counter, 1);
}
 
static inline void atomic_dec( atomic_t *v )
{
  (void)__sync_fetch_and_sub(&v->counter, 1);
}
 
static inline int atomic_dec_and_test( atomic_t *v )
{
  return !(__sync_sub_and_fetch(&v->counter, 1));
}
 
static inline int atomic_inc_and_test( atomic_t *v )
{
  return !(__sync_add_and_fetch(&v->counter, 1));
}
 
static inline int atomic_add_negative( int i, atomic_t *v )
{
  return (__sync_add_and_fetch(&v->counter, i) < 0);
}
 
#endif
 
/*****************************************************************/
/*****************************************************************/
/*****************************************************************/
 
//static inline int atomic_add( int i, atomic_t *v )
//{
//  return __sync_add_and_fetch(&v->counter, i);
//}
//
//�* @brief compare and swap
//�* @param v pointer of type atomic_t
//�*
//�* If the current value of @b v is @b oldval,
//�* then write @b newval into @b v. Returns #TRUE if
//�* the comparison is successful and @b newval was
//�* written.
//�*/
//static inline int atomic_cas( atomic_t *v, int oldval, int newval )
//{
//  return __sync_bool_compare_and_swap(&v->counter, oldval, newval);
//}