/*
 *   Copyright Institute of Communication and Computer Systems (ICCS) 
 *
 *   Licensed under the Apache License, Version 2.0 (the "License");
 *   you may not use this file except in compliance with the License.
 *   You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *   Unless required by applicable law or agreed to in writing, software
 *   distributed under the License is distributed on an "AS IS" BASIS,
 *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *   See the License for the specific language governing permissions and
 *   limitations under the License.
 *
 */

/**
 * @file   locks.h
 * @author Ioannis Koutras (joko@microlab.ntua.gr)
 * @date   September 2012
 * @brief  Locking functions
 */

#include <dmmlib/config.h>

#ifndef LOCKS_H
#define LOCKS_H

#ifdef HAVE_LOCKS

/** Enumeration of lock states */
typedef enum locktype_en {STATE_LOCKED, STATE_UNLOCKED} locktype_t;

/** Initializes a locktype_t variable */
#define INIT_DEALY_LOCK(lock) lock = STATE_UNLOCKED
/** Locks a locktype_t variable */
#define DEALY_LOCK(lock) \
    while(__sync_bool_compare_and_swap(&lock, \
                STATE_UNLOCKED, STATE_LOCKED) != STATE_UNLOCKED){}
/** Tries to lock a locktype_t variable */
#define DEALY_TRYLOCK(lock) \
    ((__sync_bool_compare_and_swap(&lock, STATE_UNLOCKED, STATE_LOCKED) != \
      STATE_UNLOCKED))
/** Unlocks a locktype_t variable */
#define DEALY_UNLOCK(lock) lock = STATE_UNLOCKED
/** Destroys a locktype_t */
#define DEALY_DESTROY_LOCK(lock) lock = STATE_UNLOCKED

#else /* HAVE_LOCKS */

/** Does nothing. */
#define INIT_DEALY_LOCK()
/** Does nothing. */
#define DEALY_LOCK()
/** Does nothing. */
#define DEALY_TRYLOCK(lock)
/** Does nothing. */
#define DEALY_UNLOCK(lock)
/** Does nothing. */
#define DEALY_DESTROY_LOCK(lock)

#endif /* HAVE_LOCKS */

#endif /* LOCKS_H */