-/*
- * Copyright (c) 2008,2009 Zmanda, Inc. All Rights Reserved.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published
- * by the Free Software Foundation.
- *
- * This program 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
- * for more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, write to the Free Software Foundation, Inc.,
- * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- *
- * Contact information: Zmanda Inc., 465 S. Mathilda Ave., Suite 300
- * Sunnyvale, CA 94085, USA, or: http://www.zmanda.com
- */
-
-/* GLib does not provide semaphores, which are useful in queue.c.
- So, we implement it here. */
-
-#include <glib.h>
-
-#ifndef SEMAPHORE_H
-
-typedef struct {
- int value;
- GMutex *mutex;
- GCond * decrement_cond;
- GCond * zero_cond;
-} semaphore_t;
-
-/* Create a new semaphore object with the given value.
- *
- * @param value: new value
- * @returns: newly allocated semaphore_t
- */
-semaphore_t* semaphore_new_with_value(int value);
-
-/* Shortcut to make a new semaphore with value 1.
- */
-#define semaphore_new() semaphore_new_with_value(1)
-
-/* Free a semaphore allocated by semaphore_with_new_value(). Be sure the
- * semaphore is no longer in use by any threads.
- *
- * @param sem: the semaphore to free
- */
-void semaphore_free(semaphore_t *sem);
-
-/* Increment the value of the semaphore by incr. This corresponds to
- * Dijkstra's V(), or the typical semaphore's release().
- *
- * This function will not block, but may wake other threads waiting
- * on semaphore_decrement().
- *
- * @param sem: the semaphore
- * @param incr: added to the semaphore's value
- */
-void semaphore_increment(semaphore_t *sem, unsigned int incr);
-
-/* Shortcut to increment the semaphore by 1.
- */
-#define semaphore_up(semaphore) semaphore_increment(semaphore,1)
-
-/* Decrement the value of the semaphore by incr. If this operation
- * would make the semaphore negative, block until the semaphore
- * value is large enough, then perform the decerement operation. Threads
- * waiting on semaphore_wait_empty() may be awakened if the value
- * reaches 0.
- *
- * @param sem: the semaphore
- * @param decr: subtracted from the semaphore's value
- */
-void semaphore_decrement(semaphore_t *sem, unsigned int decr);
-
-/* Shortcut to decrement the semaphore by 1.
- */
-#define semaphore_down(semaphore) semaphore_decrement(semaphore, 1)
-
-/* Increment or decrement (with a negative incr) the value without
- * blocking. Threads waiting on semaphore_decrement() or
- * semaphore_wait_empty() will be awakened if necessary.
- *
- * @param sem: the semaphore
- * @param incr: added to the semaphore's value
- */
-void semaphore_force_adjust(semaphore_t *sem, int incr);
-
-/* Set the semaphore to a given value without blocking. Threads
- * waiting on semaphore_decrement() or semaphore_wait_empty()
- * will be awakened if necessary.
- *
- * @param sem: the semaphore
- * @param value: the new value
- */
-void semaphore_force_set(semaphore_t *sem, int value);
-
-/* Block until the semaphore's value is zero.
- *
- * @param sem: the semaphore
- */
-void semaphore_wait_empty(semaphore_t *sem);
-
-#endif /* SEMAPHORE_H */