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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* The contents of this file are subject to the Mozilla Public
* License Version 1.1 (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.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* The Original Code is the Netscape Portable Runtime (NSPR).
*
* The Initial Developer of the Original Code is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1998-2000 Netscape Communications Corporation. All
* Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the
* terms of the GNU General Public License Version 2 or later (the
* "GPL"), in which case the provisions of the GPL are applicable
* instead of those above. If you wish to allow use of your
* version of this file only under the terms of the GPL and not to
* allow others to use your version of this file under the MPL,
* indicate your decision by deleting the provisions above and
* replace them with the notice and other provisions required by
* the GPL. If you do not delete the provisions above, a recipient
* may use your version of this file under either the MPL or the
* GPL.
*/
#include <kernel/OS.h>
#include "primpl.h"
/*
** Create a new semaphore object.
*/
PR_IMPLEMENT(PRSemaphore*)
PR_NewSem (PRUintn value)
{
PRSemaphore *semaphore;
if (!_pr_initialized) _PR_ImplicitInitialization();
semaphore = PR_NEWZAP(PRSemaphore);
if (NULL != semaphore) {
if ((semaphore->sem = create_sem(value, "nspr_sem")) < B_NO_ERROR)
return NULL;
else
return semaphore;
}
return NULL;
}
/*
** Destroy the given semaphore object.
**
*/
PR_IMPLEMENT(void)
PR_DestroySem (PRSemaphore *sem)
{
status_t result;
PR_ASSERT(sem != NULL);
result = delete_sem(sem->sem);
PR_ASSERT(result == B_NO_ERROR);
PR_DELETE(sem);
}
/*
** Wait on a Semaphore.
**
** This routine allows a calling thread to wait or proceed depending upon
** the state of the semahore sem. The thread can proceed only if the
** counter value of the semaphore sem is currently greater than 0. If the
** value of semaphore sem is positive, it is decremented by one and the
** routine returns immediately allowing the calling thread to continue. If
** the value of semaphore sem is 0, the calling thread blocks awaiting the
** semaphore to be released by another thread.
**
** This routine can return PR_PENDING_INTERRUPT if the waiting thread
** has been interrupted.
*/
PR_IMPLEMENT(PRStatus)
PR_WaitSem (PRSemaphore *sem)
{
PR_ASSERT(sem != NULL);
if (acquire_sem(sem->sem) == B_NO_ERROR)
return PR_SUCCESS;
else
return PR_FAILURE;
}
/*
** This routine increments the counter value of the semaphore. If other
** threads are blocked for the semaphore, then the scheduler will
** determine which ONE thread will be unblocked.
*/
PR_IMPLEMENT(void)
PR_PostSem (PRSemaphore *sem)
{
status_t result;
PR_ASSERT(sem != NULL);
result = release_sem(sem->sem);
PR_ASSERT(result == B_NO_ERROR);
}
/*
** Returns the value of the semaphore referenced by sem without affecting
** the state of the semaphore. The value represents the semaphore value
** at the time of the call, but may not be the actual value when the
** caller inspects it.
*/
PR_IMPLEMENT(PRUintn)
PR_GetValueSem (PRSemaphore *sem)
{
sem_info info;
PR_ASSERT(sem != NULL);
get_sem_info(sem->sem, &info);
return info.count;
}
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