xref: /onnv-gate/usr/src/cmd/lms/SyncLib/src/SemaphoreUnix.cpp (revision 9203:3ebffd0a1b10)

/*******************************************************************************
 * Copyright (C) 2004-2008 Intel Corp. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *  - Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 *  - Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 *  - Neither the name of Intel Corp. nor the names of its
 *    contributors may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL Intel Corp. OR THE CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *******************************************************************************/

//////////////////////////////////////////////////////////////////////////
// SemaphoreLinux.cpp
//
// This file contains the linux implementation of the Semaphore class
//////////////////////////////////////////////////////////////////////////
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "Semaphore.h"
#include <semaphore.h>

class OSSemaphore {
public:
	sem_t _sem;
};

Semaphore::Semaphore(int maxval)
{
	_osSemaphore = new OSSemaphore;
	sem_init(&_osSemaphore->_sem, 0, maxval);
}

Semaphore::~Semaphore()
{
	sem_destroy(&_osSemaphore->_sem);
	delete _osSemaphore;
}

void Semaphore::acquire()
{
	// blocks until value !=0, and decrements the value
	sem_wait(&_osSemaphore->_sem);
}

void Semaphore::release()
{
	// increments the value by 1
	sem_post(&_osSemaphore->_sem);
}

bool Semaphore::acquireTry()
{
	// try to acquire the semaphore: return 'true' if succeded
	return (sem_trywait(&_osSemaphore->_sem) == 0);
}