/*************************************************************************
 *
 *  $RCSfile: semaphor.hxx,v $
 *
 *  $Revision: 1.1.1.1 $
 *
 *  last change: $Author: hr $ $Date: 2000/09/18 15:18:13 $
 *
 *  The Contents of this file are made available subject to the terms of
 *  either of the following licenses
 *
 *         - GNU Lesser General Public License Version 2.1
 *         - Sun Industry Standards Source License Version 1.1
 *
 *  Sun Microsystems Inc., October, 2000
 *
 *  GNU Lesser General Public License Version 2.1
 *  =============================================
 *  Copyright 2000 by Sun Microsystems, Inc.
 *  901 San Antonio Road, Palo Alto, CA 94303, USA
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License version 2.1, as published by the Free Software Foundation.
 *
 *  This library 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
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 *  MA  02111-1307  USA
 *
 *
 *  Sun Industry Standards Source License Version 1.1
 *  =================================================
 *  The contents of this file are subject to the Sun Industry Standards
 *  Source 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.openoffice.org/license.html.
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 *  WITHOUT LIMITATION, WARRANTIES THAT THE SOFTWARE IS FREE OF DEFECTS,
 *  MERCHANTABLE, FIT FOR A PARTICULAR PURPOSE, OR NON-INFRINGING.
 *  See the License for the specific provisions governing your rights and
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 *  The Initial Developer of the Original Code is: Sun Microsystems, Inc.
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 *  Copyright: 2000 by Sun Microsystems, Inc.
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 *  Contributor(s): _______________________________________
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 ************************************************************************/

#ifndef _VOS_SEMAPHOR_HXX_
#define _VOS_SEMAPHOR_HXX_

#ifndef _VOS_TYPES_HXX_
#	include <vos/types.hxx>
#endif
#ifndef _VOS_OBJECT_HXX_
#	include <vos/object.hxx>
#endif
#ifndef _VOS_MUTEX_HXX_
#	include <vos/mutex.hxx>
#endif
#ifndef _OSL_SEMAPHOR_H_
#	include <osl/semaphor.h>
#endif

#ifdef _USE_NAMESPACE
namespace vos
{     
#endif

/** Counting semaphore (unnamed, because thread-local).
*/
class OSemaphore : public OObject, public IMutex 
{
    VOS_DECLARE_CLASSINFO(VOS_NAMESPACE(OSemaphore, vos));

public:

	/// Creates an unbound semaphore. Use create() to actually build one.
	OSemaphore();

	/// Creates a semaphore and intilize it.
	OSemaphore(sal_uInt32 InitialCount)
		{ create(InitialCount); }

	/// Destroys the semaphore
	virtual ~OSemaphore();		

	/** Creates the semaphore.
		@param InitialCount The initial value of the semaphore. Default
			   value is 1, so the first acquire() succeeds.
	*/
	void SAL_CALL create(sal_uInt32 InitialCount= 1);

	/** Decreases count by one. If count is zero, it will block until
		someone calls release(). (Dykstra's P()).
	*/
	virtual void SAL_CALL acquire();

	/** Decreases count by one. If count is zero, it will NOT block but
		return False to indicate its failure to decrease the count.
		@return True if acquire succeeded, otherwise False.
	*/
	virtual sal_Bool SAL_CALL tryToAcquire() ;

	/** Increases count by 1. Will never block. If another thread blocked
		on acquire(), it will be unblocked. (Dykstra's V()).
	*/
	virtual void SAL_CALL release();

protected:
	oslSemaphore m_Sem;

private:

	// disable copy/assignment
	OSemaphore(const OSemaphore&);	
	OSemaphore& SAL_CALL operator= (const OSemaphore&);
};

#ifdef _USE_NAMESPACE
}     
#endif

#endif  //_VOS_SEMAPHOR_HXX_


