/***************************************************************************
                          SIMPLY POWERFUL TOOLKIT (SPTK)
                          CRWLock.h  -  description
                             -------------------
    begin                : Thu Apr 28 2005
    copyright            : (C) 2005 by Ilya A. Volynets-Evenbakh
    email                : ilya@total-knowledge.com
    based on             : CWaiter.h by Alexey Parshin
 ***************************************************************************/

/***************************************************************************
   This library is free software; you can redistribute it and/or modify it 
   under the terms of the GNU Library General Public License as published by
   the Free Software Foundation; either version 2 of the License, or (at 
   your option) any later version.

   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 Library
   General Public License for more details.

   You should have received a copy of the GNU Library 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.

   Please report all bugs and problems to "alexeyp@gmail.com"
 ***************************************************************************/

#ifndef __CRWLOCK_H__
#define __CRWLOCK_H__

#ifndef _WIN32

#include <unistd.h>
#include <pthread.h>

#else

#include <windows.h>
#include <process.h>

#endif

#include <sptk3/sptk.h>

namespace sptk {

   /// @addtogroup utility Utility Classes
   /// @{

   /// Read-write synchronization object
	class SP_EXPORT CRWLock {
	protected:

#ifndef _WIN32
		pthread_rwlock_t	m_rwlock;	///< pthreads rwlock object
#else
		HANDLE               m_readLock;
		HANDLE               m_writeLock;
		CRITICAL_SECTION	m_criticalSection;
		int                  m_readerCount;
		bool                 m_writerMode;
#endif

	public:

      /// Constructor
		CRWLock();

      /// Destructor
		~CRWLock();

      /// Try to lock the object for reading. Blocks if object is locked for writing, or there are pending write locks.
      /// @param timeout int, timeout in milliseconds 
		int lockR(int timeout=-1);

      /// Try to lock the object for writing. Blocks if object is locked for reading or writing.
      /// @param timeout int, timeout in milliseconds 
		int lockRW(int timeout=-1);

      /// Releases lock on the object.
		void unlock();
	};
	/// @}
}

#endif
