/*
 * Copyright (c) 2004 X-Way Rights BV
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 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
 * 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
 */

/*!\file mutex.h
 * \brief MUTually EXclusive lock class.
 * \author Bob Deblier <bob.deblier@telenet.be>
 * \ingroup CXX_m
 */

#ifndef _CLASS_BEECRYPT_MUTEX_H
#define _CLASS_BEECRYPT_MUTEX_H

#include "beecrypt/api.h"

#ifdef __cplusplus

#if HAVE_ERRNO_H
# include <errno.h>
#endif

namespace beecrypt {
	class BEECRYPTCXXAPI mutex
	{
	private:
		#ifdef ENABLE_THREADS
		bc_mutex_t _lock;
		#endif

	public:
		inline void init() throw (char*)
		{
			#if WIN32
			_lock = CreateMutex((LPSECURITY_ATTRIBUTES) 0, FALSE, (LPCSTR) 0);
			if (!_lock)
				throw "CreateMutex failed";
			#else
			register int rc;
			# if HAVE_SYNCH_H
			if ((rc = mutex_init(&_lock, USYNC_THREAD, 0)))
				throw strerror(rc);
			# elif HAVE_PTHREAD_H
			if ((rc = pthread_mutex_init(&_lock, 0)))
				throw strerror(rc);
			# else
			#  error
			# endif
			#endif
		}

		inline void lock() throw (char*)
		{
			#if WIN32
			if (WaitForSingleObject(_lock, INFINITE) == WAIT_OBJECT_0)
				return;
			throw "WaitForSingleObject failed";
			#else
			register int rc;
			# if HAVE_SYNCH_H
			if ((rc = mutex_lock(&_lock)))
				throw strerror(rc);
			# elif HAVE_PTHREAD_H
			if ((rc = pthread_mutex_lock(&_lock)))
				throw strerror(rc);
			# else
			#  error
			# endif
			#endif
		}

		inline bool trylock() throw (char*)
		{
			#if WIN32
			switch (WaitForSingleObject(_lock, 0))
			{
			case WAIT_TIMEOUT:
				return false;
			case WAIT_OBJECT_0:
				return true;
			default:
				throw "WaitForSingleObbject failed";
			}
			#else
			register int rc;
			# if HAVE_SYNCH_H
			if ((rc = mutex_trylock(&_lock)) == 0)
				return true;
			if (rc == EBUSY)
				return false;
			throw strerror(rc);
			# elif HAVE_PTHREAD_H
			if ((rc = pthread_mutex_trylock(&_lock)) == 0)
				return true;
			if (rc == EBUSY)
				return false;
			throw strerror(rc);
			# else
			#  error
			# endif
			#endif
		}

		inline void unlock() throw (char*)
		{
			#if WIN32
			if (!ReleaseMutex(_lock))
				throw "ReleaseMutex failed";
			#else
			register int rc;
			# if HAVE_SYNCH_H
			if ((rc = mutex_unlock(&_lock)))
				throw strerror(rc);
			# elif HAVE_PTHREAD_H
			if ((rc = pthread_mutex_unlock(&_lock)))
				throw strerror(rc);
			# else
			#  error
			# endif
			#endif
		}

		inline void destroy() throw (char*)
		{
			#if WIN32
			if (!CloseHandle(_lock))
				throw "CloseHandle failed";
			#else
			register int rc;
			# if HAVE_SYNCH_H
			if ((rc = mutex_destroy(&_lock)))
				throw strerror(rc);
			# elif HAVE_PTHREAD_H
			if ((rc = pthread_mutex_destroy(&_lock)))
				throw strerror(rc);
			# else
			#  error
			# endif
			#endif
		}
	};
}

#endif

#endif