tdepim/indexlib/mmap_manager.h

#ifndef LPC_MMAP_MANAGER_H1103129409_INCLUDE_GUARD_
#define LPC_MMAP_MANAGER_H1103129409_INCLUDE_GUARD_

/* This file is part of indexlib.
 * Copyright (C) 2005 Luís Pedro Coelho <luis@luispedro.org>
 *
 * Indexlib is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License, version 2, as
 * published by the Free Software Foundation and available as file
 * GPL_V2 which is distributed along with indexlib.
 * 
 * Indexlib 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
 * General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301, USA
 * 
 * In addition, as a special exception, the copyright holders give
 * permission to link the code of this program with any edition of
 * the TQt library by Trolltech AS, Norway (or with modified versions
 * of TQt that use the same license as TQt), and distribute linked
 * combinations including the two.  You must obey the GNU General
 * Public License in all respects for all of the code used other than
 * TQt.  If you modify this file, you may extend this exception to
 * your version of the file, but you are not obligated to do so.  If
 * you do not wish to do so, delete this exception statement from
 * your version.
 */


#include "manager.h"
#include <string>
#include <cstring>
#include <unistd.h>
#include <assert.h>

class mmap_manager : public memory_manager {
	public:
		explicit mmap_manager( std::string );
		~mmap_manager();
		const unsigned char* ronly_base( unsigned offset ) const {
			assert( offset <= size() ); // allow 1-past-the-end but not more
			return reinterpret_cast<unsigned char*>( base_ ) + offset;
		}
		unsigned char* rw_base( unsigned offset ) const {
			assert( offset <= size() ); // as above
			return reinterpret_cast<unsigned char*>( base_ ) + offset;
		}
		unsigned size() const {
			return size_;
		}
		void resize( unsigned );

		static void remove( std::string fname ) {
			::unlink( fname.c_str() );
		}
	private:
		void unmap();
		void map( unsigned );
		std::string filename_;
		const unsigned pagesize_;
		int fd_;
		void* base_;
		unsigned size_;
};


#endif /* LPC_MMAP_MANAGER_H1103129409_INCLUDE_GUARD_ */