/*

 *  MemoryMap.h

 *  Ottoman

 *

 *  Created by Jens Alfke on 9/17/09.

 *  Copyright 2009 Jens Alfke. All rights reserved.

 *  BSD-Licensed: See the file "LICENSE.txt" for details.

 */

#include "File.h"

namespace Mooseyard {

    /** A flexible memory-map on a file, which can handle multiple discontiguous mapped regions.

        Clients usually access this functionality through File, which delegates to it. */

    class MemoryMap {

    public:

        MemoryMap (File* file)                          :_file(file), _nRegions(0), _regions(NULL) { }

        ~MemoryMap();

        void mapRegion (off_t position, size_t length);

        const void* mappedPosition (off_t position) const;

    private:

        UNCOPYABLE(MemoryMap);

        class Region;

        const void* _at (off_t) const;

        File *_file;

        int _nRegions;

        Region **_regions;

    };

    class MemoryMap::Region {

    public:

        Region (File*, off_t position, size_t length);

        ~Region();

        off_t position() const                  {return _position;}

        size_t length() const                   {return _length;}

        off_t end() const                       {return _position + _length;}

        bool setLength (size_t);          // Returns false if it failed

        const void* mappedPosition(off_t);

    private:

        UNCOPYABLE(Region);

        File* const _file;

        const off_t _position;

        size_t _length;

        const uint8_t *_start;

    };

}