/*

  *  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;

     };

 }