oMemoryMapped.hh

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/*
This file is part of CASToR.

    CASToR is free software: you can redistribute it and/or modify it under the
    terms of the GNU General Public License as published by the Free Software
    Foundation, either version 3 of the License, or (at your option) any later
    version.

    CASToR 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
    CASToR (in file GNU_GPL.TXT). If not, see <http://www.gnu.org/licenses/>.

Copyright 2017-2019 all CASToR contributors listed below:

    --> Didier BENOIT, Claude COMTAT, Marina FILIPOVIC, Thibaut MERLIN, Mael MILLARDET, Simon STUTE, Valentin VIELZEUF

This is CASToR version 3.0.
*/

#ifndef OMEMORYMAPPED_HH
#define OMEMORYMAPPED_HH 1

// define fixed size integer types
#if defined(_WIN32)
#include <inttypes.h>
typedef unsigned __int64 uint64_t;
#else
#include <stdint.h>
#endif

#include "gVariables.hh"
#include "sOutputManager.hh"


class oMemoryMapped
{
  public:
    enum CacheHint
    {
      Normal,         
      SequentialScan, 
      RandomAccess    
    };

    enum MapRange
    {
      WholeFile = 0   
    };

    oMemoryMapped();
    oMemoryMapped(const std::string& filename, size_t mappedBytes = WholeFile, CacheHint hint = Normal);
    ~oMemoryMapped();

    int Open(const std::string& filename, size_t mappedBytes = WholeFile, CacheHint hint = Normal);
    void Close();

    unsigned char operator[](size_t offset) const;
    unsigned char at        (size_t offset) const;

    const unsigned char* GetData() const;

    bool IsValid() const;

    uint64_t size() const;
    size_t   mappedSize() const;

    int Remap(uint64_t offset, size_t mappedBytes);

  private:
    oMemoryMapped(const oMemoryMapped&);
    oMemoryMapped& operator=(const oMemoryMapped&);

    static int GetPageSize();

    std::string _filename;
    uint64_t    _filesize;
    CacheHint   _hint;
    size_t      _mappedBytes;

#if defined(_WIN32) || defined(CASTOR_USE_MINGW)
    typedef void* FileHandle;
    void*       _mappedFile;
#else
    typedef int   FileHandle;
#endif

    FileHandle  _file;
    void*       _mappedView;
};

#endif