elastic.hpp

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/*********************************************************************/
// dar - disk archive - a backup/restoration program
// Copyright (C) 2002-2024 Denis Corbin
//
// This program 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 2
// of the License, or (at your option) any later version.
//
// This program 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.
//
// to contact the author, see the AUTHOR file
/*********************************************************************/
 
 
#ifndef ELASTIC_HPP
#define ELASTIC_HPP
 
#include "../my_config.h"
 
#include "integers.hpp"
#include "infinint.hpp"
#include "generic_file.hpp"
#include "archive_version.hpp"
 
namespace libdar
{
 
 
 
    enum elastic_direction { elastic_forward, elastic_backward };
 
 
    class elastic
    {
    public:
    elastic(U_32 size);
    elastic(const unsigned char *buffer, U_32 size, elastic_direction dir, const archive_version & reading_ver);
    elastic(generic_file &f, elastic_direction dir, const archive_version & reading_ver);
    elastic(const elastic & ref) = default;
    elastic(elastic && ref) noexcept = default;
    elastic & operator = (const elastic & ref) = default;
    elastic & operator = (elastic && ref) noexcept = default;
    ~elastic() = default;
 
    U_32 dump(unsigned char *buffer, U_32 size) const;
    U_32 get_size() const { return taille; };
 
    static U_I max_length() { return (U_I)(254)*254*254*254 - 1; };
 
    private:
    U_32 taille; // max size of elastic buffer is 4GB which is large enough
 
    void randomize(unsigned char *a) const;
    U_I base_from_version(const archive_version & reading_ver) const;
    unsigned char get_low_mark(const archive_version & reading_ver) const;
    unsigned char get_high_mark(const archive_version & reading_ver) const;
    unsigned char get_low_mark() const { return 255; };
    unsigned char get_high_mark() const { return 254; };
 
    };
 
 
} // end of namespace
 
#endif