cat_signature.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 CAT_SIGNATURE_HPP
#define CAT_SIGNATURE_HPP
 
#include "../my_config.h"
#include "generic_file.hpp"
#include "archive_version.hpp"
#include "cat_status.hpp"
 
extern "C"
{
} // end extern "C"
 
 
namespace libdar
{
 
 
    class cat_signature
    {
    public:
    cat_signature(unsigned char original, saved_status status); // -> mk_signature()
 
    cat_signature(generic_file & f, const archive_version & reading_ver);
 
 
    bool read(generic_file & f, const archive_version & reading_ver);
    void write(generic_file &f);
 
 
    bool get_base_and_status(unsigned char & base, saved_status & saved) const;
 
    static bool compatible_signature(unsigned char a, unsigned char b);
 
    private:
    static constexpr U_8 SAVED_FAKE_BIT = 0x80;
    static constexpr U_8 SAVED_NON_DELTA_BIT = 0x40;
 
 
        //. type of inode: and the nature of the object that has to be build from the following bytes
        //. status of the info: on which depends whether some or all field should be read in the following data
        //. lower case letters have binary values 011xxxxx
        //. and higher case have binary values 010xxxxx
        //. 011----- (3) status is "saved" (backward compatibility) this is a lowercase letter
        //. 010----- (2) status is "not_saved" (backward compatibily) this is an uppercase letter
        //. 111----- (7) status is "fake" (backward compatibility) used only with lowercase letters
        //. 001----- (1) status is "delta" (setting back the byte 6 to 1 gives the letter value)
        //. 100----- (4) status is "inode_only (setting back the bytes as 011 gives the letter value)
        //. 101----- (5) status is unused (setting back the high bytes to 011 gives the letter value)
        //. 110----- (6) status is unused (setting back the high bytes to 011 gives the letter value)
        //. 000----- (0) status is unused (setting back the high bytes to 011 gives the letter value)
    unsigned char field;
    };
 
} // end of namespace
 
#endif