int_tools.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 INT_TOOLS_HPP
#define INT_TOOLS_HPP
 
#include "../my_config.h"
 
#include "integers.hpp"
 
namespace libdar
{
 
 
    using int_tools_bitfield = unsigned char[8];
 
    extern void int_tools_swap_bytes(unsigned char &a, unsigned char &b);
    extern void int_tools_swap_bytes(unsigned char *a, U_I size);
    extern void int_tools_expand_byte(unsigned char a, int_tools_bitfield &bit);
    extern void int_tools_contract_byte(const int_tools_bitfield &b, unsigned char & a);
 
        // integer (agregates) manipulations
        // argument must be a regular interger (a bit field).
    template <class T> extern T int_tools_rotate_right_one_bit(T v)
    {
        bool retenue = (v & 1) != 0;
 
        v >>= 1;
        if(retenue)
            v |= T(1) << (sizeof(v)*8 - 1);
 
        return v;
    }
 
    template <class T> extern T int_tools_maxof_aggregate(T unused) { unused = 0; unused = ~unused; unused = unused > 0 ? unused : ~int_tools_rotate_right_one_bit(T(1)); return unused; }
 
    template <class B> static B int_tools_higher_power_of_2(B val)
    {
        B i = 0;
 
        while((val >> i) > 1)
            i++;
 
        return i;
    }
 
 
}
 
#endif