Disk ARchive  2.5.2
Full featured and portable backup and archiving tool
int_tools.hpp
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00001 /*********************************************************************/
00002 // dar - disk archive - a backup/restoration program
00003 // Copyright (C) 2002-2052 Denis Corbin
00004 //
00005 // This program is free software; you can redistribute it and/or
00006 // modify it under the terms of the GNU General Public License
00007 // as published by the Free Software Foundation; either version 2
00008 // of the License, or (at your option) any later version.
00009 //
00010 // This program is distributed in the hope that it will be useful,
00011 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00012 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00013 // GNU General Public License for more details.
00014 //
00015 // You should have received a copy of the GNU General Public License
00016 // along with this program; if not, write to the Free Software
00017 // Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
00018 //
00019 // to contact the author : http://dar.linux.free.fr/email.html
00020 /*********************************************************************/
00021 
00025 
00026 #ifndef INT_TOOLS_HPP
00027 #define INT_TOOLS_HPP
00028 
00029 #include "../my_config.h"
00030 
00031 #include "integers.hpp"
00032 #include "erreurs.hpp"
00033 
00034 namespace libdar
00035 {
00036 
00039 
00040     typedef unsigned char int_tools_bitfield[8];
00041 
00042     extern void int_tools_swap_bytes(unsigned char &a, unsigned char &b);
00043     extern void int_tools_swap_bytes(unsigned char *a, U_I size);
00044     extern void int_tools_expand_byte(unsigned char a, int_tools_bitfield &bit);
00045     extern void int_tools_contract_byte(const int_tools_bitfield &b, unsigned char & a);
00046 
00047         // integer (agregates) manipulations
00048         // argument must be a regular interger (a bit field).
00049     template <class T> extern T int_tools_rotate_right_one_bit(T v)
00050     {
00051         bool retenue = (v & 1) != 0;
00052 
00053         v >>= 1;
00054         if(retenue)
00055             v |= T(1) << (sizeof(v)*8 - 1);
00056 
00057         return v;
00058     }
00059 
00060     template <class T> extern T int_tools_maxof_agregate(T unused) { unused = 0; unused = ~unused; unused = unused > 0 ? unused : ~int_tools_rotate_right_one_bit(T(1)); return unused; }
00061 
00062     template <class B> static B int_tools_higher_power_of_2(B val)
00063     {
00064         B i = 0;
00065 
00066         while((val >> i) > 1)
00067             i++;
00068 
00069         return i;
00070     }
00071 
00073 
00074 }
00075 
00076 #endif
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