Disk ARchive  2.4.2
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 // $Id: int_tools.hpp,v 1.6 2011/01/09 17:25:58 edrusb Rel $
00022 //
00023 /*********************************************************************/
00024 
00028 
00029 #ifndef INT_TOOLS_HPP
00030 #define INT_TOOLS_HPP
00031 
00032 #include "../my_config.h"
00033 
00034 #include "integers.hpp"
00035 #include "erreurs.hpp"
00036 
00037 namespace libdar
00038 {
00039 
00042 
00043     typedef unsigned char int_tools_bitfield[8];
00044 
00045     extern void int_tools_swap_bytes(unsigned char &a, unsigned char &b);
00046     extern void int_tools_swap_bytes(unsigned char *a, U_I size);
00047     extern void int_tools_expand_byte(unsigned char a, int_tools_bitfield &bit);
00048     extern void int_tools_contract_byte(const int_tools_bitfield &b, unsigned char & a);
00049 
00050         // integer (agregates) manipulations
00051         // argument must be a regular interger (a bit field).
00052     template <class T> extern T int_tools_rotate_right_one_bit(T v)
00053     {
00054         bool retenue = (v & 1) != 0;
00055 
00056         v >>= 1;
00057         if(retenue)
00058             v |= T(1) << (sizeof(v)*8 - 1);
00059 
00060         return v;
00061     }
00062 
00063     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; }
00064 
00065     template <class B> static B int_tools_higher_power_of_2(B val)
00066     {
00067         B i = 0;
00068 
00069         while((val >> i) > 1)
00070             i++;
00071 
00072         return i;
00073     }
00074 
00076 
00077 }
00078 
00079 #endif
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