MyGUI  3.0.1
MyGUI_Bitwise.h
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00001 
00007 /*
00008     This file is part of MyGUI.
00009 
00010     MyGUI is free software: you can redistribute it and/or modify
00011     it under the terms of the GNU Lesser General Public License as published by
00012     the Free Software Foundation, either version 3 of the License, or
00013     (at your option) any later version.
00014 
00015     MyGUI is distributed in the hope that it will be useful,
00016     but WITHOUT ANY WARRANTY; without even the implied warranty of
00017     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00018     GNU Lesser General Public License for more details.
00019 
00020     You should have received a copy of the GNU Lesser General Public License
00021     along with MyGUI.  If not, see <http://www.gnu.org/licenses/>.
00022 */
00023 #ifndef __MYGUI_BITWISE_H__
00024 #define __MYGUI_BITWISE_H__
00025 
00026 #include "MyGUI_Prerequest.h"
00027 
00028 namespace MyGUI
00029 {
00030 
00031     class Bitwise
00032     {
00033     public:
00036         template<typename Type>
00037         static MYGUI_FORCEINLINE Type firstPO2From(Type _value)
00038         {
00039             --_value;
00040             _value |= _value >> 16;
00041             _value |= _value >> 8;
00042             _value |= _value >> 4;
00043             _value |= _value >> 2;
00044             _value |= _value >> 1;
00045             ++_value;
00046             return _value;
00047         }
00048 
00050         template<typename Type>
00051         static MYGUI_FORCEINLINE bool isPO2(Type _value)
00052         {
00053             return (_value & (_value-1)) == 0;
00054         }
00055 
00059         template<typename Type>
00060         static MYGUI_FORCEINLINE size_t getBitShift(Type _mask)
00061         {
00062             if (_mask == 0)
00063                 return 0;
00064 
00065             size_t result = 0;
00066             while ((_mask & 1) == 0)
00067             {
00068                 ++result;
00069                 _mask >>= 1;
00070             }
00071             return result;
00072         }
00073 
00074     };
00075 
00076 } // namespace MyGUI
00077 
00078 #endif // __MYGUI_BITWISE_H__