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OgreBitwise.h

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00001 /*
00002 -----------------------------------------------------------------------------
00003 This source file is part of OGRE
00004     (Object-oriented Graphics Rendering Engine)
00005 For the latest info, see http://www.ogre3d.org/
00006 
00007 Copyright © 2000-2002 The OGRE Team
00008 Also see acknowledgements in Readme.html
00009 
00010 This program is free software; you can redistribute it and/or modify it under
00011 the terms of the GNU Lesser General Public License as published by the Free Software
00012 Foundation; either version 2 of the License, or (at your option) any later
00013 version.
00014 
00015 This program is distributed in the hope that it will be useful, but WITHOUT
00016 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
00017 FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
00018 
00019 You should have received a copy of the GNU Lesser General Public License along with
00020 this program; if not, write to the Free Software Foundation, Inc., 59 Temple
00021 Place - Suite 330, Boston, MA 02111-1307, USA, or go to
00022 http://www.gnu.org/copyleft/lesser.txt.
00023 -----------------------------------------------------------------------------
00024 */
00025 #ifndef _Bitwise_H__
00026 #define _Bitwise_H__
00027 
00028 #include "OgrePrerequisites.h"
00029 
00030 namespace Ogre {
00031 
00034     class Bitwise {
00035     public:
00039         template<typename T>
00040         static FORCEINLINE unsigned int getBitShift(T mask)
00041         {
00042             if (mask == 0)
00043                 return 0;
00044 
00045             unsigned int result = 0;
00046             while ((mask & 1) == 0) {
00047                 ++result;
00048                 mask >>= 1;
00049             }
00050             return result;
00051         }
00052 
00058         template<typename SrcT, typename DestT>
00059         static inline DestT convertBitPattern(SrcT srcValue, SrcT srcBitMask, DestT destBitMask)
00060         {
00061             // Mask off irrelevant source value bits (if any)
00062             srcValue = srcValue & srcBitMask;
00063 
00064             // Shift source down to bottom of DWORD
00065             const unsigned int srcBitShift = getBitShift(srcBitMask);
00066             srcValue >>= srcBitShift;
00067 
00068             // Get max value possible in source from srcMask
00069             const SrcT srcMax = srcBitMask >> srcBitShift;
00070 
00071             // Get max avaiable in dest
00072             const unsigned int destBitShift = getBitShift(destBitMask);
00073             const DestT destMax = destBitMask >> destBitShift;
00074 
00075             // Scale source value into destination, and shift back
00076             DestT destValue = (srcValue * destMax) / srcMax;
00077             return (destValue << destBitShift);
00078         }
00079     };
00080 }
00081 
00082 #endif

Copyright © 2002-2003 by The OGRE Team
Last modified Fri May 14 23:21:53 2004