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hash.h

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00001 /***************************************************************************
00002                           hash.h  -  Hash methods
00003                              -------------------
00004     begin                : Wed Feb 12 2003
00005     copyright            : (C) 2003 by Mattias Jansson
00006     email                : mattias@realityrift.com
00007  ***************************************************************************
00008 
00009  The contents of this file are subject to the Mozilla Public License Version
00010  1.1 (the "License"); you may not use this file except in compliance with
00011  the License. You may obtain a copy of the License at 
00012  http://www.mozilla.org/MPL/
00013 
00014  Software distributed under the License is distributed on an "AS IS" basis,
00015  WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
00016  for the specific language governing rights and limitations under the
00017  License.
00018 
00019  The Original Code is the NeoEngine, hash.h
00020 
00021  The Initial Developer of the Original Code is Mattias Jansson.
00022  Portions created by Mattias Jansson are Copyright (C) 2003
00023  Reality Rift Studios. All Rights Reserved.
00024 
00025  ***************************************************************************/
00026 
00027 #ifndef __NEHASH_H
00028 #define __NEHASH_H
00029 
00030 #include "base.h"
00031 
00032 #include <string>
00033 
00034  
00041 namespace NeoEngine
00042 {
00043 
00044 
00053 inline unsigned int Hash( const char *pszString, unsigned int uiLength = 0 )
00054 {
00055     if( !pszString )
00056         return 0;
00057 
00058     if( !uiLength )
00059         uiLength = (unsigned int)strlen( pszString );
00060 
00061     unsigned int         uiRet  = 0;
00062     unsigned int         uiTmp;
00063     const unsigned char *pszStr = (const unsigned char*)pszString;
00064 
00065     for( unsigned int i = 0; i < uiLength; ++i, ++pszStr )
00066     {
00067         uiRet = ( uiRet << 4 ) + *pszStr;
00068 
00069         if( ( uiTmp = uiRet & 0xF0000000 ) )
00070             uiRet ^= ( uiTmp >> 24 );
00071 
00072         uiRet &= ~uiTmp;
00073     }
00074 
00075     return uiRet;
00076 }
00077 
00078 
00087 inline unsigned int Hash( const std::string &rstrString, unsigned int uiLength = 0 )
00088 {
00089     return Hash( rstrString.c_str(), uiLength ? uiLength : rstrString.length() );
00090 }
00091 
00092 
00093 };
00094 
00095 
00096 #endif
00097 

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