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/*
* $Id: GEN_HashedPtr.cpp 20094 2009-05-07 09:13:01Z ben2610 $
*
* ***** BEGIN GPL LICENSE BLOCK *****
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
* All rights reserved.
*
* The Original Code is: all of this file.
*
* Contributor(s): none yet.
*
* ***** END GPL LICENSE BLOCK *****
*
*/
#include "GEN_HashedPtr.h"
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "BLO_sys_types.h" // for intptr_t support
//
// Build hash index from pointer. Even though the final result
// is a 32-bit integer, use all the bits of the pointer as long
// as possible.
//
#if 1
unsigned int GEN_Hash(void * inDWord)
{
uintptr_t key = (uintptr_t)inDWord;
#if 0
// this is way too complicated
key += ~(key << 16);
key ^= (key >> 5);
key += (key << 3);
key ^= (key >> 13);
key += ~(key << 9);
key ^= (key >> 17);
return (unsigned int)(key & 0xffffffff);
#else
return (unsigned int)(key ^ (key>>4));
#endif
}
#endif
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