eliot/dic/hashtable.cpp

/*****************************************************************************
 * Eliot
 * Copyright (C) 1999-2007 Antoine Fraboulet & Olivier Teulière
 * Authors: Antoine Fraboulet <antoine.fraboulet @@ free.fr>
 *          Olivier Teulière <ipkiss @@ gmail.com>
 *
 * 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *****************************************************************************/

/**
 *  \file   hashtable.c
 *  \brief  Simple hashtable type
 *  \author Antoine Fraboulet
 *  \date   1999
 */

#include "hashtable.h"


unsigned int HashPtr(const void *iPtr, unsigned int iSize)
{
    unsigned int key = 0;

    if (iSize % sizeof(unsigned int) == 0)
    {
        const unsigned int *ptr =
            reinterpret_cast<const unsigned int*>(iPtr);
        for (unsigned int i = 0; i < (iSize / sizeof(unsigned int)); ++i)
            key ^= (key << 3) ^ (key >> 1) ^ ptr[i];
    }
    else
    {
        const unsigned char *ptr =
            reinterpret_cast<const unsigned char*>(iPtr);
        for (unsigned int i = 0; i < iSize; ++i)
            key ^= (key << 3) ^ (key >> 1) ^ ptr[i];
    }
    return key;
}