/*************************************************************************
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * Copyright 2000, 2010 Oracle and/or its affiliates.
 *
 * OpenOffice.org - a multi-platform office productivity suite
 *
 * This file is part of OpenOffice.org.
 *
 * OpenOffice.org is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License version 3
 * only, as published by the Free Software Foundation.
 *
 * OpenOffice.org 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 Lesser General Public License version 3 for more details
 * (a copy is included in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU Lesser General Public License
 * version 3 along with OpenOffice.org.  If not, see
 * <http://www.openoffice.org/license.html>
 * for a copy of the LGPLv3 License.
 *
 ************************************************************************/
#ifndef _STRINGHASH_HXX
#define _STRINGHASH_HXX

#include <tools/string.hxx>

struct StringEq
{
    sal_Bool operator() ( const String *r1,
                            const String *r2) const
    {
        return r1->Equals(*r2);
    }
};

struct StringEqRef
{
    sal_Bool operator() (const String &r1, const String &r2) const
    {
        return r1.Equals(r2);
    }
};

struct StringHash
{
    size_t operator() ( const String *rString) const
    {
        sal_Int32 h, nLen;
        h = nLen = rString->Len();
        const sal_Unicode *pStr = rString->GetBuffer();

        if ( nLen < 16 )
            while ( nLen-- > 0 )
                h = (h*37) + *(pStr++);
        else
        {
            sal_Int32               nSkip;
            const sal_Unicode* pEndStr = pStr+nLen-5;

            /* only sample some characters */
            /* the first 3, some characters between, and the last 5 */
            h = (h*39) + *(pStr++);
            h = (h*39) + *(pStr++);
            h = (h*39) + *(pStr++);

            nSkip = nLen / nLen < 32 ? 4 : 8;
            nLen -= 8;
            while ( nLen > 0 )
            {
                h = (h*39) + ( *pStr );
                pStr += nSkip;
                nLen -= nSkip;
            }

            h = (h*39) + *(pEndStr++);
            h = (h*39) + *(pEndStr++);
            h = (h*39) + *(pEndStr++);
            h = (h*39) + *(pEndStr++);
            h = (h*39) + *(pEndStr++);
        }
        return h;
    }

    size_t operator() (const String & rStr) const
    {
        return (*this)(&rStr);
    }
};

struct StringHashRef
{
    size_t operator () (const String &rStr) const
    {
        StringHash aStrHash;

        return aStrHash(&rStr);
    }
};
#endif // _STRINGHASH_HXX