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/*************************************************************************
*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* Copyright 2008 by Sun Microsystems, Inc.
*
* OpenOffice.org - a multi-platform office productivity suite
*
* $RCSfile: stringhash.hxx,v $
* $Revision: 1.6 $
*
* 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
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