xref: /aoo42x/main/sw/inc/stringhash.hxx (revision cdf0e10c)

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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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#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