sw/inc/stringhash.hxx

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  30 #ifndef _STRINGHASH_HXX
  31 #define _STRINGHASH_HXX
  32
  33 #include <tools/string.hxx>
  34
  35 struct StringEq
  36 {
  37     sal_Bool operator() ( const String *r1,
  38                             const String *r2) const
  39     {
  40         return r1->Equals(*r2);
  41     }
  42 };
  43
  44 struct StringEqRef
  45 {
  46     sal_Bool operator() (const String &r1, const String &r2) const
  47     {
  48         return r1.Equals(r2);
  49     }
  50 };
  51
  52 struct StringHash
  53 {
  54     size_t operator() ( const String *rString) const
  55     {
  56         sal_Int32 h, nLen;
  57         h = nLen = rString->Len();
  58         const sal_Unicode *pStr = rString->GetBuffer();
  59
  60         if ( nLen < 16 )
  61             while ( nLen-- > 0 )
  62                 h = (h*37) + *(pStr++);
  63         else
  64         {
  65             sal_Int32               nSkip;
  66             const sal_Unicode* pEndStr = pStr+nLen-5;
  67
  68             /* only sample some characters */
  69             /* the first 3, some characters between, and the last 5 */
  70             h = (h*39) + *(pStr++);
  71             h = (h*39) + *(pStr++);
  72             h = (h*39) + *(pStr++);
  73
  74             nSkip = nLen / nLen < 32 ? 4 : 8;
  75             nLen -= 8;
  76             while ( nLen > 0 )
  77             {
  78                 h = (h*39) + ( *pStr );
  79                 pStr += nSkip;
  80                 nLen -= nSkip;
  81             }
  82
  83             h = (h*39) + *(pEndStr++);
  84             h = (h*39) + *(pEndStr++);
  85             h = (h*39) + *(pEndStr++);
  86             h = (h*39) + *(pEndStr++);
  87             h = (h*39) + *(pEndStr++);
  88         }
  89         return h;
  90     }
  91
  92     size_t operator() (const String & rStr) const
  93     {
  94         return (*this)(&rStr);
  95     }
  96 };
  97
  98 struct StringHashRef
  99 {
 100     size_t operator () (const String &rStr) const
 101     {
 102         StringHash aStrHash;
 103
 104         return aStrHash(&rStr);
 105     }
 106 };
 107 #endif // _STRINGHASH_HXX