1 /************************************************************** 2 * 3 * Licensed to the Apache Software Foundation (ASF) under one 4 * or more contributor license agreements. See the NOTICE file 5 * distributed with this work for additional information 6 * regarding copyright ownership. The ASF licenses this file 7 * to you under the Apache License, Version 2.0 (the 8 * "License"); you may not use this file except in compliance 9 * with the License. You may obtain a copy of the License at 10 * 11 * http://www.apache.org/licenses/LICENSE-2.0 12 * 13 * Unless required by applicable law or agreed to in writing, 14 * software distributed under the License is distributed on an 15 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 16 * KIND, either express or implied. See the License for the 17 * specific language governing permissions and limitations 18 * under the License. 19 * 20 *************************************************************/ 21 22 23 #ifndef _STRINGHASH_HXX 24 #define _STRINGHASH_HXX 25 26 #include <tools/string.hxx> 27 28 struct StringEq 29 { operator ()StringEq30 sal_Bool operator() ( const String *r1, 31 const String *r2) const 32 { 33 return r1->Equals(*r2); 34 } 35 }; 36 37 struct StringEqRef 38 { operator ()StringEqRef39 sal_Bool operator() (const String &r1, const String &r2) const 40 { 41 return r1.Equals(r2); 42 } 43 }; 44 45 struct StringHash 46 { operator ()StringHash47 size_t operator() ( const String *rString) const 48 { 49 sal_Int32 h, nLen; 50 h = nLen = rString->Len(); 51 const sal_Unicode *pStr = rString->GetBuffer(); 52 53 if ( nLen < 16 ) 54 while ( nLen-- > 0 ) 55 h = (h*37) + *(pStr++); 56 else 57 { 58 sal_Int32 nSkip; 59 const sal_Unicode* pEndStr = pStr+nLen-5; 60 61 /* only sample some characters */ 62 /* the first 3, some characters between, and the last 5 */ 63 h = (h*39) + *(pStr++); 64 h = (h*39) + *(pStr++); 65 h = (h*39) + *(pStr++); 66 67 nSkip = nLen / nLen < 32 ? 4 : 8; 68 nLen -= 8; 69 while ( nLen > 0 ) 70 { 71 h = (h*39) + ( *pStr ); 72 pStr += nSkip; 73 nLen -= nSkip; 74 } 75 76 h = (h*39) + *(pEndStr++); 77 h = (h*39) + *(pEndStr++); 78 h = (h*39) + *(pEndStr++); 79 h = (h*39) + *(pEndStr++); 80 h = (h*39) + *(pEndStr++); 81 } 82 return h; 83 } 84 operator ()StringHash85 size_t operator() (const String & rStr) const 86 { 87 return (*this)(&rStr); 88 } 89 }; 90 91 struct StringHashRef 92 { operator ()StringHashRef93 size_t operator () (const String &rStr) const 94 { 95 StringHash aStrHash; 96 97 return aStrHash(&rStr); 98 } 99 }; 100 #endif // _STRINGHASH_HXX 101