Page Speed Optimization Libraries
1.5.27.2
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00001 /* 00002 * Copyright 2010 Google Inc. 00003 * 00004 * Licensed under the Apache License, Version 2.0 (the "License"); 00005 * you may not use this file except in compliance with the License. 00006 * You may obtain a copy of the License at 00007 * 00008 * http:///www.apache.org/licenses/LICENSE-2.0 00009 * 00010 * Unless required by applicable law or agreed to in writing, software 00011 * distributed under the License is distributed on an "AS IS" BASIS, 00012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 00013 * See the License for the specific language governing permissions and 00014 * limitations under the License. 00015 */ 00016 00018 00019 #ifndef NET_INSTAWEB_UTIL_PUBLIC_STRING_HASH_H_ 00020 #define NET_INSTAWEB_UTIL_PUBLIC_STRING_HASH_H_ 00021 00022 #include <cstddef> 00023 00024 #include "net/instaweb/util/public/string.h" 00025 #include "net/instaweb/util/public/string_util.h" 00026 00027 namespace net_instaweb { 00028 00031 template<class CharTransform, typename IntType> 00032 inline IntType HashString(const char* s, size_t len) { 00035 IntType result = 0; 00036 for (size_t i = 0; i < len; ++i, ++s) { 00037 result = (result * 131) + CharTransform::Normalize(*s); 00038 } 00039 return result; 00040 } 00041 00044 inline size_t JoinHash(size_t a, size_t b) { 00045 return (a + 56) * 137 + b * 151; 00046 } 00047 00049 struct CasePreserve { 00057 static unsigned char Normalize(char c) { 00058 return c; 00059 } 00060 00061 static bool Compare(const StringPiece& a, const StringPiece& b) { 00062 return a < b; 00063 } 00064 }; 00065 00067 struct CaseFold { 00068 static unsigned char Normalize(char c) { 00069 return LowerChar(c); 00070 } 00071 00072 static bool Compare(const StringPiece& a, const StringPiece& b) { 00073 return StringCaseCompare(a, b) < 0; 00074 } 00075 }; 00076 00078 struct CasePreserveStringHash { 00079 size_t operator()(const GoogleString& str) const { 00080 return HashString<CasePreserve, size_t>(str.data(), str.size()); 00081 } 00082 }; 00083 00084 struct CaseFoldStringHash { 00085 size_t operator()(const GoogleString& str) const { 00086 return HashString<CaseFold, size_t>(str.data(), str.size()); 00087 } 00088 }; 00089 00090 struct CaseFoldStringEqual { 00091 bool operator()(const GoogleString& a, const GoogleString& b) const { 00092 return MemCaseEqual(a.data(), a.size(), b.data(), b.size()); 00093 } 00094 }; 00095 00096 } 00097 00098 #endif ///< NET_INSTAWEB_UTIL_PUBLIC_STRING_HASH_H_