Page Speed Optimization Libraries
1.2.24.1
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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_util.h" 00025 00026 namespace net_instaweb { 00027 00030 template<class CharTransform, typename IntType> 00031 inline IntType HashString(const char* s, size_t len) { 00034 IntType result = 0; 00035 for (size_t i = 0; i < len; ++i, ++s) { 00036 result = (result * 131) + CharTransform::Normalize(*s); 00037 } 00038 return result; 00039 } 00040 00043 inline size_t JoinHash(size_t a, size_t b) { 00044 return (a + 56) * 137 + b * 151; 00045 } 00046 00048 struct CasePreserve { 00056 static unsigned char Normalize(char c) { 00057 return c; 00058 } 00059 00060 static bool Compare(const StringPiece& a, const StringPiece& b) { 00061 return a < b; 00062 } 00063 }; 00064 00066 struct CaseFold { 00067 static unsigned char Normalize(char c) { 00068 return LowerChar(c); 00069 } 00070 00071 static bool Compare(const StringPiece& a, const StringPiece& b) { 00072 return StringCaseCompare(a, b) < 0; 00073 } 00074 }; 00075 00076 } 00077 00078 #endif ///< NET_INSTAWEB_UTIL_PUBLIC_STRING_HASH_H_