1 /* 2 * Copyright 2021 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #pragma once 18 19 #include <functional> 20 21 namespace android { hashCombineSingleHashed(size_t & combinedHash,size_t hash)22 static inline void hashCombineSingleHashed(size_t& combinedHash, size_t hash) { 23 combinedHash = 31 * combinedHash + hash; 24 } 25 26 template<typename T> hashCombineSingle(size_t & combinedHash,const T & val)27 static inline void hashCombineSingle(size_t& combinedHash, const T& val) { 28 hashCombineSingleHashed(combinedHash, std::hash<T>{}(val)); 29 } 30 31 template<typename... Types> hashCombine(const Types &...args)32 static inline size_t hashCombine(const Types& ... args) { 33 size_t hash = 0; 34 ( hashCombineSingle(hash, args), ... ); 35 return hash; 36 } 37 38 } // namespace android