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extern/draco/dracoenc/src/draco/core/hash_utils.h
- This file was added.
| // Copyright 2016 The Draco Authors. | |||||
| // | |||||
| // Licensed under the Apache License, Version 2.0 (the "License"); | |||||
| // you may not use this file except in compliance with the License. | |||||
| // You may obtain a copy of the License at | |||||
| // | |||||
| // http://www.apache.org/licenses/LICENSE-2.0 | |||||
| // | |||||
| // Unless required by applicable law or agreed to in writing, software | |||||
| // distributed under the License is distributed on an "AS IS" BASIS, | |||||
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |||||
| // See the License for the specific language governing permissions and | |||||
| // limitations under the License. | |||||
| // | |||||
| #ifndef DRACO_CORE_HASH_UTILS_H_ | |||||
| #define DRACO_CORE_HASH_UTILS_H_ | |||||
| #include <stdint.h> | |||||
| #include <functional> | |||||
| // TODO(fgalligan): Move this to core. | |||||
| namespace draco { | |||||
| template <typename T1, typename T2> | |||||
| size_t HashCombine(T1 a, T2 b) { | |||||
| const size_t hash1 = std::hash<T1>()(a); | |||||
| const size_t hash2 = std::hash<T2>()(b); | |||||
| return (hash1 << 2) ^ (hash2 << 1); | |||||
| } | |||||
| template <typename T> | |||||
| size_t HashCombine(T a, size_t hash) { | |||||
| const size_t hasha = std::hash<T>()(a); | |||||
| return (hash) ^ (hasha + 239); | |||||
| } | |||||
| inline uint64_t HashCombine(uint64_t a, uint64_t b) { | |||||
| return (a + 1013) ^ (b + 107) << 1; | |||||
| } | |||||
| // Will never return 1 or 0. | |||||
| uint64_t FingerprintString(const char *s, size_t len); | |||||
| // Hash for std::array. | |||||
| template <typename T> | |||||
| struct HashArray { | |||||
| size_t operator()(const T &a) const { | |||||
| size_t hash = 79; // Magic number. | |||||
| for (unsigned int i = 0; i < std::tuple_size<T>::value; ++i) { | |||||
| hash = HashCombine(hash, ValueHash(a[i])); | |||||
| } | |||||
| return hash; | |||||
| } | |||||
| template <typename V> | |||||
| size_t ValueHash(const V &val) const { | |||||
| return std::hash<V>()(val); | |||||
| } | |||||
| }; | |||||
| } // namespace draco | |||||
| #endif // DRACO_CORE_HASH_UTILS_H_ | |||||