wehub-resource-sync
43 lines
1.4 KiB
C++
43 lines
1.4 KiB
C++
// Copyright (c) 2023 PaddlePaddle Authors. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#pragma once
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inline void HashCombine(std::size_t* seed) {}
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// combine hash value
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// https://stackoverflow.com/questions/2590677/how-do-i-combine-hash-values-in-c0x
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template <typename T, typename... Rest>
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inline void HashCombine(std::size_t* seed, const T& v, Rest... rest) {
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std::hash<T> hasher;
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*seed ^= hasher(v) + 0x9e3779b9 + (*seed << 6) + (*seed >> 2);
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*seed *= 0x00000100000001B3;
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HashCombine(seed, rest...);
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}
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// custom specialization of std::hash can be injected in namespace std
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// ref: https://en.cppreference.com/w/cpp/utility/hash
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namespace std {
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template <typename T>
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struct hash<std::vector<T>> {
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std::size_t operator()(std::vector<T> const& vec) const noexcept {
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std::size_t seed = 0xcbf29ce484222325;
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for (auto val : vec) {
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HashCombine(&seed, val);
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}
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return seed;
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}
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};
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} // namespace std
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