34 lines
878 B
C
34 lines
878 B
C
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/*
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* Copyright (c) Meta Platforms, Inc. and affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*/
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#pragma once
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#include <functional>
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#include <type_traits>
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namespace facebook::react {
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template <typename T>
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concept Hashable = !std::is_same_v<T, const char*> && (requires(T a) {
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{ std::hash<T>{}(a) } -> std::convertible_to<std::size_t>;
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});
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template <Hashable T, Hashable... Rest>
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void hash_combine(std::size_t& seed, const T& v, const Rest&... rest) {
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seed ^= std::hash<T>{}(v) + 0x9e3779b9 + (seed << 6) + (seed >> 2);
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(hash_combine(seed, rest), ...);
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}
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template <Hashable T, Hashable... Args>
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std::size_t hash_combine(const T& v, const Args&... args) {
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std::size_t seed = 0;
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hash_combine<T, Args...>(seed, v, args...);
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return seed;
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}
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} // namespace facebook::react
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