mirror of
https://github.com/NixOS/nix
synced 2025-07-06 09:11:47 +02:00
27 lines
619 B
C++
27 lines
619 B
C++
#pragma once
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/**
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* @file
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*
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* Hashing utilities for use with `std::unordered_map`, etc. (i.e. low
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* level implementation logic, not domain logic like Nix hashing).
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*/
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#include <functional>
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namespace nix {
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/**
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* `hash_combine()` from Boost. Hash several hashable values together
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* into a single hash.
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*/
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inline void hash_combine(std::size_t & seed) {}
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template<typename T, typename... Rest>
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inline void hash_combine(std::size_t & seed, const T & v, Rest... rest)
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{
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std::hash<T> hasher;
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seed ^= hasher(v) + 0x9e3779b9 + (seed << 6) + (seed >> 2);
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hash_combine(seed, rest...);
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}
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} // namespace nix
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