57 lines
1.4 KiB
C++
57 lines
1.4 KiB
C++
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///////////////////////////////////////////////////////////////////////////////
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// Copyright 2021 Matt Borland. Distributed under the Boost
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// Software License, Version 1.0. (See accompanying file
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// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_MP_DETAIL_HASH_HPP
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#define BOOST_MP_DETAIL_HASH_HPP
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#include <cstddef>
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#include <functional>
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#include <boost/multiprecision/detail/standalone_config.hpp>
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namespace boost { namespace multiprecision { namespace detail {
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template <typename T>
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inline std::size_t hash_value(const T& v)
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{
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std::hash<T> hasher;
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return hasher(v);
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}
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#if defined(BOOST_HAS_INT128)
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std::size_t hash_value(const uint128_type& val);
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inline std::size_t hash_value(const int128_type& val)
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{
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return hash_value(static_cast<uint128_type>(val));
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}
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#endif
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inline void hash_combine(std::size_t&) {}
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template <typename T, typename... Args>
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inline void hash_combine(std::size_t& seed, const T& v, Args... args)
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{
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constexpr std::size_t adder = 0x9e3779b9;
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seed = seed ^ (hash_value(v) + adder + (seed<<6) + (seed>>2));
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hash_combine(seed, args...);
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}
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#if defined(BOOST_HAS_INT128)
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inline std::size_t hash_value(const uint128_type& val)
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{
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std::size_t result = static_cast<std::size_t>(val);
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hash_combine(result, static_cast<std::size_t>(val >> 64));
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return result;
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}
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#endif
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}}} // Namespaces
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#endif // BOOST_MP_DETAIL_HASH_HPP
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