intrusive/detail/hash_combine.hpp

0001 /////////////////////////////////////////////////////////////////////////////
0002 //
0003 // Copyright 2005-2014 Daniel James.
0004 // Distributed under the Boost Software License, Version 1.0. (See accompanying
0005 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0006 //
0007 //  Based on Peter Dimov's proposal
0008 //  http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2005/n1756.pdf
0009 //  issue 6.18.
0010 //
0011 //  This also contains public domain code from MurmurHash. From the
0012 //  MurmurHash header:
0013 //
0014 // MurmurHash3 was written by Austin Appleby, and is placed in the public
0015 // domain. The author hereby disclaims copyright to this source code.
0016 //
0017 // Copyright 2021 Ion Gaztanaga
0018 // Refactored the original Boost ContainerHash library to avoid
0019 // any heavy std header dependencies to just combine two hash
0020 // values represented in a std::size_t type.
0021 //
0022 // See http://www.boost.org/libs/intrusive for documentation.
0023 //
0024 /////////////////////////////////////////////////////////////////////////////
0025
0026
0027 #ifndef BOOST_INTRUSIVE_DETAIL_HASH_COMBINE_HPP
0028 #define BOOST_INTRUSIVE_DETAIL_HASH_COMBINE_HPP
0029
0030 #ifndef BOOST_CONFIG_HPP
0031 #  include <boost/config.hpp>
0032 #endif
0033
0034 #if defined(BOOST_HAS_PRAGMA_ONCE)
0035 #  pragma once
0036 #endif
0037
0038 #include <boost/cstdint.hpp>
0039 #include "hash_mix.hpp"
0040
0041 namespace boost {
0042 namespace intrusive {
0043 namespace detail {
0044
0045 inline void hash_combine_size_t(std::size_t& seed, std::size_t value)
0046 {
0047    seed = boost::intrusive::detail::hash_mix(seed + 0x9e3779b9 + value);
0048 }
0049
0050 }  //namespace detail {
0051 }  //namespace intrusive {
0052 }  //namespace boost {
0053
0054 #endif   //BOOST_INTRUSIVE_DETAIL_HASH_COMBINE_HPP