55 lines
1.1 KiB
C++
55 lines
1.1 KiB
C++
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#ifndef BOOST_CORE_DETAIL_SPLITMIX64_HPP_INCLUDED
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#define BOOST_CORE_DETAIL_SPLITMIX64_HPP_INCLUDED
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// Copyright 2020 Peter Dimov
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// Distributed under the Boost Software License, Version 1.0.
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// https://www.boost.org/LICENSE_1_0.txt
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//
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// An implementation of splitmix64 for testing purposes,
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// derived from Sebastiano Vigna's public domain implementation
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// http://xorshift.di.unimi.it/splitmix64.c
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#include <boost/cstdint.hpp>
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namespace boost
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{
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namespace detail
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{
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class splitmix64
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{
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private:
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boost::uint64_t x_;
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public:
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splitmix64(): x_( 0 )
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{
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}
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explicit splitmix64( boost::uint64_t seed ): x_( seed )
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{
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}
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boost::uint64_t operator()()
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{
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x_ += ( boost::uint64_t(0x9e3779b9u) << 32 ) + 0x7f4a7c15u;
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boost::uint64_t z = x_;
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z ^= z >> 30;
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z *= ( boost::uint64_t(0xbf58476du) << 32 ) + 0x1ce4e5b9u;
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z ^= z >> 27;
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z *= ( boost::uint64_t(0x94d049bbu) << 32 ) + 0x133111ebu;
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z ^= z >> 31;
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return z;
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}
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};
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} // namespace detail
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} // namespace boost
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#endif // #ifndef BOOST_CORE_DETAIL_SPLITMIX64_HPP_INCLUDED
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