59 lines
1.0 KiB
C++
59 lines
1.0 KiB
C++
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#ifndef BOOST_UTILITY_DETAIL_MINSTD_RAND_HPP_INCLUDED
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#define BOOST_UTILITY_DETAIL_MINSTD_RAND_HPP_INCLUDED
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// Copyright 2017 Peter Dimov
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//
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// Distributed under the Boost Software License, Version 1.0.
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//
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// See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt
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//
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// An implementation of minstd_rand that does not require
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// the Random library
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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 minstd_rand
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{
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private:
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boost::uint_least32_t x_;
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enum { a = 48271, m = 2147483647 };
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public:
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minstd_rand(): x_( 1 )
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{
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}
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explicit minstd_rand( boost::uint_least32_t x ): x_( x % m )
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{
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if( x_ == 0 )
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{
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x_ = 1;
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}
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}
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boost::uint_least32_t operator()()
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{
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boost::uint_least64_t y = x_;
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y = ( a * y ) % m;
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x_ = static_cast<boost::uint_least32_t>( y );
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return x_;
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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_UTILITY_DETAIL_MINSTD_RAND_HPP_INCLUDED
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