12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758 |
- #ifndef BOOST_UTILITY_DETAIL_MINSTD_RAND_HPP_INCLUDED
- #define BOOST_UTILITY_DETAIL_MINSTD_RAND_HPP_INCLUDED
- // Copyright 2017 Peter Dimov
- //
- // Distributed under the Boost Software License, Version 1.0.
- //
- // See accompanying file LICENSE_1_0.txt or copy at
- // http://www.boost.org/LICENSE_1_0.txt
- //
- // An implementation of minstd_rand that does not require
- // the Random library
- #include <boost/cstdint.hpp>
- namespace boost
- {
- namespace detail
- {
- class minstd_rand
- {
- private:
- boost::uint_least32_t x_;
- enum { a = 48271, m = 2147483647 };
- public:
- minstd_rand(): x_( 1 )
- {
- }
- explicit minstd_rand( boost::uint_least32_t x ): x_( x % m )
- {
- if( x_ == 0 )
- {
- x_ = 1;
- }
- }
- boost::uint_least32_t operator()()
- {
- boost::uint_least64_t y = x_;
- y = ( a * y ) % m;
- x_ = static_cast<boost::uint_least32_t>( y );
- return x_;
- }
- };
- } // namespace detail
- } // namespace boost
- #endif // #ifndef BOOST_UTILITY_DETAIL_MINSTD_RAND_HPP_INCLUDED
|