45 lines
1.0 KiB
C++
45 lines
1.0 KiB
C++
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/* Written in 2015 by Sebastiano Vigna (vigna@acm.org)
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*
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* To the extent possible under law, the author has dedicated all copyright
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* and related and neighboring rights to this software to the public domain
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* worldwide. This software is distributed without any warranty.
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*/
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#include "../std.hpp"
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#include <limits>
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namespace cruft::rand {
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class splitmix64 {
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public:
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using result_type = u64;
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splitmix64 (u64 seed):
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m_state (seed)
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{ ; }
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result_type operator() (void)
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{
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u64 z = (m_state += 0x9e3779b97f4a7c15);
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z = (z ^ (z >> 30)) * 0xbf58476d1ce4e5b9;
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z = (z ^ (z >> 27)) * 0x94d049bb133111eb;
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return z ^ (z >> 31);
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}
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static constexpr result_type min (void)
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{
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return std::numeric_limits<result_type>::min ();
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}
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static constexpr result_type max (void)
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{
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return std::numeric_limits<result_type>::max ();
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}
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private:
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u64 m_state;
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};
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}
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