67 lines
1.7 KiB
C++
67 lines
1.7 KiB
C++
/*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* Copyright 2015-2016 Danny Robson <danny@nerdcruft.net>
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*/
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#include "./xorshift.hpp"
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#include "../debug.hpp"
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#include <cstdint>
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using util::rand::xorshift;
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///////////////////////////////////////////////////////////////////////////////
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template <typename T>
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xorshift<T>::xorshift (T seed):
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m_state (seed)
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{
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// state must not be zero, or the period will be zero.
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CHECK_NEZ (m_state);
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}
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///////////////////////////////////////////////////////////////////////////////
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namespace util { namespace rand {
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template <>
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uint32_t
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xorshift<uint32_t>::operator() (void)
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{
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m_state ^= m_state << 13u;
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m_state ^= m_state >> 17u;
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m_state ^= m_state << 5u;
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return m_state;
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}
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//-----------------------------------------------------------------------------
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template <>
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uint64_t
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xorshift<uint64_t>::operator() (void)
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{
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m_state ^= m_state << 13u;
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m_state ^= m_state >> 7u;
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m_state ^= m_state << 17u;
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return m_state;
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}
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} }
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///////////////////////////////////////////////////////////////////////////////
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template struct util::rand::xorshift<uint32_t>;
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template struct util::rand::xorshift<uint64_t>;
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