///////////////////////////////////////////////////////////////
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// Copyright 2019 John Maddock. Distributed under the Boost
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// Software License, Version 1.0. (See accompanying file
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// LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt
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#ifndef BOOST_MP_CONSTEXPR_HPP
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#define BOOST_MP_CONSTEXPR_HPP
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#include <boost/config.hpp>
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namespace boost {
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namespace multiprecision {
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namespace std_constexpr {
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template <class T>
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inline BOOST_CXX14_CONSTEXPR void swap(T& a, T& b)
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{
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T t(a);
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a = b;
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b = t;
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}
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template <class InputIterator, class OutputIterator>
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inline BOOST_CXX14_CONSTEXPR OutputIterator copy(InputIterator first, InputIterator last, OutputIterator result)
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{
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//
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// There are 3 branches here, only one of which is selected at compile time:
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//
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#ifndef BOOST_MP_NO_CONSTEXPR_DETECTION
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if (BOOST_MP_IS_CONST_EVALUATED(*first))
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{
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// constexpr safe code, never generates runtime code:
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while (first != last)
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{
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*result = *first;
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++first;
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++result;
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}
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return result;
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}
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else
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#endif
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{
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#ifndef BOOST_NO_CXX17_IF_CONSTEXPR
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if constexpr (std::is_pointer<InputIterator>::value && std::is_pointer<OutputIterator>::value && std::is_trivially_copyable<typename std::remove_reference<decltype(*first)>::type>::value)
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{
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// The normal runtime branch:
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std::memcpy(result, first, (last - first) * sizeof(*first));
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return result + (last - first);
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}
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else
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#endif
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{
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// Alternate runtime branch:
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while (first != last)
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{
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*result = *first;
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++first;
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++result;
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}
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return result;
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}
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}
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}
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template <class I>
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inline BOOST_CXX14_CONSTEXPR bool equal(const I* first, const I* last, const I* other)
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{
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while (first != last)
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{
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if (*first != *other)
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return false;
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++first;
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++other;
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}
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return true;
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}
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}
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}
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} // namespace boost::multiprecision::std_constexpr
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#endif
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