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118 lines
2.9 KiB
C++
118 lines
2.9 KiB
C++
// Copyright (C) 2003, 2008 Fernando Luis Cacciola Carballal.
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// Copyright (C) 2015 Andrzej Krzemienski.
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//
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// Use, modification, and distribution is subject to the Boost Software
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// License, Version 1.0. (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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// See http://www.boost.org/libs/optional for documentation.
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//
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// You are welcome to contact the author at:
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// akrzemi1@gmail.com
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#ifndef BOOST_OPTIONAL_DETAIL_OPTIONAL_SWAP_AJK_28JAN2015_HPP
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#define BOOST_OPTIONAL_DETAIL_OPTIONAL_SWAP_AJK_28JAN2015_HPP
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#include <boost/core/swap.hpp>
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#include <boost/optional/optional_fwd.hpp>
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namespace boost {
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namespace optional_detail {
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template <bool use_default_constructor> struct swap_selector;
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template <>
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struct swap_selector<true>
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{
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template <class T>
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static void optional_swap ( optional<T>& x, optional<T>& y )
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{
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const bool hasX = !!x;
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const bool hasY = !!y;
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if ( !hasX && !hasY )
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return;
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if( !hasX )
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x.emplace();
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else if ( !hasY )
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y.emplace();
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// Boost.Utility.Swap will take care of ADL and workarounds for broken compilers
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boost::swap(x.get(), y.get());
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if( !hasX )
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y = boost::none ;
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else if( !hasY )
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x = boost::none ;
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}
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};
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#ifdef BOOST_OPTIONAL_DETAIL_MOVE
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# undef BOOST_OPTIONAL_DETAIL_MOVE
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#endif
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#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
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# define BOOST_OPTIONAL_DETAIL_MOVE(EXPR_) boost::move(EXPR_)
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#else
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# define BOOST_OPTIONAL_DETAIL_MOVE(EXPR_) EXPR_
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#endif
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template <>
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struct swap_selector<false>
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{
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template <class T>
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static void optional_swap ( optional<T>& x, optional<T>& y )
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//BOOST_NOEXCEPT_IF(::boost::is_nothrow_move_constructible<T>::value && BOOST_NOEXCEPT_EXPR(boost::swap(*x, *y)))
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{
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if (x)
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{
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if (y)
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{
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boost::swap(*x, *y);
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}
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else
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{
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y = BOOST_OPTIONAL_DETAIL_MOVE(*x);
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x = boost::none;
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}
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}
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else
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{
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if (y)
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{
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x = BOOST_OPTIONAL_DETAIL_MOVE(*y);
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y = boost::none;
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}
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}
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}
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};
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} // namespace optional_detail
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#if (!defined BOOST_NO_CXX11_RVALUE_REFERENCES) && (!defined BOOST_CONFIG_RESTORE_OBSOLETE_SWAP_IMPLEMENTATION)
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template<class T>
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struct optional_swap_should_use_default_constructor : boost::false_type {} ;
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#else
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template<class T>
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struct optional_swap_should_use_default_constructor : has_nothrow_default_constructor<T> {} ;
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#endif
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template <class T>
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inline void swap ( optional<T>& x, optional<T>& y )
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//BOOST_NOEXCEPT_IF(::boost::is_nothrow_move_constructible<T>::value && BOOST_NOEXCEPT_EXPR(boost::swap(*x, *y)))
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{
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optional_detail::swap_selector<optional_swap_should_use_default_constructor<T>::value>::optional_swap(x, y);
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}
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} // namespace boost
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#undef BOOST_OPTIONAL_DETAIL_MOVE
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#endif // header guard
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