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