148 lines
5.4 KiB
C++
148 lines
5.4 KiB
C++
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/*!
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@file
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Defines `boost::hana::pair`.
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@copyright Louis Dionne 2013-2016
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Distributed under the Boost Software License, Version 1.0.
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(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
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*/
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#ifndef BOOST_HANA_PAIR_HPP
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#define BOOST_HANA_PAIR_HPP
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#include <boost/hana/fwd/pair.hpp>
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#include <boost/hana/basic_tuple.hpp>
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#include <boost/hana/config.hpp>
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#include <boost/hana/detail/decay.hpp>
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#include <boost/hana/detail/intrinsics.hpp>
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#include <boost/hana/detail/operators/adl.hpp>
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#include <boost/hana/detail/operators/comparable.hpp>
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#include <boost/hana/detail/operators/orderable.hpp>
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#include <boost/hana/fwd/core/make.hpp>
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#include <boost/hana/fwd/first.hpp>
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#include <boost/hana/fwd/second.hpp>
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#include <type_traits>
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#include <utility>
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BOOST_HANA_NAMESPACE_BEGIN
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//////////////////////////////////////////////////////////////////////////
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// pair
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//////////////////////////////////////////////////////////////////////////
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//! @cond
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template <typename First, typename Second>
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struct pair : detail::operators::adl<pair<First, Second>> {
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template <typename ...dummy, typename = typename std::enable_if<
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BOOST_HANA_TT_IS_CONSTRUCTIBLE(First, dummy...) &&
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BOOST_HANA_TT_IS_CONSTRUCTIBLE(Second, dummy...)
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>::type>
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constexpr pair()
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: storage_()
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{ }
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template <typename ...dummy, typename = typename std::enable_if<
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BOOST_HANA_TT_IS_CONSTRUCTIBLE(First, First const&, dummy...) &&
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BOOST_HANA_TT_IS_CONSTRUCTIBLE(Second, Second const&, dummy...)
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>::type>
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constexpr pair(First const& first, Second const& second)
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: storage_{first, second}
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{ }
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template <typename T, typename U, typename = typename std::enable_if<
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BOOST_HANA_TT_IS_CONVERTIBLE(T&&, First) &&
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BOOST_HANA_TT_IS_CONVERTIBLE(U&&, Second)
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>::type>
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constexpr pair(T&& t, U&& u)
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: storage_{static_cast<T&&>(t), static_cast<U&&>(u)}
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{ }
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template <typename T, typename U, typename = typename std::enable_if<
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BOOST_HANA_TT_IS_CONVERTIBLE(T const&, First) &&
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BOOST_HANA_TT_IS_CONVERTIBLE(U const&, Second)
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>::type>
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constexpr pair(pair<T, U> const& other)
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: storage_{hana::get_impl<0>(other.storage_),
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hana::get_impl<1>(other.storage_)}
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{ }
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template <typename T, typename U, typename = typename std::enable_if<
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BOOST_HANA_TT_IS_CONVERTIBLE(T&&, First) &&
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BOOST_HANA_TT_IS_CONVERTIBLE(U&&, Second)
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>::type>
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constexpr pair(pair<T, U>&& other)
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: storage_{static_cast<T&&>(hana::get_impl<0>(other.storage_)),
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static_cast<U&&>(hana::get_impl<1>(other.storage_))}
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{ }
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template <typename T, typename U, typename = typename std::enable_if<
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BOOST_HANA_TT_IS_ASSIGNABLE(First&, T const&) &&
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BOOST_HANA_TT_IS_ASSIGNABLE(Second&, U const&)
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>::type>
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constexpr pair& operator=(pair<T, U> const& other) {
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hana::get_impl<0>(storage_) = hana::get_impl<0>(other.storage_);
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hana::get_impl<1>(storage_) = hana::get_impl<1>(other.storage_);
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return *this;
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}
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template <typename T, typename U, typename = typename std::enable_if<
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BOOST_HANA_TT_IS_ASSIGNABLE(First&, T&&) &&
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BOOST_HANA_TT_IS_ASSIGNABLE(Second&, U&&)
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>::type>
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constexpr pair& operator=(pair<T, U>&& other) {
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hana::get_impl<0>(storage_) = static_cast<T&&>(hana::get_impl<0>(other.storage_));
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hana::get_impl<1>(storage_) = static_cast<U&&>(hana::get_impl<1>(other.storage_));
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return *this;
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}
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using hana_tag = pair_tag;
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basic_tuple<First, Second> storage_;
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};
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//! @endcond
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//////////////////////////////////////////////////////////////////////////
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// Operators
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//////////////////////////////////////////////////////////////////////////
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namespace detail {
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template <>
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struct comparable_operators<pair_tag> {
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static constexpr bool value = true;
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};
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template <>
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struct orderable_operators<pair_tag> {
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static constexpr bool value = true;
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};
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}
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//////////////////////////////////////////////////////////////////////////
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// Product
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//////////////////////////////////////////////////////////////////////////
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template <>
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struct make_impl<pair_tag> {
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template <typename F, typename S>
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static constexpr pair<
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typename detail::decay<F>::type,
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typename detail::decay<S>::type
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> apply(F&& f, S&& s) {
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return {static_cast<F&&>(f), static_cast<S&&>(s)};
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}
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};
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template <>
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struct first_impl<pair_tag> {
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template <typename P>
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static constexpr decltype(auto) apply(P&& p)
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{ return hana::get_impl<0>(static_cast<P&&>(p).storage_); }
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};
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template <>
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struct second_impl<pair_tag> {
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template <typename P>
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static constexpr decltype(auto) apply(P&& p)
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{ return hana::get_impl<1>(static_cast<P&&>(p).storage_); }
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};
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BOOST_HANA_NAMESPACE_END
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#endif // !BOOST_HANA_PAIR_HPP
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