pfr/detail/stdtuple.hpp

0001 // Copyright (c) 2016-2023 Antony Polukhin
0002 //
0003 // Distributed under the Boost Software License, Version 1.0. (See accompanying
0004 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0005
0006 #ifndef BOOST_PFR_DETAIL_STDTUPLE_HPP
0007 #define BOOST_PFR_DETAIL_STDTUPLE_HPP
0008 #pragma once
0009
0010 #include <boost/pfr/detail/config.hpp>
0011
0012 #include <utility>      // metaprogramming stuff
0013 #include <tuple>
0014
0015 #include <boost/pfr/detail/sequence_tuple.hpp>
0016
0017 namespace boost { namespace pfr { namespace detail {
0018
0019 template <class T, std::size_t... I>
0020 constexpr auto make_stdtuple_from_tietuple(const T& t, std::index_sequence<I...>) noexcept {
0021     return std::make_tuple(
0022         boost::pfr::detail::sequence_tuple::get<I>(t)...
0023     );
0024 }
0025
0026 template <class T, std::size_t... I>
0027 constexpr auto make_stdtiedtuple_from_tietuple(const T& t, std::index_sequence<I...>) noexcept {
0028     return std::tie(
0029         boost::pfr::detail::sequence_tuple::get<I>(t)...
0030     );
0031 }
0032
0033 template <class T, std::size_t... I>
0034 constexpr auto make_conststdtiedtuple_from_tietuple(const T& t, std::index_sequence<I...>) noexcept {
0035     return std::tuple<
0036         std::add_lvalue_reference_t<std::add_const_t<
0037             std::remove_reference_t<decltype(boost::pfr::detail::sequence_tuple::get<I>(t))>
0038         >>...
0039     >(
0040         boost::pfr::detail::sequence_tuple::get<I>(t)...
0041     );
0042 }
0043
0044 }}} // namespace boost::pfr::detail
0045
0046 #endif // BOOST_PFR_DETAIL_STDTUPLE_HPP