Added thirdparty: boost library

thirdparty/include/boost/pfr/detail/stdarray.hpp

@@ -0,0 +1,41 @@
+// Copyright (c) 2023 Denis Mikhailov
+//
+// Distributed under 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)
+
+#ifndef BOOST_PFR_DETAIL_STDARRAY_HPP
+#define BOOST_PFR_DETAIL_STDARRAY_HPP
+#pragma once
+
+#include <boost/pfr/detail/config.hpp>
+
+#include <utility> // metaprogramming stuff
+#include <array>
+#include <type_traits> // for std::common_type_t
+#include <cstddef>
+
+#include <boost/pfr/detail/sequence_tuple.hpp>
+
+namespace boost { namespace pfr { namespace detail {
+
+template <class... Types>
+constexpr auto make_stdarray(const Types&... t) noexcept {
+    return std::array<std::common_type_t<Types...>, sizeof...(Types)>{t...};
+}
+
+template <class T, std::size_t... I>
+constexpr auto make_stdarray_from_tietuple(const T& t, std::index_sequence<I...>, int) noexcept {
+    return detail::make_stdarray(
+        boost::pfr::detail::sequence_tuple::get<I>(t)...
+    );
+}
+
+template <class T>
+constexpr auto make_stdarray_from_tietuple(const T&, std::index_sequence<>, long) noexcept {
+    return std::array<std::nullptr_t, 0>{};
+}
+
+}}} // namespace boost::pfr::detail
+
+#endif // BOOST_PFR_DETAIL_STDARRAY_HPP
+