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- // Utility functions for uses-allocator construction -*- C++ -*-
- // Copyright (C) 2019-2022 Free Software Foundation, Inc.
- //
- // This file is part of the GNU ISO C++ Library. This library is free
- // software; you can redistribute it and/or modify it under the
- // terms of the GNU General Public License as published by the
- // Free Software Foundation; either version 3, or (at your option)
- // any later version.
- // This library is distributed in the hope that it will be useful,
- // but WITHOUT ANY WARRANTY; without even the implied warranty of
- // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- // GNU General Public License for more details.
- // Under Section 7 of GPL version 3, you are granted additional
- // permissions described in the GCC Runtime Library Exception, version
- // 3.1, as published by the Free Software Foundation.
- // You should have received a copy of the GNU General Public License and
- // a copy of the GCC Runtime Library Exception along with this program;
- // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
- // <http://www.gnu.org/licenses/>.
- /** @file include/bits/uses_allocator_args.h
- * This is an internal header file, included by other library headers.
- * Do not attempt to use it directly. @headername{memory}
- */
- #ifndef _USES_ALLOCATOR_ARGS
- #define _USES_ALLOCATOR_ARGS 1
- #pragma GCC system_header
- #if __cplusplus > 201703L && __cpp_concepts
- #include <new> // for placement operator new
- #include <tuple> // for tuple, make_tuple, make_from_tuple
- #include <bits/stl_construct.h> // construct_at
- #include <bits/stl_pair.h> // pair
- namespace std _GLIBCXX_VISIBILITY(default)
- {
- _GLIBCXX_BEGIN_NAMESPACE_VERSION
- template<typename _Tp>
- concept _Std_pair = __is_pair<_Tp>;
- /** @addtogroup allocators
- * @{
- */
- // Not specified by C++20, used internally
- #define __cpp_lib_make_obj_using_allocator 201811L
- template<typename _Tp, typename _Alloc, typename... _Args>
- constexpr auto
- uses_allocator_construction_args(const _Alloc& __a,
- _Args&&... __args) noexcept
- requires (! _Std_pair<_Tp>)
- {
- if constexpr (uses_allocator_v<remove_cv_t<_Tp>, _Alloc>)
- {
- if constexpr (is_constructible_v<_Tp, allocator_arg_t,
- const _Alloc&, _Args...>)
- {
- return tuple<allocator_arg_t, const _Alloc&, _Args&&...>(
- allocator_arg, __a, std::forward<_Args>(__args)...);
- }
- else
- {
- static_assert(is_constructible_v<_Tp, _Args..., const _Alloc&>,
- "construction with an allocator must be possible"
- " if uses_allocator is true");
- return tuple<_Args&&..., const _Alloc&>(
- std::forward<_Args>(__args)..., __a);
- }
- }
- else
- {
- static_assert(is_constructible_v<_Tp, _Args...>);
- return tuple<_Args&&...>(std::forward<_Args>(__args)...);
- }
- }
- template<_Std_pair _Tp, typename _Alloc, typename _Tuple1, typename _Tuple2>
- constexpr auto
- uses_allocator_construction_args(const _Alloc& __a, piecewise_construct_t,
- _Tuple1&& __x, _Tuple2&& __y) noexcept;
- template<_Std_pair _Tp, typename _Alloc>
- constexpr auto
- uses_allocator_construction_args(const _Alloc&) noexcept;
- template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp>
- constexpr auto
- uses_allocator_construction_args(const _Alloc&, _Up&&, _Vp&&) noexcept;
- template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp>
- constexpr auto
- uses_allocator_construction_args(const _Alloc&,
- const pair<_Up, _Vp>&) noexcept;
- template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp>
- constexpr auto
- uses_allocator_construction_args(const _Alloc&, pair<_Up, _Vp>&&) noexcept;
- template<_Std_pair _Tp, typename _Alloc, typename _Tuple1, typename _Tuple2>
- constexpr auto
- uses_allocator_construction_args(const _Alloc& __a, piecewise_construct_t,
- _Tuple1&& __x, _Tuple2&& __y) noexcept
- {
- using _Tp1 = typename _Tp::first_type;
- using _Tp2 = typename _Tp::second_type;
- return std::make_tuple(piecewise_construct,
- std::apply([&__a](auto&&... __args1) {
- return std::uses_allocator_construction_args<_Tp1>(
- __a, std::forward<decltype(__args1)>(__args1)...);
- }, std::forward<_Tuple1>(__x)),
- std::apply([&__a](auto&&... __args2) {
- return std::uses_allocator_construction_args<_Tp2>(
- __a, std::forward<decltype(__args2)>(__args2)...);
- }, std::forward<_Tuple2>(__y)));
- }
- template<_Std_pair _Tp, typename _Alloc>
- constexpr auto
- uses_allocator_construction_args(const _Alloc& __a) noexcept
- {
- using _Tp1 = typename _Tp::first_type;
- using _Tp2 = typename _Tp::second_type;
- return std::make_tuple(piecewise_construct,
- std::uses_allocator_construction_args<_Tp1>(__a),
- std::uses_allocator_construction_args<_Tp2>(__a));
- }
- template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp>
- constexpr auto
- uses_allocator_construction_args(const _Alloc& __a, _Up&& __u, _Vp&& __v)
- noexcept
- {
- using _Tp1 = typename _Tp::first_type;
- using _Tp2 = typename _Tp::second_type;
- return std::make_tuple(piecewise_construct,
- std::uses_allocator_construction_args<_Tp1>(__a,
- std::forward<_Up>(__u)),
- std::uses_allocator_construction_args<_Tp2>(__a,
- std::forward<_Vp>(__v)));
- }
- template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp>
- constexpr auto
- uses_allocator_construction_args(const _Alloc& __a,
- const pair<_Up, _Vp>& __pr) noexcept
- {
- using _Tp1 = typename _Tp::first_type;
- using _Tp2 = typename _Tp::second_type;
- return std::make_tuple(piecewise_construct,
- std::uses_allocator_construction_args<_Tp1>(__a, __pr.first),
- std::uses_allocator_construction_args<_Tp2>(__a, __pr.second));
- }
- template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp>
- constexpr auto
- uses_allocator_construction_args(const _Alloc& __a,
- pair<_Up, _Vp>&& __pr) noexcept
- {
- using _Tp1 = typename _Tp::first_type;
- using _Tp2 = typename _Tp::second_type;
- return std::make_tuple(piecewise_construct,
- std::uses_allocator_construction_args<_Tp1>(__a,
- std::move(__pr).first),
- std::uses_allocator_construction_args<_Tp2>(__a,
- std::move(__pr).second));
- }
- template<typename _Tp, typename _Alloc, typename... _Args>
- constexpr _Tp
- make_obj_using_allocator(const _Alloc& __a, _Args&&... __args)
- {
- return std::make_from_tuple<_Tp>(
- std::uses_allocator_construction_args<_Tp>(__a,
- std::forward<_Args>(__args)...));
- }
- template<typename _Tp, typename _Alloc, typename... _Args>
- constexpr _Tp*
- uninitialized_construct_using_allocator(_Tp* __p, const _Alloc& __a,
- _Args&&... __args)
- {
- return std::apply([&](auto&&... __xs) {
- return std::construct_at(__p, std::forward<decltype(__xs)>(__xs)...);
- }, std::uses_allocator_construction_args<_Tp>(__a,
- std::forward<_Args>(__args)...));
- }
- /// @}
- _GLIBCXX_END_NAMESPACE_VERSION
- } // namespace std
- #endif // C++20
- #endif // _USES_ALLOCATOR_ARGS
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