1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP___FUNCTIONAL_ALLOCATOR_ARG_T_H
11#define _LIBCPP___FUNCTIONAL_ALLOCATOR_ARG_T_H
12
13#include <__config>
14#include <__memory/uses_allocator.h>
15#include <__type_traits/integral_constant.h>
16#include <__type_traits/is_constructible.h>
17#include <__type_traits/remove_cvref.h>
18#include <__utility/forward.h>
19
20#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
21#  pragma GCC system_header
22#endif
23
24_LIBCPP_BEGIN_NAMESPACE_STD
25
26struct _LIBCPP_TEMPLATE_VIS allocator_arg_t {
27  explicit allocator_arg_t() = default;
28};
29
30#if _LIBCPP_STD_VER >= 17
31inline constexpr allocator_arg_t allocator_arg = allocator_arg_t();
32#elif !defined(_LIBCPP_CXX03_LANG)
33constexpr allocator_arg_t allocator_arg = allocator_arg_t();
34#endif
35
36#ifndef _LIBCPP_CXX03_LANG
37
38// allocator construction
39
40template <class _Tp, class _Alloc, class... _Args>
41struct __uses_alloc_ctor_imp {
42  typedef _LIBCPP_NODEBUG __remove_cvref_t<_Alloc> _RawAlloc;
43  static const bool __ua = uses_allocator<_Tp, _RawAlloc>::value;
44  static const bool __ic = is_constructible<_Tp, allocator_arg_t, _Alloc, _Args...>::value;
45  static const int value = __ua ? 2 - __ic : 0;
46};
47
48template <class _Tp, class _Alloc, class... _Args>
49struct __uses_alloc_ctor : integral_constant<int, __uses_alloc_ctor_imp<_Tp, _Alloc, _Args...>::value> {};
50
51template <class _Tp, class _Allocator, class... _Args>
52inline _LIBCPP_HIDE_FROM_ABI void
53__user_alloc_construct_impl(integral_constant<int, 0>, _Tp* __storage, const _Allocator&, _Args&&... __args) {
54  new (__storage) _Tp(std::forward<_Args>(__args)...);
55}
56
57// FIXME: This should have a version which takes a non-const alloc.
58template <class _Tp, class _Allocator, class... _Args>
59inline _LIBCPP_HIDE_FROM_ABI void
60__user_alloc_construct_impl(integral_constant<int, 1>, _Tp* __storage, const _Allocator& __a, _Args&&... __args) {
61  new (__storage) _Tp(allocator_arg, __a, std::forward<_Args>(__args)...);
62}
63
64// FIXME: This should have a version which takes a non-const alloc.
65template <class _Tp, class _Allocator, class... _Args>
66inline _LIBCPP_HIDE_FROM_ABI void
67__user_alloc_construct_impl(integral_constant<int, 2>, _Tp* __storage, const _Allocator& __a, _Args&&... __args) {
68  new (__storage) _Tp(std::forward<_Args>(__args)..., __a);
69}
70
71#endif // _LIBCPP_CXX03_LANG
72
73_LIBCPP_END_NAMESPACE_STD
74
75#endif // _LIBCPP___FUNCTIONAL_ALLOCATOR_ARG_T_H
76