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
26 struct _LIBCPP_TEMPLATE_VIS allocator_arg_t {
27 explicit allocator_arg_t() = default;
28 };
29
30 #if _LIBCPP_STD_VER >= 17
31 inline constexpr allocator_arg_t allocator_arg = allocator_arg_t();
32 #elif !defined(_LIBCPP_CXX03_LANG)
33 constexpr allocator_arg_t allocator_arg = allocator_arg_t();
34 #endif
35
36 #ifndef _LIBCPP_CXX03_LANG
37
38 // allocator construction
39
40 template <class _Tp, class _Alloc, class... _Args>
41 struct __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
48 template <class _Tp, class _Alloc, class... _Args>
49 struct __uses_alloc_ctor : integral_constant<int, __uses_alloc_ctor_imp<_Tp, _Alloc, _Args...>::value> {};
50
51 template <class _Tp, class _Allocator, class... _Args>
52 inline _LIBCPP_HIDE_FROM_ABI void
__user_alloc_construct_impl(integral_constant<int,0>,_Tp * __storage,const _Allocator &,_Args &&...__args)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.
58 template <class _Tp, class _Allocator, class... _Args>
59 inline _LIBCPP_HIDE_FROM_ABI void
__user_alloc_construct_impl(integral_constant<int,1>,_Tp * __storage,const _Allocator & __a,_Args &&...__args)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.
65 template <class _Tp, class _Allocator, class... _Args>
66 inline _LIBCPP_HIDE_FROM_ABI void
__user_alloc_construct_impl(integral_constant<int,2>,_Tp * __storage,const _Allocator & __a,_Args &&...__args)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