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 { explicit allocator_arg_t() = default; };
27
28#if defined(_LIBCPP_CXX03_LANG) || defined(_LIBCPP_BUILDING_LIBRARY)
29extern _LIBCPP_EXPORTED_FROM_ABI const allocator_arg_t allocator_arg;
30#else
31/* inline */ constexpr allocator_arg_t allocator_arg = allocator_arg_t();
32#endif
33
34#ifndef _LIBCPP_CXX03_LANG
35
36// allocator construction
37
38template <class _Tp, class _Alloc, class ..._Args>
39struct __uses_alloc_ctor_imp
40{
41    typedef _LIBCPP_NODEBUG __remove_cvref_t<_Alloc> _RawAlloc;
42    static const bool __ua = uses_allocator<_Tp, _RawAlloc>::value;
43    static const bool __ic =
44        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
50    : integral_constant<int, __uses_alloc_ctor_imp<_Tp, _Alloc, _Args...>::value>
51    {};
52
53template <class _Tp, class _Allocator, class... _Args>
54inline _LIBCPP_INLINE_VISIBILITY
55void __user_alloc_construct_impl (integral_constant<int, 0>, _Tp *__storage, const _Allocator &, _Args &&... __args )
56{
57    new (__storage) _Tp (_VSTD::forward<_Args>(__args)...);
58}
59
60// FIXME: This should have a version which takes a non-const alloc.
61template <class _Tp, class _Allocator, class... _Args>
62inline _LIBCPP_INLINE_VISIBILITY
63void __user_alloc_construct_impl (integral_constant<int, 1>, _Tp *__storage, const _Allocator &__a, _Args &&... __args )
64{
65    new (__storage) _Tp (allocator_arg, __a, _VSTD::forward<_Args>(__args)...);
66}
67
68// FIXME: This should have a version which takes a non-const alloc.
69template <class _Tp, class _Allocator, class... _Args>
70inline _LIBCPP_INLINE_VISIBILITY
71void __user_alloc_construct_impl (integral_constant<int, 2>, _Tp *__storage, const _Allocator &__a, _Args &&... __args )
72{
73    new (__storage) _Tp (_VSTD::forward<_Args>(__args)..., __a);
74}
75
76#endif // _LIBCPP_CXX03_LANG
77
78_LIBCPP_END_NAMESPACE_STD
79
80#endif // _LIBCPP___FUNCTIONAL_ALLOCATOR_ARG_T_H
81