1// Uses-allocator Construction -*- C++ -*-
2
3// Copyright (C) 2010-2018 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library. This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14// GNU General Public License for more details.
15
16// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23// <http://www.gnu.org/licenses/>.
24
25#ifndef _USES_ALLOCATOR_H
26#define _USES_ALLOCATOR_H 1
27
28#if __cplusplus < 201103L
29# include <bits/c++0x_warning.h>
30#else
31
32#include <type_traits>
33#include <bits/move.h>
34
35namespace std _GLIBCXX_VISIBILITY(default)
36{
37_GLIBCXX_BEGIN_NAMESPACE_VERSION
38
39 struct __erased_type { };
40
41 template<typename _Alloc, typename _Tp>
42 using __is_erased_or_convertible
43 = __or_<is_same<_Tp, __erased_type>, is_convertible<_Alloc, _Tp>>;
44
45 /// [allocator.tag]
46 struct allocator_arg_t { explicit allocator_arg_t() = default; };
47
48 _GLIBCXX17_INLINE constexpr allocator_arg_t allocator_arg =
49 allocator_arg_t();
50
51 template<typename _Tp, typename _Alloc, typename = __void_t<>>
52 struct __uses_allocator_helper
53 : false_type { };
54
55 template<typename _Tp, typename _Alloc>
56 struct __uses_allocator_helper<_Tp, _Alloc,
57 __void_t<typename _Tp::allocator_type>>
58 : __is_erased_or_convertible<_Alloc, typename _Tp::allocator_type>::type
59 { };
60
61 /// [allocator.uses.trait]
62 template<typename _Tp, typename _Alloc>
63 struct uses_allocator
64 : __uses_allocator_helper<_Tp, _Alloc>::type
65 { };
66
67 struct __uses_alloc_base { };
68
69 struct __uses_alloc0 : __uses_alloc_base
70 {
71 struct _Sink { void operator=(const void*) { } } _M_a;
72 };
73
74 template<typename _Alloc>
75 struct __uses_alloc1 : __uses_alloc_base { const _Alloc* _M_a; };
76
77 template<typename _Alloc>
78 struct __uses_alloc2 : __uses_alloc_base { const _Alloc* _M_a; };
79
80 template<bool, typename _Tp, typename _Alloc, typename... _Args>
81 struct __uses_alloc;
82
83 template<typename _Tp, typename _Alloc, typename... _Args>
84 struct __uses_alloc<true, _Tp, _Alloc, _Args...>
85 : conditional<
86 is_constructible<_Tp, allocator_arg_t, _Alloc, _Args...>::value,
87 __uses_alloc1<_Alloc>,
88 __uses_alloc2<_Alloc>>::type
89 {
90 static_assert(__or_<
91 is_constructible<_Tp, allocator_arg_t, _Alloc, _Args...>,
92 is_constructible<_Tp, _Args..., _Alloc>>::value, "construction with"
93 " an allocator must be possible if uses_allocator is true");
94 };
95
96 template<typename _Tp, typename _Alloc, typename... _Args>
97 struct __uses_alloc<false, _Tp, _Alloc, _Args...>
98 : __uses_alloc0 { };
99
100 template<typename _Tp, typename _Alloc, typename... _Args>
101 using __uses_alloc_t =
102 __uses_alloc<uses_allocator<_Tp, _Alloc>::value, _Tp, _Alloc, _Args...>;
103
104 template<typename _Tp, typename _Alloc, typename... _Args>
105 inline __uses_alloc_t<_Tp, _Alloc, _Args...>
106 __use_alloc(const _Alloc& __a)
107 {
108 __uses_alloc_t<_Tp, _Alloc, _Args...> __ret;
109 __ret._M_a = std::__addressof(__a);
110 return __ret;
111 }
112
113 template<typename _Tp, typename _Alloc, typename... _Args>
114 void
115 __use_alloc(const _Alloc&&) = delete;
116
117#if __cplusplus > 201402L
118 template <typename _Tp, typename _Alloc>
119 inline constexpr bool uses_allocator_v =
120 uses_allocator<_Tp, _Alloc>::value;
121#endif // C++17
122
123 template<template<typename...> class _Predicate,
124 typename _Tp, typename _Alloc, typename... _Args>
125 struct __is_uses_allocator_predicate
126 : conditional<uses_allocator<_Tp, _Alloc>::value,
127 __or_<_Predicate<_Tp, allocator_arg_t, _Alloc, _Args...>,
128 _Predicate<_Tp, _Args..., _Alloc>>,
129 _Predicate<_Tp, _Args...>>::type { };
130
131 template<typename _Tp, typename _Alloc, typename... _Args>
132 struct __is_uses_allocator_constructible
133 : __is_uses_allocator_predicate<is_constructible, _Tp, _Alloc, _Args...>
134 { };
135
136#if __cplusplus >= 201402L
137 template<typename _Tp, typename _Alloc, typename... _Args>
138 _GLIBCXX17_INLINE constexpr bool __is_uses_allocator_constructible_v =
139 __is_uses_allocator_constructible<_Tp, _Alloc, _Args...>::value;
140#endif // C++14
141
142 template<typename _Tp, typename _Alloc, typename... _Args>
143 struct __is_nothrow_uses_allocator_constructible
144 : __is_uses_allocator_predicate<is_nothrow_constructible,
145 _Tp, _Alloc, _Args...>
146 { };
147
148
149#if __cplusplus >= 201402L
150 template<typename _Tp, typename _Alloc, typename... _Args>
151 _GLIBCXX17_INLINE constexpr bool
152 __is_nothrow_uses_allocator_constructible_v =
153 __is_nothrow_uses_allocator_constructible<_Tp, _Alloc, _Args...>::value;
154#endif // C++14
155
156 template<typename _Tp, typename... _Args>
157 void __uses_allocator_construct_impl(__uses_alloc0 __a, _Tp* __ptr,
158 _Args&&... __args)
159 { ::new ((void*)__ptr) _Tp(std::forward<_Args>(__args)...); }
160
161 template<typename _Tp, typename _Alloc, typename... _Args>
162 void __uses_allocator_construct_impl(__uses_alloc1<_Alloc> __a, _Tp* __ptr,
163 _Args&&... __args)
164 {
165 ::new ((void*)__ptr) _Tp(allocator_arg, *__a._M_a,
166 std::forward<_Args>(__args)...);
167 }
168
169 template<typename _Tp, typename _Alloc, typename... _Args>
170 void __uses_allocator_construct_impl(__uses_alloc2<_Alloc> __a, _Tp* __ptr,
171 _Args&&... __args)
172 { ::new ((void*)__ptr) _Tp(std::forward<_Args>(__args)..., *__a._M_a); }
173
174 template<typename _Tp, typename _Alloc, typename... _Args>
175 void __uses_allocator_construct(const _Alloc& __a, _Tp* __ptr,
176 _Args&&... __args)
177 {
178 __uses_allocator_construct_impl(__use_alloc<_Tp, _Alloc, _Args...>(__a),
179 __ptr, std::forward<_Args>(__args)...);
180 }
181
182_GLIBCXX_END_NAMESPACE_VERSION
183} // namespace std
184
185#endif
186#endif
187