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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___CXX03___MEMORY_POINTER_TRAITS_H
11#define _LIBCPP___CXX03___MEMORY_POINTER_TRAITS_H
12
13#include <__cxx03/__config>
14#include <__cxx03/__memory/addressof.h>
15#include <__cxx03/__type_traits/conditional.h>
16#include <__cxx03/__type_traits/conjunction.h>
17#include <__cxx03/__type_traits/decay.h>
18#include <__cxx03/__type_traits/is_class.h>
19#include <__cxx03/__type_traits/is_function.h>
20#include <__cxx03/__type_traits/is_void.h>
21#include <__cxx03/__type_traits/void_t.h>
22#include <__cxx03/__utility/declval.h>
23#include <__cxx03/__utility/forward.h>
24#include <__cxx03/cstddef>
25
26#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
27# pragma GCC system_header
28#endif
29
30_LIBCPP_PUSH_MACROS
31#include <__cxx03/__undef_macros>
32
33_LIBCPP_BEGIN_NAMESPACE_STD
34
35// clang-format off
36#define _LIBCPP_CLASS_TRAITS_HAS_XXX(NAME, PROPERTY) \
37 template <class _Tp, class = void> \
38 struct NAME : false_type {}; \
39 template <class _Tp> \
40 struct NAME<_Tp, __void_t<typename _Tp::PROPERTY> > : true_type {}
41// clang-format on
42
43_LIBCPP_CLASS_TRAITS_HAS_XXX(__has_pointer, pointer);
44_LIBCPP_CLASS_TRAITS_HAS_XXX(__has_element_type, element_type);
45
46template <class _Ptr, bool = __has_element_type<_Ptr>::value>
47struct __pointer_traits_element_type {};
48
49template <class _Ptr>
50struct __pointer_traits_element_type<_Ptr, true> {
51 typedef _LIBCPP_NODEBUG typename _Ptr::element_type type;
52};
53
54template <template <class, class...> class _Sp, class _Tp, class... _Args>
55struct __pointer_traits_element_type<_Sp<_Tp, _Args...>, true> {
56 typedef _LIBCPP_NODEBUG typename _Sp<_Tp, _Args...>::element_type type;
57};
58
59template <template <class, class...> class _Sp, class _Tp, class... _Args>
60struct __pointer_traits_element_type<_Sp<_Tp, _Args...>, false> {
61 typedef _LIBCPP_NODEBUG _Tp type;
62};
63
64template <class _Tp, class = void>
65struct __has_difference_type : false_type {};
66
67template <class _Tp>
68struct __has_difference_type<_Tp, __void_t<typename _Tp::difference_type> > : true_type {};
69
70template <class _Ptr, bool = __has_difference_type<_Ptr>::value>
71struct __pointer_traits_difference_type {
72 typedef _LIBCPP_NODEBUG ptrdiff_t type;
73};
74
75template <class _Ptr>
76struct __pointer_traits_difference_type<_Ptr, true> {
77 typedef _LIBCPP_NODEBUG typename _Ptr::difference_type type;
78};
79
80template <class _Tp, class _Up>
81struct __has_rebind {
82private:
83 template <class _Xp>
84 static false_type __test(...);
85 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
86 template <class _Xp>
87 static true_type __test(typename _Xp::template rebind<_Up>* = 0);
88 _LIBCPP_SUPPRESS_DEPRECATED_POP
89
90public:
91 static const bool value = decltype(__test<_Tp>(0))::value;
92};
93
94template <class _Tp, class _Up, bool = __has_rebind<_Tp, _Up>::value>
95struct __pointer_traits_rebind {
96 typedef _LIBCPP_NODEBUG typename _Tp::template rebind<_Up>::other type;
97};
98
99template <template <class, class...> class _Sp, class _Tp, class... _Args, class _Up>
100struct __pointer_traits_rebind<_Sp<_Tp, _Args...>, _Up, true> {
101 typedef _LIBCPP_NODEBUG typename _Sp<_Tp, _Args...>::template rebind<_Up>::other type;
102};
103
104template <template <class, class...> class _Sp, class _Tp, class... _Args, class _Up>
105struct __pointer_traits_rebind<_Sp<_Tp, _Args...>, _Up, false> {
106 typedef _Sp<_Up, _Args...> type;
107};
108
109template <class _Ptr, class = void>
110struct __pointer_traits_impl {};
111
112template <class _Ptr>
113struct __pointer_traits_impl<_Ptr, __void_t<typename __pointer_traits_element_type<_Ptr>::type> > {
114 typedef _Ptr pointer;
115 typedef typename __pointer_traits_element_type<pointer>::type element_type;
116 typedef typename __pointer_traits_difference_type<pointer>::type difference_type;
117
118 template <class _Up>
119 struct rebind {
120 typedef typename __pointer_traits_rebind<pointer, _Up>::type other;
121 };
122
123private:
124 struct __nat {};
125
126public:
127 _LIBCPP_HIDE_FROM_ABI static pointer
128 pointer_to(__conditional_t<is_void<element_type>::value, __nat, element_type>& __r) {
129 return pointer::pointer_to(__r);
130 }
131};
132
133template <class _Ptr>
134struct _LIBCPP_TEMPLATE_VIS pointer_traits : __pointer_traits_impl<_Ptr> {};
135
136template <class _Tp>
137struct _LIBCPP_TEMPLATE_VIS pointer_traits<_Tp*> {
138 typedef _Tp* pointer;
139 typedef _Tp element_type;
140 typedef ptrdiff_t difference_type;
141
142 template <class _Up>
143 struct rebind {
144 typedef _Up* other;
145 };
146
147private:
148 struct __nat {};
149
150public:
151 _LIBCPP_HIDE_FROM_ABI static pointer
152 pointer_to(__conditional_t<is_void<element_type>::value, __nat, element_type>& __r) _NOEXCEPT {
153 return std::addressof(__r);
154 }
155};
156
157template <class _From, class _To>
158using __rebind_pointer_t = typename pointer_traits<_From>::template rebind<_To>::other;
159
160// to_address
161
162template <class _Pointer, class = void>
163struct __to_address_helper;
164
165template <class _Tp>
166_LIBCPP_HIDE_FROM_ABI _Tp* __to_address(_Tp* __p) _NOEXCEPT {
167 static_assert(!is_function<_Tp>::value, "_Tp is a function type");
168 return __p;
169}
170
171template <class _Pointer, class = void>
172struct _HasToAddress : false_type {};
173
174template <class _Pointer>
175struct _HasToAddress<_Pointer, decltype((void)pointer_traits<_Pointer>::to_address(std::declval<const _Pointer&>())) >
176 : true_type {};
177
178template <class _Pointer, class = void>
179struct _HasArrow : false_type {};
180
181template <class _Pointer>
182struct _HasArrow<_Pointer, decltype((void)std::declval<const _Pointer&>().operator->()) > : true_type {};
183
184template <class _Pointer>
185struct _IsFancyPointer {
186 static const bool value = _HasArrow<_Pointer>::value || _HasToAddress<_Pointer>::value;
187};
188
189// enable_if is needed here to avoid instantiating checks for fancy pointers on raw pointers
190template <class _Pointer, __enable_if_t< _And<is_class<_Pointer>, _IsFancyPointer<_Pointer> >::value, int> = 0>
191_LIBCPP_HIDE_FROM_ABI __decay_t<decltype(__to_address_helper<_Pointer>::__call(std::declval<const _Pointer&>()))>
192__to_address(const _Pointer& __p) _NOEXCEPT {
193 return __to_address_helper<_Pointer>::__call(__p);
194}
195
196template <class _Pointer, class>
197struct __to_address_helper {
198 _LIBCPP_HIDE_FROM_ABI static decltype(std::__to_address(std::declval<const _Pointer&>().operator->()))
199 __call(const _Pointer& __p) _NOEXCEPT {
200 return std::__to_address(__p.operator->());
201 }
202};
203
204template <class _Pointer>
205struct __to_address_helper<_Pointer,
206 decltype((void)pointer_traits<_Pointer>::to_address(std::declval<const _Pointer&>()))> {
207 _LIBCPP_HIDE_FROM_ABI static decltype(pointer_traits<_Pointer>::to_address(std::declval<const _Pointer&>()))
208 __call(const _Pointer& __p) _NOEXCEPT {
209 return pointer_traits<_Pointer>::to_address(__p);
210 }
211};
212
213_LIBCPP_END_NAMESPACE_STD
214
215_LIBCPP_POP_MACROS
216
217#endif // _LIBCPP___CXX03___MEMORY_POINTER_TRAITS_H
218

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source code of libcxx/include/__cxx03/__memory/pointer_traits.h