aboutsummaryrefslogtreecommitdiff
path: root/libcxx/include/__memory/pointer_traits.h
blob: d5442b84e2aaea8b525f45c707e5f69ce1501a2a (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP___MEMORY_POINTER_TRAITS_H
#define _LIBCPP___MEMORY_POINTER_TRAITS_H

#include <__config>
#include <__memory/addressof.h>
#include <type_traits>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif

_LIBCPP_PUSH_MACROS
#include <__undef_macros>

_LIBCPP_BEGIN_NAMESPACE_STD

template <class _Tp, class = void>
struct __has_element_type : false_type {};

template <class _Tp>
struct __has_element_type<_Tp,
              typename __void_t<typename _Tp::element_type>::type> : true_type {};

template <class _Ptr, bool = __has_element_type<_Ptr>::value>
struct __pointer_traits_element_type;

template <class _Ptr>
struct __pointer_traits_element_type<_Ptr, true>
{
    typedef _LIBCPP_NODEBUG_TYPE typename _Ptr::element_type type;
};

template <template <class, class...> class _Sp, class _Tp, class ..._Args>
struct __pointer_traits_element_type<_Sp<_Tp, _Args...>, true>
{
    typedef _LIBCPP_NODEBUG_TYPE typename _Sp<_Tp, _Args...>::element_type type;
};

template <template <class, class...> class _Sp, class _Tp, class ..._Args>
struct __pointer_traits_element_type<_Sp<_Tp, _Args...>, false>
{
    typedef _LIBCPP_NODEBUG_TYPE _Tp type;
};

template <class _Tp, class = void>
struct __has_difference_type : false_type {};

template <class _Tp>
struct __has_difference_type<_Tp,
            typename __void_t<typename _Tp::difference_type>::type> : true_type {};

template <class _Ptr, bool = __has_difference_type<_Ptr>::value>
struct __pointer_traits_difference_type
{
    typedef _LIBCPP_NODEBUG_TYPE ptrdiff_t type;
};

template <class _Ptr>
struct __pointer_traits_difference_type<_Ptr, true>
{
    typedef _LIBCPP_NODEBUG_TYPE typename _Ptr::difference_type type;
};

template <class _Tp, class _Up>
struct __has_rebind
{
private:
    struct __two {char __lx; char __lxx;};
    template <class _Xp> static __two __test(...);
    _LIBCPP_SUPPRESS_DEPRECATED_PUSH
    template <class _Xp> static char __test(typename _Xp::template rebind<_Up>* = 0);
    _LIBCPP_SUPPRESS_DEPRECATED_POP
public:
    static const bool value = sizeof(__test<_Tp>(0)) == 1;
};

template <class _Tp, class _Up, bool = __has_rebind<_Tp, _Up>::value>
struct __pointer_traits_rebind
{
#ifndef _LIBCPP_CXX03_LANG
    typedef _LIBCPP_NODEBUG_TYPE typename _Tp::template rebind<_Up> type;
#else
    typedef _LIBCPP_NODEBUG_TYPE typename _Tp::template rebind<_Up>::other type;
#endif
};

template <template <class, class...> class _Sp, class _Tp, class ..._Args, class _Up>
struct __pointer_traits_rebind<_Sp<_Tp, _Args...>, _Up, true>
{
#ifndef _LIBCPP_CXX03_LANG
    typedef _LIBCPP_NODEBUG_TYPE typename _Sp<_Tp, _Args...>::template rebind<_Up> type;
#else
    typedef _LIBCPP_NODEBUG_TYPE typename _Sp<_Tp, _Args...>::template rebind<_Up>::other type;
#endif
};

template <template <class, class...> class _Sp, class _Tp, class ..._Args, class _Up>
struct __pointer_traits_rebind<_Sp<_Tp, _Args...>, _Up, false>
{
    typedef _Sp<_Up, _Args...> type;
};

template <class _Ptr>
struct _LIBCPP_TEMPLATE_VIS pointer_traits
{
    typedef _Ptr                                                     pointer;
    typedef typename __pointer_traits_element_type<pointer>::type    element_type;
    typedef typename __pointer_traits_difference_type<pointer>::type difference_type;

#ifndef _LIBCPP_CXX03_LANG
    template <class _Up> using rebind = typename __pointer_traits_rebind<pointer, _Up>::type;
#else
    template <class _Up> struct rebind
        {typedef typename __pointer_traits_rebind<pointer, _Up>::type other;};
#endif // _LIBCPP_CXX03_LANG

private:
    struct __nat {};
public:
    _LIBCPP_INLINE_VISIBILITY
    static pointer pointer_to(typename conditional<is_void<element_type>::value,
                                           __nat, element_type>::type& __r)
        {return pointer::pointer_to(__r);}
};

template <class _Tp>
struct _LIBCPP_TEMPLATE_VIS pointer_traits<_Tp*>
{
    typedef _Tp*      pointer;
    typedef _Tp       element_type;
    typedef ptrdiff_t difference_type;

#ifndef _LIBCPP_CXX03_LANG
    template <class _Up> using rebind = _Up*;
#else
    template <class _Up> struct rebind {typedef _Up* other;};
#endif

private:
    struct __nat {};
public:
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
    static pointer pointer_to(typename conditional<is_void<element_type>::value,
                                      __nat, element_type>::type& __r) _NOEXCEPT
        {return _VSTD::addressof(__r);}
};

template <class _From, class _To>
struct __rebind_pointer {
#ifndef _LIBCPP_CXX03_LANG
    typedef typename pointer_traits<_From>::template rebind<_To>        type;
#else
    typedef typename pointer_traits<_From>::template rebind<_To>::other type;
#endif
};

// to_address

template <class _Pointer, class = void>
struct __to_address_helper;

template <class _Tp>
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
_Tp* __to_address(_Tp* __p) _NOEXCEPT {
    static_assert(!is_function<_Tp>::value, "_Tp is a function type");
    return __p;
}

// enable_if is needed here to avoid instantiating checks for fancy pointers on raw pointers
template <class _Pointer, class = _EnableIf<!is_pointer<_Pointer>::value> >
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
typename decay<decltype(__to_address_helper<_Pointer>::__call(declval<const _Pointer&>()))>::type
__to_address(const _Pointer& __p) _NOEXCEPT {
    return __to_address_helper<_Pointer>::__call(__p);
}

template <class _Pointer, class>
struct __to_address_helper {
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
    static decltype(_VSTD::__to_address(declval<const _Pointer&>().operator->()))
    __call(const _Pointer&__p) _NOEXCEPT {
        return _VSTD::__to_address(__p.operator->());
    }
};

template <class _Pointer>
struct __to_address_helper<_Pointer, decltype((void)pointer_traits<_Pointer>::to_address(declval<const _Pointer&>()))> {
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
    static decltype(pointer_traits<_Pointer>::to_address(declval<const _Pointer&>()))
    __call(const _Pointer&__p) _NOEXCEPT {
        return pointer_traits<_Pointer>::to_address(__p);
    }
};

#if _LIBCPP_STD_VER > 17
template <class _Pointer>
inline _LIBCPP_INLINE_VISIBILITY constexpr
auto to_address(const _Pointer& __p) noexcept {
    return _VSTD::__to_address(__p);
}
#endif

_LIBCPP_END_NAMESPACE_STD

_LIBCPP_POP_MACROS

#endif // _LIBCPP___MEMORY_POINTER_TRAITS_H