master
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___RANGES_ACCESS_H
11#define _LIBCPP___RANGES_ACCESS_H
12
13#include <__concepts/class_or_enum.h>
14#include <__config>
15#include <__cstddef/size_t.h>
16#include <__iterator/concepts.h>
17#include <__iterator/readable_traits.h>
18#include <__ranges/enable_borrowed_range.h>
19#include <__type_traits/decay.h>
20#include <__type_traits/is_reference.h>
21#include <__type_traits/remove_cvref.h>
22#include <__type_traits/remove_reference.h>
23#include <__utility/auto_cast.h>
24#include <__utility/declval.h>
25
26#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
27# pragma GCC system_header
28#endif
29
30_LIBCPP_BEGIN_NAMESPACE_STD
31
32#if _LIBCPP_STD_VER >= 20
33
34namespace ranges {
35template <class _Tp>
36concept __can_borrow = is_lvalue_reference_v<_Tp> || enable_borrowed_range<remove_cvref_t<_Tp>>;
37} // namespace ranges
38
39// [range.access.begin]
40
41namespace ranges {
42namespace __begin {
43template <class _Tp>
44concept __member_begin = __can_borrow<_Tp> && requires(_Tp&& __t) {
45 { _LIBCPP_AUTO_CAST(__t.begin()) } -> input_or_output_iterator;
46};
47
48void begin() = delete;
49
50template <class _Tp>
51concept __unqualified_begin =
52 !__member_begin<_Tp> && __can_borrow<_Tp> && __class_or_enum<remove_cvref_t<_Tp>> && requires(_Tp&& __t) {
53 { _LIBCPP_AUTO_CAST(begin(__t)) } -> input_or_output_iterator;
54 };
55
56struct __fn {
57 template <class _Tp>
58 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp (&__t)[]) const noexcept
59 requires(sizeof(_Tp) >= 0) // Disallow incomplete element types.
60 {
61 return __t + 0;
62 }
63
64 template <class _Tp, size_t _Np>
65 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp (&__t)[_Np]) const noexcept
66 requires(sizeof(_Tp) >= 0) // Disallow incomplete element types.
67 {
68 return __t + 0;
69 }
70
71 template <class _Tp>
72 requires __member_begin<_Tp>
73 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
74 noexcept(noexcept(_LIBCPP_AUTO_CAST(__t.begin()))) {
75 return _LIBCPP_AUTO_CAST(__t.begin());
76 }
77
78 template <class _Tp>
79 requires __unqualified_begin<_Tp>
80 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
81 noexcept(noexcept(_LIBCPP_AUTO_CAST(begin(__t)))) {
82 return _LIBCPP_AUTO_CAST(begin(__t));
83 }
84
85 void operator()(auto&&) const = delete;
86};
87} // namespace __begin
88
89inline namespace __cpo {
90inline constexpr auto begin = __begin::__fn{};
91} // namespace __cpo
92} // namespace ranges
93
94// [range.range]
95
96namespace ranges {
97template <class _Tp>
98using iterator_t = decltype(ranges::begin(std::declval<_Tp&>()));
99} // namespace ranges
100
101// [range.access.end]
102
103namespace ranges {
104namespace __end {
105template <class _Tp>
106concept __member_end = __can_borrow<_Tp> && requires(_Tp&& __t) {
107 typename iterator_t<_Tp>;
108 { _LIBCPP_AUTO_CAST(__t.end()) } -> sentinel_for<iterator_t<_Tp>>;
109};
110
111void end() = delete;
112
113template <class _Tp>
114concept __unqualified_end =
115 !__member_end<_Tp> && __can_borrow<_Tp> && __class_or_enum<remove_cvref_t<_Tp>> && requires(_Tp&& __t) {
116 typename iterator_t<_Tp>;
117 { _LIBCPP_AUTO_CAST(end(__t)) } -> sentinel_for<iterator_t<_Tp>>;
118 };
119
120struct __fn {
121 template <class _Tp, size_t _Np>
122 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp (&__t)[_Np]) const noexcept
123 requires(sizeof(_Tp) >= 0) // Disallow incomplete element types.
124 {
125 return __t + _Np;
126 }
127
128 template <class _Tp>
129 requires __member_end<_Tp>
130 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
131 noexcept(noexcept(_LIBCPP_AUTO_CAST(__t.end()))) {
132 return _LIBCPP_AUTO_CAST(__t.end());
133 }
134
135 template <class _Tp>
136 requires __unqualified_end<_Tp>
137 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
138 noexcept(noexcept(_LIBCPP_AUTO_CAST(end(__t)))) {
139 return _LIBCPP_AUTO_CAST(end(__t));
140 }
141
142 void operator()(auto&&) const = delete;
143};
144} // namespace __end
145
146inline namespace __cpo {
147inline constexpr auto end = __end::__fn{};
148} // namespace __cpo
149} // namespace ranges
150
151// [range.access.cbegin]
152
153namespace ranges {
154namespace __cbegin {
155struct __fn {
156 template <class _Tp>
157 requires is_lvalue_reference_v<_Tp&&>
158 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
159 noexcept(noexcept(ranges::begin(static_cast<const remove_reference_t<_Tp>&>(__t))))
160 -> decltype(ranges::begin(static_cast<const remove_reference_t<_Tp>&>(__t))) {
161 return ranges::begin(static_cast<const remove_reference_t<_Tp>&>(__t));
162 }
163
164 template <class _Tp>
165 requires is_rvalue_reference_v<_Tp&&>
166 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
167 noexcept(noexcept(ranges::begin(static_cast<const _Tp&&>(__t))))
168 -> decltype(ranges::begin(static_cast<const _Tp&&>(__t))) {
169 return ranges::begin(static_cast<const _Tp&&>(__t));
170 }
171};
172} // namespace __cbegin
173
174inline namespace __cpo {
175inline constexpr auto cbegin = __cbegin::__fn{};
176} // namespace __cpo
177} // namespace ranges
178
179// [range.access.cend]
180
181namespace ranges {
182namespace __cend {
183struct __fn {
184 template <class _Tp>
185 requires is_lvalue_reference_v<_Tp&&>
186 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
187 noexcept(noexcept(ranges::end(static_cast<const remove_reference_t<_Tp>&>(__t))))
188 -> decltype(ranges::end(static_cast<const remove_reference_t<_Tp>&>(__t))) {
189 return ranges::end(static_cast<const remove_reference_t<_Tp>&>(__t));
190 }
191
192 template <class _Tp>
193 requires is_rvalue_reference_v<_Tp&&>
194 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const noexcept(
195 noexcept(ranges::end(static_cast<const _Tp&&>(__t)))) -> decltype(ranges::end(static_cast<const _Tp&&>(__t))) {
196 return ranges::end(static_cast<const _Tp&&>(__t));
197 }
198};
199} // namespace __cend
200
201inline namespace __cpo {
202inline constexpr auto cend = __cend::__fn{};
203} // namespace __cpo
204} // namespace ranges
205
206#endif // _LIBCPP_STD_VER >= 20
207
208_LIBCPP_END_NAMESPACE_STD
209
210#endif // _LIBCPP___RANGES_ACCESS_H