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_CONCEPTS_H
11#define _LIBCPP___RANGES_CONCEPTS_H
12
13#include <__concepts/constructible.h>
14#include <__concepts/movable.h>
15#include <__concepts/same_as.h>
16#include <__config>
17#include <__iterator/concepts.h>
18#include <__iterator/incrementable_traits.h>
19#include <__iterator/iter_move.h>
20#include <__iterator/iterator_traits.h>
21#include <__iterator/readable_traits.h>
22#include <__ranges/access.h>
23#include <__ranges/data.h>
24#include <__ranges/enable_borrowed_range.h>
25#include <__ranges/enable_view.h>
26#include <__ranges/size.h>
27#include <__type_traits/add_pointer.h>
28#include <__type_traits/is_reference.h>
29#include <__type_traits/remove_cvref.h>
30#include <__type_traits/remove_reference.h>
31#include <__utility/declval.h>
32#include <initializer_list>
33
34#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
35#  pragma GCC system_header
36#endif
37
38_LIBCPP_BEGIN_NAMESPACE_STD
39
40#if _LIBCPP_STD_VER >= 20
41
42namespace ranges {
43
44// [range.range]
45
46template <class _Tp>
47concept range = requires(_Tp& __t) {
48  ranges::begin(__t); // sometimes equality-preserving
49  ranges::end(__t);
50};
51
52template <class _Tp>
53concept input_range = range<_Tp> && input_iterator<iterator_t<_Tp>>;
54
55template <class _Range>
56concept borrowed_range =
57    range<_Range> && (is_lvalue_reference_v<_Range> || enable_borrowed_range<remove_cvref_t<_Range>>);
58
59// `iterator_t` defined in <__ranges/access.h>
60
61template <range _Rp>
62using sentinel_t = decltype(ranges::end(std::declval<_Rp&>()));
63
64template <range _Rp>
65using range_difference_t = iter_difference_t<iterator_t<_Rp>>;
66
67template <range _Rp>
68using range_value_t = iter_value_t<iterator_t<_Rp>>;
69
70template <range _Rp>
71using range_reference_t = iter_reference_t<iterator_t<_Rp>>;
72
73template <range _Rp>
74using range_rvalue_reference_t = iter_rvalue_reference_t<iterator_t<_Rp>>;
75
76template <range _Rp>
77using range_common_reference_t = iter_common_reference_t<iterator_t<_Rp>>;
78
79// [range.sized]
80template <class _Tp>
81concept sized_range = range<_Tp> && requires(_Tp& __t) { ranges::size(__t); };
82
83template <sized_range _Rp>
84using range_size_t = decltype(ranges::size(std::declval<_Rp&>()));
85
86// `disable_sized_range` defined in `<__ranges/size.h>`
87
88// [range.view], views
89
90// `enable_view` defined in <__ranges/enable_view.h>
91// `view_base` defined in <__ranges/enable_view.h>
92
93template <class _Tp>
94concept view = range<_Tp> && movable<_Tp> && enable_view<_Tp>;
95
96template <class _Range>
97concept __simple_view =
98    view<_Range> && range<const _Range> && same_as<iterator_t<_Range>, iterator_t<const _Range>> &&
99    same_as<sentinel_t<_Range>, sentinel_t<const _Range>>;
100
101// [range.refinements], other range refinements
102template <class _Rp, class _Tp>
103concept output_range = range<_Rp> && output_iterator<iterator_t<_Rp>, _Tp>;
104
105template <class _Tp>
106concept forward_range = input_range<_Tp> && forward_iterator<iterator_t<_Tp>>;
107
108template <class _Tp>
109concept bidirectional_range = forward_range<_Tp> && bidirectional_iterator<iterator_t<_Tp>>;
110
111template <class _Tp>
112concept random_access_range = bidirectional_range<_Tp> && random_access_iterator<iterator_t<_Tp>>;
113
114template <class _Tp>
115concept contiguous_range = random_access_range<_Tp> && contiguous_iterator<iterator_t<_Tp>> && requires(_Tp& __t) {
116  { ranges::data(__t) } -> same_as<add_pointer_t<range_reference_t<_Tp>>>;
117};
118
119template <class _Tp>
120concept common_range = range<_Tp> && same_as<iterator_t<_Tp>, sentinel_t<_Tp>>;
121
122template <class _Tp>
123inline constexpr bool __is_std_initializer_list = false;
124
125template <class _Ep>
126inline constexpr bool __is_std_initializer_list<initializer_list<_Ep>> = true;
127
128template <class _Tp>
129concept viewable_range =
130    range<_Tp> &&
131    ((view<remove_cvref_t<_Tp>> && constructible_from<remove_cvref_t<_Tp>, _Tp>) ||
132     (!view<remove_cvref_t<_Tp>> &&
133      (is_lvalue_reference_v<_Tp> ||
134       (movable<remove_reference_t<_Tp>> && !__is_std_initializer_list<remove_cvref_t<_Tp>>))));
135
136} // namespace ranges
137
138#endif // _LIBCPP_STD_VER >= 20
139
140_LIBCPP_END_NAMESPACE_STD
141
142#endif // _LIBCPP___RANGES_CONCEPTS_H
143