aboutsummaryrefslogtreecommitdiff
path: root/contrib/llvm-project/libcxx/include/__ranges/common_view.h
blob: 4b5b04c9894b5a9fea300bcda026c77d8738c6be (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
// -*- 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___RANGES_COMMON_VIEW_H
#define _LIBCPP___RANGES_COMMON_VIEW_H

#include <__concepts/constructible.h>
#include <__concepts/copyable.h>
#include <__config>
#include <__iterator/common_iterator.h>
#include <__iterator/iterator_traits.h>
#include <__ranges/access.h>
#include <__ranges/all.h>
#include <__ranges/concepts.h>
#include <__ranges/enable_borrowed_range.h>
#include <__ranges/range_adaptor.h>
#include <__ranges/size.h>
#include <__ranges/view_interface.h>
#include <__utility/forward.h>
#include <__utility/move.h>

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

_LIBCPP_PUSH_MACROS
#include <__undef_macros>

_LIBCPP_BEGIN_NAMESPACE_STD

#if _LIBCPP_STD_VER >= 20

namespace ranges {

template <view _View>
  requires(!common_range<_View> && copyable<iterator_t<_View>>)
class common_view : public view_interface<common_view<_View>> {
  _View __base_ = _View();

public:
  _LIBCPP_HIDE_FROM_ABI common_view()
    requires default_initializable<_View>
  = default;

  _LIBCPP_HIDE_FROM_ABI constexpr explicit common_view(_View __v) : __base_(std::move(__v)) {}

  _LIBCPP_HIDE_FROM_ABI constexpr _View base() const&
    requires copy_constructible<_View>
  {
    return __base_;
  }

  _LIBCPP_HIDE_FROM_ABI constexpr _View base() && { return std::move(__base_); }

  _LIBCPP_HIDE_FROM_ABI constexpr auto begin() {
    if constexpr (random_access_range<_View> && sized_range<_View>)
      return ranges::begin(__base_);
    else
      return common_iterator<iterator_t<_View>, sentinel_t<_View>>(ranges::begin(__base_));
  }

  _LIBCPP_HIDE_FROM_ABI constexpr auto begin() const
    requires range<const _View>
  {
    if constexpr (random_access_range<const _View> && sized_range<const _View>)
      return ranges::begin(__base_);
    else
      return common_iterator<iterator_t<const _View>, sentinel_t<const _View>>(ranges::begin(__base_));
  }

  _LIBCPP_HIDE_FROM_ABI constexpr auto end() {
    if constexpr (random_access_range<_View> && sized_range<_View>)
      return ranges::begin(__base_) + ranges::size(__base_);
    else
      return common_iterator<iterator_t<_View>, sentinel_t<_View>>(ranges::end(__base_));
  }

  _LIBCPP_HIDE_FROM_ABI constexpr auto end() const
    requires range<const _View>
  {
    if constexpr (random_access_range<const _View> && sized_range<const _View>)
      return ranges::begin(__base_) + ranges::size(__base_);
    else
      return common_iterator<iterator_t<const _View>, sentinel_t<const _View>>(ranges::end(__base_));
  }

  _LIBCPP_HIDE_FROM_ABI constexpr auto size()
    requires sized_range<_View>
  {
    return ranges::size(__base_);
  }

  _LIBCPP_HIDE_FROM_ABI constexpr auto size() const
    requires sized_range<const _View>
  {
    return ranges::size(__base_);
  }
};

template <class _Range>
common_view(_Range&&) -> common_view<views::all_t<_Range>>;

template <class _View>
inline constexpr bool enable_borrowed_range<common_view<_View>> = enable_borrowed_range<_View>;

namespace views {
namespace __common {
struct __fn : __range_adaptor_closure<__fn> {
  template <class _Range>
    requires common_range<_Range>
  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Range&& __range) const
      noexcept(noexcept(views::all(std::forward<_Range>(__range))))
          -> decltype(views::all(std::forward<_Range>(__range))) {
    return views::all(std::forward<_Range>(__range));
  }

  template <class _Range>
  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Range&& __range) const
      noexcept(noexcept(common_view{std::forward<_Range>(__range)}))
          -> decltype(common_view{std::forward<_Range>(__range)}) {
    return common_view{std::forward<_Range>(__range)};
  }
};
} // namespace __common

inline namespace __cpo {
inline constexpr auto common = __common::__fn{};
} // namespace __cpo
} // namespace views
} // namespace ranges

#endif // _LIBCPP_STD_VER >= 20

_LIBCPP_END_NAMESPACE_STD

_LIBCPP_POP_MACROS

#endif // _LIBCPP___RANGES_COMMON_VIEW_H