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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___RANGES_TAKE_WHILE_VIEW_H
11#define _LIBCPP___RANGES_TAKE_WHILE_VIEW_H
12
13#include <__concepts/constructible.h>
14#include <__concepts/convertible_to.h>
15#include <__config>
16#include <__functional/bind_back.h>
17#include <__functional/invoke.h>
18#include <__iterator/concepts.h>
19#include <__memory/addressof.h>
20#include <__ranges/access.h>
21#include <__ranges/all.h>
22#include <__ranges/concepts.h>
23#include <__ranges/movable_box.h>
24#include <__ranges/range_adaptor.h>
25#include <__ranges/view_interface.h>
26#include <__type_traits/decay.h>
27#include <__type_traits/is_nothrow_constructible.h>
28#include <__type_traits/is_object.h>
29#include <__type_traits/maybe_const.h>
30#include <__utility/forward.h>
31#include <__utility/in_place.h>
32#include <__utility/move.h>
33
34#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
35# pragma GCC system_header
36#endif
37
38_LIBCPP_PUSH_MACROS
39#include <__undef_macros>
40
41_LIBCPP_BEGIN_NAMESPACE_STD
42
43#if _LIBCPP_STD_VER >= 20
44
45namespace ranges {
46
47template <view _View, class _Pred>
48 requires input_range<_View> && is_object_v<_Pred> && indirect_unary_predicate<const _Pred, iterator_t<_View>>
49class _LIBCPP_ABI_LLVM18_NO_UNIQUE_ADDRESS take_while_view : public view_interface<take_while_view<_View, _Pred>> {
50 template <bool>
51 class __sentinel;
52
53 _LIBCPP_NO_UNIQUE_ADDRESS _View __base_ = _View();
54 _LIBCPP_NO_UNIQUE_ADDRESS __movable_box<_Pred> __pred_;
55
56public:
57 _LIBCPP_HIDE_FROM_ABI take_while_view()
58 requires default_initializable<_View> && default_initializable<_Pred>
59 = default;
60
61 _LIBCPP_HIDE_FROM_ABI constexpr _LIBCPP_EXPLICIT_SINCE_CXX23 take_while_view(_View __base, _Pred __pred)
62 : __base_(std::move(__base)), __pred_(std::in_place, std::move(__pred)) {}
63
64 _LIBCPP_HIDE_FROM_ABI constexpr _View base() const&
65 requires copy_constructible<_View>
66 {
67 return __base_;
68 }
69
70 _LIBCPP_HIDE_FROM_ABI constexpr _View base() && { return std::move(__base_); }
71
72 _LIBCPP_HIDE_FROM_ABI constexpr const _Pred& pred() const { return *__pred_; }
73
74 _LIBCPP_HIDE_FROM_ABI constexpr auto begin()
75 requires(!__simple_view<_View>)
76 {
77 return ranges::begin(__base_);
78 }
79
80 _LIBCPP_HIDE_FROM_ABI constexpr auto begin() const
81 requires range<const _View> && indirect_unary_predicate<const _Pred, iterator_t<const _View>>
82 {
83 return ranges::begin(__base_);
84 }
85
86 _LIBCPP_HIDE_FROM_ABI constexpr auto end()
87 requires(!__simple_view<_View>)
88 {
89 return __sentinel</*_Const=*/false>(ranges::end(__base_), std::addressof(*__pred_));
90 }
91
92 _LIBCPP_HIDE_FROM_ABI constexpr auto end() const
93 requires range<const _View> && indirect_unary_predicate<const _Pred, iterator_t<const _View>>
94 {
95 return __sentinel</*_Const=*/true>(ranges::end(__base_), std::addressof(*__pred_));
96 }
97};
98
99template <class _Range, class _Pred>
100take_while_view(_Range&&, _Pred) -> take_while_view<views::all_t<_Range>, _Pred>;
101
102template <view _View, class _Pred>
103 requires input_range<_View> && is_object_v<_Pred> && indirect_unary_predicate<const _Pred, iterator_t<_View>>
104template <bool _Const>
105class take_while_view<_View, _Pred>::__sentinel {
106 using _Base _LIBCPP_NODEBUG = __maybe_const<_Const, _View>;
107
108 sentinel_t<_Base> __end_ = sentinel_t<_Base>();
109 const _Pred* __pred_ = nullptr;
110
111 friend class __sentinel<!_Const>;
112
113public:
114 _LIBCPP_HIDE_FROM_ABI __sentinel() = default;
115
116 _LIBCPP_HIDE_FROM_ABI constexpr explicit __sentinel(sentinel_t<_Base> __end, const _Pred* __pred)
117 : __end_(std::move(__end)), __pred_(__pred) {}
118
119 _LIBCPP_HIDE_FROM_ABI constexpr __sentinel(__sentinel<!_Const> __s)
120 requires _Const && convertible_to<sentinel_t<_View>, sentinel_t<_Base>>
121 : __end_(std::move(__s.__end_)), __pred_(__s.__pred_) {}
122
123 _LIBCPP_HIDE_FROM_ABI constexpr sentinel_t<_Base> base() const { return __end_; }
124
125 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const iterator_t<_Base>& __x, const __sentinel& __y) {
126 return __x == __y.__end_ || !std::invoke(*__y.__pred_, *__x);
127 }
128
129 template <bool _OtherConst = !_Const>
130 requires sentinel_for<sentinel_t<_Base>, iterator_t<__maybe_const<_OtherConst, _View>>>
131 _LIBCPP_HIDE_FROM_ABI friend constexpr bool
132 operator==(const iterator_t<__maybe_const<_OtherConst, _View>>& __x, const __sentinel& __y) {
133 return __x == __y.__end_ || !std::invoke(*__y.__pred_, *__x);
134 }
135};
136
137namespace views {
138namespace __take_while {
139
140struct __fn {
141 template <class _Range, class _Pred>
142 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Range&& __range, _Pred&& __pred) const
143 noexcept(noexcept(/**/ take_while_view(std::forward<_Range>(__range), std::forward<_Pred>(__pred))))
144 -> decltype(/*--*/ take_while_view(std::forward<_Range>(__range), std::forward<_Pred>(__pred))) {
145 return /*-------------*/ take_while_view(std::forward<_Range>(__range), std::forward<_Pred>(__pred));
146 }
147
148 template <class _Pred>
149 requires constructible_from<decay_t<_Pred>, _Pred>
150 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Pred&& __pred) const
151 noexcept(is_nothrow_constructible_v<decay_t<_Pred>, _Pred>) {
152 return __pipeable(std::__bind_back(*this, std::forward<_Pred>(__pred)));
153 }
154};
155
156} // namespace __take_while
157
158inline namespace __cpo {
159inline constexpr auto take_while = __take_while::__fn{};
160} // namespace __cpo
161} // namespace views
162} // namespace ranges
163
164#endif // _LIBCPP_STD_VER >= 20
165
166_LIBCPP_END_NAMESPACE_STD
167
168_LIBCPP_POP_MACROS
169
170#endif // _LIBCPP___RANGES_TAKE_WHILE_VIEW_H