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_ZIP_TRANSFORM_VIEW_H
11#define _LIBCPP___RANGES_ZIP_TRANSFORM_VIEW_H
12
13#include <__config>
14
15#include <__concepts/constructible.h>
16#include <__concepts/convertible_to.h>
17#include <__concepts/derived_from.h>
18#include <__concepts/equality_comparable.h>
19#include <__concepts/invocable.h>
20#include <__concepts/referenceable.h>
21#include <__functional/invoke.h>
22#include <__iterator/concepts.h>
23#include <__iterator/incrementable_traits.h>
24#include <__iterator/iterator_traits.h>
25#include <__memory/addressof.h>
26#include <__ranges/access.h>
27#include <__ranges/all.h>
28#include <__ranges/concepts.h>
29#include <__ranges/empty_view.h>
30#include <__ranges/movable_box.h>
31#include <__ranges/view_interface.h>
32#include <__ranges/zip_view.h>
33#include <__type_traits/decay.h>
34#include <__type_traits/invoke.h>
35#include <__type_traits/is_object.h>
36#include <__type_traits/is_reference.h>
37#include <__type_traits/maybe_const.h>
38#include <__type_traits/remove_cvref.h>
39#include <__utility/forward.h>
40#include <__utility/in_place.h>
41#include <__utility/move.h>
42#include <tuple> // for std::apply
43
44#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
45# pragma GCC system_header
46#endif
47
48_LIBCPP_PUSH_MACROS
49#include <__undef_macros>
50
51#if _LIBCPP_STD_VER >= 23
52
53_LIBCPP_BEGIN_NAMESPACE_STD
54
55namespace ranges {
56
57template <move_constructible _Fn, input_range... _Views>
58 requires(view<_Views> && ...) &&
59 (sizeof...(_Views) > 0) && is_object_v<_Fn> && regular_invocable<_Fn&, range_reference_t<_Views>...> &&
60 __referenceable<invoke_result_t<_Fn&, range_reference_t<_Views>...>>
61class zip_transform_view : public view_interface<zip_transform_view<_Fn, _Views...>> {
62 _LIBCPP_NO_UNIQUE_ADDRESS zip_view<_Views...> __zip_;
63 _LIBCPP_NO_UNIQUE_ADDRESS __movable_box<_Fn> __fun_;
64
65 using _InnerView _LIBCPP_NODEBUG = zip_view<_Views...>;
66 template <bool _Const>
67 using __ziperator _LIBCPP_NODEBUG = iterator_t<__maybe_const<_Const, _InnerView>>;
68 template <bool _Const>
69 using __zentinel _LIBCPP_NODEBUG = sentinel_t<__maybe_const<_Const, _InnerView>>;
70
71 template <bool>
72 class __iterator;
73
74 template <bool>
75 class __sentinel;
76
77public:
78 _LIBCPP_HIDE_FROM_ABI zip_transform_view() = default;
79
80 _LIBCPP_HIDE_FROM_ABI constexpr explicit zip_transform_view(_Fn __fun, _Views... __views)
81 : __zip_(std::move(__views)...), __fun_(in_place, std::move(__fun)) {}
82
83 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto begin() { return __iterator<false>(*this, __zip_.begin()); }
84
85 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto begin() const
86 requires range<const _InnerView> && regular_invocable<const _Fn&, range_reference_t<const _Views>...>
87 {
88 return __iterator<true>(*this, __zip_.begin());
89 }
90
91 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto end() {
92 if constexpr (common_range<_InnerView>) {
93 return __iterator<false>(*this, __zip_.end());
94 } else {
95 return __sentinel<false>(__zip_.end());
96 }
97 }
98
99 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto end() const
100 requires range<const _InnerView> && regular_invocable<const _Fn&, range_reference_t<const _Views>...>
101 {
102 if constexpr (common_range<const _InnerView>) {
103 return __iterator<true>(*this, __zip_.end());
104 } else {
105 return __sentinel<true>(__zip_.end());
106 }
107 }
108
109 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto size()
110 requires sized_range<_InnerView>
111 {
112 return __zip_.size();
113 }
114
115 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto size() const
116 requires sized_range<const _InnerView>
117 {
118 return __zip_.size();
119 }
120};
121
122template <class _Fn, class... _Ranges>
123zip_transform_view(_Fn, _Ranges&&...) -> zip_transform_view<_Fn, views::all_t<_Ranges>...>;
124
125template <bool _Const, class _Fn, class... _Views>
126struct __zip_transform_iterator_category_base {};
127
128template <bool _Const, class _Fn, class... _Views>
129 requires forward_range<__maybe_const<_Const, zip_view<_Views...>>>
130struct __zip_transform_iterator_category_base<_Const, _Fn, _Views...> {
131private:
132 template <class _View>
133 using __tag _LIBCPP_NODEBUG = typename iterator_traits<iterator_t<__maybe_const<_Const, _View>>>::iterator_category;
134
135 static consteval auto __get_iterator_category() {
136 if constexpr (!is_reference_v<invoke_result_t<__maybe_const<_Const, _Fn>&,
137 range_reference_t<__maybe_const<_Const, _Views>>...>>) {
138 return input_iterator_tag();
139 } else if constexpr ((derived_from<__tag<_Views>, random_access_iterator_tag> && ...)) {
140 return random_access_iterator_tag();
141 } else if constexpr ((derived_from<__tag<_Views>, bidirectional_iterator_tag> && ...)) {
142 return bidirectional_iterator_tag();
143 } else if constexpr ((derived_from<__tag<_Views>, forward_iterator_tag> && ...)) {
144 return forward_iterator_tag();
145 } else {
146 return input_iterator_tag();
147 }
148 }
149
150public:
151 using iterator_category = decltype(__get_iterator_category());
152};
153
154template <move_constructible _Fn, input_range... _Views>
155 requires(view<_Views> && ...) &&
156 (sizeof...(_Views) > 0) && is_object_v<_Fn> && regular_invocable<_Fn&, range_reference_t<_Views>...> &&
157 __referenceable<invoke_result_t<_Fn&, range_reference_t<_Views>...>>
158template <bool _Const>
159class zip_transform_view<_Fn, _Views...>::__iterator
160 : public __zip_transform_iterator_category_base<_Const, _Fn, _Views...> {
161 using _Parent _LIBCPP_NODEBUG = __maybe_const<_Const, zip_transform_view>;
162 using _Base _LIBCPP_NODEBUG = __maybe_const<_Const, _InnerView>;
163
164 friend zip_transform_view<_Fn, _Views...>;
165
166 _Parent* __parent_ = nullptr;
167 __ziperator<_Const> __inner_;
168
169 _LIBCPP_HIDE_FROM_ABI constexpr __iterator(_Parent& __parent, __ziperator<_Const> __inner)
170 : __parent_(std::addressof(__parent)), __inner_(std::move(__inner)) {}
171
172 _LIBCPP_HIDE_FROM_ABI constexpr auto __get_deref_and_invoke() const noexcept {
173 return [&__fun = *__parent_->__fun_](const auto&... __iters) noexcept(noexcept(std::invoke(
174 *__parent_->__fun_, *__iters...))) -> decltype(auto) { return std::invoke(__fun, *__iters...); };
175 }
176
177public:
178 using iterator_concept = typename __ziperator<_Const>::iterator_concept;
179 using value_type =
180 remove_cvref_t<invoke_result_t<__maybe_const<_Const, _Fn>&, range_reference_t<__maybe_const<_Const, _Views>>...>>;
181 using difference_type = range_difference_t<_Base>;
182
183 _LIBCPP_HIDE_FROM_ABI __iterator() = default;
184 _LIBCPP_HIDE_FROM_ABI constexpr __iterator(__iterator<!_Const> __i)
185 requires _Const && convertible_to<__ziperator<false>, __ziperator<_Const>>
186 : __parent_(__i.__parent_), __inner_(std::move(__i.__inner_)) {}
187
188 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator*() const
189 noexcept(noexcept(std::apply(__get_deref_and_invoke(), __zip_view_iterator_access::__get_underlying(__inner_)))) {
190 return std::apply(__get_deref_and_invoke(), __zip_view_iterator_access::__get_underlying(__inner_));
191 }
192
193 _LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator++() {
194 ++__inner_;
195 return *this;
196 }
197
198 _LIBCPP_HIDE_FROM_ABI constexpr void operator++(int) { ++*this; }
199
200 _LIBCPP_HIDE_FROM_ABI constexpr __iterator operator++(int)
201 requires forward_range<_Base>
202 {
203 auto __tmp = *this;
204 ++*this;
205 return __tmp;
206 }
207
208 _LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator--()
209 requires bidirectional_range<_Base>
210 {
211 --__inner_;
212 return *this;
213 }
214
215 _LIBCPP_HIDE_FROM_ABI constexpr __iterator operator--(int)
216 requires bidirectional_range<_Base>
217 {
218 auto __tmp = *this;
219 --*this;
220 return __tmp;
221 }
222
223 _LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator+=(difference_type __x)
224 requires random_access_range<_Base>
225 {
226 __inner_ += __x;
227 return *this;
228 }
229
230 _LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator-=(difference_type __x)
231 requires random_access_range<_Base>
232 {
233 __inner_ -= __x;
234 return *this;
235 }
236
237 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator[](difference_type __n) const
238 requires random_access_range<_Base>
239 {
240 return std::apply(
241 [&]<class... _Is>(const _Is&... __iters) -> decltype(auto) {
242 return std::invoke(*__parent_->__fun_, __iters[iter_difference_t<_Is>(__n)]...);
243 },
244 __zip_view_iterator_access::__get_underlying(__inner_));
245 }
246
247 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const __iterator& __x, const __iterator& __y)
248 requires equality_comparable<__ziperator<_Const>>
249 {
250 return __x.__inner_ == __y.__inner_;
251 }
252
253 _LIBCPP_HIDE_FROM_ABI friend constexpr auto operator<=>(const __iterator& __x, const __iterator& __y)
254 requires random_access_range<_Base>
255 {
256 return __x.__inner_ <=> __y.__inner_;
257 }
258
259 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI friend constexpr __iterator operator+(const __iterator& __i, difference_type __n)
260 requires random_access_range<_Base>
261 {
262 return __iterator(*__i.__parent_, __i.__inner_ + __n);
263 }
264
265 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI friend constexpr __iterator operator+(difference_type __n, const __iterator& __i)
266 requires random_access_range<_Base>
267 {
268 return __iterator(*__i.__parent_, __i.__inner_ + __n);
269 }
270
271 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI friend constexpr __iterator operator-(const __iterator& __i, difference_type __n)
272 requires random_access_range<_Base>
273 {
274 return __iterator(*__i.__parent_, __i.__inner_ - __n);
275 }
276
277 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI friend constexpr difference_type
278 operator-(const __iterator& __x, const __iterator& __y)
279 requires sized_sentinel_for<__ziperator<_Const>, __ziperator<_Const>>
280 {
281 return __x.__inner_ - __y.__inner_;
282 }
283};
284
285template <move_constructible _Fn, input_range... _Views>
286 requires(view<_Views> && ...) &&
287 (sizeof...(_Views) > 0) && is_object_v<_Fn> && regular_invocable<_Fn&, range_reference_t<_Views>...> &&
288 __referenceable<invoke_result_t<_Fn&, range_reference_t<_Views>...>>
289template <bool _Const>
290class zip_transform_view<_Fn, _Views...>::__sentinel {
291 __zentinel<_Const> __inner_;
292
293 friend zip_transform_view<_Fn, _Views...>;
294
295 _LIBCPP_HIDE_FROM_ABI constexpr explicit __sentinel(__zentinel<_Const> __inner) : __inner_(__inner) {}
296
297public:
298 _LIBCPP_HIDE_FROM_ABI __sentinel() = default;
299
300 _LIBCPP_HIDE_FROM_ABI constexpr __sentinel(__sentinel<!_Const> __i)
301 requires _Const && convertible_to<__zentinel<false>, __zentinel<_Const>>
302 : __inner_(__i.__inner_) {}
303
304 template <bool _OtherConst>
305 requires sentinel_for<__zentinel<_Const>, __ziperator<_OtherConst>>
306 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const __iterator<_OtherConst>& __x, const __sentinel& __y) {
307 return __x.__inner_ == __y.__inner_;
308 }
309
310 template <bool _OtherConst>
311 requires sized_sentinel_for<__zentinel<_Const>, __ziperator<_OtherConst>>
312 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI friend constexpr range_difference_t<__maybe_const<_OtherConst, _InnerView>>
313 operator-(const __iterator<_OtherConst>& __x, const __sentinel& __y) {
314 return __x.__inner_ - __y.__inner_;
315 }
316
317 template <bool _OtherConst>
318 requires sized_sentinel_for<__zentinel<_Const>, __ziperator<_OtherConst>>
319 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI friend constexpr range_difference_t<__maybe_const<_OtherConst, _InnerView>>
320 operator-(const __sentinel& __x, const __iterator<_OtherConst>& __y) {
321 return __x.__inner_ - __y.__inner_;
322 }
323};
324
325namespace views {
326namespace __zip_transform {
327
328struct __fn {
329 template <class _Fn>
330 requires(move_constructible<decay_t<_Fn>> && regular_invocable<decay_t<_Fn>&> &&
331 is_object_v<invoke_result_t<decay_t<_Fn>&>>)
332 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Fn&&) const
333 noexcept(noexcept(auto(views::empty<decay_t<invoke_result_t<decay_t<_Fn>&>>>))) {
334 return views::empty<decay_t<invoke_result_t<decay_t<_Fn>&>>>;
335 }
336
337 template <class _Fn, class... _Ranges>
338 requires(sizeof...(_Ranges) > 0)
339 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Fn&& __fun, _Ranges&&... __rs) const
340 noexcept(noexcept(zip_transform_view(std::forward<_Fn>(__fun), std::forward<_Ranges>(__rs)...)))
341 -> decltype(zip_transform_view(std::forward<_Fn>(__fun), std::forward<_Ranges>(__rs)...)) {
342 return zip_transform_view(std::forward<_Fn>(__fun), std::forward<_Ranges>(__rs)...);
343 }
344};
345
346} // namespace __zip_transform
347inline namespace __cpo {
348inline constexpr auto zip_transform = __zip_transform::__fn{};
349} // namespace __cpo
350} // namespace views
351} // namespace ranges
352
353_LIBCPP_END_NAMESPACE_STD
354
355#endif // _LIBCPP_STD_VER >= 23
356
357_LIBCPP_POP_MACROS
358
359#endif // _LIBCPP___RANGES_ZIP_TRANSFORM_VIEW_H
360