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_ADJACENT_TRANSFORM_VIEW_H
11#define _LIBCPP___RANGES_ADJACENT_TRANSFORM_VIEW_H
12
13#include <__config>
14
15#include <__algorithm/min.h>
16#include <__compare/three_way_comparable.h>
17#include <__concepts/constructible.h>
18#include <__concepts/convertible_to.h>
19#include <__concepts/derived_from.h>
20#include <__concepts/equality_comparable.h>
21#include <__concepts/invocable.h>
22#include <__cstddef/size_t.h>
23#include <__functional/bind_back.h>
24#include <__functional/invoke.h>
25#include <__functional/operations.h>
26#include <__iterator/concepts.h>
27#include <__iterator/incrementable_traits.h>
28#include <__iterator/iter_move.h>
29#include <__iterator/iter_swap.h>
30#include <__iterator/iterator_traits.h>
31#include <__iterator/next.h>
32#include <__iterator/prev.h>
33#include <__memory/addressof.h>
34#include <__ranges/access.h>
35#include <__ranges/adjacent_view.h>
36#include <__ranges/all.h>
37#include <__ranges/concepts.h>
38#include <__ranges/empty_view.h>
39#include <__ranges/movable_box.h>
40#include <__ranges/range_adaptor.h>
41#include <__ranges/size.h>
42#include <__ranges/view_interface.h>
43#include <__ranges/zip_transform_view.h>
44#include <__type_traits/common_type.h>
45#include <__type_traits/decay.h>
46#include <__type_traits/is_nothrow_constructible.h>
47#include <__type_traits/is_object.h>
48#include <__type_traits/is_referenceable.h>
49#include <__type_traits/make_unsigned.h>
50#include <__type_traits/maybe_const.h>
51#include <__utility/declval.h>
52#include <__utility/forward.h>
53#include <__utility/in_place.h>
54#include <__utility/integer_sequence.h>
55#include <__utility/move.h>
56
57#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
58# pragma GCC system_header
59#endif
60
61_LIBCPP_PUSH_MACROS
62#include <__undef_macros>
63
64_LIBCPP_BEGIN_NAMESPACE_STD
65
66#if _LIBCPP_STD_VER >= 23
67
68namespace ranges {
69
70template <class _Fn, size_t _Np>
71struct __apply_n {
72 template <class _Tp, size_t... _Is>
73 static auto __apply(index_sequence<_Is...>) -> invoke_result_t<_Fn, decltype((void)_Is, std::declval<_Tp>())...>;
74
75 template <class _Tp>
76 static auto operator()(_Tp&&) -> decltype(__apply<_Tp>(make_index_sequence<_Np>{}));
77};
78
79template <forward_range _View, move_constructible _Fn, size_t _Np>
80 requires view<_View> && (_Np > 0) && is_object_v<_Fn> &&
81 regular_invocable<__apply_n<_Fn&, _Np>, range_reference_t<_View>> &&
82 __referenceable<invoke_result_t<__apply_n<_Fn&, _Np>, range_reference_t<_View>>>
83class adjacent_transform_view : public view_interface<adjacent_transform_view<_View, _Fn, _Np>> {
84private:
85 _LIBCPP_NO_UNIQUE_ADDRESS adjacent_view<_View, _Np> __inner_;
86 _LIBCPP_NO_UNIQUE_ADDRESS __movable_box<_Fn> __fun_;
87
88 using _InnerView _LIBCPP_NODEBUG = adjacent_view<_View, _Np>;
89
90 template <bool _Const>
91 using __inner_iterator _LIBCPP_NODEBUG = iterator_t<__maybe_const<_Const, _InnerView>>;
92
93 template <bool _Const>
94 using __inner_sentinel _LIBCPP_NODEBUG = sentinel_t<__maybe_const<_Const, _InnerView>>;
95
96 template <bool>
97 class __iterator;
98
99 template <bool>
100 class __sentinel;
101
102public:
103 _LIBCPP_HIDE_FROM_ABI adjacent_transform_view() = default;
104
105 _LIBCPP_HIDE_FROM_ABI constexpr explicit adjacent_transform_view(_View __base, _Fn __fun)
106 : __inner_(std::move(__base)), __fun_(std::in_place, std::move(__fun)) {}
107
108 _LIBCPP_HIDE_FROM_ABI constexpr _View base() const&
109 requires copy_constructible<_View>
110 {
111 return __inner_.base();
112 }
113 _LIBCPP_HIDE_FROM_ABI constexpr _View base() && { return std::move(__inner_).base(); }
114
115 _LIBCPP_HIDE_FROM_ABI constexpr auto begin() { return __iterator<false>(*this, __inner_.begin()); }
116
117 _LIBCPP_HIDE_FROM_ABI constexpr auto begin() const
118 requires range<const _InnerView> && regular_invocable<__apply_n<const _Fn&, _Np>, range_reference_t<const _View>>
119 {
120 return __iterator<true>(*this, __inner_.begin());
121 }
122
123 _LIBCPP_HIDE_FROM_ABI constexpr auto end() {
124 if constexpr (common_range<_InnerView>) {
125 return __iterator<false>(*this, __inner_.end());
126 } else {
127 return __sentinel<false>(__inner_.end());
128 }
129 }
130
131 _LIBCPP_HIDE_FROM_ABI constexpr auto end() const
132 requires range<const _InnerView> && regular_invocable<__apply_n<const _Fn&, _Np>, range_reference_t<const _View>>
133 {
134 if constexpr (common_range<const _InnerView>) {
135 return __iterator<true>(*this, __inner_.end());
136 } else {
137 return __sentinel<true>(__inner_.end());
138 }
139 }
140
141 _LIBCPP_HIDE_FROM_ABI constexpr auto size()
142 requires sized_range<_InnerView>
143 {
144 return __inner_.size();
145 }
146
147 _LIBCPP_HIDE_FROM_ABI constexpr auto size() const
148 requires sized_range<const _InnerView>
149 {
150 return __inner_.size();
151 }
152};
153
154template <forward_range _View, move_constructible _Fn, size_t _Np>
155 requires view<_View> && (_Np > 0) && is_object_v<_Fn> &&
156 regular_invocable<__apply_n<_Fn&, _Np>, range_reference_t<_View>> &&
157 __referenceable<invoke_result_t<__apply_n<_Fn&, _Np>, range_reference_t<_View>>>
158template <bool _Const>
159class adjacent_transform_view<_View, _Fn, _Np>::__iterator {
160 friend adjacent_transform_view;
161
162 using _Parent _LIBCPP_NODEBUG = __maybe_const<_Const, adjacent_transform_view>;
163 using _Base _LIBCPP_NODEBUG = __maybe_const<_Const, _View>;
164
165 _Parent* __parent_ = nullptr;
166 __inner_iterator<_Const> __inner_;
167
168 _LIBCPP_HIDE_FROM_ABI constexpr __iterator(_Parent& __parent, __inner_iterator<_Const> __inner)
169 : __parent_(std::addressof(__parent)), __inner_(std::move(__inner)) {}
170
171 static consteval auto __get_iterator_category() {
172 using _Cat = iterator_traits<iterator_t<_Base>>::iterator_category;
173 if constexpr (!is_reference_v<
174 invoke_result_t<__apply_n<__maybe_const<_Const, _Fn>&, _Np>, range_reference_t<_Base>>>)
175 return input_iterator_tag{};
176 else if constexpr (derived_from<_Cat, random_access_iterator_tag>)
177 return random_access_iterator_tag{};
178 else if constexpr (derived_from<_Cat, bidirectional_iterator_tag>)
179 return bidirectional_iterator_tag{};
180 else if constexpr (derived_from<_Cat, forward_iterator_tag>)
181 return forward_iterator_tag{};
182 else
183 return input_iterator_tag{};
184 }
185
186 template <size_t... _Is>
187 static consteval bool __noexcept_dereference(index_sequence<_Is...>) {
188 return noexcept(std::invoke(
189 std::declval<__maybe_const<_Const, _Fn>&>(), ((void)_Is, *std::declval<iterator_t<_Base> const&>())...));
190 }
191
192public:
193 using iterator_category = decltype(__get_iterator_category());
194 using iterator_concept = typename __inner_iterator<_Const>::iterator_concept;
195 using value_type =
196 remove_cvref_t<invoke_result_t<__apply_n<__maybe_const<_Const, _Fn>&, _Np>, range_reference_t<_Base>>>;
197 using difference_type = range_difference_t<_Base>;
198
199 _LIBCPP_HIDE_FROM_ABI __iterator() = default;
200
201 _LIBCPP_HIDE_FROM_ABI constexpr __iterator(__iterator<!_Const> __i)
202 requires _Const && convertible_to<__inner_iterator<false>, __inner_iterator<true>>
203 : __parent_(__i.__parent_), __inner_(std::move(__i.__inner_)) {}
204
205 _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator*() const
206 noexcept(__noexcept_dereference(make_index_sequence<_Np>{})) {
207 return std::apply(
208 [&](const auto&... __iters) -> decltype(auto) { return std::invoke(*__parent_->__fun_, *__iters...); },
209 __adjacent_view_iter_access::__get_current(__inner_));
210 }
211
212 _LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator++() {
213 ++__inner_;
214 return *this;
215 }
216
217 _LIBCPP_HIDE_FROM_ABI constexpr __iterator operator++(int) {
218 auto __tmp = *this;
219 ++*this;
220 return __tmp;
221 }
222
223 _LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator--()
224 requires bidirectional_range<_Base>
225 {
226 --__inner_;
227 return *this;
228 }
229
230 _LIBCPP_HIDE_FROM_ABI constexpr __iterator operator--(int)
231 requires bidirectional_range<_Base>
232 {
233 auto __tmp = *this;
234 --*this;
235 return __tmp;
236 }
237
238 _LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator+=(difference_type __x)
239 requires random_access_range<_Base>
240 {
241 __inner_ += __x;
242 return *this;
243 }
244
245 _LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator-=(difference_type __x)
246 requires random_access_range<_Base>
247 {
248 __inner_ -= __x;
249 return *this;
250 }
251
252 _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator[](difference_type __n) const
253 requires random_access_range<_Base>
254 {
255 return std::apply(
256 [&](const auto&... __iters) -> decltype(auto) { return std::invoke(*__parent_->__fun_, __iters[__n]...); },
257 __adjacent_view_iter_access::__get_current(__inner_));
258 }
259
260 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const __iterator& __x, const __iterator& __y) {
261 return __x.__inner_ == __y.__inner_;
262 }
263
264 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<(const __iterator& __x, const __iterator& __y)
265 requires random_access_range<_Base>
266 {
267 return __x.__inner_ < __y.__inner_;
268 }
269
270 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>(const __iterator& __x, const __iterator& __y)
271 requires random_access_range<_Base>
272 {
273 return __x.__inner_ > __y.__inner_;
274 }
275
276 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<=(const __iterator& __x, const __iterator& __y)
277 requires random_access_range<_Base>
278 {
279 return __x.__inner_ <= __y.__inner_;
280 }
281
282 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>=(const __iterator& __x, const __iterator& __y)
283 requires random_access_range<_Base>
284 {
285 return __x.__inner_ >= __y.__inner_;
286 }
287
288 _LIBCPP_HIDE_FROM_ABI friend constexpr auto operator<=>(const __iterator& __x, const __iterator& __y)
289 requires random_access_range<_Base> && three_way_comparable<__inner_iterator<_Const>>
290 {
291 return __x.__inner_ <=> __y.__inner_;
292 }
293
294 _LIBCPP_HIDE_FROM_ABI friend constexpr __iterator operator+(const __iterator& __i, difference_type __n)
295 requires random_access_range<_Base>
296 {
297 return __iterator(*__i.__parent_, __i.__inner_ + __n);
298 }
299
300 _LIBCPP_HIDE_FROM_ABI friend constexpr __iterator operator+(difference_type __n, const __iterator& __i)
301 requires random_access_range<_Base>
302 {
303 return __iterator(*__i.__parent_, __i.__inner_ + __n);
304 }
305
306 _LIBCPP_HIDE_FROM_ABI friend constexpr __iterator operator-(const __iterator& __i, difference_type __n)
307 requires random_access_range<_Base>
308 {
309 return __iterator(*__i.__parent_, __i.__inner_ - __n);
310 }
311
312 _LIBCPP_HIDE_FROM_ABI friend constexpr difference_type operator-(const __iterator& __x, const __iterator& __y)
313 requires sized_sentinel_for<__inner_iterator<_Const>, __inner_iterator<_Const>>
314 {
315 return __x.__inner_ - __y.__inner_;
316 }
317};
318
319template <forward_range _View, move_constructible _Fn, size_t _Np>
320 requires view<_View> && (_Np > 0) && is_object_v<_Fn> &&
321 regular_invocable<__apply_n<_Fn&, _Np>, range_reference_t<_View>> &&
322 __referenceable<invoke_result_t<__apply_n<_Fn&, _Np>, range_reference_t<_View>>>
323template <bool _Const>
324class adjacent_transform_view<_View, _Fn, _Np>::__sentinel {
325 friend adjacent_transform_view;
326
327 __inner_sentinel<_Const> __inner_;
328
329 _LIBCPP_HIDE_FROM_ABI constexpr explicit __sentinel(__inner_sentinel<_Const> __inner)
330 : __inner_(std::move(__inner)) {}
331
332public:
333 _LIBCPP_HIDE_FROM_ABI __sentinel() = default;
334
335 _LIBCPP_HIDE_FROM_ABI constexpr __sentinel(__sentinel<!_Const> __i)
336 requires _Const && convertible_to<__inner_sentinel<false>, __inner_sentinel<_Const>>
337 : __inner_(std::move(__i.__inner_)) {}
338
339 template <bool _OtherConst>
340 requires sentinel_for<__inner_sentinel<_Const>, __inner_iterator<_OtherConst>>
341 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const __iterator<_OtherConst>& __x, const __sentinel& __y) {
342 return __x.__inner_ == __y.__inner_;
343 }
344
345 template <bool _OtherConst>
346 requires sized_sentinel_for<__inner_sentinel<_Const>, __inner_iterator<_OtherConst>>
347 _LIBCPP_HIDE_FROM_ABI friend constexpr range_difference_t<__maybe_const<_OtherConst, _InnerView>>
348 operator-(const __iterator<_OtherConst>& __x, const __sentinel& __y) {
349 return __x.__inner_ - __y.__inner_;
350 }
351
352 template <bool _OtherConst>
353 requires sized_sentinel_for<__inner_sentinel<_Const>, __inner_iterator<_OtherConst>>
354 _LIBCPP_HIDE_FROM_ABI friend constexpr range_difference_t<__maybe_const<_OtherConst, _InnerView>>
355 operator-(const __sentinel& __x, const __iterator<_OtherConst>& __y) {
356 return __x.__inner_ - __y.__inner_;
357 }
358};
359
360namespace views {
361namespace __adjacent_transform {
362
363template <size_t _Np>
364struct __fn : __range_adaptor_closure<__fn<_Np>> {
365 template <class _Range, class _Fn>
366 requires(_Np == 0 && forward_range<_Range &&>)
367 _LIBCPP_HIDE_FROM_ABI static constexpr auto
368 operator()(_Range&&, _Fn&& __fn) noexcept(noexcept(views::zip_transform(std::forward<_Fn>(__fn))))
369 -> decltype(views::zip_transform(std::forward<_Fn>(__fn))) {
370 return views::zip_transform(std::forward<_Fn>(__fn));
371 }
372
373 template <class _Range, class _Fn>
374 _LIBCPP_HIDE_FROM_ABI static constexpr auto operator()(_Range&& __range, _Fn&& __fn) noexcept(
375 noexcept(adjacent_transform_view<views::all_t<_Range&&>, decay_t<_Fn>, _Np>(
376 std::forward<_Range>(__range), std::forward<_Fn>(__fn))))
377 -> decltype(adjacent_transform_view<views::all_t<_Range&&>, decay_t<_Fn>, _Np>(
378 std::forward<_Range>(__range), std::forward<_Fn>(__fn))) {
379 return adjacent_transform_view<views::all_t<_Range&&>, decay_t<_Fn>, _Np>(
380 std::forward<_Range>(__range), std::forward<_Fn>(__fn));
381 }
382
383 template <class _Fn>
384 requires constructible_from<decay_t<_Fn>, _Fn>
385 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Fn&& __f) const
386 noexcept(is_nothrow_constructible_v<decay_t<_Fn>, _Fn>) {
387 return __pipeable(std::__bind_back(*this, std::forward<_Fn>(__f)));
388 }
389};
390
391} // namespace __adjacent_transform
392inline namespace __cpo {
393template <size_t _Np>
394inline constexpr auto adjacent_transform = __adjacent_transform::__fn<_Np>{};
395inline constexpr auto pairwise_transform = adjacent_transform<2>;
396} // namespace __cpo
397} // namespace views
398} // namespace ranges
399
400#endif // _LIBCPP_STD_VER >= 23
401
402_LIBCPP_END_NAMESPACE_STD
403
404_LIBCPP_POP_MACROS
405
406#endif // _LIBCPP___RANGES_ADJACENT_TRANSFORM_VIEW_H
407