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_VIEW_H
11#define _LIBCPP___RANGES_ZIP_VIEW_H
12
13#include <__config>
14
15#include <__algorithm/ranges_min.h>
16#include <__compare/three_way_comparable.h>
17#include <__concepts/convertible_to.h>
18#include <__concepts/equality_comparable.h>
19#include <__functional/invoke.h>
20#include <__functional/operations.h>
21#include <__iterator/concepts.h>
22#include <__iterator/incrementable_traits.h>
23#include <__iterator/iter_move.h>
24#include <__iterator/iter_swap.h>
25#include <__iterator/iterator_traits.h>
26#include <__iterator/product_iterator.h>
27#include <__ranges/access.h>
28#include <__ranges/all.h>
29#include <__ranges/concepts.h>
30#include <__ranges/empty_view.h>
31#include <__ranges/enable_borrowed_range.h>
32#include <__ranges/size.h>
33#include <__ranges/view_interface.h>
34#include <__tuple/tuple_transform.h>
35#include <__type_traits/is_nothrow_constructible.h>
36#include <__type_traits/make_unsigned.h>
37#include <__utility/declval.h>
38#include <__utility/forward.h>
39#include <__utility/integer_sequence.h>
40#include <__utility/move.h>
41#include <tuple>
42
43#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
44# pragma GCC system_header
45#endif
46
47_LIBCPP_PUSH_MACROS
48#include <__undef_macros>
49
50_LIBCPP_BEGIN_NAMESPACE_STD
51
52#if _LIBCPP_STD_VER >= 23
53
54namespace ranges {
55
56template <class... _Ranges>
57concept __zip_is_common =
58 (sizeof...(_Ranges) == 1 && (common_range<_Ranges> && ...)) ||
59 (!(bidirectional_range<_Ranges> && ...) && (common_range<_Ranges> && ...)) ||
60 ((random_access_range<_Ranges> && ...) && (sized_range<_Ranges> && ...));
61
62template <class _Fun, class _Tuple>
63_LIBCPP_HIDE_FROM_ABI constexpr void __tuple_for_each(_Fun&& __f, _Tuple&& __tuple) {
64 std::apply(
65 [&]<class... _Types>(_Types&&... __elements) {
66 (static_cast<void>(std::invoke(__f, std::forward<_Types>(__elements))), ...);
67 },
68 std::forward<_Tuple>(__tuple));
69}
70
71template <class _Fun, class _Tuple1, class _Tuple2, size_t... _Indices>
72_LIBCPP_HIDE_FROM_ABI constexpr tuple<
73 invoke_result_t<_Fun&,
74 typename tuple_element<_Indices, remove_cvref_t<_Tuple1>>::type,
75 typename tuple_element<_Indices, remove_cvref_t<_Tuple2>>::type>...>
76__tuple_zip_transform(_Fun&& __f, _Tuple1&& __tuple1, _Tuple2&& __tuple2, index_sequence<_Indices...>) {
77 return {std::invoke(__f,
78 std::get<_Indices>(std::forward<_Tuple1>(__tuple1)),
79 std::get<_Indices>(std::forward<_Tuple2>(__tuple2)))...};
80}
81
82template <class _Fun, class _Tuple1, class _Tuple2>
83_LIBCPP_HIDE_FROM_ABI constexpr auto __tuple_zip_transform(_Fun&& __f, _Tuple1&& __tuple1, _Tuple2&& __tuple2) {
84 return ranges::__tuple_zip_transform(
85 __f,
86 std::forward<_Tuple1>(__tuple1),
87 std::forward<_Tuple2>(__tuple2),
88 std::make_index_sequence<tuple_size<remove_cvref_t<_Tuple1>>::value>());
89}
90
91template <class _Fun, class _Tuple1, class _Tuple2, size_t... _Indices>
92_LIBCPP_HIDE_FROM_ABI constexpr void
93__tuple_zip_for_each(_Fun&& __f, _Tuple1&& __tuple1, _Tuple2&& __tuple2, index_sequence<_Indices...>) {
94 (std::invoke(
95 __f, std::get<_Indices>(std::forward<_Tuple1>(__tuple1)), std::get<_Indices>(std::forward<_Tuple2>(__tuple2))),
96 ...);
97}
98
99template <class _Fun, class _Tuple1, class _Tuple2>
100_LIBCPP_HIDE_FROM_ABI constexpr auto __tuple_zip_for_each(_Fun&& __f, _Tuple1&& __tuple1, _Tuple2&& __tuple2) {
101 return ranges::__tuple_zip_for_each(
102 __f,
103 std::forward<_Tuple1>(__tuple1),
104 std::forward<_Tuple2>(__tuple2),
105 std::make_index_sequence<tuple_size<remove_cvref_t<_Tuple1>>::value>());
106}
107
108template <class _Tuple1, class _Tuple2>
109_LIBCPP_HIDE_FROM_ABI constexpr bool __tuple_any_equals(const _Tuple1& __tuple1, const _Tuple2& __tuple2) {
110 const auto __equals = ranges::__tuple_zip_transform(std::equal_to<>(), __tuple1, __tuple2);
111 return std::apply([](auto... __bools) { return (__bools || ...); }, __equals);
112}
113
114// abs in cstdlib is not constexpr
115// TODO : remove __abs once P0533R9 is implemented.
116template <class _Tp>
117_LIBCPP_HIDE_FROM_ABI constexpr _Tp __abs(_Tp __t) {
118 return __t < 0 ? -__t : __t;
119}
120
121template <input_range... _Views>
122 requires(view<_Views> && ...) && (sizeof...(_Views) > 0)
123class zip_view : public view_interface<zip_view<_Views...>> {
124 _LIBCPP_NO_UNIQUE_ADDRESS tuple<_Views...> __views_;
125
126 template <bool>
127 class __iterator;
128
129 template <bool>
130 class __sentinel;
131
132public:
133 _LIBCPP_HIDE_FROM_ABI zip_view() = default;
134
135 _LIBCPP_HIDE_FROM_ABI constexpr explicit zip_view(_Views... __views) : __views_(std::move(__views)...) {}
136
137 _LIBCPP_HIDE_FROM_ABI constexpr auto begin()
138 requires(!(__simple_view<_Views> && ...))
139 {
140 return __iterator<false>(std::__tuple_transform(ranges::begin, __views_));
141 }
142
143 _LIBCPP_HIDE_FROM_ABI constexpr auto begin() const
144 requires(range<const _Views> && ...)
145 {
146 return __iterator<true>(std::__tuple_transform(ranges::begin, __views_));
147 }
148
149 _LIBCPP_HIDE_FROM_ABI constexpr auto end()
150 requires(!(__simple_view<_Views> && ...))
151 {
152 if constexpr (!__zip_is_common<_Views...>) {
153 return __sentinel<false>(std::__tuple_transform(ranges::end, __views_));
154 } else if constexpr ((random_access_range<_Views> && ...)) {
155 return begin() + iter_difference_t<__iterator<false>>(size());
156 } else {
157 return __iterator<false>(std::__tuple_transform(ranges::end, __views_));
158 }
159 }
160
161 _LIBCPP_HIDE_FROM_ABI constexpr auto end() const
162 requires(range<const _Views> && ...)
163 {
164 if constexpr (!__zip_is_common<const _Views...>) {
165 return __sentinel<true>(std::__tuple_transform(ranges::end, __views_));
166 } else if constexpr ((random_access_range<const _Views> && ...)) {
167 return begin() + iter_difference_t<__iterator<true>>(size());
168 } else {
169 return __iterator<true>(std::__tuple_transform(ranges::end, __views_));
170 }
171 }
172
173 _LIBCPP_HIDE_FROM_ABI constexpr auto size()
174 requires(sized_range<_Views> && ...)
175 {
176 return std::apply(
177 [](auto... __sizes) {
178 using _CT = make_unsigned_t<common_type_t<decltype(__sizes)...>>;
179 return ranges::min({_CT(__sizes)...});
180 },
181 std::__tuple_transform(ranges::size, __views_));
182 }
183
184 _LIBCPP_HIDE_FROM_ABI constexpr auto size() const
185 requires(sized_range<const _Views> && ...)
186 {
187 return std::apply(
188 [](auto... __sizes) {
189 using _CT = make_unsigned_t<common_type_t<decltype(__sizes)...>>;
190 return ranges::min({_CT(__sizes)...});
191 },
192 std::__tuple_transform(ranges::size, __views_));
193 }
194};
195
196template <class... _Ranges>
197zip_view(_Ranges&&...) -> zip_view<views::all_t<_Ranges>...>;
198
199template <bool _Const, class... _Views>
200concept __zip_all_random_access = (random_access_range<__maybe_const<_Const, _Views>> && ...);
201
202template <bool _Const, class... _Views>
203concept __zip_all_bidirectional = (bidirectional_range<__maybe_const<_Const, _Views>> && ...);
204
205template <bool _Const, class... _Views>
206concept __zip_all_forward = (forward_range<__maybe_const<_Const, _Views>> && ...);
207
208template <bool _Const, class... _Views>
209consteval auto __get_zip_view_iterator_tag() {
210 if constexpr (__zip_all_random_access<_Const, _Views...>) {
211 return random_access_iterator_tag();
212 } else if constexpr (__zip_all_bidirectional<_Const, _Views...>) {
213 return bidirectional_iterator_tag();
214 } else if constexpr (__zip_all_forward<_Const, _Views...>) {
215 return forward_iterator_tag();
216 } else {
217 return input_iterator_tag();
218 }
219}
220
221template <bool _Const, class... _Views>
222struct __zip_view_iterator_category_base {};
223
224template <bool _Const, class... _Views>
225 requires __zip_all_forward<_Const, _Views...>
226struct __zip_view_iterator_category_base<_Const, _Views...> {
227 using iterator_category = input_iterator_tag;
228};
229
230struct __zip_view_iterator_access {
231 template <class _Iter>
232 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto) __get_underlying(_Iter& __iter) noexcept {
233 return (__iter.__current_);
234 }
235};
236
237template <input_range... _Views>
238 requires(view<_Views> && ...) && (sizeof...(_Views) > 0)
239template <bool _Const>
240class zip_view<_Views...>::__iterator : public __zip_view_iterator_category_base<_Const, _Views...> {
241 tuple<iterator_t<__maybe_const<_Const, _Views>>...> __current_;
242
243 _LIBCPP_HIDE_FROM_ABI constexpr explicit __iterator(tuple<iterator_t<__maybe_const<_Const, _Views>>...> __current)
244 : __current_(std::move(__current)) {}
245
246 template <bool>
247 friend class zip_view<_Views...>::__iterator;
248
249 template <bool>
250 friend class zip_view<_Views...>::__sentinel;
251
252 friend class zip_view<_Views...>;
253
254 static constexpr bool __is_zip_view_iterator = true;
255
256 friend struct __product_iterator_traits<__iterator>;
257 friend __zip_view_iterator_access;
258
259public:
260 using iterator_concept = decltype(ranges::__get_zip_view_iterator_tag<_Const, _Views...>());
261 using value_type = tuple<range_value_t<__maybe_const<_Const, _Views>>...>;
262 using difference_type = common_type_t<range_difference_t<__maybe_const<_Const, _Views>>...>;
263
264 _LIBCPP_HIDE_FROM_ABI __iterator() = default;
265
266 _LIBCPP_HIDE_FROM_ABI constexpr __iterator(__iterator<!_Const> __i)
267 requires _Const && (convertible_to<iterator_t<_Views>, iterator_t<__maybe_const<_Const, _Views>>> && ...)
268 : __current_(std::move(__i.__current_)) {}
269
270 _LIBCPP_HIDE_FROM_ABI constexpr auto operator*() const {
271 return std::__tuple_transform([](auto& __i) -> decltype(auto) { return *__i; }, __current_);
272 }
273
274 _LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator++() {
275 ranges::__tuple_for_each([](auto& __i) { ++__i; }, __current_);
276 return *this;
277 }
278
279 _LIBCPP_HIDE_FROM_ABI constexpr void operator++(int) { ++*this; }
280
281 _LIBCPP_HIDE_FROM_ABI constexpr __iterator operator++(int)
282 requires __zip_all_forward<_Const, _Views...>
283 {
284 auto __tmp = *this;
285 ++*this;
286 return __tmp;
287 }
288
289 _LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator--()
290 requires __zip_all_bidirectional<_Const, _Views...>
291 {
292 ranges::__tuple_for_each([](auto& __i) { --__i; }, __current_);
293 return *this;
294 }
295
296 _LIBCPP_HIDE_FROM_ABI constexpr __iterator operator--(int)
297 requires __zip_all_bidirectional<_Const, _Views...>
298 {
299 auto __tmp = *this;
300 --*this;
301 return __tmp;
302 }
303
304 _LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator+=(difference_type __x)
305 requires __zip_all_random_access<_Const, _Views...>
306 {
307 ranges::__tuple_for_each([&]<class _Iter>(_Iter& __i) { __i += iter_difference_t<_Iter>(__x); }, __current_);
308 return *this;
309 }
310
311 _LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator-=(difference_type __x)
312 requires __zip_all_random_access<_Const, _Views...>
313 {
314 ranges::__tuple_for_each([&]<class _Iter>(_Iter& __i) { __i -= iter_difference_t<_Iter>(__x); }, __current_);
315 return *this;
316 }
317
318 _LIBCPP_HIDE_FROM_ABI constexpr auto operator[](difference_type __n) const
319 requires __zip_all_random_access<_Const, _Views...>
320 {
321 return std::__tuple_transform(
322 [&]<class _Iter>(_Iter& __i) -> decltype(auto) { return __i[iter_difference_t<_Iter>(__n)]; }, __current_);
323 }
324
325 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const __iterator& __x, const __iterator& __y)
326 requires(equality_comparable<iterator_t<__maybe_const<_Const, _Views>>> && ...)
327 {
328 if constexpr (__zip_all_bidirectional<_Const, _Views...>) {
329 return __x.__current_ == __y.__current_;
330 } else {
331 return ranges::__tuple_any_equals(__x.__current_, __y.__current_);
332 }
333 }
334
335 _LIBCPP_HIDE_FROM_ABI friend constexpr auto operator<=>(const __iterator& __x, const __iterator& __y)
336 requires __zip_all_random_access<_Const, _Views...>
337 {
338 return __x.__current_ <=> __y.__current_;
339 }
340
341 _LIBCPP_HIDE_FROM_ABI friend constexpr __iterator operator+(const __iterator& __i, difference_type __n)
342 requires __zip_all_random_access<_Const, _Views...>
343 {
344 auto __r = __i;
345 __r += __n;
346 return __r;
347 }
348
349 _LIBCPP_HIDE_FROM_ABI friend constexpr __iterator operator+(difference_type __n, const __iterator& __i)
350 requires __zip_all_random_access<_Const, _Views...>
351 {
352 return __i + __n;
353 }
354
355 _LIBCPP_HIDE_FROM_ABI friend constexpr __iterator operator-(const __iterator& __i, difference_type __n)
356 requires __zip_all_random_access<_Const, _Views...>
357 {
358 auto __r = __i;
359 __r -= __n;
360 return __r;
361 }
362
363 _LIBCPP_HIDE_FROM_ABI friend constexpr difference_type operator-(const __iterator& __x, const __iterator& __y)
364 requires(sized_sentinel_for<iterator_t<__maybe_const<_Const, _Views>>, iterator_t<__maybe_const<_Const, _Views>>> &&
365 ...)
366 {
367 const auto __diffs = ranges::__tuple_zip_transform(minus<>(), __x.__current_, __y.__current_);
368 return std::apply(
369 [](auto... __ds) {
370 return ranges::min({difference_type(__ds)...}, [](auto __a, auto __b) {
371 return ranges::__abs(__a) < ranges::__abs(__b);
372 });
373 },
374 __diffs);
375 }
376
377 _LIBCPP_HIDE_FROM_ABI friend constexpr auto iter_move(const __iterator& __i) noexcept(
378 (noexcept(ranges::iter_move(std::declval<const iterator_t<__maybe_const<_Const, _Views>>&>())) && ...) &&
379 (is_nothrow_move_constructible_v<range_rvalue_reference_t<__maybe_const<_Const, _Views>>> && ...)) {
380 return std::__tuple_transform(ranges::iter_move, __i.__current_);
381 }
382
383 _LIBCPP_HIDE_FROM_ABI friend constexpr void iter_swap(const __iterator& __l, const __iterator& __r) noexcept(
384 (noexcept(ranges::iter_swap(std::declval<const iterator_t<__maybe_const<_Const, _Views>>&>(),
385 std::declval<const iterator_t<__maybe_const<_Const, _Views>>&>())) &&
386 ...))
387 requires(indirectly_swappable<iterator_t<__maybe_const<_Const, _Views>>> && ...)
388 {
389 ranges::__tuple_zip_for_each(ranges::iter_swap, __l.__current_, __r.__current_);
390 }
391};
392
393template <input_range... _Views>
394 requires(view<_Views> && ...) && (sizeof...(_Views) > 0)
395template <bool _Const>
396class zip_view<_Views...>::__sentinel {
397 tuple<sentinel_t<__maybe_const<_Const, _Views>>...> __end_;
398
399 _LIBCPP_HIDE_FROM_ABI constexpr explicit __sentinel(tuple<sentinel_t<__maybe_const<_Const, _Views>>...> __end)
400 : __end_(__end) {}
401
402 friend class zip_view<_Views...>;
403
404 // hidden friend cannot access private member of iterator because they are friends of friends
405 template <bool _OtherConst>
406 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto)
407 __iter_current(zip_view<_Views...>::__iterator<_OtherConst> const& __it) {
408 return (__it.__current_);
409 }
410
411public:
412 _LIBCPP_HIDE_FROM_ABI __sentinel() = default;
413
414 _LIBCPP_HIDE_FROM_ABI constexpr __sentinel(__sentinel<!_Const> __i)
415 requires _Const && (convertible_to<sentinel_t<_Views>, sentinel_t<__maybe_const<_Const, _Views>>> && ...)
416 : __end_(std::move(__i.__end_)) {}
417
418 template <bool _OtherConst>
419 requires(sentinel_for<sentinel_t<__maybe_const<_Const, _Views>>, iterator_t<__maybe_const<_OtherConst, _Views>>> &&
420 ...)
421 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const __iterator<_OtherConst>& __x, const __sentinel& __y) {
422 return ranges::__tuple_any_equals(__iter_current(__x), __y.__end_);
423 }
424
425 template <bool _OtherConst>
426 requires(
427 sized_sentinel_for<sentinel_t<__maybe_const<_Const, _Views>>, iterator_t<__maybe_const<_OtherConst, _Views>>> &&
428 ...)
429 _LIBCPP_HIDE_FROM_ABI friend constexpr common_type_t<range_difference_t<__maybe_const<_OtherConst, _Views>>...>
430 operator-(const __iterator<_OtherConst>& __x, const __sentinel& __y) {
431 const auto __diffs = ranges::__tuple_zip_transform(minus<>(), __iter_current(__x), __y.__end_);
432 return std::apply(
433 [](auto... __ds) {
434 using _Diff = common_type_t<range_difference_t<__maybe_const<_OtherConst, _Views>>...>;
435 return ranges::min({_Diff(__ds)...}, [](auto __a, auto __b) {
436 return ranges::__abs(__a) < ranges::__abs(__b);
437 });
438 },
439 __diffs);
440 }
441
442 template <bool _OtherConst>
443 requires(
444 sized_sentinel_for<sentinel_t<__maybe_const<_Const, _Views>>, iterator_t<__maybe_const<_OtherConst, _Views>>> &&
445 ...)
446 _LIBCPP_HIDE_FROM_ABI friend constexpr common_type_t<range_difference_t<__maybe_const<_OtherConst, _Views>>...>
447 operator-(const __sentinel& __y, const __iterator<_OtherConst>& __x) {
448 return -(__x - __y);
449 }
450};
451
452template <class... _Views>
453inline constexpr bool enable_borrowed_range<zip_view<_Views...>> = (enable_borrowed_range<_Views> && ...);
454
455namespace views {
456namespace __zip {
457
458struct __fn {
459 _LIBCPP_HIDE_FROM_ABI static constexpr auto operator()() noexcept { return empty_view<tuple<>>{}; }
460
461 template <class... _Ranges>
462 _LIBCPP_HIDE_FROM_ABI static constexpr auto
463 operator()(_Ranges&&... __rs) noexcept(noexcept(zip_view<all_t<_Ranges&&>...>(std::forward<_Ranges>(__rs)...)))
464 -> decltype(zip_view<all_t<_Ranges&&>...>(std::forward<_Ranges>(__rs)...)) {
465 return zip_view<all_t<_Ranges>...>(std::forward<_Ranges>(__rs)...);
466 }
467};
468
469} // namespace __zip
470inline namespace __cpo {
471inline constexpr auto zip = __zip::__fn{};
472} // namespace __cpo
473} // namespace views
474} // namespace ranges
475
476template <class _Iterator>
477 requires _Iterator::__is_zip_view_iterator
478struct __product_iterator_traits<_Iterator> {
479 static constexpr size_t __size = tuple_size<decltype(std::declval<_Iterator>().__current_)>::value;
480
481 template <size_t _Nth, class _Iter>
482 requires(_Nth < __size)
483 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto) __get_iterator_element(_Iter&& __it) {
484 return std::get<_Nth>(std::forward<_Iter>(__it).__current_);
485 }
486
487 template <class... _Iters>
488 _LIBCPP_HIDE_FROM_ABI static constexpr _Iterator __make_product_iterator(_Iters&&... __iters) {
489 return _Iterator(std::tuple(std::forward<_Iters>(__iters)...));
490 }
491};
492
493#endif // _LIBCPP_STD_VER >= 23
494
495_LIBCPP_END_NAMESPACE_STD
496
497_LIBCPP_POP_MACROS
498
499#endif // _LIBCPP___RANGES_ZIP_VIEW_H
500