1// Utilities for representing and manipulating ranges -*- C++ -*-
2
3// Copyright (C) 2019-2024 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library. This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14// GNU General Public License for more details.
15
16// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23// <http://www.gnu.org/licenses/>.
24
25/** @file bits/ranges_util.h
26 * This is an internal header file, included by other library headers.
27 * Do not attempt to use it directly. @headername{ranges}
28 */
29
30#ifndef _RANGES_UTIL_H
31#define _RANGES_UTIL_H 1
32
33#if __cplusplus > 201703L
34# include <bits/ranges_base.h>
35# include <bits/utility.h>
36# include <bits/invoke.h>
37
38#ifdef __glibcxx_ranges
39namespace std _GLIBCXX_VISIBILITY(default)
40{
41_GLIBCXX_BEGIN_NAMESPACE_VERSION
42namespace ranges
43{
44 // C++20 24.5 [range.utility] Range utilities
45
46 namespace __detail
47 {
48 template<typename _Range>
49 concept __simple_view = view<_Range> && range<const _Range>
50 && same_as<iterator_t<_Range>, iterator_t<const _Range>>
51 && same_as<sentinel_t<_Range>, sentinel_t<const _Range>>;
52
53 template<typename _It>
54 concept __has_arrow = input_iterator<_It>
55 && (is_pointer_v<_It> || requires(_It __it) { __it.operator->(); });
56
57 using std::__detail::__different_from;
58 } // namespace __detail
59
60 /// The ranges::view_interface class template
61 template<typename _Derived>
62 requires is_class_v<_Derived> && same_as<_Derived, remove_cv_t<_Derived>>
63 class view_interface
64 {
65 private:
66 constexpr _Derived& _M_derived() noexcept
67 {
68 static_assert(derived_from<_Derived, view_interface<_Derived>>);
69 static_assert(view<_Derived>);
70 return static_cast<_Derived&>(*this);
71 }
72
73 constexpr const _Derived& _M_derived() const noexcept
74 {
75 static_assert(derived_from<_Derived, view_interface<_Derived>>);
76 static_assert(view<_Derived>);
77 return static_cast<const _Derived&>(*this);
78 }
79
80 static constexpr bool
81 _S_bool(bool) noexcept; // not defined
82
83 template<typename _Tp>
84 static constexpr bool
85 _S_empty(_Tp& __t)
86 noexcept(noexcept(_S_bool(ranges::begin(__t) == ranges::end(__t))))
87 { return ranges::begin(__t) == ranges::end(__t); }
88
89 template<typename _Tp>
90 static constexpr auto
91 _S_size(_Tp& __t)
92 noexcept(noexcept(ranges::end(__t) - ranges::begin(__t)))
93 { return ranges::end(__t) - ranges::begin(__t); }
94
95 public:
96 constexpr bool
97 empty()
98 noexcept(noexcept(_S_empty(_M_derived())))
99 requires forward_range<_Derived> && (!sized_range<_Derived>)
100 { return _S_empty(_M_derived()); }
101
102 constexpr bool
103 empty()
104 noexcept(noexcept(ranges::size(_M_derived()) == 0))
105 requires sized_range<_Derived>
106 { return ranges::size(_M_derived()) == 0; }
107
108 constexpr bool
109 empty() const
110 noexcept(noexcept(_S_empty(_M_derived())))
111 requires forward_range<const _Derived> && (!sized_range<const _Derived>)
112 { return _S_empty(_M_derived()); }
113
114 constexpr bool
115 empty() const
116 noexcept(noexcept(ranges::size(_M_derived()) == 0))
117 requires sized_range<const _Derived>
118 { return ranges::size(_M_derived()) == 0; }
119
120 constexpr explicit
121 operator bool() noexcept(noexcept(ranges::empty(_M_derived())))
122 requires requires { ranges::empty(_M_derived()); }
123 { return !ranges::empty(_M_derived()); }
124
125 constexpr explicit
126 operator bool() const noexcept(noexcept(ranges::empty(_M_derived())))
127 requires requires { ranges::empty(_M_derived()); }
128 { return !ranges::empty(_M_derived()); }
129
130 constexpr auto
131 data() noexcept(noexcept(ranges::begin(_M_derived())))
132 requires contiguous_iterator<iterator_t<_Derived>>
133 { return std::to_address(ranges::begin(_M_derived())); }
134
135 constexpr auto
136 data() const noexcept(noexcept(ranges::begin(_M_derived())))
137 requires range<const _Derived>
138 && contiguous_iterator<iterator_t<const _Derived>>
139 { return std::to_address(ranges::begin(_M_derived())); }
140
141 constexpr auto
142 size() noexcept(noexcept(_S_size(_M_derived())))
143 requires forward_range<_Derived>
144 && sized_sentinel_for<sentinel_t<_Derived>, iterator_t<_Derived>>
145 { return _S_size(_M_derived()); }
146
147 constexpr auto
148 size() const noexcept(noexcept(_S_size(_M_derived())))
149 requires forward_range<const _Derived>
150 && sized_sentinel_for<sentinel_t<const _Derived>,
151 iterator_t<const _Derived>>
152 { return _S_size(_M_derived()); }
153
154 constexpr decltype(auto)
155 front() requires forward_range<_Derived>
156 {
157 __glibcxx_assert(!empty());
158 return *ranges::begin(_M_derived());
159 }
160
161 constexpr decltype(auto)
162 front() const requires forward_range<const _Derived>
163 {
164 __glibcxx_assert(!empty());
165 return *ranges::begin(_M_derived());
166 }
167
168 constexpr decltype(auto)
169 back()
170 requires bidirectional_range<_Derived> && common_range<_Derived>
171 {
172 __glibcxx_assert(!empty());
173 return *ranges::prev(ranges::end(_M_derived()));
174 }
175
176 constexpr decltype(auto)
177 back() const
178 requires bidirectional_range<const _Derived>
179 && common_range<const _Derived>
180 {
181 __glibcxx_assert(!empty());
182 return *ranges::prev(ranges::end(_M_derived()));
183 }
184
185 template<random_access_range _Range = _Derived>
186 constexpr decltype(auto)
187 operator[](range_difference_t<_Range> __n)
188 { return ranges::begin(_M_derived())[__n]; }
189
190 template<random_access_range _Range = const _Derived>
191 constexpr decltype(auto)
192 operator[](range_difference_t<_Range> __n) const
193 { return ranges::begin(_M_derived())[__n]; }
194
195#if __cplusplus > 202002L
196 constexpr auto
197 cbegin() requires input_range<_Derived>
198 { return ranges::cbegin(_M_derived()); }
199
200 constexpr auto
201 cbegin() const requires input_range<const _Derived>
202 { return ranges::cbegin(_M_derived()); }
203
204 constexpr auto
205 cend() requires input_range<_Derived>
206 { return ranges::cend(_M_derived()); }
207
208 constexpr auto
209 cend() const requires input_range<const _Derived>
210 { return ranges::cend(_M_derived()); }
211#endif
212 };
213
214 namespace __detail
215 {
216 template<typename _From, typename _To>
217 concept __uses_nonqualification_pointer_conversion
218 = is_pointer_v<_From> && is_pointer_v<_To>
219 && !convertible_to<remove_pointer_t<_From>(*)[],
220 remove_pointer_t<_To>(*)[]>;
221
222 template<typename _From, typename _To>
223 concept __convertible_to_non_slicing = convertible_to<_From, _To>
224 && !__uses_nonqualification_pointer_conversion<decay_t<_From>,
225 decay_t<_To>>;
226
227#if __glibcxx_tuple_like // >= C++23
228 // P2165R4 version of __pair_like is defined in <bits/stl_pair.h>.
229#else
230 // C++20 version of __pair_like from P2321R2.
231 template<typename _Tp>
232 concept __pair_like
233 = !is_reference_v<_Tp> && requires(_Tp __t)
234 {
235 typename tuple_size<_Tp>::type;
236 requires derived_from<tuple_size<_Tp>, integral_constant<size_t, 2>>;
237 typename tuple_element_t<0, remove_const_t<_Tp>>;
238 typename tuple_element_t<1, remove_const_t<_Tp>>;
239 { get<0>(__t) } -> convertible_to<const tuple_element_t<0, _Tp>&>;
240 { get<1>(__t) } -> convertible_to<const tuple_element_t<1, _Tp>&>;
241 };
242#endif
243
244 template<typename _Tp, typename _Up, typename _Vp>
245 concept __pair_like_convertible_from
246 = !range<_Tp> && !is_reference_v<_Vp> && __pair_like<_Tp>
247 && constructible_from<_Tp, _Up, _Vp>
248 && __convertible_to_non_slicing<_Up, tuple_element_t<0, _Tp>>
249 && convertible_to<_Vp, tuple_element_t<1, _Tp>>;
250
251 } // namespace __detail
252
253 namespace views { struct _Drop; } // defined in <ranges>
254
255 enum class subrange_kind : bool { unsized, sized };
256
257 /// The ranges::subrange class template
258 template<input_or_output_iterator _It, sentinel_for<_It> _Sent = _It,
259 subrange_kind _Kind = sized_sentinel_for<_Sent, _It>
260 ? subrange_kind::sized : subrange_kind::unsized>
261 requires (_Kind == subrange_kind::sized || !sized_sentinel_for<_Sent, _It>)
262 class subrange : public view_interface<subrange<_It, _Sent, _Kind>>
263 {
264 private:
265 static constexpr bool _S_store_size
266 = _Kind == subrange_kind::sized && !sized_sentinel_for<_Sent, _It>;
267
268 friend struct views::_Drop; // Needs to inspect _S_store_size.
269
270 _It _M_begin = _It();
271 [[no_unique_address]] _Sent _M_end = _Sent();
272
273 using __size_type
274 = __detail::__make_unsigned_like_t<iter_difference_t<_It>>;
275
276 template<typename _Tp, bool = _S_store_size>
277 struct _Size
278 {
279 [[__gnu__::__always_inline__]]
280 constexpr _Size(_Tp = {}) { }
281 };
282
283 template<typename _Tp>
284 struct _Size<_Tp, true>
285 {
286 [[__gnu__::__always_inline__]]
287 constexpr _Size(_Tp __s = {}) : _M_size(__s) { }
288
289 _Tp _M_size;
290 };
291
292 [[no_unique_address]] _Size<__size_type> _M_size = {};
293
294 public:
295 subrange() requires default_initializable<_It> = default;
296
297 constexpr
298 subrange(__detail::__convertible_to_non_slicing<_It> auto __i, _Sent __s)
299 noexcept(is_nothrow_constructible_v<_It, decltype(__i)>
300 && is_nothrow_constructible_v<_Sent, _Sent&>)
301 requires (!_S_store_size)
302 : _M_begin(std::move(__i)), _M_end(__s)
303 { }
304
305 constexpr
306 subrange(__detail::__convertible_to_non_slicing<_It> auto __i, _Sent __s,
307 __size_type __n)
308 noexcept(is_nothrow_constructible_v<_It, decltype(__i)>
309 && is_nothrow_constructible_v<_Sent, _Sent&>)
310 requires (_Kind == subrange_kind::sized)
311 : _M_begin(std::move(__i)), _M_end(__s), _M_size(__n)
312 { }
313
314 template<__detail::__different_from<subrange> _Rng>
315 requires borrowed_range<_Rng>
316 && __detail::__convertible_to_non_slicing<iterator_t<_Rng>, _It>
317 && convertible_to<sentinel_t<_Rng>, _Sent>
318 constexpr
319 subrange(_Rng&& __r)
320 noexcept(noexcept(subrange(__r, ranges::size(__r))))
321 requires _S_store_size && sized_range<_Rng>
322 : subrange(__r, ranges::size(__r))
323 { }
324
325 template<__detail::__different_from<subrange> _Rng>
326 requires borrowed_range<_Rng>
327 && __detail::__convertible_to_non_slicing<iterator_t<_Rng>, _It>
328 && convertible_to<sentinel_t<_Rng>, _Sent>
329 constexpr
330 subrange(_Rng&& __r)
331 noexcept(noexcept(subrange(ranges::begin(__r), ranges::end(__r))))
332 requires (!_S_store_size)
333 : subrange(ranges::begin(__r), ranges::end(__r))
334 { }
335
336 template<borrowed_range _Rng>
337 requires __detail::__convertible_to_non_slicing<iterator_t<_Rng>, _It>
338 && convertible_to<sentinel_t<_Rng>, _Sent>
339 constexpr
340 subrange(_Rng&& __r, __size_type __n)
341 noexcept(noexcept(subrange(ranges::begin(__r), ranges::end(__r), __n)))
342 requires (_Kind == subrange_kind::sized)
343 : subrange{ranges::begin(__r), ranges::end(__r), __n}
344 { }
345
346 template<__detail::__different_from<subrange> _PairLike>
347 requires __detail::__pair_like_convertible_from<_PairLike, const _It&,
348 const _Sent&>
349 constexpr
350 operator _PairLike() const
351 { return _PairLike(_M_begin, _M_end); }
352
353 constexpr _It
354 begin() const requires copyable<_It>
355 { return _M_begin; }
356
357 [[nodiscard]] constexpr _It
358 begin() requires (!copyable<_It>)
359 { return std::move(_M_begin); }
360
361 constexpr _Sent end() const { return _M_end; }
362
363 constexpr bool empty() const { return _M_begin == _M_end; }
364
365 constexpr __size_type
366 size() const requires (_Kind == subrange_kind::sized)
367 {
368 if constexpr (_S_store_size)
369 return _M_size._M_size;
370 else
371 return __detail::__to_unsigned_like(_M_end - _M_begin);
372 }
373
374 [[nodiscard]] constexpr subrange
375 next(iter_difference_t<_It> __n = 1) const &
376 requires forward_iterator<_It>
377 {
378 auto __tmp = *this;
379 __tmp.advance(__n);
380 return __tmp;
381 }
382
383 [[nodiscard]] constexpr subrange
384 next(iter_difference_t<_It> __n = 1) &&
385 {
386 advance(__n);
387 return std::move(*this);
388 }
389
390 [[nodiscard]] constexpr subrange
391 prev(iter_difference_t<_It> __n = 1) const
392 requires bidirectional_iterator<_It>
393 {
394 auto __tmp = *this;
395 __tmp.advance(-__n);
396 return __tmp;
397 }
398
399 constexpr subrange&
400 advance(iter_difference_t<_It> __n)
401 {
402 // _GLIBCXX_RESOLVE_LIB_DEFECTS
403 // 3433. subrange::advance(n) has UB when n < 0
404 if constexpr (bidirectional_iterator<_It>)
405 if (__n < 0)
406 {
407 ranges::advance(_M_begin, __n);
408 if constexpr (_S_store_size)
409 _M_size._M_size += __detail::__to_unsigned_like(-__n);
410 return *this;
411 }
412
413 __glibcxx_assert(__n >= 0);
414 auto __d = __n - ranges::advance(_M_begin, __n, _M_end);
415 if constexpr (_S_store_size)
416 _M_size._M_size -= __detail::__to_unsigned_like(__d);
417 return *this;
418 }
419 };
420
421 template<input_or_output_iterator _It, sentinel_for<_It> _Sent>
422 subrange(_It, _Sent) -> subrange<_It, _Sent>;
423
424 template<input_or_output_iterator _It, sentinel_for<_It> _Sent>
425 subrange(_It, _Sent,
426 __detail::__make_unsigned_like_t<iter_difference_t<_It>>)
427 -> subrange<_It, _Sent, subrange_kind::sized>;
428
429 template<borrowed_range _Rng>
430 subrange(_Rng&&)
431 -> subrange<iterator_t<_Rng>, sentinel_t<_Rng>,
432 (sized_range<_Rng>
433 || sized_sentinel_for<sentinel_t<_Rng>, iterator_t<_Rng>>)
434 ? subrange_kind::sized : subrange_kind::unsized>;
435
436 template<borrowed_range _Rng>
437 subrange(_Rng&&,
438 __detail::__make_unsigned_like_t<range_difference_t<_Rng>>)
439 -> subrange<iterator_t<_Rng>, sentinel_t<_Rng>, subrange_kind::sized>;
440
441 template<size_t _Num, class _It, class _Sent, subrange_kind _Kind>
442 requires (_Num < 2)
443 constexpr auto
444 get(const subrange<_It, _Sent, _Kind>& __r)
445 {
446 if constexpr (_Num == 0)
447 return __r.begin();
448 else
449 return __r.end();
450 }
451
452 template<size_t _Num, class _It, class _Sent, subrange_kind _Kind>
453 requires (_Num < 2)
454 constexpr auto
455 get(subrange<_It, _Sent, _Kind>&& __r)
456 {
457 if constexpr (_Num == 0)
458 return __r.begin();
459 else
460 return __r.end();
461 }
462
463 template<typename _It, typename _Sent, subrange_kind _Kind>
464 inline constexpr bool
465 enable_borrowed_range<subrange<_It, _Sent, _Kind>> = true;
466
467 template<range _Range>
468 using borrowed_subrange_t = __conditional_t<borrowed_range<_Range>,
469 subrange<iterator_t<_Range>>,
470 dangling>;
471
472 // __is_subrange is defined in <bits/utility.h>.
473 template<typename _Iter, typename _Sent, subrange_kind _Kind>
474 inline constexpr bool __detail::__is_subrange<subrange<_Iter, _Sent, _Kind>> = true;
475} // namespace ranges
476
477#if __glibcxx_tuple_like // >= C++23
478 // __is_tuple_like_v is defined in <bits/stl_pair.h>.
479 template<typename _It, typename _Sent, ranges::subrange_kind _Kind>
480 inline constexpr bool __is_tuple_like_v<ranges::subrange<_It, _Sent, _Kind>> = true;
481#endif
482
483// The following ranges algorithms are used by <ranges>, and are defined here
484// so that <ranges> can avoid including all of <bits/ranges_algo.h>.
485namespace ranges
486{
487 struct __find_fn
488 {
489 template<input_iterator _Iter, sentinel_for<_Iter> _Sent, typename _Tp,
490 typename _Proj = identity>
491 requires indirect_binary_predicate<ranges::equal_to,
492 projected<_Iter, _Proj>, const _Tp*>
493 constexpr _Iter
494 operator()(_Iter __first, _Sent __last,
495 const _Tp& __value, _Proj __proj = {}) const
496 {
497 while (__first != __last
498 && !(std::__invoke(__proj, *__first) == __value))
499 ++__first;
500 return __first;
501 }
502
503 template<input_range _Range, typename _Tp, typename _Proj = identity>
504 requires indirect_binary_predicate<ranges::equal_to,
505 projected<iterator_t<_Range>, _Proj>,
506 const _Tp*>
507 constexpr borrowed_iterator_t<_Range>
508 operator()(_Range&& __r, const _Tp& __value, _Proj __proj = {}) const
509 {
510 return (*this)(ranges::begin(__r), ranges::end(__r),
511 __value, std::move(__proj));
512 }
513 };
514
515 inline constexpr __find_fn find{};
516
517 struct __find_if_fn
518 {
519 template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
520 typename _Proj = identity,
521 indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
522 constexpr _Iter
523 operator()(_Iter __first, _Sent __last,
524 _Pred __pred, _Proj __proj = {}) const
525 {
526 while (__first != __last
527 && !(bool)std::__invoke(__pred, std::__invoke(__proj, *__first)))
528 ++__first;
529 return __first;
530 }
531
532 template<input_range _Range, typename _Proj = identity,
533 indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>>
534 _Pred>
535 constexpr borrowed_iterator_t<_Range>
536 operator()(_Range&& __r, _Pred __pred, _Proj __proj = {}) const
537 {
538 return (*this)(ranges::begin(__r), ranges::end(__r),
539 std::move(__pred), std::move(__proj));
540 }
541 };
542
543 inline constexpr __find_if_fn find_if{};
544
545 struct __find_if_not_fn
546 {
547 template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
548 typename _Proj = identity,
549 indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
550 constexpr _Iter
551 operator()(_Iter __first, _Sent __last,
552 _Pred __pred, _Proj __proj = {}) const
553 {
554 while (__first != __last
555 && (bool)std::__invoke(__pred, std::__invoke(__proj, *__first)))
556 ++__first;
557 return __first;
558 }
559
560 template<input_range _Range, typename _Proj = identity,
561 indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>>
562 _Pred>
563 constexpr borrowed_iterator_t<_Range>
564 operator()(_Range&& __r, _Pred __pred, _Proj __proj = {}) const
565 {
566 return (*this)(ranges::begin(__r), ranges::end(__r),
567 std::move(__pred), std::move(__proj));
568 }
569 };
570
571 inline constexpr __find_if_not_fn find_if_not{};
572
573 template<typename _Iter1, typename _Iter2>
574 struct in_in_result
575 {
576 [[no_unique_address]] _Iter1 in1;
577 [[no_unique_address]] _Iter2 in2;
578
579 template<typename _IIter1, typename _IIter2>
580 requires convertible_to<const _Iter1&, _IIter1>
581 && convertible_to<const _Iter2&, _IIter2>
582 constexpr
583 operator in_in_result<_IIter1, _IIter2>() const &
584 { return {in1, in2}; }
585
586 template<typename _IIter1, typename _IIter2>
587 requires convertible_to<_Iter1, _IIter1>
588 && convertible_to<_Iter2, _IIter2>
589 constexpr
590 operator in_in_result<_IIter1, _IIter2>() &&
591 { return {std::move(in1), std::move(in2)}; }
592 };
593
594 template<typename _Iter1, typename _Iter2>
595 using mismatch_result = in_in_result<_Iter1, _Iter2>;
596
597 struct __mismatch_fn
598 {
599 template<input_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
600 input_iterator _Iter2, sentinel_for<_Iter2> _Sent2,
601 typename _Pred = ranges::equal_to,
602 typename _Proj1 = identity, typename _Proj2 = identity>
603 requires indirectly_comparable<_Iter1, _Iter2, _Pred, _Proj1, _Proj2>
604 constexpr mismatch_result<_Iter1, _Iter2>
605 operator()(_Iter1 __first1, _Sent1 __last1,
606 _Iter2 __first2, _Sent2 __last2, _Pred __pred = {},
607 _Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
608 {
609 while (__first1 != __last1 && __first2 != __last2
610 && (bool)std::__invoke(__pred,
611 std::__invoke(__proj1, *__first1),
612 std::__invoke(__proj2, *__first2)))
613 {
614 ++__first1;
615 ++__first2;
616 }
617 return { std::move(__first1), std::move(__first2) };
618 }
619
620 template<input_range _Range1, input_range _Range2,
621 typename _Pred = ranges::equal_to,
622 typename _Proj1 = identity, typename _Proj2 = identity>
623 requires indirectly_comparable<iterator_t<_Range1>, iterator_t<_Range2>,
624 _Pred, _Proj1, _Proj2>
625 constexpr mismatch_result<iterator_t<_Range1>, iterator_t<_Range2>>
626 operator()(_Range1&& __r1, _Range2&& __r2, _Pred __pred = {},
627 _Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
628 {
629 return (*this)(ranges::begin(__r1), ranges::end(__r1),
630 ranges::begin(__r2), ranges::end(__r2),
631 std::move(__pred),
632 std::move(__proj1), std::move(__proj2));
633 }
634 };
635
636 inline constexpr __mismatch_fn mismatch{};
637
638 struct __search_fn
639 {
640 template<forward_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
641 forward_iterator _Iter2, sentinel_for<_Iter2> _Sent2,
642 typename _Pred = ranges::equal_to,
643 typename _Proj1 = identity, typename _Proj2 = identity>
644 requires indirectly_comparable<_Iter1, _Iter2, _Pred, _Proj1, _Proj2>
645 constexpr subrange<_Iter1>
646 operator()(_Iter1 __first1, _Sent1 __last1,
647 _Iter2 __first2, _Sent2 __last2, _Pred __pred = {},
648 _Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
649 {
650 if (__first1 == __last1 || __first2 == __last2)
651 return {__first1, __first1};
652
653 for (;;)
654 {
655 for (;;)
656 {
657 if (__first1 == __last1)
658 return {__first1, __first1};
659 if (std::__invoke(__pred,
660 std::__invoke(__proj1, *__first1),
661 std::__invoke(__proj2, *__first2)))
662 break;
663 ++__first1;
664 }
665 auto __cur1 = __first1;
666 auto __cur2 = __first2;
667 for (;;)
668 {
669 if (++__cur2 == __last2)
670 return {__first1, ++__cur1};
671 if (++__cur1 == __last1)
672 return {__cur1, __cur1};
673 if (!(bool)std::__invoke(__pred,
674 std::__invoke(__proj1, *__cur1),
675 std::__invoke(__proj2, *__cur2)))
676 {
677 ++__first1;
678 break;
679 }
680 }
681 }
682 }
683
684 template<forward_range _Range1, forward_range _Range2,
685 typename _Pred = ranges::equal_to,
686 typename _Proj1 = identity, typename _Proj2 = identity>
687 requires indirectly_comparable<iterator_t<_Range1>, iterator_t<_Range2>,
688 _Pred, _Proj1, _Proj2>
689 constexpr borrowed_subrange_t<_Range1>
690 operator()(_Range1&& __r1, _Range2&& __r2, _Pred __pred = {},
691 _Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
692 {
693 return (*this)(ranges::begin(__r1), ranges::end(__r1),
694 ranges::begin(__r2), ranges::end(__r2),
695 std::move(__pred),
696 std::move(__proj1), std::move(__proj2));
697 }
698 };
699
700 inline constexpr __search_fn search{};
701
702 struct __min_fn
703 {
704 template<typename _Tp, typename _Proj = identity,
705 indirect_strict_weak_order<projected<const _Tp*, _Proj>>
706 _Comp = ranges::less>
707 constexpr const _Tp&
708 operator()(const _Tp& __a, const _Tp& __b,
709 _Comp __comp = {}, _Proj __proj = {}) const
710 {
711 if (std::__invoke(__comp,
712 std::__invoke(__proj, __b),
713 std::__invoke(__proj, __a)))
714 return __b;
715 else
716 return __a;
717 }
718
719 template<input_range _Range, typename _Proj = identity,
720 indirect_strict_weak_order<projected<iterator_t<_Range>, _Proj>>
721 _Comp = ranges::less>
722 requires indirectly_copyable_storable<iterator_t<_Range>,
723 range_value_t<_Range>*>
724 constexpr range_value_t<_Range>
725 operator()(_Range&& __r, _Comp __comp = {}, _Proj __proj = {}) const
726 {
727 auto __first = ranges::begin(__r);
728 auto __last = ranges::end(__r);
729 __glibcxx_assert(__first != __last);
730 auto __result = *__first;
731 while (++__first != __last)
732 {
733 auto __tmp = *__first;
734 if (std::__invoke(__comp,
735 std::__invoke(__proj, __tmp),
736 std::__invoke(__proj, __result)))
737 __result = std::move(__tmp);
738 }
739 return __result;
740 }
741
742 template<copyable _Tp, typename _Proj = identity,
743 indirect_strict_weak_order<projected<const _Tp*, _Proj>>
744 _Comp = ranges::less>
745 constexpr _Tp
746 operator()(initializer_list<_Tp> __r,
747 _Comp __comp = {}, _Proj __proj = {}) const
748 {
749 return (*this)(ranges::subrange(__r),
750 std::move(__comp), std::move(__proj));
751 }
752 };
753
754 inline constexpr __min_fn min{};
755
756 struct __adjacent_find_fn
757 {
758 template<forward_iterator _Iter, sentinel_for<_Iter> _Sent,
759 typename _Proj = identity,
760 indirect_binary_predicate<projected<_Iter, _Proj>,
761 projected<_Iter, _Proj>> _Pred
762 = ranges::equal_to>
763 constexpr _Iter
764 operator()(_Iter __first, _Sent __last,
765 _Pred __pred = {}, _Proj __proj = {}) const
766 {
767 if (__first == __last)
768 return __first;
769 auto __next = __first;
770 for (; ++__next != __last; __first = __next)
771 {
772 if (std::__invoke(__pred,
773 std::__invoke(__proj, *__first),
774 std::__invoke(__proj, *__next)))
775 return __first;
776 }
777 return __next;
778 }
779
780 template<forward_range _Range, typename _Proj = identity,
781 indirect_binary_predicate<
782 projected<iterator_t<_Range>, _Proj>,
783 projected<iterator_t<_Range>, _Proj>> _Pred = ranges::equal_to>
784 constexpr borrowed_iterator_t<_Range>
785 operator()(_Range&& __r, _Pred __pred = {}, _Proj __proj = {}) const
786 {
787 return (*this)(ranges::begin(__r), ranges::end(__r),
788 std::move(__pred), std::move(__proj));
789 }
790 };
791
792 inline constexpr __adjacent_find_fn adjacent_find{};
793
794} // namespace ranges
795
796 using ranges::get;
797
798 template<typename _Iter, typename _Sent, ranges::subrange_kind _Kind>
799 struct tuple_size<ranges::subrange<_Iter, _Sent, _Kind>>
800 : integral_constant<size_t, 2>
801 { };
802
803 template<typename _Iter, typename _Sent, ranges::subrange_kind _Kind>
804 struct tuple_element<0, ranges::subrange<_Iter, _Sent, _Kind>>
805 { using type = _Iter; };
806
807 template<typename _Iter, typename _Sent, ranges::subrange_kind _Kind>
808 struct tuple_element<1, ranges::subrange<_Iter, _Sent, _Kind>>
809 { using type = _Sent; };
810
811 template<typename _Iter, typename _Sent, ranges::subrange_kind _Kind>
812 struct tuple_element<0, const ranges::subrange<_Iter, _Sent, _Kind>>
813 { using type = _Iter; };
814
815 template<typename _Iter, typename _Sent, ranges::subrange_kind _Kind>
816 struct tuple_element<1, const ranges::subrange<_Iter, _Sent, _Kind>>
817 { using type = _Sent; };
818
819_GLIBCXX_END_NAMESPACE_VERSION
820} // namespace std
821#endif // library concepts
822#endif // C++20
823#endif // _RANGES_UTIL_H
824