3// Copyright (C) 2019-2023 Free Software Foundation, Inc.
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
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16// Under Section 7 of GPL version 3, you are granted additional
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18// 3.1, as published by the Free Software Foundation.
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25/** @file include/ranges
26 * This is a Standard C++ Library header.
30#ifndef _GLIBCXX_RANGES
31#define _GLIBCXX_RANGES 1
33#if __cplusplus > 201703L
35#pragma GCC system_header
42#include <initializer_list>
48#if __cplusplus > 202002L
51#include <bits/ranges_util.h>
52#include <bits/refwrap.h>
55 * @defgroup ranges Ranges
57 * Components for dealing with ranges of elements.
60namespace std _GLIBCXX_VISIBILITY(default)
62_GLIBCXX_BEGIN_NAMESPACE_VERSION
65 // [range.access] customization point objects
66 // [range.req] range and view concepts
67 // [range.dangling] dangling iterator handling
68 // Defined in <bits/ranges_base.h>
70 // [view.interface] View interface
71 // [range.subrange] Sub-ranges
72 // Defined in <bits/ranges_util.h>
74 // C++20 24.6 [range.factories] Range factories
76 /// A view that contains no elements.
77 template<typename _Tp> requires is_object_v<_Tp>
79 : public view_interface<empty_view<_Tp>>
82 static constexpr _Tp* begin() noexcept { return nullptr; }
83 static constexpr _Tp* end() noexcept { return nullptr; }
84 static constexpr _Tp* data() noexcept { return nullptr; }
85 static constexpr size_t size() noexcept { return 0; }
86 static constexpr bool empty() noexcept { return true; }
89 template<typename _Tp>
90 inline constexpr bool enable_borrowed_range<empty_view<_Tp>> = true;
94 template<typename _Tp>
95 concept __boxable = copy_constructible<_Tp> && is_object_v<_Tp>;
97 template<__boxable _Tp>
98 struct __box : std::optional<_Tp>
100 using std::optional<_Tp>::optional;
104 noexcept(is_nothrow_default_constructible_v<_Tp>)
105 requires default_initializable<_Tp>
106 : std::optional<_Tp>{std::in_place}
109 __box(const __box&) = default;
110 __box(__box&&) = default;
112 using std::optional<_Tp>::operator=;
114 // _GLIBCXX_RESOLVE_LIB_DEFECTS
115 // 3477. Simplify constraints for semiregular-box
116 // 3572. copyable-box should be fully constexpr
118 operator=(const __box& __that)
119 noexcept(is_nothrow_copy_constructible_v<_Tp>)
120 requires (!copyable<_Tp>)
122 if (this != std::__addressof(__that))
125 this->emplace(*__that);
133 operator=(__box&& __that)
134 noexcept(is_nothrow_move_constructible_v<_Tp>)
135 requires (!movable<_Tp>)
137 if (this != std::__addressof(__that))
140 this->emplace(std::move(*__that));
148 // For types which are already copyable, this specialization of the
149 // copyable wrapper stores the object directly without going through
150 // std::optional. It provides just the subset of the primary template's
151 // API that we currently use.
152 template<__boxable _Tp>
153 requires copyable<_Tp> || (is_nothrow_move_constructible_v<_Tp>
154 && is_nothrow_copy_constructible_v<_Tp>)
158 [[no_unique_address]] _Tp _M_value = _Tp();
161 __box() requires default_initializable<_Tp> = default;
164 __box(const _Tp& __t)
165 noexcept(is_nothrow_copy_constructible_v<_Tp>)
171 noexcept(is_nothrow_move_constructible_v<_Tp>)
172 : _M_value(std::move(__t))
175 template<typename... _Args>
176 requires constructible_from<_Tp, _Args...>
178 __box(in_place_t, _Args&&... __args)
179 noexcept(is_nothrow_constructible_v<_Tp, _Args...>)
180 : _M_value(std::forward<_Args>(__args)...)
183 __box(const __box&) = default;
184 __box(__box&&) = default;
185 __box& operator=(const __box&) requires copyable<_Tp> = default;
186 __box& operator=(__box&&) requires copyable<_Tp> = default;
188 // When _Tp is nothrow_copy_constructible but not copy_assignable,
189 // copy assignment is implemented via destroy-then-copy-construct.
191 operator=(const __box& __that) noexcept
193 static_assert(is_nothrow_copy_constructible_v<_Tp>);
194 if (this != std::__addressof(__that))
197 std::construct_at(std::__addressof(_M_value), *__that);
202 // Likewise for move assignment.
204 operator=(__box&& __that) noexcept
206 static_assert(is_nothrow_move_constructible_v<_Tp>);
207 if (this != std::__addressof(__that))
210 std::construct_at(std::__addressof(_M_value), std::move(*__that));
216 has_value() const noexcept
224 operator*() const noexcept
228 operator->() noexcept
229 { return std::__addressof(_M_value); }
232 operator->() const noexcept
233 { return std::__addressof(_M_value); }
235 } // namespace __detail
237 /// A view that contains exactly one element.
238 template<copy_constructible _Tp> requires is_object_v<_Tp>
239 class single_view : public view_interface<single_view<_Tp>>
242 single_view() requires default_initializable<_Tp> = default;
245 single_view(const _Tp& __t)
246 noexcept(is_nothrow_copy_constructible_v<_Tp>)
251 single_view(_Tp&& __t)
252 noexcept(is_nothrow_move_constructible_v<_Tp>)
253 : _M_value(std::move(__t))
256 // _GLIBCXX_RESOLVE_LIB_DEFECTS
257 // 3428. single_view's in place constructor should be explicit
258 template<typename... _Args>
259 requires constructible_from<_Tp, _Args...>
261 single_view(in_place_t, _Args&&... __args)
262 noexcept(is_nothrow_constructible_v<_Tp, _Args...>)
263 : _M_value{in_place, std::forward<_Args>(__args)...}
271 begin() const noexcept
276 { return data() + 1; }
280 { return data() + 1; }
282 static constexpr size_t
288 { return _M_value.operator->(); }
291 data() const noexcept
292 { return _M_value.operator->(); }
295 [[no_unique_address]] __detail::__box<_Tp> _M_value;
298 template<typename _Tp>
299 single_view(_Tp) -> single_view<_Tp>;
303 template<typename _Wp>
304 constexpr auto __to_signed_like(_Wp __w) noexcept
306 if constexpr (!integral<_Wp>)
307 return iter_difference_t<_Wp>();
308 else if constexpr (sizeof(iter_difference_t<_Wp>) > sizeof(_Wp))
309 return iter_difference_t<_Wp>(__w);
310 else if constexpr (sizeof(ptrdiff_t) > sizeof(_Wp))
311 return ptrdiff_t(__w);
312 else if constexpr (sizeof(long long) > sizeof(_Wp))
313 return (long long)(__w);
314#ifdef __SIZEOF_INT128__
315 else if constexpr (__SIZEOF_INT128__ > sizeof(_Wp))
316 return __int128(__w);
319 return __max_diff_type(__w);
322 template<typename _Wp>
323 using __iota_diff_t = decltype(__to_signed_like(std::declval<_Wp>()));
325 template<typename _It>
326 concept __decrementable = incrementable<_It>
329 { --__i } -> same_as<_It&>;
330 { __i-- } -> same_as<_It>;
333 template<typename _It>
334 concept __advanceable = __decrementable<_It> && totally_ordered<_It>
335 && requires( _It __i, const _It __j, const __iota_diff_t<_It> __n)
337 { __i += __n } -> same_as<_It&>;
338 { __i -= __n } -> same_as<_It&>;
342 { __j - __j } -> convertible_to<__iota_diff_t<_It>>;
345 template<typename _Winc>
346 struct __iota_view_iter_cat
349 template<incrementable _Winc>
350 struct __iota_view_iter_cat<_Winc>
351 { using iterator_category = input_iterator_tag; };
352 } // namespace __detail
354 template<weakly_incrementable _Winc,
355 semiregular _Bound = unreachable_sentinel_t>
356 requires std::__detail::__weakly_eq_cmp_with<_Winc, _Bound>
358 class iota_view : public view_interface<iota_view<_Winc, _Bound>>
363 struct _Iterator : __detail::__iota_view_iter_cat<_Winc>
369 using namespace __detail;
370 if constexpr (__advanceable<_Winc>)
371 return random_access_iterator_tag{};
372 else if constexpr (__decrementable<_Winc>)
373 return bidirectional_iterator_tag{};
374 else if constexpr (incrementable<_Winc>)
375 return forward_iterator_tag{};
377 return input_iterator_tag{};
381 using iterator_concept = decltype(_S_iter_concept());
382 // iterator_category defined in __iota_view_iter_cat
383 using value_type = _Winc;
384 using difference_type = __detail::__iota_diff_t<_Winc>;
386 _Iterator() requires default_initializable<_Winc> = default;
389 _Iterator(_Winc __value)
390 : _M_value(__value) { }
393 operator*() const noexcept(is_nothrow_copy_constructible_v<_Winc>)
408 operator++(int) requires incrementable<_Winc>
416 operator--() requires __detail::__decrementable<_Winc>
423 operator--(int) requires __detail::__decrementable<_Winc>
431 operator+=(difference_type __n) requires __detail::__advanceable<_Winc>
433 using __detail::__is_integer_like;
434 using __detail::__is_signed_integer_like;
435 if constexpr (__is_integer_like<_Winc>
436 && !__is_signed_integer_like<_Winc>)
438 if (__n >= difference_type(0))
439 _M_value += static_cast<_Winc>(__n);
441 _M_value -= static_cast<_Winc>(-__n);
449 operator-=(difference_type __n) requires __detail::__advanceable<_Winc>
451 using __detail::__is_integer_like;
452 using __detail::__is_signed_integer_like;
453 if constexpr (__is_integer_like<_Winc>
454 && !__is_signed_integer_like<_Winc>)
456 if (__n >= difference_type(0))
457 _M_value -= static_cast<_Winc>(__n);
459 _M_value += static_cast<_Winc>(-__n);
467 operator[](difference_type __n) const
468 requires __detail::__advanceable<_Winc>
469 { return _Winc(_M_value + __n); }
471 friend constexpr bool
472 operator==(const _Iterator& __x, const _Iterator& __y)
473 requires equality_comparable<_Winc>
474 { return __x._M_value == __y._M_value; }
476 friend constexpr bool
477 operator<(const _Iterator& __x, const _Iterator& __y)
478 requires totally_ordered<_Winc>
479 { return __x._M_value < __y._M_value; }
481 friend constexpr bool
482 operator>(const _Iterator& __x, const _Iterator& __y)
483 requires totally_ordered<_Winc>
484 { return __y < __x; }
486 friend constexpr bool
487 operator<=(const _Iterator& __x, const _Iterator& __y)
488 requires totally_ordered<_Winc>
489 { return !(__y < __x); }
491 friend constexpr bool
492 operator>=(const _Iterator& __x, const _Iterator& __y)
493 requires totally_ordered<_Winc>
494 { return !(__x < __y); }
496#ifdef __cpp_lib_three_way_comparison
497 friend constexpr auto
498 operator<=>(const _Iterator& __x, const _Iterator& __y)
499 requires totally_ordered<_Winc> && three_way_comparable<_Winc>
500 { return __x._M_value <=> __y._M_value; }
503 friend constexpr _Iterator
504 operator+(_Iterator __i, difference_type __n)
505 requires __detail::__advanceable<_Winc>
511 friend constexpr _Iterator
512 operator+(difference_type __n, _Iterator __i)
513 requires __detail::__advanceable<_Winc>
514 { return __i += __n; }
516 friend constexpr _Iterator
517 operator-(_Iterator __i, difference_type __n)
518 requires __detail::__advanceable<_Winc>
524 friend constexpr difference_type
525 operator-(const _Iterator& __x, const _Iterator& __y)
526 requires __detail::__advanceable<_Winc>
528 using __detail::__is_integer_like;
529 using __detail::__is_signed_integer_like;
530 using _Dt = difference_type;
531 if constexpr (__is_integer_like<_Winc>)
533 if constexpr (__is_signed_integer_like<_Winc>)
534 return _Dt(_Dt(__x._M_value) - _Dt(__y._M_value));
536 return (__y._M_value > __x._M_value)
537 ? _Dt(-_Dt(__y._M_value - __x._M_value))
538 : _Dt(__x._M_value - __y._M_value);
541 return __x._M_value - __y._M_value;
545 _Winc _M_value = _Winc();
555 _M_equal(const _Iterator& __x) const
556 { return __x._M_value == _M_bound; }
559 _M_distance_from(const _Iterator& __x) const
560 { return _M_bound - __x._M_value; }
562 _Bound _M_bound = _Bound();
565 _Sentinel() = default;
568 _Sentinel(_Bound __bound)
569 : _M_bound(__bound) { }
571 friend constexpr bool
572 operator==(const _Iterator& __x, const _Sentinel& __y)
573 { return __y._M_equal(__x); }
575 friend constexpr iter_difference_t<_Winc>
576 operator-(const _Iterator& __x, const _Sentinel& __y)
577 requires sized_sentinel_for<_Bound, _Winc>
578 { return -__y._M_distance_from(__x); }
580 friend constexpr iter_difference_t<_Winc>
581 operator-(const _Sentinel& __x, const _Iterator& __y)
582 requires sized_sentinel_for<_Bound, _Winc>
583 { return __x._M_distance_from(__y); }
588 _Winc _M_value = _Winc();
589 [[no_unique_address]] _Bound _M_bound = _Bound();
592 iota_view() requires default_initializable<_Winc> = default;
595 iota_view(_Winc __value)
600 iota_view(type_identity_t<_Winc> __value,
601 type_identity_t<_Bound> __bound)
602 : _M_value(__value), _M_bound(__bound)
604 if constexpr (totally_ordered_with<_Winc, _Bound>)
605 __glibcxx_assert( bool(__value <= __bound) );
609 iota_view(_Iterator __first, _Iterator __last)
610 requires same_as<_Winc, _Bound>
611 : iota_view(__first._M_value, __last._M_value)
615 iota_view(_Iterator __first, unreachable_sentinel_t __last)
616 requires same_as<_Bound, unreachable_sentinel_t>
617 : iota_view(__first._M_value, __last)
621 iota_view(_Iterator __first, _Sentinel __last)
622 requires (!same_as<_Winc, _Bound>) && (!same_as<_Bound, unreachable_sentinel_t>)
623 : iota_view(__first._M_value, __last._M_bound)
627 begin() const { return _Iterator{_M_value}; }
632 if constexpr (same_as<_Bound, unreachable_sentinel_t>)
633 return unreachable_sentinel;
635 return _Sentinel{_M_bound};
639 end() const requires same_as<_Winc, _Bound>
640 { return _Iterator{_M_bound}; }
644 requires (same_as<_Winc, _Bound> && __detail::__advanceable<_Winc>)
645 || (integral<_Winc> && integral<_Bound>)
646 || sized_sentinel_for<_Bound, _Winc>
648 using __detail::__is_integer_like;
649 using __detail::__to_unsigned_like;
650 if constexpr (integral<_Winc> && integral<_Bound>)
652 using _Up = make_unsigned_t<decltype(_M_bound - _M_value)>;
653 return _Up(_M_bound) - _Up(_M_value);
655 else if constexpr (__is_integer_like<_Winc>)
656 return __to_unsigned_like(_M_bound) - __to_unsigned_like(_M_value);
658 return __to_unsigned_like(_M_bound - _M_value);
662 template<typename _Winc, typename _Bound>
663 requires (!__detail::__is_integer_like<_Winc>
664 || !__detail::__is_integer_like<_Bound>
665 || (__detail::__is_signed_integer_like<_Winc>
666 == __detail::__is_signed_integer_like<_Bound>))
667 iota_view(_Winc, _Bound) -> iota_view<_Winc, _Bound>;
669 template<typename _Winc, typename _Bound>
670 inline constexpr bool
671 enable_borrowed_range<iota_view<_Winc, _Bound>> = true;
675 template<typename _Tp>
676 inline constexpr empty_view<_Tp> empty{};
680 template<typename _Tp>
681 concept __can_single_view
682 = requires { single_view<decay_t<_Tp>>(std::declval<_Tp>()); };
683 } // namespace __detail
687 template<__detail::__can_single_view _Tp>
689 operator() [[nodiscard]] (_Tp&& __e) const
690 noexcept(noexcept(single_view<decay_t<_Tp>>(std::forward<_Tp>(__e))))
691 { return single_view<decay_t<_Tp>>(std::forward<_Tp>(__e)); }
694 inline constexpr _Single single{};
698 template<typename... _Args>
699 concept __can_iota_view = requires { iota_view(std::declval<_Args>()...); };
700 } // namespace __detail
704 template<__detail::__can_iota_view _Tp>
706 operator() [[nodiscard]] (_Tp&& __e) const
707 { return iota_view(std::forward<_Tp>(__e)); }
709 template<typename _Tp, typename _Up>
710 requires __detail::__can_iota_view<_Tp, _Up>
712 operator() [[nodiscard]] (_Tp&& __e, _Up&& __f) const
713 { return iota_view(std::forward<_Tp>(__e), std::forward<_Up>(__f)); }
716 inline constexpr _Iota iota{};
722 template<typename _Val, typename _CharT, typename _Traits>
723 concept __stream_extractable
724 = requires(basic_istream<_CharT, _Traits>& is, _Val& t) { is >> t; };
725 } // namespace __detail
727 template<movable _Val, typename _CharT,
728 typename _Traits = char_traits<_CharT>>
729 requires default_initializable<_Val>
730 && __detail::__stream_extractable<_Val, _CharT, _Traits>
731 class basic_istream_view
732 : public view_interface<basic_istream_view<_Val, _CharT, _Traits>>
736 basic_istream_view(basic_istream<_CharT, _Traits>& __stream)
737 : _M_stream(std::__addressof(__stream))
743 *_M_stream >> _M_object;
744 return _Iterator{this};
747 constexpr default_sentinel_t
749 { return default_sentinel; }
752 basic_istream<_CharT, _Traits>* _M_stream;
753 _Val _M_object = _Val();
758 using iterator_concept = input_iterator_tag;
759 using difference_type = ptrdiff_t;
760 using value_type = _Val;
763 _Iterator(basic_istream_view* __parent) noexcept
764 : _M_parent(__parent)
767 _Iterator(const _Iterator&) = delete;
768 _Iterator(_Iterator&&) = default;
769 _Iterator& operator=(const _Iterator&) = delete;
770 _Iterator& operator=(_Iterator&&) = default;
775 *_M_parent->_M_stream >> _M_parent->_M_object;
785 { return _M_parent->_M_object; }
788 operator==(const _Iterator& __x, default_sentinel_t)
789 { return __x._M_at_end(); }
792 basic_istream_view* _M_parent;
796 { return !*_M_parent->_M_stream; }
802 template<typename _Val>
803 using istream_view = basic_istream_view<_Val, char>;
805 template<typename _Val>
806 using wistream_view = basic_istream_view<_Val, wchar_t>;
812 template<typename _Tp, typename _Up>
813 concept __can_istream_view = requires (_Up __e) {
814 basic_istream_view<_Tp, typename _Up::char_type, typename _Up::traits_type>(__e);
816 } // namespace __detail
818 template<typename _Tp>
821 template<typename _CharT, typename _Traits>
823 operator() [[nodiscard]] (basic_istream<_CharT, _Traits>& __e) const
824 requires __detail::__can_istream_view<_Tp, remove_reference_t<decltype(__e)>>
825 { return basic_istream_view<_Tp, _CharT, _Traits>(__e); }
828 template<typename _Tp>
829 inline constexpr _Istream<_Tp> istream;
833 // C++20 24.7 [range.adaptors] Range adaptors
839 // Alias for a type that is conditionally present
840 // (and is an empty type otherwise).
841 // Data members using this alias should use [[no_unique_address]] so that
842 // they take no space when not needed.
843 template<bool _Present, typename _Tp>
844 using __maybe_present_t = __conditional_t<_Present, _Tp, _Empty>;
846 // Alias for a type that is conditionally const.
847 template<bool _Const, typename _Tp>
848 using __maybe_const_t = __conditional_t<_Const, const _Tp, _Tp>;
850} // namespace __detail
852// Shorthand for __detail::__maybe_const_t.
853using __detail::__maybe_const_t;
855namespace views::__adaptor
857 // True if the range adaptor _Adaptor can be applied with _Args.
858 template<typename _Adaptor, typename... _Args>
859 concept __adaptor_invocable
860 = requires { std::declval<_Adaptor>()(declval<_Args>()...); };
862 // True if the range adaptor non-closure _Adaptor can be partially applied
864 template<typename _Adaptor, typename... _Args>
865 concept __adaptor_partial_app_viable = (_Adaptor::_S_arity > 1)
866 && (sizeof...(_Args) == _Adaptor::_S_arity - 1)
867 && (constructible_from<decay_t<_Args>, _Args> && ...);
869 template<typename _Adaptor, typename... _Args>
872 template<typename _Lhs, typename _Rhs>
875 // The base class of every range adaptor closure.
877 // The derived class should define the optional static data member
878 // _S_has_simple_call_op to true if the behavior of this adaptor is
879 // independent of the constness/value category of the adaptor object.
880 struct _RangeAdaptorClosure
882 // range | adaptor is equivalent to adaptor(range).
883 template<typename _Self, typename _Range>
884 requires derived_from<remove_cvref_t<_Self>, _RangeAdaptorClosure>
885 && __adaptor_invocable<_Self, _Range>
886 friend constexpr auto
887 operator|(_Range&& __r, _Self&& __self)
888 { return std::forward<_Self>(__self)(std::forward<_Range>(__r)); }
890 // Compose the adaptors __lhs and __rhs into a pipeline, returning
891 // another range adaptor closure object.
892 template<typename _Lhs, typename _Rhs>
893 requires derived_from<_Lhs, _RangeAdaptorClosure>
894 && derived_from<_Rhs, _RangeAdaptorClosure>
895 friend constexpr auto
896 operator|(_Lhs __lhs, _Rhs __rhs)
897 { return _Pipe<_Lhs, _Rhs>{std::move(__lhs), std::move(__rhs)}; }
900 // The base class of every range adaptor non-closure.
902 // The static data member _Derived::_S_arity must contain the total number of
903 // arguments that the adaptor takes, and the class _Derived must introduce
904 // _RangeAdaptor::operator() into the class scope via a using-declaration.
906 // The optional static data member _Derived::_S_has_simple_extra_args should
907 // be defined to true if the behavior of this adaptor is independent of the
908 // constness/value category of the extra arguments. This data member could
909 // also be defined as a variable template parameterized by the types of the
911 template<typename _Derived>
914 // Partially apply the arguments __args to the range adaptor _Derived,
915 // returning a range adaptor closure object.
916 template<typename... _Args>
917 requires __adaptor_partial_app_viable<_Derived, _Args...>
919 operator()(_Args&&... __args) const
921 return _Partial<_Derived, decay_t<_Args>...>{std::forward<_Args>(__args)...};
925 // True if the range adaptor closure _Adaptor has a simple operator(), i.e.
926 // one that's not overloaded according to constness or value category of the
928 template<typename _Adaptor>
929 concept __closure_has_simple_call_op = _Adaptor::_S_has_simple_call_op;
931 // True if the behavior of the range adaptor non-closure _Adaptor is
932 // independent of the value category of its extra arguments _Args.
933 template<typename _Adaptor, typename... _Args>
934 concept __adaptor_has_simple_extra_args = _Adaptor::_S_has_simple_extra_args
935 || _Adaptor::template _S_has_simple_extra_args<_Args...>;
937 // A range adaptor closure that represents partial application of
938 // the range adaptor _Adaptor with arguments _Args.
939 template<typename _Adaptor, typename... _Args>
940 struct _Partial : _RangeAdaptorClosure
942 tuple<_Args...> _M_args;
945 _Partial(_Args... __args)
946 : _M_args(std::move(__args)...)
949 // Invoke _Adaptor with arguments __r, _M_args... according to the
950 // value category of this _Partial object.
951 template<typename _Range>
952 requires __adaptor_invocable<_Adaptor, _Range, const _Args&...>
954 operator()(_Range&& __r) const &
956 auto __forwarder = [&__r] (const auto&... __args) {
957 return _Adaptor{}(std::forward<_Range>(__r), __args...);
959 return std::apply(__forwarder, _M_args);
962 template<typename _Range>
963 requires __adaptor_invocable<_Adaptor, _Range, _Args...>
965 operator()(_Range&& __r) &&
967 auto __forwarder = [&__r] (auto&... __args) {
968 return _Adaptor{}(std::forward<_Range>(__r), std::move(__args)...);
970 return std::apply(__forwarder, _M_args);
973 template<typename _Range>
975 operator()(_Range&& __r) const && = delete;
978 // A lightweight specialization of the above primary template for
979 // the common case where _Adaptor accepts a single extra argument.
980 template<typename _Adaptor, typename _Arg>
981 struct _Partial<_Adaptor, _Arg> : _RangeAdaptorClosure
987 : _M_arg(std::move(__arg))
990 template<typename _Range>
991 requires __adaptor_invocable<_Adaptor, _Range, const _Arg&>
993 operator()(_Range&& __r) const &
994 { return _Adaptor{}(std::forward<_Range>(__r), _M_arg); }
996 template<typename _Range>
997 requires __adaptor_invocable<_Adaptor, _Range, _Arg>
999 operator()(_Range&& __r) &&
1000 { return _Adaptor{}(std::forward<_Range>(__r), std::move(_M_arg)); }
1002 template<typename _Range>
1004 operator()(_Range&& __r) const && = delete;
1007 // Partial specialization of the primary template for the case where the extra
1008 // arguments of the adaptor can always be safely and efficiently forwarded by
1009 // const reference. This lets us get away with a single operator() overload,
1010 // which makes overload resolution failure diagnostics more concise.
1011 template<typename _Adaptor, typename... _Args>
1012 requires __adaptor_has_simple_extra_args<_Adaptor, _Args...>
1013 && (is_trivially_copyable_v<_Args> && ...)
1014 struct _Partial<_Adaptor, _Args...> : _RangeAdaptorClosure
1016 tuple<_Args...> _M_args;
1019 _Partial(_Args... __args)
1020 : _M_args(std::move(__args)...)
1023 // Invoke _Adaptor with arguments __r, const _M_args&... regardless
1024 // of the value category of this _Partial object.
1025 template<typename _Range>
1026 requires __adaptor_invocable<_Adaptor, _Range, const _Args&...>
1028 operator()(_Range&& __r) const
1030 auto __forwarder = [&__r] (const auto&... __args) {
1031 return _Adaptor{}(std::forward<_Range>(__r), __args...);
1033 return std::apply(__forwarder, _M_args);
1036 static constexpr bool _S_has_simple_call_op = true;
1039 // A lightweight specialization of the above template for the common case
1040 // where _Adaptor accepts a single extra argument.
1041 template<typename _Adaptor, typename _Arg>
1042 requires __adaptor_has_simple_extra_args<_Adaptor, _Arg>
1043 && is_trivially_copyable_v<_Arg>
1044 struct _Partial<_Adaptor, _Arg> : _RangeAdaptorClosure
1049 _Partial(_Arg __arg)
1050 : _M_arg(std::move(__arg))
1053 template<typename _Range>
1054 requires __adaptor_invocable<_Adaptor, _Range, const _Arg&>
1056 operator()(_Range&& __r) const
1057 { return _Adaptor{}(std::forward<_Range>(__r), _M_arg); }
1059 static constexpr bool _S_has_simple_call_op = true;
1062 template<typename _Lhs, typename _Rhs, typename _Range>
1063 concept __pipe_invocable
1064 = requires { std::declval<_Rhs>()(std::declval<_Lhs>()(std::declval<_Range>())); };
1066 // A range adaptor closure that represents composition of the range
1067 // adaptor closures _Lhs and _Rhs.
1068 template<typename _Lhs, typename _Rhs>
1069 struct _Pipe : _RangeAdaptorClosure
1071 [[no_unique_address]] _Lhs _M_lhs;
1072 [[no_unique_address]] _Rhs _M_rhs;
1075 _Pipe(_Lhs __lhs, _Rhs __rhs)
1076 : _M_lhs(std::move(__lhs)), _M_rhs(std::move(__rhs))
1079 // Invoke _M_rhs(_M_lhs(__r)) according to the value category of this
1080 // range adaptor closure object.
1081 template<typename _Range>
1082 requires __pipe_invocable<const _Lhs&, const _Rhs&, _Range>
1084 operator()(_Range&& __r) const &
1085 { return _M_rhs(_M_lhs(std::forward<_Range>(__r))); }
1087 template<typename _Range>
1088 requires __pipe_invocable<_Lhs, _Rhs, _Range>
1090 operator()(_Range&& __r) &&
1091 { return std::move(_M_rhs)(std::move(_M_lhs)(std::forward<_Range>(__r))); }
1093 template<typename _Range>
1095 operator()(_Range&& __r) const && = delete;
1098 // A partial specialization of the above primary template for the case where
1099 // both adaptor operands have a simple operator(). This in turn lets us
1100 // implement composition using a single simple operator(), which makes
1101 // overload resolution failure diagnostics more concise.
1102 template<typename _Lhs, typename _Rhs>
1103 requires __closure_has_simple_call_op<_Lhs>
1104 && __closure_has_simple_call_op<_Rhs>
1105 struct _Pipe<_Lhs, _Rhs> : _RangeAdaptorClosure
1107 [[no_unique_address]] _Lhs _M_lhs;
1108 [[no_unique_address]] _Rhs _M_rhs;
1111 _Pipe(_Lhs __lhs, _Rhs __rhs)
1112 : _M_lhs(std::move(__lhs)), _M_rhs(std::move(__rhs))
1115 template<typename _Range>
1116 requires __pipe_invocable<const _Lhs&, const _Rhs&, _Range>
1118 operator()(_Range&& __r) const
1119 { return _M_rhs(_M_lhs(std::forward<_Range>(__r))); }
1121 static constexpr bool _S_has_simple_call_op = true;
1123} // namespace views::__adaptor
1125 template<range _Range> requires is_object_v<_Range>
1126 class ref_view : public view_interface<ref_view<_Range>>
1131 static void _S_fun(_Range&); // not defined
1132 static void _S_fun(_Range&&) = delete;
1135 template<__detail::__different_from<ref_view> _Tp>
1136 requires convertible_to<_Tp, _Range&>
1137 && requires { _S_fun(declval<_Tp>()); }
1140 noexcept(noexcept(static_cast<_Range&>(std::declval<_Tp>())))
1141 : _M_r(std::__addressof(static_cast<_Range&>(std::forward<_Tp>(__t))))
1148 constexpr iterator_t<_Range>
1150 { return ranges::begin(*_M_r); }
1152 constexpr sentinel_t<_Range>
1154 { return ranges::end(*_M_r); }
1157 empty() const requires requires { ranges::empty(*_M_r); }
1158 { return ranges::empty(*_M_r); }
1161 size() const requires sized_range<_Range>
1162 { return ranges::size(*_M_r); }
1165 data() const requires contiguous_range<_Range>
1166 { return ranges::data(*_M_r); }
1169 template<typename _Range>
1170 ref_view(_Range&) -> ref_view<_Range>;
1172 template<typename _Tp>
1173 inline constexpr bool enable_borrowed_range<ref_view<_Tp>> = true;
1175 template<range _Range>
1176 requires movable<_Range>
1177 && (!__detail::__is_initializer_list<remove_cv_t<_Range>>)
1178 class owning_view : public view_interface<owning_view<_Range>>
1181 _Range _M_r = _Range();
1184 owning_view() requires default_initializable<_Range> = default;
1187 owning_view(_Range&& __t)
1188 noexcept(is_nothrow_move_constructible_v<_Range>)
1189 : _M_r(std::move(__t))
1192 owning_view(owning_view&&) = default;
1193 owning_view& operator=(owning_view&&) = default;
1199 constexpr const _Range&
1200 base() const& noexcept
1205 { return std::move(_M_r); }
1207 constexpr const _Range&&
1208 base() const&& noexcept
1209 { return std::move(_M_r); }
1211 constexpr iterator_t<_Range>
1213 { return ranges::begin(_M_r); }
1215 constexpr sentinel_t<_Range>
1217 { return ranges::end(_M_r); }
1220 begin() const requires range<const _Range>
1221 { return ranges::begin(_M_r); }
1224 end() const requires range<const _Range>
1225 { return ranges::end(_M_r); }
1228 empty() requires requires { ranges::empty(_M_r); }
1229 { return ranges::empty(_M_r); }
1232 empty() const requires requires { ranges::empty(_M_r); }
1233 { return ranges::empty(_M_r); }
1236 size() requires sized_range<_Range>
1237 { return ranges::size(_M_r); }
1240 size() const requires sized_range<const _Range>
1241 { return ranges::size(_M_r); }
1244 data() requires contiguous_range<_Range>
1245 { return ranges::data(_M_r); }
1248 data() const requires contiguous_range<const _Range>
1249 { return ranges::data(_M_r); }
1252 template<typename _Tp>
1253 inline constexpr bool enable_borrowed_range<owning_view<_Tp>>
1254 = enable_borrowed_range<_Tp>;
1260 template<typename _Range>
1261 concept __can_ref_view = requires { ref_view{std::declval<_Range>()}; };
1263 template<typename _Range>
1264 concept __can_owning_view = requires { owning_view{std::declval<_Range>()}; };
1265 } // namespace __detail
1267 struct _All : __adaptor::_RangeAdaptorClosure
1269 template<typename _Range>
1270 static constexpr bool
1273 if constexpr (view<decay_t<_Range>>)
1274 return is_nothrow_constructible_v<decay_t<_Range>, _Range>;
1275 else if constexpr (__detail::__can_ref_view<_Range>)
1278 return noexcept(owning_view{std::declval<_Range>()});
1281 template<viewable_range _Range>
1282 requires view<decay_t<_Range>>
1283 || __detail::__can_ref_view<_Range>
1284 || __detail::__can_owning_view<_Range>
1286 operator() [[nodiscard]] (_Range&& __r) const
1287 noexcept(_S_noexcept<_Range>())
1289 if constexpr (view<decay_t<_Range>>)
1290 return std::forward<_Range>(__r);
1291 else if constexpr (__detail::__can_ref_view<_Range>)
1292 return ref_view{std::forward<_Range>(__r)};
1294 return owning_view{std::forward<_Range>(__r)};
1297 static constexpr bool _S_has_simple_call_op = true;
1300 inline constexpr _All all;
1302 template<viewable_range _Range>
1303 using all_t = decltype(all(std::declval<_Range>()));
1304 } // namespace views
1308 template<typename _Tp>
1309 struct __non_propagating_cache
1311 // When _Tp is not an object type (e.g. is a reference type), we make
1312 // __non_propagating_cache<_Tp> empty rather than ill-formed so that
1313 // users can easily conditionally declare data members with this type
1314 // (such as join_view::_M_inner).
1317 template<typename _Tp>
1318 requires is_object_v<_Tp>
1319 struct __non_propagating_cache<_Tp>
1320 : protected _Optional_base<_Tp>
1322 __non_propagating_cache() = default;
1325 __non_propagating_cache(const __non_propagating_cache&) noexcept
1329 __non_propagating_cache(__non_propagating_cache&& __other) noexcept
1330 { __other._M_reset(); }
1332 constexpr __non_propagating_cache&
1333 operator=(const __non_propagating_cache& __other) noexcept
1335 if (std::__addressof(__other) != this)
1340 constexpr __non_propagating_cache&
1341 operator=(__non_propagating_cache&& __other) noexcept
1348 constexpr __non_propagating_cache&
1349 operator=(_Tp __val)
1352 this->_M_payload._M_construct(std::move(__val));
1357 operator bool() const noexcept
1358 { return this->_M_is_engaged(); }
1361 operator*() noexcept
1362 { return this->_M_get(); }
1364 constexpr const _Tp&
1365 operator*() const noexcept
1366 { return this->_M_get(); }
1368 template<typename _Iter>
1370 _M_emplace_deref(const _Iter& __i)
1373 auto __f = [] (auto& __x) { return *__x; };
1374 this->_M_payload._M_apply(_Optional_func{__f}, __i);
1375 return this->_M_get();
1379 template<range _Range>
1380 struct _CachedPosition
1383 _M_has_value() const
1386 constexpr iterator_t<_Range>
1387 _M_get(const _Range&) const
1389 __glibcxx_assert(false);
1390 __builtin_unreachable();
1394 _M_set(const _Range&, const iterator_t<_Range>&) const
1398 template<forward_range _Range>
1399 struct _CachedPosition<_Range>
1400 : protected __non_propagating_cache<iterator_t<_Range>>
1403 _M_has_value() const
1404 { return this->_M_is_engaged(); }
1406 constexpr iterator_t<_Range>
1407 _M_get(const _Range&) const
1409 __glibcxx_assert(_M_has_value());
1414 _M_set(const _Range&, const iterator_t<_Range>& __it)
1416 __glibcxx_assert(!_M_has_value());
1417 std::construct_at(std::__addressof(this->_M_payload._M_payload),
1419 this->_M_payload._M_engaged = true;
1423 template<random_access_range _Range>
1424 requires (sizeof(range_difference_t<_Range>)
1425 <= sizeof(iterator_t<_Range>))
1426 struct _CachedPosition<_Range>
1429 range_difference_t<_Range> _M_offset = -1;
1432 _CachedPosition() = default;
1435 _CachedPosition(const _CachedPosition&) = default;
1438 _CachedPosition(_CachedPosition&& __other) noexcept
1439 { *this = std::move(__other); }
1441 constexpr _CachedPosition&
1442 operator=(const _CachedPosition&) = default;
1444 constexpr _CachedPosition&
1445 operator=(_CachedPosition&& __other) noexcept
1447 // Propagate the cached offset, but invalidate the source.
1448 _M_offset = __other._M_offset;
1449 __other._M_offset = -1;
1454 _M_has_value() const
1455 { return _M_offset >= 0; }
1457 constexpr iterator_t<_Range>
1458 _M_get(_Range& __r) const
1460 __glibcxx_assert(_M_has_value());
1461 return ranges::begin(__r) + _M_offset;
1465 _M_set(_Range& __r, const iterator_t<_Range>& __it)
1467 __glibcxx_assert(!_M_has_value());
1468 _M_offset = __it - ranges::begin(__r);
1471 } // namespace __detail
1475 template<typename _Base>
1476 struct __filter_view_iter_cat
1479 template<forward_range _Base>
1480 struct __filter_view_iter_cat<_Base>
1486 using _Cat = typename iterator_traits<iterator_t<_Base>>::iterator_category;
1487 if constexpr (derived_from<_Cat, bidirectional_iterator_tag>)
1488 return bidirectional_iterator_tag{};
1489 else if constexpr (derived_from<_Cat, forward_iterator_tag>)
1490 return forward_iterator_tag{};
1495 using iterator_category = decltype(_S_iter_cat());
1497 } // namespace __detail
1499 template<input_range _Vp,
1500 indirect_unary_predicate<iterator_t<_Vp>> _Pred>
1501 requires view<_Vp> && is_object_v<_Pred>
1502 class filter_view : public view_interface<filter_view<_Vp, _Pred>>
1507 struct _Iterator : __detail::__filter_view_iter_cat<_Vp>
1510 static constexpr auto
1513 if constexpr (bidirectional_range<_Vp>)
1514 return bidirectional_iterator_tag{};
1515 else if constexpr (forward_range<_Vp>)
1516 return forward_iterator_tag{};
1518 return input_iterator_tag{};
1523 using _Vp_iter = iterator_t<_Vp>;
1525 _Vp_iter _M_current = _Vp_iter();
1526 filter_view* _M_parent = nullptr;
1529 using iterator_concept = decltype(_S_iter_concept());
1530 // iterator_category defined in __filter_view_iter_cat
1531 using value_type = range_value_t<_Vp>;
1532 using difference_type = range_difference_t<_Vp>;
1534 _Iterator() requires default_initializable<_Vp_iter> = default;
1537 _Iterator(filter_view* __parent, _Vp_iter __current)
1538 : _M_current(std::move(__current)),
1542 constexpr const _Vp_iter&
1543 base() const & noexcept
1544 { return _M_current; }
1548 { return std::move(_M_current); }
1550 constexpr range_reference_t<_Vp>
1552 { return *_M_current; }
1556 requires __detail::__has_arrow<_Vp_iter>
1557 && copyable<_Vp_iter>
1558 { return _M_current; }
1560 constexpr _Iterator&
1563 _M_current = ranges::find_if(std::move(++_M_current),
1564 ranges::end(_M_parent->_M_base),
1565 std::ref(*_M_parent->_M_pred));
1574 operator++(int) requires forward_range<_Vp>
1581 constexpr _Iterator&
1582 operator--() requires bidirectional_range<_Vp>
1586 while (!std::__invoke(*_M_parent->_M_pred, *_M_current));
1591 operator--(int) requires bidirectional_range<_Vp>
1598 friend constexpr bool
1599 operator==(const _Iterator& __x, const _Iterator& __y)
1600 requires equality_comparable<_Vp_iter>
1601 { return __x._M_current == __y._M_current; }
1603 friend constexpr range_rvalue_reference_t<_Vp>
1604 iter_move(const _Iterator& __i)
1605 noexcept(noexcept(ranges::iter_move(__i._M_current)))
1606 { return ranges::iter_move(__i._M_current); }
1608 friend constexpr void
1609 iter_swap(const _Iterator& __x, const _Iterator& __y)
1610 noexcept(noexcept(ranges::iter_swap(__x._M_current, __y._M_current)))
1611 requires indirectly_swappable<_Vp_iter>
1612 { ranges::iter_swap(__x._M_current, __y._M_current); }
1618 sentinel_t<_Vp> _M_end = sentinel_t<_Vp>();
1621 __equal(const _Iterator& __i) const
1622 { return __i._M_current == _M_end; }
1625 _Sentinel() = default;
1628 _Sentinel(filter_view* __parent)
1629 : _M_end(ranges::end(__parent->_M_base))
1632 constexpr sentinel_t<_Vp>
1636 friend constexpr bool
1637 operator==(const _Iterator& __x, const _Sentinel& __y)
1638 { return __y.__equal(__x); }
1641 _Vp _M_base = _Vp();
1642 [[no_unique_address]] __detail::__box<_Pred> _M_pred;
1643 [[no_unique_address]] __detail::_CachedPosition<_Vp> _M_cached_begin;
1646 filter_view() requires (default_initializable<_Vp>
1647 && default_initializable<_Pred>)
1651 filter_view(_Vp __base, _Pred __pred)
1652 : _M_base(std::move(__base)), _M_pred(std::move(__pred))
1656 base() const& requires copy_constructible<_Vp>
1661 { return std::move(_M_base); }
1663 constexpr const _Pred&
1665 { return *_M_pred; }
1670 if (_M_cached_begin._M_has_value())
1671 return {this, _M_cached_begin._M_get(_M_base)};
1673 __glibcxx_assert(_M_pred.has_value());
1674 auto __it = ranges::find_if(ranges::begin(_M_base),
1675 ranges::end(_M_base),
1676 std::ref(*_M_pred));
1677 _M_cached_begin._M_set(_M_base, __it);
1678 return {this, std::move(__it)};
1684 if constexpr (common_range<_Vp>)
1685 return _Iterator{this, ranges::end(_M_base)};
1687 return _Sentinel{this};
1691 template<typename _Range, typename _Pred>
1692 filter_view(_Range&&, _Pred) -> filter_view<views::all_t<_Range>, _Pred>;
1698 template<typename _Range, typename _Pred>
1699 concept __can_filter_view
1700 = requires { filter_view(std::declval<_Range>(), std::declval<_Pred>()); };
1701 } // namespace __detail
1703 struct _Filter : __adaptor::_RangeAdaptor<_Filter>
1705 template<viewable_range _Range, typename _Pred>
1706 requires __detail::__can_filter_view<_Range, _Pred>
1708 operator() [[nodiscard]] (_Range&& __r, _Pred&& __p) const
1710 return filter_view(std::forward<_Range>(__r), std::forward<_Pred>(__p));
1713 using _RangeAdaptor<_Filter>::operator();
1714 static constexpr int _S_arity = 2;
1715 static constexpr bool _S_has_simple_extra_args = true;
1718 inline constexpr _Filter filter;
1719 } // namespace views
1721 template<input_range _Vp, copy_constructible _Fp>
1722 requires view<_Vp> && is_object_v<_Fp>
1723 && regular_invocable<_Fp&, range_reference_t<_Vp>>
1724 && std::__detail::__can_reference<invoke_result_t<_Fp&,
1725 range_reference_t<_Vp>>>
1726 class transform_view : public view_interface<transform_view<_Vp, _Fp>>
1729 template<bool _Const>
1730 using _Base = __detail::__maybe_const_t<_Const, _Vp>;
1732 template<bool _Const>
1736 template<bool _Const>
1737 requires forward_range<_Base<_Const>>
1738 struct __iter_cat<_Const>
1744 using _Base = transform_view::_Base<_Const>;
1745 using _Res = invoke_result_t<_Fp&, range_reference_t<_Base>>;
1746 if constexpr (is_lvalue_reference_v<_Res>)
1749 = typename iterator_traits<iterator_t<_Base>>::iterator_category;
1750 if constexpr (derived_from<_Cat, contiguous_iterator_tag>)
1751 return random_access_iterator_tag{};
1756 return input_iterator_tag{};
1759 using iterator_category = decltype(_S_iter_cat());
1762 template<bool _Const>
1765 template<bool _Const>
1766 struct _Iterator : __iter_cat<_Const>
1769 using _Parent = __detail::__maybe_const_t<_Const, transform_view>;
1770 using _Base = transform_view::_Base<_Const>;
1775 if constexpr (random_access_range<_Base>)
1776 return random_access_iterator_tag{};
1777 else if constexpr (bidirectional_range<_Base>)
1778 return bidirectional_iterator_tag{};
1779 else if constexpr (forward_range<_Base>)
1780 return forward_iterator_tag{};
1782 return input_iterator_tag{};
1785 using _Base_iter = iterator_t<_Base>;
1787 _Base_iter _M_current = _Base_iter();
1788 _Parent* _M_parent = nullptr;
1791 using iterator_concept = decltype(_S_iter_concept());
1792 // iterator_category defined in __transform_view_iter_cat
1794 = remove_cvref_t<invoke_result_t<_Fp&, range_reference_t<_Base>>>;
1795 using difference_type = range_difference_t<_Base>;
1797 _Iterator() requires default_initializable<_Base_iter> = default;
1800 _Iterator(_Parent* __parent, _Base_iter __current)
1801 : _M_current(std::move(__current)),
1806 _Iterator(_Iterator<!_Const> __i)
1808 && convertible_to<iterator_t<_Vp>, _Base_iter>
1809 : _M_current(std::move(__i._M_current)), _M_parent(__i._M_parent)
1812 constexpr const _Base_iter&
1813 base() const & noexcept
1814 { return _M_current; }
1816 constexpr _Base_iter
1818 { return std::move(_M_current); }
1820 constexpr decltype(auto)
1822 noexcept(noexcept(std::__invoke(*_M_parent->_M_fun, *_M_current)))
1823 { return std::__invoke(*_M_parent->_M_fun, *_M_current); }
1825 constexpr _Iterator&
1837 operator++(int) requires forward_range<_Base>
1844 constexpr _Iterator&
1845 operator--() requires bidirectional_range<_Base>
1852 operator--(int) requires bidirectional_range<_Base>
1859 constexpr _Iterator&
1860 operator+=(difference_type __n) requires random_access_range<_Base>
1866 constexpr _Iterator&
1867 operator-=(difference_type __n) requires random_access_range<_Base>
1873 constexpr decltype(auto)
1874 operator[](difference_type __n) const
1875 requires random_access_range<_Base>
1876 { return std::__invoke(*_M_parent->_M_fun, _M_current[__n]); }
1878 friend constexpr bool
1879 operator==(const _Iterator& __x, const _Iterator& __y)
1880 requires equality_comparable<_Base_iter>
1881 { return __x._M_current == __y._M_current; }
1883 friend constexpr bool
1884 operator<(const _Iterator& __x, const _Iterator& __y)
1885 requires random_access_range<_Base>
1886 { return __x._M_current < __y._M_current; }
1888 friend constexpr bool
1889 operator>(const _Iterator& __x, const _Iterator& __y)
1890 requires random_access_range<_Base>
1891 { return __y < __x; }
1893 friend constexpr bool
1894 operator<=(const _Iterator& __x, const _Iterator& __y)
1895 requires random_access_range<_Base>
1896 { return !(__y < __x); }
1898 friend constexpr bool
1899 operator>=(const _Iterator& __x, const _Iterator& __y)
1900 requires random_access_range<_Base>
1901 { return !(__x < __y); }
1903#ifdef __cpp_lib_three_way_comparison
1904 friend constexpr auto
1905 operator<=>(const _Iterator& __x, const _Iterator& __y)
1906 requires random_access_range<_Base>
1907 && three_way_comparable<_Base_iter>
1908 { return __x._M_current <=> __y._M_current; }
1911 friend constexpr _Iterator
1912 operator+(_Iterator __i, difference_type __n)
1913 requires random_access_range<_Base>
1914 { return {__i._M_parent, __i._M_current + __n}; }
1916 friend constexpr _Iterator
1917 operator+(difference_type __n, _Iterator __i)
1918 requires random_access_range<_Base>
1919 { return {__i._M_parent, __i._M_current + __n}; }
1921 friend constexpr _Iterator
1922 operator-(_Iterator __i, difference_type __n)
1923 requires random_access_range<_Base>
1924 { return {__i._M_parent, __i._M_current - __n}; }
1926 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1927 // 3483. transform_view::iterator's difference is overconstrained
1928 friend constexpr difference_type
1929 operator-(const _Iterator& __x, const _Iterator& __y)
1930 requires sized_sentinel_for<iterator_t<_Base>, iterator_t<_Base>>
1931 { return __x._M_current - __y._M_current; }
1933 friend constexpr decltype(auto)
1934 iter_move(const _Iterator& __i) noexcept(noexcept(*__i))
1936 if constexpr (is_lvalue_reference_v<decltype(*__i)>)
1937 return std::move(*__i);
1942 friend _Iterator<!_Const>;
1943 template<bool> friend struct _Sentinel;
1946 template<bool _Const>
1950 using _Parent = __detail::__maybe_const_t<_Const, transform_view>;
1951 using _Base = transform_view::_Base<_Const>;
1953 template<bool _Const2>
1955 __distance_from(const _Iterator<_Const2>& __i) const
1956 { return _M_end - __i._M_current; }
1958 template<bool _Const2>
1960 __equal(const _Iterator<_Const2>& __i) const
1961 { return __i._M_current == _M_end; }
1963 sentinel_t<_Base> _M_end = sentinel_t<_Base>();
1966 _Sentinel() = default;
1969 _Sentinel(sentinel_t<_Base> __end)
1974 _Sentinel(_Sentinel<!_Const> __i)
1976 && convertible_to<sentinel_t<_Vp>, sentinel_t<_Base>>
1977 : _M_end(std::move(__i._M_end))
1980 constexpr sentinel_t<_Base>
1984 template<bool _Const2>
1985 requires sentinel_for<sentinel_t<_Base>,
1986 iterator_t<__detail::__maybe_const_t<_Const2, _Vp>>>
1987 friend constexpr bool
1988 operator==(const _Iterator<_Const2>& __x, const _Sentinel& __y)
1989 { return __y.__equal(__x); }
1991 template<bool _Const2,
1992 typename _Base2 = __detail::__maybe_const_t<_Const2, _Vp>>
1993 requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<_Base2>>
1994 friend constexpr range_difference_t<_Base2>
1995 operator-(const _Iterator<_Const2>& __x, const _Sentinel& __y)
1996 { return -__y.__distance_from(__x); }
1998 template<bool _Const2,
1999 typename _Base2 = __detail::__maybe_const_t<_Const2, _Vp>>
2000 requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<_Base2>>
2001 friend constexpr range_difference_t<_Base2>
2002 operator-(const _Sentinel& __y, const _Iterator<_Const2>& __x)
2003 { return __y.__distance_from(__x); }
2005 friend _Sentinel<!_Const>;
2008 _Vp _M_base = _Vp();
2009 [[no_unique_address]] __detail::__box<_Fp> _M_fun;
2012 transform_view() requires (default_initializable<_Vp>
2013 && default_initializable<_Fp>)
2017 transform_view(_Vp __base, _Fp __fun)
2018 : _M_base(std::move(__base)), _M_fun(std::move(__fun))
2022 base() const& requires copy_constructible<_Vp>
2023 { return _M_base ; }
2027 { return std::move(_M_base); }
2029 constexpr _Iterator<false>
2031 { return _Iterator<false>{this, ranges::begin(_M_base)}; }
2033 constexpr _Iterator<true>
2035 requires range<const _Vp>
2036 && regular_invocable<const _Fp&, range_reference_t<const _Vp>>
2037 { return _Iterator<true>{this, ranges::begin(_M_base)}; }
2039 constexpr _Sentinel<false>
2041 { return _Sentinel<false>{ranges::end(_M_base)}; }
2043 constexpr _Iterator<false>
2044 end() requires common_range<_Vp>
2045 { return _Iterator<false>{this, ranges::end(_M_base)}; }
2047 constexpr _Sentinel<true>
2049 requires range<const _Vp>
2050 && regular_invocable<const _Fp&, range_reference_t<const _Vp>>
2051 { return _Sentinel<true>{ranges::end(_M_base)}; }
2053 constexpr _Iterator<true>
2055 requires common_range<const _Vp>
2056 && regular_invocable<const _Fp&, range_reference_t<const _Vp>>
2057 { return _Iterator<true>{this, ranges::end(_M_base)}; }
2060 size() requires sized_range<_Vp>
2061 { return ranges::size(_M_base); }
2064 size() const requires sized_range<const _Vp>
2065 { return ranges::size(_M_base); }
2068 template<typename _Range, typename _Fp>
2069 transform_view(_Range&&, _Fp) -> transform_view<views::all_t<_Range>, _Fp>;
2075 template<typename _Range, typename _Fp>
2076 concept __can_transform_view
2077 = requires { transform_view(std::declval<_Range>(), std::declval<_Fp>()); };
2078 } // namespace __detail
2080 struct _Transform : __adaptor::_RangeAdaptor<_Transform>
2082 template<viewable_range _Range, typename _Fp>
2083 requires __detail::__can_transform_view<_Range, _Fp>
2085 operator() [[nodiscard]] (_Range&& __r, _Fp&& __f) const
2087 return transform_view(std::forward<_Range>(__r), std::forward<_Fp>(__f));
2090 using _RangeAdaptor<_Transform>::operator();
2091 static constexpr int _S_arity = 2;
2092 static constexpr bool _S_has_simple_extra_args = true;
2095 inline constexpr _Transform transform;
2096 } // namespace views
2099 class take_view : public view_interface<take_view<_Vp>>
2102 template<bool _Const>
2103 using _CI = counted_iterator<
2104 iterator_t<__detail::__maybe_const_t<_Const, _Vp>>>;
2106 template<bool _Const>
2110 using _Base = __detail::__maybe_const_t<_Const, _Vp>;
2111 sentinel_t<_Base> _M_end = sentinel_t<_Base>();
2114 _Sentinel() = default;
2117 _Sentinel(sentinel_t<_Base> __end)
2122 _Sentinel(_Sentinel<!_Const> __s)
2123 requires _Const && convertible_to<sentinel_t<_Vp>, sentinel_t<_Base>>
2124 : _M_end(std::move(__s._M_end))
2127 constexpr sentinel_t<_Base>
2131 friend constexpr bool
2132 operator==(const _CI<_Const>& __y, const _Sentinel& __x)
2133 { return __y.count() == 0 || __y.base() == __x._M_end; }
2135 template<bool _OtherConst = !_Const,
2136 typename _Base2 = __detail::__maybe_const_t<_OtherConst, _Vp>>
2137 requires sentinel_for<sentinel_t<_Base>, iterator_t<_Base2>>
2138 friend constexpr bool
2139 operator==(const _CI<_OtherConst>& __y, const _Sentinel& __x)
2140 { return __y.count() == 0 || __y.base() == __x._M_end; }
2142 friend _Sentinel<!_Const>;
2145 _Vp _M_base = _Vp();
2146 range_difference_t<_Vp> _M_count = 0;
2149 take_view() requires default_initializable<_Vp> = default;
2152 take_view(_Vp __base, range_difference_t<_Vp> __count)
2153 : _M_base(std::move(__base)), _M_count(std::move(__count))
2157 base() const& requires copy_constructible<_Vp>
2162 { return std::move(_M_base); }
2165 begin() requires (!__detail::__simple_view<_Vp>)
2167 if constexpr (sized_range<_Vp>)
2169 if constexpr (random_access_range<_Vp>)
2170 return ranges::begin(_M_base);
2174 return counted_iterator(ranges::begin(_M_base), __sz);
2178 return counted_iterator(ranges::begin(_M_base), _M_count);
2182 begin() const requires range<const _Vp>
2184 if constexpr (sized_range<const _Vp>)
2186 if constexpr (random_access_range<const _Vp>)
2187 return ranges::begin(_M_base);
2191 return counted_iterator(ranges::begin(_M_base), __sz);
2195 return counted_iterator(ranges::begin(_M_base), _M_count);
2199 end() requires (!__detail::__simple_view<_Vp>)
2201 if constexpr (sized_range<_Vp>)
2203 if constexpr (random_access_range<_Vp>)
2204 return ranges::begin(_M_base) + size();
2206 return default_sentinel;
2209 return _Sentinel<false>{ranges::end(_M_base)};
2213 end() const requires range<const _Vp>
2215 if constexpr (sized_range<const _Vp>)
2217 if constexpr (random_access_range<const _Vp>)
2218 return ranges::begin(_M_base) + size();
2220 return default_sentinel;
2223 return _Sentinel<true>{ranges::end(_M_base)};
2227 size() requires sized_range<_Vp>
2229 auto __n = ranges::size(_M_base);
2230 return std::min(__n, static_cast<decltype(__n)>(_M_count));
2234 size() const requires sized_range<const _Vp>
2236 auto __n = ranges::size(_M_base);
2237 return std::min(__n, static_cast<decltype(__n)>(_M_count));
2241 // _GLIBCXX_RESOLVE_LIB_DEFECTS
2242 // 3447. Deduction guides for take_view and drop_view have different
2244 template<typename _Range>
2245 take_view(_Range&&, range_difference_t<_Range>)
2246 -> take_view<views::all_t<_Range>>;
2248 template<typename _Tp>
2249 inline constexpr bool enable_borrowed_range<take_view<_Tp>>
2250 = enable_borrowed_range<_Tp>;
2256 template<typename _Range>
2257 inline constexpr bool __is_empty_view = false;
2259 template<typename _Tp>
2260 inline constexpr bool __is_empty_view<empty_view<_Tp>> = true;
2262 template<typename _Range>
2263 inline constexpr bool __is_basic_string_view = false;
2265 template<typename _CharT, typename _Traits>
2266 inline constexpr bool __is_basic_string_view<basic_string_view<_CharT, _Traits>>
2269 template<typename _Range>
2270 inline constexpr bool __is_subrange = false;
2272 template<typename _Iter, typename _Sent, subrange_kind _Kind>
2273 inline constexpr bool __is_subrange<subrange<_Iter, _Sent, _Kind>> = true;
2275 template<typename _Range>
2276 inline constexpr bool __is_iota_view = false;
2278 template<typename _Winc, typename _Bound>
2279 inline constexpr bool __is_iota_view<iota_view<_Winc, _Bound>> = true;
2281 template<typename _Range>
2282 inline constexpr bool __is_repeat_view = false;
2284 template<typename _Range>
2286 __take_of_repeat_view(_Range&&, range_difference_t<_Range>); // defined later
2288 template<typename _Range, typename _Dp>
2289 concept __can_take_view
2290 = requires { take_view(std::declval<_Range>(), std::declval<_Dp>()); };
2291 } // namespace __detail
2293 struct _Take : __adaptor::_RangeAdaptor<_Take>
2295 template<viewable_range _Range, typename _Dp = range_difference_t<_Range>>
2296 requires __detail::__can_take_view<_Range, _Dp>
2298 operator() [[nodiscard]] (_Range&& __r, type_identity_t<_Dp> __n) const
2300 using _Tp = remove_cvref_t<_Range>;
2301 if constexpr (__detail::__is_empty_view<_Tp>)
2303 else if constexpr (random_access_range<_Tp>
2305 && (std::__detail::__is_span<_Tp>
2306 || __detail::__is_basic_string_view<_Tp>
2307 || __detail::__is_subrange<_Tp>
2308 || __detail::__is_iota_view<_Tp>))
2310 __n = std::min<_Dp>(ranges::distance(__r), __n);
2311 auto __begin = ranges::begin(__r);
2312 auto __end = __begin + __n;
2313 if constexpr (std::__detail::__is_span<_Tp>)
2314 return span<typename _Tp::element_type>(__begin, __end);
2315 else if constexpr (__detail::__is_basic_string_view<_Tp>)
2316 return _Tp(__begin, __end);
2317 else if constexpr (__detail::__is_subrange<_Tp>)
2318 return subrange<iterator_t<_Tp>>(__begin, __end);
2320 return iota_view(*__begin, *__end);
2322 else if constexpr (__detail::__is_repeat_view<_Tp>)
2323 return __detail::__take_of_repeat_view(std::forward<_Range>(__r), __n);
2325 return take_view(std::forward<_Range>(__r), __n);
2328 using _RangeAdaptor<_Take>::operator();
2329 static constexpr int _S_arity = 2;
2330 // The count argument of views::take is not always simple -- it can be
2331 // e.g. a move-only class that's implicitly convertible to the difference
2332 // type. But an integer-like count argument is surely simple.
2333 template<typename _Tp>
2334 static constexpr bool _S_has_simple_extra_args
2335 = ranges::__detail::__is_integer_like<_Tp>;
2338 inline constexpr _Take take;
2339 } // namespace views
2341 template<view _Vp, typename _Pred>
2342 requires input_range<_Vp> && is_object_v<_Pred>
2343 && indirect_unary_predicate<const _Pred, iterator_t<_Vp>>
2344 class take_while_view : public view_interface<take_while_view<_Vp, _Pred>>
2346 template<bool _Const>
2350 using _Base = __detail::__maybe_const_t<_Const, _Vp>;
2352 sentinel_t<_Base> _M_end = sentinel_t<_Base>();
2353 const _Pred* _M_pred = nullptr;
2356 _Sentinel() = default;
2359 _Sentinel(sentinel_t<_Base> __end, const _Pred* __pred)
2360 : _M_end(__end), _M_pred(__pred)
2364 _Sentinel(_Sentinel<!_Const> __s)
2365 requires _Const && convertible_to<sentinel_t<_Vp>, sentinel_t<_Base>>
2366 : _M_end(__s._M_end), _M_pred(__s._M_pred)
2369 constexpr sentinel_t<_Base>
2370 base() const { return _M_end; }
2372 friend constexpr bool
2373 operator==(const iterator_t<_Base>& __x, const _Sentinel& __y)
2374 { return __y._M_end == __x || !std::__invoke(*__y._M_pred, *__x); }
2376 template<bool _OtherConst = !_Const,
2377 typename _Base2 = __detail::__maybe_const_t<_OtherConst, _Vp>>
2378 requires sentinel_for<sentinel_t<_Base>, iterator_t<_Base2>>
2379 friend constexpr bool
2380 operator==(const iterator_t<_Base2>& __x, const _Sentinel& __y)
2381 { return __y._M_end == __x || !std::__invoke(*__y._M_pred, *__x); }
2383 friend _Sentinel<!_Const>;
2386 _Vp _M_base = _Vp();
2387 [[no_unique_address]] __detail::__box<_Pred> _M_pred;
2390 take_while_view() requires (default_initializable<_Vp>
2391 && default_initializable<_Pred>)
2395 take_while_view(_Vp __base, _Pred __pred)
2396 : _M_base(std::move(__base)), _M_pred(std::move(__pred))
2400 base() const& requires copy_constructible<_Vp>
2405 { return std::move(_M_base); }
2407 constexpr const _Pred&
2409 { return *_M_pred; }
2412 begin() requires (!__detail::__simple_view<_Vp>)
2413 { return ranges::begin(_M_base); }
2416 begin() const requires range<const _Vp>
2417 && indirect_unary_predicate<const _Pred, iterator_t<const _Vp>>
2418 { return ranges::begin(_M_base); }
2421 end() requires (!__detail::__simple_view<_Vp>)
2422 { return _Sentinel<false>(ranges::end(_M_base),
2423 std::__addressof(*_M_pred)); }
2426 end() const requires range<const _Vp>
2427 && indirect_unary_predicate<const _Pred, iterator_t<const _Vp>>
2428 { return _Sentinel<true>(ranges::end(_M_base),
2429 std::__addressof(*_M_pred)); }
2432 template<typename _Range, typename _Pred>
2433 take_while_view(_Range&&, _Pred)
2434 -> take_while_view<views::all_t<_Range>, _Pred>;
2440 template<typename _Range, typename _Pred>
2441 concept __can_take_while_view
2442 = requires { take_while_view(std::declval<_Range>(), std::declval<_Pred>()); };
2443 } // namespace __detail
2445 struct _TakeWhile : __adaptor::_RangeAdaptor<_TakeWhile>
2447 template<viewable_range _Range, typename _Pred>
2448 requires __detail::__can_take_while_view<_Range, _Pred>
2450 operator() [[nodiscard]] (_Range&& __r, _Pred&& __p) const
2452 return take_while_view(std::forward<_Range>(__r), std::forward<_Pred>(__p));
2455 using _RangeAdaptor<_TakeWhile>::operator();
2456 static constexpr int _S_arity = 2;
2457 static constexpr bool _S_has_simple_extra_args = true;
2460 inline constexpr _TakeWhile take_while;
2461 } // namespace views
2464 class drop_view : public view_interface<drop_view<_Vp>>
2467 _Vp _M_base = _Vp();
2468 range_difference_t<_Vp> _M_count = 0;
2470 // ranges::next(begin(base), count, end(base)) is O(1) if _Vp satisfies
2471 // both random_access_range and sized_range. Otherwise, cache its result.
2472 static constexpr bool _S_needs_cached_begin
2473 = !(random_access_range<const _Vp> && sized_range<const _Vp>);
2474 [[no_unique_address]]
2475 __detail::__maybe_present_t<_S_needs_cached_begin,
2476 __detail::_CachedPosition<_Vp>>
2480 drop_view() requires default_initializable<_Vp> = default;
2483 drop_view(_Vp __base, range_difference_t<_Vp> __count)
2484 : _M_base(std::move(__base)), _M_count(__count)
2485 { __glibcxx_assert(__count >= 0); }
2488 base() const& requires copy_constructible<_Vp>
2493 { return std::move(_M_base); }
2495 // This overload is disabled for simple views with constant-time begin().
2498 requires (!(__detail::__simple_view<_Vp>
2499 && random_access_range<const _Vp>
2500 && sized_range<const _Vp>))
2502 if constexpr (_S_needs_cached_begin)
2503 if (_M_cached_begin._M_has_value())
2504 return _M_cached_begin._M_get(_M_base);
2506 auto __it = ranges::next(ranges::begin(_M_base),
2507 _M_count, ranges::end(_M_base));
2508 if constexpr (_S_needs_cached_begin)
2509 _M_cached_begin._M_set(_M_base, __it);
2513 // _GLIBCXX_RESOLVE_LIB_DEFECTS
2514 // 3482. drop_view's const begin should additionally require sized_range
2517 requires random_access_range<const _Vp> && sized_range<const _Vp>
2519 return ranges::next(ranges::begin(_M_base), _M_count,
2520 ranges::end(_M_base));
2524 end() requires (!__detail::__simple_view<_Vp>)
2525 { return ranges::end(_M_base); }
2528 end() const requires range<const _Vp>
2529 { return ranges::end(_M_base); }
2532 size() requires sized_range<_Vp>
2534 const auto __s = ranges::size(_M_base);
2535 const auto __c = static_cast<decltype(__s)>(_M_count);
2536 return __s < __c ? 0 : __s - __c;
2540 size() const requires sized_range<const _Vp>
2542 const auto __s = ranges::size(_M_base);
2543 const auto __c = static_cast<decltype(__s)>(_M_count);
2544 return __s < __c ? 0 : __s - __c;
2548 template<typename _Range>
2549 drop_view(_Range&&, range_difference_t<_Range>)
2550 -> drop_view<views::all_t<_Range>>;
2552 template<typename _Tp>
2553 inline constexpr bool enable_borrowed_range<drop_view<_Tp>>
2554 = enable_borrowed_range<_Tp>;
2560 template<typename _Range>
2562 __drop_of_repeat_view(_Range&&, range_difference_t<_Range>); // defined later
2564 template<typename _Range, typename _Dp>
2565 concept __can_drop_view
2566 = requires { drop_view(std::declval<_Range>(), std::declval<_Dp>()); };
2567 } // namespace __detail
2569 struct _Drop : __adaptor::_RangeAdaptor<_Drop>
2571 template<viewable_range _Range, typename _Dp = range_difference_t<_Range>>
2572 requires __detail::__can_drop_view<_Range, _Dp>
2574 operator() [[nodiscard]] (_Range&& __r, type_identity_t<_Dp> __n) const
2576 using _Tp = remove_cvref_t<_Range>;
2577 if constexpr (__detail::__is_empty_view<_Tp>)
2579 else if constexpr (random_access_range<_Tp>
2581 && (std::__detail::__is_span<_Tp>
2582 || __detail::__is_basic_string_view<_Tp>
2583 || __detail::__is_iota_view<_Tp>
2584 || __detail::__is_subrange<_Tp>))
2586 __n = std::min<_Dp>(ranges::distance(__r), __n);
2587 auto __begin = ranges::begin(__r) + __n;
2588 auto __end = ranges::end(__r);
2589 if constexpr (std::__detail::__is_span<_Tp>)
2590 return span<typename _Tp::element_type>(__begin, __end);
2591 else if constexpr (__detail::__is_subrange<_Tp>)
2593 if constexpr (_Tp::_S_store_size)
2595 using ranges::__detail::__to_unsigned_like;
2596 auto __m = ranges::distance(__r) - __n;
2597 return _Tp(__begin, __end, __to_unsigned_like(__m));
2600 return _Tp(__begin, __end);
2603 return _Tp(__begin, __end);
2605 else if constexpr (__detail::__is_repeat_view<_Tp>)
2606 return __detail::__drop_of_repeat_view(std::forward<_Range>(__r), __n);
2608 return drop_view(std::forward<_Range>(__r), __n);
2611 using _RangeAdaptor<_Drop>::operator();
2612 static constexpr int _S_arity = 2;
2613 template<typename _Tp>
2614 static constexpr bool _S_has_simple_extra_args
2615 = _Take::_S_has_simple_extra_args<_Tp>;
2618 inline constexpr _Drop drop;
2619 } // namespace views
2621 template<view _Vp, typename _Pred>
2622 requires input_range<_Vp> && is_object_v<_Pred>
2623 && indirect_unary_predicate<const _Pred, iterator_t<_Vp>>
2624 class drop_while_view : public view_interface<drop_while_view<_Vp, _Pred>>
2627 _Vp _M_base = _Vp();
2628 [[no_unique_address]] __detail::__box<_Pred> _M_pred;
2629 [[no_unique_address]] __detail::_CachedPosition<_Vp> _M_cached_begin;
2632 drop_while_view() requires (default_initializable<_Vp>
2633 && default_initializable<_Pred>)
2637 drop_while_view(_Vp __base, _Pred __pred)
2638 : _M_base(std::move(__base)), _M_pred(std::move(__pred))
2642 base() const& requires copy_constructible<_Vp>
2647 { return std::move(_M_base); }
2649 constexpr const _Pred&
2651 { return *_M_pred; }
2656 if (_M_cached_begin._M_has_value())
2657 return _M_cached_begin._M_get(_M_base);
2659 __glibcxx_assert(_M_pred.has_value());
2660 auto __it = ranges::find_if_not(ranges::begin(_M_base),
2661 ranges::end(_M_base),
2662 std::cref(*_M_pred));
2663 _M_cached_begin._M_set(_M_base, __it);
2669 { return ranges::end(_M_base); }
2672 template<typename _Range, typename _Pred>
2673 drop_while_view(_Range&&, _Pred)
2674 -> drop_while_view<views::all_t<_Range>, _Pred>;
2676 template<typename _Tp, typename _Pred>
2677 inline constexpr bool enable_borrowed_range<drop_while_view<_Tp, _Pred>>
2678 = enable_borrowed_range<_Tp>;
2684 template<typename _Range, typename _Pred>
2685 concept __can_drop_while_view
2686 = requires { drop_while_view(std::declval<_Range>(), std::declval<_Pred>()); };
2687 } // namespace __detail
2689 struct _DropWhile : __adaptor::_RangeAdaptor<_DropWhile>
2691 template<viewable_range _Range, typename _Pred>
2692 requires __detail::__can_drop_while_view<_Range, _Pred>
2694 operator() [[nodiscard]] (_Range&& __r, _Pred&& __p) const
2696 return drop_while_view(std::forward<_Range>(__r),
2697 std::forward<_Pred>(__p));
2700 using _RangeAdaptor<_DropWhile>::operator();
2701 static constexpr int _S_arity = 2;
2702 static constexpr bool _S_has_simple_extra_args = true;
2705 inline constexpr _DropWhile drop_while;
2706 } // namespace views
2708 template<input_range _Vp>
2709 requires view<_Vp> && input_range<range_reference_t<_Vp>>
2710 class join_view : public view_interface<join_view<_Vp>>
2713 using _InnerRange = range_reference_t<_Vp>;
2715 template<bool _Const>
2716 using _Base = __detail::__maybe_const_t<_Const, _Vp>;
2718 template<bool _Const>
2719 using _Outer_iter = iterator_t<_Base<_Const>>;
2721 template<bool _Const>
2722 using _Inner_iter = iterator_t<range_reference_t<_Base<_Const>>>;
2724 template<bool _Const>
2725 static constexpr bool _S_ref_is_glvalue
2726 = is_reference_v<range_reference_t<_Base<_Const>>>;
2728 template<bool _Const>
2732 template<bool _Const>
2733 requires _S_ref_is_glvalue<_Const>
2734 && forward_range<_Base<_Const>>
2735 && forward_range<range_reference_t<_Base<_Const>>>
2736 struct __iter_cat<_Const>
2739 static constexpr auto
2742 using _Outer_iter = join_view::_Outer_iter<_Const>;
2743 using _Inner_iter = join_view::_Inner_iter<_Const>;
2744 using _OuterCat = typename iterator_traits<_Outer_iter>::iterator_category;
2745 using _InnerCat = typename iterator_traits<_Inner_iter>::iterator_category;
2746 if constexpr (derived_from<_OuterCat, bidirectional_iterator_tag>
2747 && derived_from<_InnerCat, bidirectional_iterator_tag>
2748 && common_range<range_reference_t<_Base<_Const>>>)
2749 return bidirectional_iterator_tag{};
2750 else if constexpr (derived_from<_OuterCat, forward_iterator_tag>
2751 && derived_from<_InnerCat, forward_iterator_tag>)
2752 return forward_iterator_tag{};
2754 return input_iterator_tag{};
2757 using iterator_category = decltype(_S_iter_cat());
2760 template<bool _Const>
2763 template<bool _Const>
2764 struct _Iterator : __iter_cat<_Const>
2767 using _Parent = __detail::__maybe_const_t<_Const, join_view>;
2768 using _Base = join_view::_Base<_Const>;
2770 static constexpr bool _S_ref_is_glvalue
2771 = join_view::_S_ref_is_glvalue<_Const>;
2776 auto __update_inner = [this] (const iterator_t<_Base>& __x) -> auto&& {
2777 if constexpr (_S_ref_is_glvalue)
2780 return _M_parent->_M_inner._M_emplace_deref(__x);
2783 for (; _M_outer != ranges::end(_M_parent->_M_base); ++_M_outer)
2785 auto&& __inner = __update_inner(_M_outer);
2786 _M_inner = ranges::begin(__inner);
2787 if (_M_inner != ranges::end(__inner))
2791 if constexpr (_S_ref_is_glvalue)
2795 static constexpr auto
2798 if constexpr (_S_ref_is_glvalue
2799 && bidirectional_range<_Base>
2800 && bidirectional_range<range_reference_t<_Base>>
2801 && common_range<range_reference_t<_Base>>)
2802 return bidirectional_iterator_tag{};
2803 else if constexpr (_S_ref_is_glvalue
2804 && forward_range<_Base>
2805 && forward_range<range_reference_t<_Base>>)
2806 return forward_iterator_tag{};
2808 return input_iterator_tag{};
2811 using _Outer_iter = join_view::_Outer_iter<_Const>;
2812 using _Inner_iter = join_view::_Inner_iter<_Const>;
2814 _Outer_iter _M_outer = _Outer_iter();
2815 optional<_Inner_iter> _M_inner;
2816 _Parent* _M_parent = nullptr;
2819 using iterator_concept = decltype(_S_iter_concept());
2820 // iterator_category defined in __join_view_iter_cat
2821 using value_type = range_value_t<range_reference_t<_Base>>;
2822 using difference_type
2823 = common_type_t<range_difference_t<_Base>,
2824 range_difference_t<range_reference_t<_Base>>>;
2826 _Iterator() requires default_initializable<_Outer_iter> = default;
2829 _Iterator(_Parent* __parent, _Outer_iter __outer)
2830 : _M_outer(std::move(__outer)),
2835 _Iterator(_Iterator<!_Const> __i)
2837 && convertible_to<iterator_t<_Vp>, _Outer_iter>
2838 && convertible_to<iterator_t<_InnerRange>, _Inner_iter>
2839 : _M_outer(std::move(__i._M_outer)), _M_inner(std::move(__i._M_inner)),
2840 _M_parent(__i._M_parent)
2843 constexpr decltype(auto)
2845 { return **_M_inner; }
2847 // _GLIBCXX_RESOLVE_LIB_DEFECTS
2848 // 3500. join_view::iterator::operator->() is bogus
2849 constexpr _Inner_iter
2851 requires __detail::__has_arrow<_Inner_iter>
2852 && copyable<_Inner_iter>
2853 { return *_M_inner; }
2855 constexpr _Iterator&
2858 auto&& __inner_range = [this] () -> auto&& {
2859 if constexpr (_S_ref_is_glvalue)
2862 return *_M_parent->_M_inner;
2864 if (++*_M_inner == ranges::end(__inner_range))
2878 requires _S_ref_is_glvalue && forward_range<_Base>
2879 && forward_range<range_reference_t<_Base>>
2886 constexpr _Iterator&
2888 requires _S_ref_is_glvalue && bidirectional_range<_Base>
2889 && bidirectional_range<range_reference_t<_Base>>
2890 && common_range<range_reference_t<_Base>>
2892 if (_M_outer == ranges::end(_M_parent->_M_base))
2893 _M_inner = ranges::end(*--_M_outer);
2894 while (*_M_inner == ranges::begin(*_M_outer))
2895 *_M_inner = ranges::end(*--_M_outer);
2902 requires _S_ref_is_glvalue && bidirectional_range<_Base>
2903 && bidirectional_range<range_reference_t<_Base>>
2904 && common_range<range_reference_t<_Base>>
2911 friend constexpr bool
2912 operator==(const _Iterator& __x, const _Iterator& __y)
2913 requires _S_ref_is_glvalue
2914 && equality_comparable<_Outer_iter>
2915 && equality_comparable<_Inner_iter>
2917 return (__x._M_outer == __y._M_outer
2918 && __x._M_inner == __y._M_inner);
2921 friend constexpr decltype(auto)
2922 iter_move(const _Iterator& __i)
2923 noexcept(noexcept(ranges::iter_move(*__i._M_inner)))
2924 { return ranges::iter_move(*__i._M_inner); }
2926 friend constexpr void
2927 iter_swap(const _Iterator& __x, const _Iterator& __y)
2928 noexcept(noexcept(ranges::iter_swap(*__x._M_inner, *__y._M_inner)))
2929 requires indirectly_swappable<_Inner_iter>
2930 { return ranges::iter_swap(*__x._M_inner, *__y._M_inner); }
2932 friend _Iterator<!_Const>;
2933 template<bool> friend struct _Sentinel;
2936 template<bool _Const>
2940 using _Parent = __detail::__maybe_const_t<_Const, join_view>;
2941 using _Base = join_view::_Base<_Const>;
2943 template<bool _Const2>
2945 __equal(const _Iterator<_Const2>& __i) const
2946 { return __i._M_outer == _M_end; }
2948 sentinel_t<_Base> _M_end = sentinel_t<_Base>();
2951 _Sentinel() = default;
2954 _Sentinel(_Parent* __parent)
2955 : _M_end(ranges::end(__parent->_M_base))
2959 _Sentinel(_Sentinel<!_Const> __s)
2960 requires _Const && convertible_to<sentinel_t<_Vp>, sentinel_t<_Base>>
2961 : _M_end(std::move(__s._M_end))
2964 template<bool _Const2>
2965 requires sentinel_for<sentinel_t<_Base>,
2966 iterator_t<__detail::__maybe_const_t<_Const2, _Vp>>>
2967 friend constexpr bool
2968 operator==(const _Iterator<_Const2>& __x, const _Sentinel& __y)
2969 { return __y.__equal(__x); }
2971 friend _Sentinel<!_Const>;
2974 _Vp _M_base = _Vp();
2975 [[no_unique_address]]
2976 __detail::__non_propagating_cache<remove_cv_t<_InnerRange>> _M_inner;
2979 join_view() requires default_initializable<_Vp> = default;
2982 join_view(_Vp __base)
2983 : _M_base(std::move(__base))
2987 base() const& requires copy_constructible<_Vp>
2992 { return std::move(_M_base); }
2997 constexpr bool __use_const
2998 = (__detail::__simple_view<_Vp>
2999 && is_reference_v<range_reference_t<_Vp>>);
3000 return _Iterator<__use_const>{this, ranges::begin(_M_base)};
3005 requires input_range<const _Vp>
3006 && is_reference_v<range_reference_t<const _Vp>>
3008 return _Iterator<true>{this, ranges::begin(_M_base)};
3014 if constexpr (forward_range<_Vp> && is_reference_v<_InnerRange>
3015 && forward_range<_InnerRange>
3016 && common_range<_Vp> && common_range<_InnerRange>)
3017 return _Iterator<__detail::__simple_view<_Vp>>{this,
3018 ranges::end(_M_base)};
3020 return _Sentinel<__detail::__simple_view<_Vp>>{this};
3025 requires input_range<const _Vp>
3026 && is_reference_v<range_reference_t<const _Vp>>
3028 if constexpr (forward_range<const _Vp>
3029 && is_reference_v<range_reference_t<const _Vp>>
3030 && forward_range<range_reference_t<const _Vp>>
3031 && common_range<const _Vp>
3032 && common_range<range_reference_t<const _Vp>>)
3033 return _Iterator<true>{this, ranges::end(_M_base)};
3035 return _Sentinel<true>{this};
3039 template<typename _Range>
3040 explicit join_view(_Range&&) -> join_view<views::all_t<_Range>>;
3046 template<typename _Range>
3047 concept __can_join_view
3048 = requires { join_view<all_t<_Range>>{std::declval<_Range>()}; };
3049 } // namespace __detail
3051 struct _Join : __adaptor::_RangeAdaptorClosure
3053 template<viewable_range _Range>
3054 requires __detail::__can_join_view<_Range>
3056 operator() [[nodiscard]] (_Range&& __r) const
3058 // _GLIBCXX_RESOLVE_LIB_DEFECTS
3059 // 3474. Nesting join_views is broken because of CTAD
3060 return join_view<all_t<_Range>>{std::forward<_Range>(__r)};
3063 static constexpr bool _S_has_simple_call_op = true;
3066 inline constexpr _Join join;
3067 } // namespace views
3072 struct __require_constant;
3074 template<typename _Range>
3075 concept __tiny_range = sized_range<_Range>
3077 { typename __require_constant<remove_reference_t<_Range>::size()>; }
3078 && (remove_reference_t<_Range>::size() <= 1);
3080 template<typename _Base>
3081 struct __lazy_split_view_outer_iter_cat
3084 template<forward_range _Base>
3085 struct __lazy_split_view_outer_iter_cat<_Base>
3086 { using iterator_category = input_iterator_tag; };
3088 template<typename _Base>
3089 struct __lazy_split_view_inner_iter_cat
3092 template<forward_range _Base>
3093 struct __lazy_split_view_inner_iter_cat<_Base>
3096 static constexpr auto
3099 using _Cat = typename iterator_traits<iterator_t<_Base>>::iterator_category;
3100 if constexpr (derived_from<_Cat, forward_iterator_tag>)
3101 return forward_iterator_tag{};
3106 using iterator_category = decltype(_S_iter_cat());
3110 template<input_range _Vp, forward_range _Pattern>
3111 requires view<_Vp> && view<_Pattern>
3112 && indirectly_comparable<iterator_t<_Vp>, iterator_t<_Pattern>,
3114 && (forward_range<_Vp> || __detail::__tiny_range<_Pattern>)
3115 class lazy_split_view : public view_interface<lazy_split_view<_Vp, _Pattern>>
3118 template<bool _Const>
3119 using _Base = __detail::__maybe_const_t<_Const, _Vp>;
3121 template<bool _Const>
3124 template<bool _Const>
3126 : __detail::__lazy_split_view_outer_iter_cat<_Base<_Const>>
3129 using _Parent = __detail::__maybe_const_t<_Const, lazy_split_view>;
3130 using _Base = lazy_split_view::_Base<_Const>;
3134 { return __current() == ranges::end(_M_parent->_M_base) && !_M_trailing_empty; }
3136 // [range.lazy.split.outer] p1
3137 // Many of the following specifications refer to the notional member
3138 // current of outer-iterator. current is equivalent to current_ if
3139 // V models forward_range, and parent_->current_ otherwise.
3141 __current() noexcept
3143 if constexpr (forward_range<_Vp>)
3146 return *_M_parent->_M_current;
3150 __current() const noexcept
3152 if constexpr (forward_range<_Vp>)
3155 return *_M_parent->_M_current;
3158 _Parent* _M_parent = nullptr;
3160 [[no_unique_address]]
3161 __detail::__maybe_present_t<forward_range<_Vp>,
3162 iterator_t<_Base>> _M_current;
3163 bool _M_trailing_empty = false;
3166 using iterator_concept = __conditional_t<forward_range<_Base>,
3167 forward_iterator_tag,
3168 input_iterator_tag>;
3169 // iterator_category defined in __lazy_split_view_outer_iter_cat
3170 using difference_type = range_difference_t<_Base>;
3172 struct value_type : view_interface<value_type>
3175 _OuterIter _M_i = _OuterIter();
3178 value_type() = default;
3181 value_type(_OuterIter __i)
3182 : _M_i(std::move(__i))
3185 constexpr _InnerIter<_Const>
3187 { return _InnerIter<_Const>{_M_i}; }
3189 constexpr default_sentinel_t
3190 end() const noexcept
3191 { return default_sentinel; }
3194 _OuterIter() = default;
3197 _OuterIter(_Parent* __parent) requires (!forward_range<_Base>)
3198 : _M_parent(__parent)
3202 _OuterIter(_Parent* __parent, iterator_t<_Base> __current)
3203 requires forward_range<_Base>
3204 : _M_parent(__parent),
3205 _M_current(std::move(__current))
3209 _OuterIter(_OuterIter<!_Const> __i)
3211 && convertible_to<iterator_t<_Vp>, iterator_t<_Base>>
3212 : _M_parent(__i._M_parent), _M_current(std::move(__i._M_current))
3215 constexpr value_type
3217 { return value_type{*this}; }
3219 constexpr _OuterIter&
3222 // _GLIBCXX_RESOLVE_LIB_DEFECTS
3223 // 3505. lazy_split_view::outer-iterator::operator++ misspecified
3224 const auto __end = ranges::end(_M_parent->_M_base);
3225 if (__current() == __end)
3227 _M_trailing_empty = false;
3230 const auto [__pbegin, __pend] = subrange{_M_parent->_M_pattern};
3231 if (__pbegin == __pend)
3233 else if constexpr (__detail::__tiny_range<_Pattern>)
3235 __current() = ranges::find(std::move(__current()), __end,
3237 if (__current() != __end)
3240 if (__current() == __end)
3241 _M_trailing_empty = true;
3248 = ranges::mismatch(__current(), __end, __pbegin, __pend);
3252 if (__current() == __end)
3253 _M_trailing_empty = true;
3256 } while (++__current() != __end);
3260 constexpr decltype(auto)
3263 if constexpr (forward_range<_Base>)
3273 friend constexpr bool
3274 operator==(const _OuterIter& __x, const _OuterIter& __y)
3275 requires forward_range<_Base>
3277 return __x._M_current == __y._M_current
3278 && __x._M_trailing_empty == __y._M_trailing_empty;
3281 friend constexpr bool
3282 operator==(const _OuterIter& __x, default_sentinel_t)
3283 { return __x.__at_end(); };
3285 friend _OuterIter<!_Const>;
3286 friend _InnerIter<_Const>;
3289 template<bool _Const>
3291 : __detail::__lazy_split_view_inner_iter_cat<_Base<_Const>>
3294 using _Base = lazy_split_view::_Base<_Const>;
3299 auto [__pcur, __pend] = subrange{_M_i._M_parent->_M_pattern};
3300 auto __end = ranges::end(_M_i._M_parent->_M_base);
3301 if constexpr (__detail::__tiny_range<_Pattern>)
3303 const auto& __cur = _M_i_current();
3306 if (__pcur == __pend)
3307 return _M_incremented;
3308 return *__cur == *__pcur;
3312 auto __cur = _M_i_current();
3315 if (__pcur == __pend)
3316 return _M_incremented;
3319 if (*__cur != *__pcur)
3321 if (++__pcur == __pend)
3323 } while (++__cur != __end);
3329 _M_i_current() noexcept
3330 { return _M_i.__current(); }
3333 _M_i_current() const noexcept
3334 { return _M_i.__current(); }
3336 _OuterIter<_Const> _M_i = _OuterIter<_Const>();
3337 bool _M_incremented = false;
3340 using iterator_concept
3341 = typename _OuterIter<_Const>::iterator_concept;
3342 // iterator_category defined in __lazy_split_view_inner_iter_cat
3343 using value_type = range_value_t<_Base>;
3344 using difference_type = range_difference_t<_Base>;
3346 _InnerIter() = default;
3349 _InnerIter(_OuterIter<_Const> __i)
3350 : _M_i(std::move(__i))
3353 constexpr const iterator_t<_Base>&
3354 base() const& noexcept
3355 { return _M_i_current(); }
3357 constexpr iterator_t<_Base>
3358 base() && requires forward_range<_Vp>
3359 { return std::move(_M_i_current()); }
3361 constexpr decltype(auto)
3363 { return *_M_i_current(); }
3365 constexpr _InnerIter&
3368 _M_incremented = true;
3369 if constexpr (!forward_range<_Base>)
3370 if constexpr (_Pattern::size() == 0)
3376 constexpr decltype(auto)
3379 if constexpr (forward_range<_Base>)
3389 friend constexpr bool
3390 operator==(const _InnerIter& __x, const _InnerIter& __y)
3391 requires forward_range<_Base>
3392 { return __x._M_i == __y._M_i; }
3394 friend constexpr bool
3395 operator==(const _InnerIter& __x, default_sentinel_t)
3396 { return __x.__at_end(); }
3398 friend constexpr decltype(auto)
3399 iter_move(const _InnerIter& __i)
3400 noexcept(noexcept(ranges::iter_move(__i._M_i_current())))
3401 { return ranges::iter_move(__i._M_i_current()); }
3403 friend constexpr void
3404 iter_swap(const _InnerIter& __x, const _InnerIter& __y)
3405 noexcept(noexcept(ranges::iter_swap(__x._M_i_current(),
3406 __y._M_i_current())))
3407 requires indirectly_swappable<iterator_t<_Base>>
3408 { ranges::iter_swap(__x._M_i_current(), __y._M_i_current()); }
3411 _Vp _M_base = _Vp();
3412 _Pattern _M_pattern = _Pattern();
3413 [[no_unique_address]]
3414 __detail::__maybe_present_t<!forward_range<_Vp>,
3415 __detail::__non_propagating_cache<iterator_t<_Vp>>> _M_current;
3419 lazy_split_view() requires (default_initializable<_Vp>
3420 && default_initializable<_Pattern>)
3424 lazy_split_view(_Vp __base, _Pattern __pattern)
3425 : _M_base(std::move(__base)), _M_pattern(std::move(__pattern))
3428 template<input_range _Range>
3429 requires constructible_from<_Vp, views::all_t<_Range>>
3430 && constructible_from<_Pattern, single_view<range_value_t<_Range>>>
3432 lazy_split_view(_Range&& __r, range_value_t<_Range> __e)
3433 : _M_base(views::all(std::forward<_Range>(__r))),
3434 _M_pattern(views::single(std::move(__e)))
3438 base() const& requires copy_constructible<_Vp>
3443 { return std::move(_M_base); }
3448 if constexpr (forward_range<_Vp>)
3450 constexpr bool __simple
3451 = __detail::__simple_view<_Vp> && __detail::__simple_view<_Pattern>;
3452 return _OuterIter<__simple>{this, ranges::begin(_M_base)};
3456 _M_current = ranges::begin(_M_base);
3457 return _OuterIter<false>{this};
3462 begin() const requires forward_range<_Vp> && forward_range<const _Vp>
3464 return _OuterIter<true>{this, ranges::begin(_M_base)};
3468 end() requires forward_range<_Vp> && common_range<_Vp>
3470 constexpr bool __simple
3471 = __detail::__simple_view<_Vp> && __detail::__simple_view<_Pattern>;
3472 return _OuterIter<__simple>{this, ranges::end(_M_base)};
3478 if constexpr (forward_range<_Vp>
3479 && forward_range<const _Vp>
3480 && common_range<const _Vp>)
3481 return _OuterIter<true>{this, ranges::end(_M_base)};
3483 return default_sentinel;
3487 template<typename _Range, typename _Pattern>
3488 lazy_split_view(_Range&&, _Pattern&&)
3489 -> lazy_split_view<views::all_t<_Range>, views::all_t<_Pattern>>;
3491 template<input_range _Range>
3492 lazy_split_view(_Range&&, range_value_t<_Range>)
3493 -> lazy_split_view<views::all_t<_Range>, single_view<range_value_t<_Range>>>;
3499 template<typename _Range, typename _Pattern>
3500 concept __can_lazy_split_view
3501 = requires { lazy_split_view(std::declval<_Range>(), std::declval<_Pattern>()); };
3502 } // namespace __detail
3504 struct _LazySplit : __adaptor::_RangeAdaptor<_LazySplit>
3506 template<viewable_range _Range, typename _Pattern>
3507 requires __detail::__can_lazy_split_view<_Range, _Pattern>
3509 operator() [[nodiscard]] (_Range&& __r, _Pattern&& __f) const
3511 return lazy_split_view(std::forward<_Range>(__r), std::forward<_Pattern>(__f));
3514 using _RangeAdaptor<_LazySplit>::operator();
3515 static constexpr int _S_arity = 2;
3516 // The pattern argument of views::lazy_split is not always simple -- it can be
3517 // a non-view range, the value category of which affects whether the call
3518 // is well-formed. But a scalar or a view pattern argument is surely
3520 template<typename _Pattern>
3521 static constexpr bool _S_has_simple_extra_args
3522 = is_scalar_v<_Pattern> || (view<_Pattern>
3523 && copy_constructible<_Pattern>);
3526 inline constexpr _LazySplit lazy_split;
3527 } // namespace views
3529 template<forward_range _Vp, forward_range _Pattern>
3530 requires view<_Vp> && view<_Pattern>
3531 && indirectly_comparable<iterator_t<_Vp>, iterator_t<_Pattern>,
3533 class split_view : public view_interface<split_view<_Vp, _Pattern>>
3536 _Vp _M_base = _Vp();
3537 _Pattern _M_pattern = _Pattern();
3538 __detail::__non_propagating_cache<subrange<iterator_t<_Vp>>> _M_cached_begin;
3544 split_view() requires (default_initializable<_Vp>
3545 && default_initializable<_Pattern>)
3549 split_view(_Vp __base, _Pattern __pattern)
3550 : _M_base(std::move(__base)), _M_pattern(std::move(__pattern))
3553 template<forward_range _Range>
3554 requires constructible_from<_Vp, views::all_t<_Range>>
3555 && constructible_from<_Pattern, single_view<range_value_t<_Range>>>
3557 split_view(_Range&& __r, range_value_t<_Range> __e)
3558 : _M_base(views::all(std::forward<_Range>(__r))),
3559 _M_pattern(views::single(std::move(__e)))
3563 base() const& requires copy_constructible<_Vp>
3568 { return std::move(_M_base); }
3573 if (!_M_cached_begin)
3574 _M_cached_begin = _M_find_next(ranges::begin(_M_base));
3575 return {this, ranges::begin(_M_base), *_M_cached_begin};
3581 if constexpr (common_range<_Vp>)
3582 return _Iterator{this, ranges::end(_M_base), {}};
3584 return _Sentinel{this};
3587 constexpr subrange<iterator_t<_Vp>>
3588 _M_find_next(iterator_t<_Vp> __it)
3590 auto [__b, __e] = ranges::search(subrange(__it, ranges::end(_M_base)), _M_pattern);
3591 if (__b != ranges::end(_M_base) && ranges::empty(_M_pattern))
3603 split_view* _M_parent = nullptr;
3604 iterator_t<_Vp> _M_cur = iterator_t<_Vp>();
3605 subrange<iterator_t<_Vp>> _M_next = subrange<iterator_t<_Vp>>();
3606 bool _M_trailing_empty = false;
3608 friend struct _Sentinel;
3611 using iterator_concept = forward_iterator_tag;
3612 using iterator_category = input_iterator_tag;
3613 using value_type = subrange<iterator_t<_Vp>>;
3614 using difference_type = range_difference_t<_Vp>;
3616 _Iterator() = default;
3619 _Iterator(split_view* __parent,
3620 iterator_t<_Vp> __current,
3621 subrange<iterator_t<_Vp>> __next)
3622 : _M_parent(__parent),
3623 _M_cur(std::move(__current)),
3624 _M_next(std::move(__next))
3627 constexpr iterator_t<_Vp>
3631 constexpr value_type
3633 { return {_M_cur, _M_next.begin()}; }
3635 constexpr _Iterator&
3638 _M_cur = _M_next.begin();
3639 if (_M_cur != ranges::end(_M_parent->_M_base))
3641 _M_cur = _M_next.end();
3642 if (_M_cur == ranges::end(_M_parent->_M_base))
3644 _M_trailing_empty = true;
3645 _M_next = {_M_cur, _M_cur};
3648 _M_next = _M_parent->_M_find_next(_M_cur);
3651 _M_trailing_empty = false;
3663 friend constexpr bool
3664 operator==(const _Iterator& __x, const _Iterator& __y)
3666 return __x._M_cur == __y._M_cur
3667 && __x._M_trailing_empty == __y._M_trailing_empty;
3674 sentinel_t<_Vp> _M_end = sentinel_t<_Vp>();
3677 _M_equal(const _Iterator& __x) const
3678 { return __x._M_cur == _M_end && !__x._M_trailing_empty; }
3681 _Sentinel() = default;
3684 _Sentinel(split_view* __parent)
3685 : _M_end(ranges::end(__parent->_M_base))
3688 friend constexpr bool
3689 operator==(const _Iterator& __x, const _Sentinel& __y)
3690 { return __y._M_equal(__x); }
3694 template<typename _Range, typename _Pattern>
3695 split_view(_Range&&, _Pattern&&)
3696 -> split_view<views::all_t<_Range>, views::all_t<_Pattern>>;
3698 template<forward_range _Range>
3699 split_view(_Range&&, range_value_t<_Range>)
3700 -> split_view<views::all_t<_Range>, single_view<range_value_t<_Range>>>;
3706 template<typename _Range, typename _Pattern>
3707 concept __can_split_view
3708 = requires { split_view(std::declval<_Range>(), std::declval<_Pattern>()); };
3709 } // namespace __detail
3711 struct _Split : __adaptor::_RangeAdaptor<_Split>
3713 template<viewable_range _Range, typename _Pattern>
3714 requires __detail::__can_split_view<_Range, _Pattern>
3716 operator() [[nodiscard]] (_Range&& __r, _Pattern&& __f) const
3718 return split_view(std::forward<_Range>(__r), std::forward<_Pattern>(__f));
3721 using _RangeAdaptor<_Split>::operator();
3722 static constexpr int _S_arity = 2;
3723 template<typename _Pattern>
3724 static constexpr bool _S_has_simple_extra_args
3725 = _LazySplit::_S_has_simple_extra_args<_Pattern>;
3728 inline constexpr _Split split;
3729 } // namespace views
3735 template<input_or_output_iterator _Iter>
3737 operator() [[nodiscard]] (_Iter __i, iter_difference_t<_Iter> __n) const
3739 if constexpr (contiguous_iterator<_Iter>)
3740 return span(std::__to_address(__i), __n);
3741 else if constexpr (random_access_iterator<_Iter>)
3742 return subrange(__i, __i + __n);
3744 return subrange(counted_iterator(std::move(__i), __n),
3749 inline constexpr _Counted counted{};
3750 } // namespace views
3753 requires (!common_range<_Vp>) && copyable<iterator_t<_Vp>>
3754 class common_view : public view_interface<common_view<_Vp>>
3757 _Vp _M_base = _Vp();
3760 common_view() requires default_initializable<_Vp> = default;
3763 common_view(_Vp __r)
3764 : _M_base(std::move(__r))
3768 base() const& requires copy_constructible<_Vp>
3773 { return std::move(_M_base); }
3778 if constexpr (random_access_range<_Vp> && sized_range<_Vp>)
3779 return ranges::begin(_M_base);
3781 return common_iterator<iterator_t<_Vp>, sentinel_t<_Vp>>
3782 (ranges::begin(_M_base));
3786 begin() const requires range<const _Vp>
3788 if constexpr (random_access_range<const _Vp> && sized_range<const _Vp>)
3789 return ranges::begin(_M_base);
3791 return common_iterator<iterator_t<const _Vp>, sentinel_t<const _Vp>>
3792 (ranges::begin(_M_base));
3798 if constexpr (random_access_range<_Vp> && sized_range<_Vp>)
3799 return ranges::begin(_M_base) + ranges::size(_M_base);
3801 return common_iterator<iterator_t<_Vp>, sentinel_t<_Vp>>
3802 (ranges::end(_M_base));
3806 end() const requires range<const _Vp>
3808 if constexpr (random_access_range<const _Vp> && sized_range<const _Vp>)
3809 return ranges::begin(_M_base) + ranges::size(_M_base);
3811 return common_iterator<iterator_t<const _Vp>, sentinel_t<const _Vp>>
3812 (ranges::end(_M_base));
3816 size() requires sized_range<_Vp>
3817 { return ranges::size(_M_base); }
3820 size() const requires sized_range<const _Vp>
3821 { return ranges::size(_M_base); }
3824 template<typename _Range>
3825 common_view(_Range&&) -> common_view<views::all_t<_Range>>;
3827 template<typename _Tp>
3828 inline constexpr bool enable_borrowed_range<common_view<_Tp>>
3829 = enable_borrowed_range<_Tp>;
3835 template<typename _Range>
3836 concept __already_common = common_range<_Range>
3837 && requires { views::all(std::declval<_Range>()); };
3839 template<typename _Range>
3840 concept __can_common_view
3841 = requires { common_view{std::declval<_Range>()}; };
3842 } // namespace __detail
3844 struct _Common : __adaptor::_RangeAdaptorClosure
3846 template<viewable_range _Range>
3847 requires __detail::__already_common<_Range>
3848 || __detail::__can_common_view<_Range>
3850 operator() [[nodiscard]] (_Range&& __r) const
3852 if constexpr (__detail::__already_common<_Range>)
3853 return views::all(std::forward<_Range>(__r));
3855 return common_view{std::forward<_Range>(__r)};
3858 static constexpr bool _S_has_simple_call_op = true;
3861 inline constexpr _Common common;
3862 } // namespace views
3865 requires bidirectional_range<_Vp>
3866 class reverse_view : public view_interface<reverse_view<_Vp>>
3869 static constexpr bool _S_needs_cached_begin
3870 = !common_range<_Vp> && !(random_access_range<_Vp>
3871 && sized_sentinel_for<sentinel_t<_Vp>,
3874 _Vp _M_base = _Vp();
3875 [[no_unique_address]]
3876 __detail::__maybe_present_t<_S_needs_cached_begin,
3877 __detail::_CachedPosition<_Vp>>
3881 reverse_view() requires default_initializable<_Vp> = default;
3884 reverse_view(_Vp __r)
3885 : _M_base(std::move(__r))
3889 base() const& requires copy_constructible<_Vp>
3894 { return std::move(_M_base); }
3896 constexpr reverse_iterator<iterator_t<_Vp>>
3899 if constexpr (_S_needs_cached_begin)
3900 if (_M_cached_begin._M_has_value())
3901 return std::make_reverse_iterator(_M_cached_begin._M_get(_M_base));
3903 auto __it = ranges::next(ranges::begin(_M_base), ranges::end(_M_base));
3904 if constexpr (_S_needs_cached_begin)
3905 _M_cached_begin._M_set(_M_base, __it);
3906 return std::make_reverse_iterator(std::move(__it));
3910 begin() requires common_range<_Vp>
3911 { return std::make_reverse_iterator(ranges::end(_M_base)); }
3914 begin() const requires common_range<const _Vp>
3915 { return std::make_reverse_iterator(ranges::end(_M_base)); }
3917 constexpr reverse_iterator<iterator_t<_Vp>>
3919 { return std::make_reverse_iterator(ranges::begin(_M_base)); }
3922 end() const requires common_range<const _Vp>
3923 { return std::make_reverse_iterator(ranges::begin(_M_base)); }
3926 size() requires sized_range<_Vp>
3927 { return ranges::size(_M_base); }
3930 size() const requires sized_range<const _Vp>
3931 { return ranges::size(_M_base); }
3934 template<typename _Range>
3935 reverse_view(_Range&&) -> reverse_view<views::all_t<_Range>>;
3937 template<typename _Tp>
3938 inline constexpr bool enable_borrowed_range<reverse_view<_Tp>>
3939 = enable_borrowed_range<_Tp>;
3946 inline constexpr bool __is_reversible_subrange = false;
3948 template<typename _Iter, subrange_kind _Kind>
3949 inline constexpr bool
3950 __is_reversible_subrange<subrange<reverse_iterator<_Iter>,
3951 reverse_iterator<_Iter>,
3955 inline constexpr bool __is_reverse_view = false;
3957 template<typename _Vp>
3958 inline constexpr bool __is_reverse_view<reverse_view<_Vp>> = true;
3960 template<typename _Range>
3961 concept __can_reverse_view
3962 = requires { reverse_view{std::declval<_Range>()}; };
3963 } // namespace __detail
3965 struct _Reverse : __adaptor::_RangeAdaptorClosure
3967 template<viewable_range _Range>
3968 requires __detail::__is_reverse_view<remove_cvref_t<_Range>>
3969 || __detail::__is_reversible_subrange<remove_cvref_t<_Range>>
3970 || __detail::__can_reverse_view<_Range>
3972 operator() [[nodiscard]] (_Range&& __r) const
3974 using _Tp = remove_cvref_t<_Range>;
3975 if constexpr (__detail::__is_reverse_view<_Tp>)
3976 return std::forward<_Range>(__r).base();
3977 else if constexpr (__detail::__is_reversible_subrange<_Tp>)
3979 using _Iter = decltype(ranges::begin(__r).base());
3980 if constexpr (sized_range<_Tp>)
3981 return subrange<_Iter, _Iter, subrange_kind::sized>
3982 {__r.end().base(), __r.begin().base(), __r.size()};
3984 return subrange<_Iter, _Iter, subrange_kind::unsized>
3985 {__r.end().base(), __r.begin().base()};
3988 return reverse_view{std::forward<_Range>(__r)};
3991 static constexpr bool _S_has_simple_call_op = true;
3994 inline constexpr _Reverse reverse;
3995 } // namespace views
3999 template<typename _Tp, size_t _Nm>
4000 concept __has_tuple_element = requires(_Tp __t)
4002 typename tuple_size<_Tp>::type;
4003 requires _Nm < tuple_size_v<_Tp>;
4004 typename tuple_element_t<_Nm, _Tp>;
4005 { std::get<_Nm>(__t) }
4006 -> convertible_to<const tuple_element_t<_Nm, _Tp>&>;
4009 template<typename _Tp, size_t _Nm>
4010 concept __returnable_element
4011 = is_reference_v<_Tp> || move_constructible<tuple_element_t<_Nm, _Tp>>;
4014 template<input_range _Vp, size_t _Nm>
4016 && __detail::__has_tuple_element<range_value_t<_Vp>, _Nm>
4017 && __detail::__has_tuple_element<remove_reference_t<range_reference_t<_Vp>>,
4019 && __detail::__returnable_element<range_reference_t<_Vp>, _Nm>
4020 class elements_view : public view_interface<elements_view<_Vp, _Nm>>
4023 elements_view() requires default_initializable<_Vp> = default;
4026 elements_view(_Vp __base)
4027 : _M_base(std::move(__base))
4031 base() const& requires copy_constructible<_Vp>
4036 { return std::move(_M_base); }
4039 begin() requires (!__detail::__simple_view<_Vp>)
4040 { return _Iterator<false>(ranges::begin(_M_base)); }
4043 begin() const requires range<const _Vp>
4044 { return _Iterator<true>(ranges::begin(_M_base)); }
4047 end() requires (!__detail::__simple_view<_Vp> && !common_range<_Vp>)
4048 { return _Sentinel<false>{ranges::end(_M_base)}; }
4051 end() requires (!__detail::__simple_view<_Vp> && common_range<_Vp>)
4052 { return _Iterator<false>{ranges::end(_M_base)}; }
4055 end() const requires range<const _Vp>
4056 { return _Sentinel<true>{ranges::end(_M_base)}; }
4059 end() const requires common_range<const _Vp>
4060 { return _Iterator<true>{ranges::end(_M_base)}; }
4063 size() requires sized_range<_Vp>
4064 { return ranges::size(_M_base); }
4067 size() const requires sized_range<const _Vp>
4068 { return ranges::size(_M_base); }
4071 template<bool _Const>
4072 using _Base = __detail::__maybe_const_t<_Const, _Vp>;
4074 template<bool _Const>
4078 template<bool _Const>
4079 requires forward_range<_Base<_Const>>
4080 struct __iter_cat<_Const>
4083 static auto _S_iter_cat()
4085 using _Base = elements_view::_Base<_Const>;
4086 using _Cat = typename iterator_traits<iterator_t<_Base>>::iterator_category;
4087 using _Res = decltype((std::get<_Nm>(*std::declval<iterator_t<_Base>>())));
4088 if constexpr (!is_lvalue_reference_v<_Res>)
4089 return input_iterator_tag{};
4090 else if constexpr (derived_from<_Cat, random_access_iterator_tag>)
4091 return random_access_iterator_tag{};
4096 using iterator_category = decltype(_S_iter_cat());
4099 template<bool _Const>
4102 template<bool _Const>
4103 struct _Iterator : __iter_cat<_Const>
4106 using _Base = elements_view::_Base<_Const>;
4108 iterator_t<_Base> _M_current = iterator_t<_Base>();
4110 static constexpr decltype(auto)
4111 _S_get_element(const iterator_t<_Base>& __i)
4113 if constexpr (is_reference_v<range_reference_t<_Base>>)
4114 return std::get<_Nm>(*__i);
4117 using _Et = remove_cv_t<tuple_element_t<_Nm, range_reference_t<_Base>>>;
4118 return static_cast<_Et>(std::get<_Nm>(*__i));
4125 if constexpr (random_access_range<_Base>)
4126 return random_access_iterator_tag{};
4127 else if constexpr (bidirectional_range<_Base>)
4128 return bidirectional_iterator_tag{};
4129 else if constexpr (forward_range<_Base>)
4130 return forward_iterator_tag{};
4132 return input_iterator_tag{};
4135 friend _Iterator<!_Const>;
4138 using iterator_concept = decltype(_S_iter_concept());
4139 // iterator_category defined in elements_view::__iter_cat
4141 = remove_cvref_t<tuple_element_t<_Nm, range_value_t<_Base>>>;
4142 using difference_type = range_difference_t<_Base>;
4144 _Iterator() requires default_initializable<iterator_t<_Base>> = default;
4147 _Iterator(iterator_t<_Base> __current)
4148 : _M_current(std::move(__current))
4152 _Iterator(_Iterator<!_Const> __i)
4153 requires _Const && convertible_to<iterator_t<_Vp>, iterator_t<_Base>>
4154 : _M_current(std::move(__i._M_current))
4157 constexpr const iterator_t<_Base>&
4158 base() const& noexcept
4159 { return _M_current; }
4161 constexpr iterator_t<_Base>
4163 { return std::move(_M_current); }
4165 constexpr decltype(auto)
4167 { return _S_get_element(_M_current); }
4169 constexpr _Iterator&
4181 operator++(int) requires forward_range<_Base>
4188 constexpr _Iterator&
4189 operator--() requires bidirectional_range<_Base>
4196 operator--(int) requires bidirectional_range<_Base>
4203 constexpr _Iterator&
4204 operator+=(difference_type __n)
4205 requires random_access_range<_Base>
4211 constexpr _Iterator&
4212 operator-=(difference_type __n)
4213 requires random_access_range<_Base>
4219 constexpr decltype(auto)
4220 operator[](difference_type __n) const
4221 requires random_access_range<_Base>
4222 { return _S_get_element(_M_current + __n); }
4224 friend constexpr bool
4225 operator==(const _Iterator& __x, const _Iterator& __y)
4226 requires equality_comparable<iterator_t<_Base>>
4227 { return __x._M_current == __y._M_current; }
4229 friend constexpr bool
4230 operator<(const _Iterator& __x, const _Iterator& __y)
4231 requires random_access_range<_Base>
4232 { return __x._M_current < __y._M_current; }
4234 friend constexpr bool
4235 operator>(const _Iterator& __x, const _Iterator& __y)
4236 requires random_access_range<_Base>
4237 { return __y._M_current < __x._M_current; }
4239 friend constexpr bool
4240 operator<=(const _Iterator& __x, const _Iterator& __y)
4241 requires random_access_range<_Base>
4242 { return !(__y._M_current > __x._M_current); }
4244 friend constexpr bool
4245 operator>=(const _Iterator& __x, const _Iterator& __y)
4246 requires random_access_range<_Base>
4247 { return !(__x._M_current > __y._M_current); }
4249#ifdef __cpp_lib_three_way_comparison
4250 friend constexpr auto
4251 operator<=>(const _Iterator& __x, const _Iterator& __y)
4252 requires random_access_range<_Base>
4253 && three_way_comparable<iterator_t<_Base>>
4254 { return __x._M_current <=> __y._M_current; }
4257 friend constexpr _Iterator
4258 operator+(const _Iterator& __x, difference_type __y)
4259 requires random_access_range<_Base>
4260 { return _Iterator{__x} += __y; }
4262 friend constexpr _Iterator
4263 operator+(difference_type __x, const _Iterator& __y)
4264 requires random_access_range<_Base>
4265 { return __y + __x; }
4267 friend constexpr _Iterator
4268 operator-(const _Iterator& __x, difference_type __y)
4269 requires random_access_range<_Base>
4270 { return _Iterator{__x} -= __y; }
4272 // _GLIBCXX_RESOLVE_LIB_DEFECTS
4273 // 3483. transform_view::iterator's difference is overconstrained
4274 friend constexpr difference_type
4275 operator-(const _Iterator& __x, const _Iterator& __y)
4276 requires sized_sentinel_for<iterator_t<_Base>, iterator_t<_Base>>
4277 { return __x._M_current - __y._M_current; }
4279 template <bool> friend struct _Sentinel;
4282 template<bool _Const>
4286 template<bool _Const2>
4288 _M_equal(const _Iterator<_Const2>& __x) const
4289 { return __x._M_current == _M_end; }
4291 template<bool _Const2>
4293 _M_distance_from(const _Iterator<_Const2>& __i) const
4294 { return _M_end - __i._M_current; }
4296 using _Base = elements_view::_Base<_Const>;
4297 sentinel_t<_Base> _M_end = sentinel_t<_Base>();
4300 _Sentinel() = default;
4303 _Sentinel(sentinel_t<_Base> __end)
4304 : _M_end(std::move(__end))
4308 _Sentinel(_Sentinel<!_Const> __other)
4310 && convertible_to<sentinel_t<_Vp>, sentinel_t<_Base>>
4311 : _M_end(std::move(__other._M_end))
4314 constexpr sentinel_t<_Base>
4318 template<bool _Const2>
4319 requires sentinel_for<sentinel_t<_Base>,
4320 iterator_t<__detail::__maybe_const_t<_Const2, _Vp>>>
4321 friend constexpr bool
4322 operator==(const _Iterator<_Const2>& __x, const _Sentinel& __y)
4323 { return __y._M_equal(__x); }
4325 template<bool _Const2,
4326 typename _Base2 = __detail::__maybe_const_t<_Const2, _Vp>>
4327 requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<_Base2>>
4328 friend constexpr range_difference_t<_Base2>
4329 operator-(const _Iterator<_Const2>& __x, const _Sentinel& __y)
4330 { return -__y._M_distance_from(__x); }
4332 template<bool _Const2,
4333 typename _Base2 = __detail::__maybe_const_t<_Const2, _Vp>>
4334 requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<_Base2>>
4335 friend constexpr range_difference_t<_Base2>
4336 operator-(const _Sentinel& __x, const _Iterator<_Const2>& __y)
4337 { return __x._M_distance_from(__y); }
4339 friend _Sentinel<!_Const>;
4342 _Vp _M_base = _Vp();
4345 template<typename _Tp, size_t _Nm>
4346 inline constexpr bool enable_borrowed_range<elements_view<_Tp, _Nm>>
4347 = enable_borrowed_range<_Tp>;
4349 template<typename _Range>
4350 using keys_view = elements_view<views::all_t<_Range>, 0>;
4352 template<typename _Range>
4353 using values_view = elements_view<views::all_t<_Range>, 1>;
4359 template<size_t _Nm, typename _Range>
4360 concept __can_elements_view
4361 = requires { elements_view<all_t<_Range>, _Nm>{std::declval<_Range>()}; };
4362 } // namespace __detail
4364 template<size_t _Nm>
4365 struct _Elements : __adaptor::_RangeAdaptorClosure
4367 template<viewable_range _Range>
4368 requires __detail::__can_elements_view<_Nm, _Range>
4370 operator() [[nodiscard]] (_Range&& __r) const
4372 return elements_view<all_t<_Range>, _Nm>{std::forward<_Range>(__r)};
4375 static constexpr bool _S_has_simple_call_op = true;
4378 template<size_t _Nm>
4379 inline constexpr _Elements<_Nm> elements;
4380 inline constexpr auto keys = elements<0>;
4381 inline constexpr auto values = elements<1>;
4382 } // namespace views
4384#if __cplusplus > 202002L
4386#define __cpp_lib_ranges_zip 202110L
4390 template<typename... _Rs>
4391 concept __zip_is_common = (sizeof...(_Rs) == 1 && (common_range<_Rs> && ...))
4392 || (!(bidirectional_range<_Rs> && ...) && (common_range<_Rs> && ...))
4393 || ((random_access_range<_Rs> && ...) && (sized_range<_Rs> && ...));
4395 template<typename... _Ts>
4396 struct __tuple_or_pair
4397 { using type = std::tuple<_Ts...>; };
4399 template<typename _Tp, typename _Up>
4400 struct __tuple_or_pair<_Tp, _Up>
4401 { using type = pair<_Tp, _Up>; };
4403 template<typename... _Ts>
4404 using __tuple_or_pair_t = typename __tuple_or_pair<_Ts...>::type;
4406 template<typename _Fp, typename _Tuple>
4408 __tuple_transform(_Fp&& __f, _Tuple&& __tuple)
4410 return std::apply([&]<typename... _Ts>(_Ts&&... __elts) {
4411 return __tuple_or_pair_t<invoke_result_t<_Fp&, _Ts>...>
4412 (std::__invoke(__f, std::forward<_Ts>(__elts))...);
4413 }, std::forward<_Tuple>(__tuple));
4416 template<typename _Fp, typename _Tuple>
4418 __tuple_for_each(_Fp&& __f, _Tuple&& __tuple)
4420 std::apply([&]<typename... _Ts>(_Ts&&... __elts) {
4421 (std::__invoke(__f, std::forward<_Ts>(__elts)), ...);
4422 }, std::forward<_Tuple>(__tuple));
4424 } // namespace __detail
4426 template<input_range... _Vs>
4427 requires (view<_Vs> && ...) && (sizeof...(_Vs) > 0)
4428 class zip_view : public view_interface<zip_view<_Vs...>>
4430 tuple<_Vs...> _M_views;
4432 template<bool> class _Iterator;
4433 template<bool> class _Sentinel;
4436 zip_view() = default;
4439 zip_view(_Vs... __views)
4440 : _M_views(std::move(__views)...)
4444 begin() requires (!(__detail::__simple_view<_Vs> && ...))
4445 { return _Iterator<false>(__detail::__tuple_transform(ranges::begin, _M_views)); }
4448 begin() const requires (range<const _Vs> && ...)
4449 { return _Iterator<true>(__detail::__tuple_transform(ranges::begin, _M_views)); }
4452 end() requires (!(__detail::__simple_view<_Vs> && ...))
4454 if constexpr (!__detail::__zip_is_common<_Vs...>)
4455 return _Sentinel<false>(__detail::__tuple_transform(ranges::end, _M_views));
4456 else if constexpr ((random_access_range<_Vs> && ...))
4457 return begin() + iter_difference_t<_Iterator<false>>(size());
4459 return _Iterator<false>(__detail::__tuple_transform(ranges::end, _M_views));
4463 end() const requires (range<const _Vs> && ...)
4465 if constexpr (!__detail::__zip_is_common<const _Vs...>)
4466 return _Sentinel<true>(__detail::__tuple_transform(ranges::end, _M_views));
4467 else if constexpr ((random_access_range<const _Vs> && ...))
4468 return begin() + iter_difference_t<_Iterator<true>>(size());
4470 return _Iterator<true>(__detail::__tuple_transform(ranges::end, _M_views));
4474 size() requires (sized_range<_Vs> && ...)
4476 return std::apply([](auto... sizes) {
4477 using _CT = __detail::__make_unsigned_like_t<common_type_t<decltype(sizes)...>>;
4478 return ranges::min({_CT(sizes)...});
4479 }, __detail::__tuple_transform(ranges::size, _M_views));
4483 size() const requires (sized_range<const _Vs> && ...)
4485 return std::apply([](auto... sizes) {
4486 using _CT = __detail::__make_unsigned_like_t<common_type_t<decltype(sizes)...>>;
4487 return ranges::min({_CT(sizes)...});
4488 }, __detail::__tuple_transform(ranges::size, _M_views));
4492 template<typename... _Rs>
4493 zip_view(_Rs&&...) -> zip_view<views::all_t<_Rs>...>;
4495 template<typename... _Views>
4496 inline constexpr bool enable_borrowed_range<zip_view<_Views...>>
4497 = (enable_borrowed_range<_Views> && ...);
4501 template<bool _Const, typename... _Vs>
4502 concept __all_random_access
4503 = (random_access_range<__maybe_const_t<_Const, _Vs>> && ...);
4505 template<bool _Const, typename... _Vs>
4506 concept __all_bidirectional
4507 = (bidirectional_range<__maybe_const_t<_Const, _Vs>> && ...);
4509 template<bool _Const, typename... _Vs>
4510 concept __all_forward
4511 = (forward_range<__maybe_const_t<_Const, _Vs>> && ...);
4513 template<bool _Const, typename... _Views>
4514 struct __zip_view_iter_cat
4517 template<bool _Const, typename... _Views>
4518 requires __all_forward<_Const, _Views...>
4519 struct __zip_view_iter_cat<_Const, _Views...>
4520 { using iterator_category = input_iterator_tag; };
4521 } // namespace __detail
4523 template<input_range... _Vs>
4524 requires (view<_Vs> && ...) && (sizeof...(_Vs) > 0)
4525 template<bool _Const>
4526 class zip_view<_Vs...>::_Iterator
4527 : public __detail::__zip_view_iter_cat<_Const, _Vs...>
4529 __detail::__tuple_or_pair_t<iterator_t<__detail::__maybe_const_t<_Const, _Vs>>...> _M_current;
4532 _Iterator(decltype(_M_current) __current)
4533 : _M_current(std::move(__current))
4539 if constexpr (__detail::__all_random_access<_Const, _Vs...>)
4540 return random_access_iterator_tag{};
4541 else if constexpr (__detail::__all_bidirectional<_Const, _Vs...>)
4542 return bidirectional_iterator_tag{};
4543 else if constexpr (__detail::__all_forward<_Const, _Vs...>)
4544 return forward_iterator_tag{};
4546 return input_iterator_tag{};
4549 template<copy_constructible _Fp, input_range... _Ws>
4550 requires (view<_Ws> && ...) && (sizeof...(_Ws) > 0) && is_object_v<_Fp>
4551 && regular_invocable<_Fp&, range_reference_t<_Ws>...>
4552 && std::__detail::__can_reference<invoke_result_t<_Fp&, range_reference_t<_Ws>...>>
4553 friend class zip_transform_view;
4556 // iterator_category defined in __zip_view_iter_cat
4557 using iterator_concept = decltype(_S_iter_concept());
4559 = __detail::__tuple_or_pair_t<range_value_t<__detail::__maybe_const_t<_Const, _Vs>>...>;
4560 using difference_type
4561 = common_type_t<range_difference_t<__detail::__maybe_const_t<_Const, _Vs>>...>;
4563 _Iterator() = default;
4566 _Iterator(_Iterator<!_Const> __i)
4568 && (convertible_to<iterator_t<_Vs>,
4569 iterator_t<__detail::__maybe_const_t<_Const, _Vs>>> && ...)
4570 : _M_current(std::move(__i._M_current))
4576 auto __f = [](auto& __i) -> decltype(auto) {
4579 return __detail::__tuple_transform(__f, _M_current);
4582 constexpr _Iterator&
4585 __detail::__tuple_for_each([](auto& __i) { ++__i; }, _M_current);
4595 requires __detail::__all_forward<_Const, _Vs...>
4602 constexpr _Iterator&
4604 requires __detail::__all_bidirectional<_Const, _Vs...>
4606 __detail::__tuple_for_each([](auto& __i) { --__i; }, _M_current);
4612 requires __detail::__all_bidirectional<_Const, _Vs...>
4619 constexpr _Iterator&
4620 operator+=(difference_type __x)
4621 requires __detail::__all_random_access<_Const, _Vs...>
4623 auto __f = [&]<typename _It>(_It& __i) {
4624 __i += iter_difference_t<_It>(__x);
4626 __detail::__tuple_for_each(__f, _M_current);
4630 constexpr _Iterator&
4631 operator-=(difference_type __x)
4632 requires __detail::__all_random_access<_Const, _Vs...>
4634 auto __f = [&]<typename _It>(_It& __i) {
4635 __i -= iter_difference_t<_It>(__x);
4637 __detail::__tuple_for_each(__f, _M_current);
4642 operator[](difference_type __n) const
4643 requires __detail::__all_random_access<_Const, _Vs...>
4645 auto __f = [&]<typename _It>(_It& __i) -> decltype(auto) {
4646 return __i[iter_difference_t<_It>(__n)];
4648 return __detail::__tuple_transform(__f, _M_current);
4651 friend constexpr bool
4652 operator==(const _Iterator& __x, const _Iterator& __y)
4653 requires (equality_comparable<iterator_t<__detail::__maybe_const_t<_Const, _Vs>>> && ...)
4655 if constexpr (__detail::__all_bidirectional<_Const, _Vs...>)
4656 return __x._M_current == __y._M_current;
4658 return [&]<size_t... _Is>(index_sequence<_Is...>) {
4659 return ((std::get<_Is>(__x._M_current) == std::get<_Is>(__y._M_current)) || ...);
4660 }(make_index_sequence<sizeof...(_Vs)>{});
4663 friend constexpr auto
4664 operator<=>(const _Iterator& __x, const _Iterator& __y)
4665 requires __detail::__all_random_access<_Const, _Vs...>
4666 { return __x._M_current <=> __y._M_current; }
4668 friend constexpr _Iterator
4669 operator+(const _Iterator& __i, difference_type __n)
4670 requires __detail::__all_random_access<_Const, _Vs...>
4677 friend constexpr _Iterator
4678 operator+(difference_type __n, const _Iterator& __i)
4679 requires __detail::__all_random_access<_Const, _Vs...>
4686 friend constexpr _Iterator
4687 operator-(const _Iterator& __i, difference_type __n)
4688 requires __detail::__all_random_access<_Const, _Vs...>
4695 friend constexpr difference_type
4696 operator-(const _Iterator& __x, const _Iterator& __y)
4697 requires (sized_sentinel_for<iterator_t<__detail::__maybe_const_t<_Const, _Vs>>,
4698 iterator_t<__detail::__maybe_const_t<_Const, _Vs>>> && ...)
4700 return [&]<size_t... _Is>(index_sequence<_Is...>) {
4701 return ranges::min({difference_type(std::get<_Is>(__x._M_current)
4702 - std::get<_Is>(__y._M_current))...},
4704 [](difference_type __i) {
4705 return __detail::__to_unsigned_like(__i < 0 ? -__i : __i);
4707 }(make_index_sequence<sizeof...(_Vs)>{});
4710 friend constexpr auto
4711 iter_move(const _Iterator& __i)
4712 { return __detail::__tuple_transform(ranges::iter_move, __i._M_current); }
4714 friend constexpr void
4715 iter_swap(const _Iterator& __l, const _Iterator& __r)
4716 requires (indirectly_swappable<iterator_t<__detail::__maybe_const_t<_Const, _Vs>>> && ...)
4718 [&]<size_t... _Is>(index_sequence<_Is...>) {
4719 (ranges::iter_swap(std::get<_Is>(__l._M_current), std::get<_Is>(__r._M_current)), ...);
4720 }(make_index_sequence<sizeof...(_Vs)>{});
4723 friend class zip_view;
4726 template<input_range... _Vs>
4727 requires (view<_Vs> && ...) && (sizeof...(_Vs) > 0)
4728 template<bool _Const>
4729 class zip_view<_Vs...>::_Sentinel
4731 __detail::__tuple_or_pair_t<sentinel_t<__detail::__maybe_const_t<_Const, _Vs>>...> _M_end;
4734 _Sentinel(decltype(_M_end) __end)
4738 friend class zip_view;
4741 _Sentinel() = default;
4744 _Sentinel(_Sentinel<!_Const> __i)
4746 && (convertible_to<sentinel_t<_Vs>,
4747 sentinel_t<__detail::__maybe_const_t<_Const, _Vs>>> && ...)
4748 : _M_end(std::move(__i._M_end))
4751 template<bool _OtherConst>
4752 requires (sentinel_for<sentinel_t<__detail::__maybe_const_t<_Const, _Vs>>,
4753 iterator_t<__detail::__maybe_const_t<_OtherConst, _Vs>>> && ...)
4754 friend constexpr bool
4755 operator==(const _Iterator<_OtherConst>& __x, const _Sentinel& __y)
4757 return [&]<size_t... _Is>(index_sequence<_Is...>) {
4758 return ((std::get<_Is>(__x._M_current) == std::get<_Is>(__y._M_end)) || ...);
4759 }(make_index_sequence<sizeof...(_Vs)>{});
4762 template<bool _OtherConst>
4763 requires (sized_sentinel_for<sentinel_t<__detail::__maybe_const_t<_Const, _Vs>>,
4764 iterator_t<__detail::__maybe_const_t<_OtherConst, _Vs>>> && ...)
4765 friend constexpr auto
4766 operator-(const _Iterator<_OtherConst>& __x, const _Sentinel& __y)
4769 = common_type_t<range_difference_t<__detail::__maybe_const_t<_OtherConst, _Vs>>...>;
4770 return [&]<size_t... _Is>(index_sequence<_Is...>) {
4771 return ranges::min({_Ret(std::get<_Is>(__x._M_current) - std::get<_Is>(__y._M_end))...},
4774 return __detail::__to_unsigned_like(__i < 0 ? -__i : __i);
4776 }(make_index_sequence<sizeof...(_Vs)>{});
4779 template<bool _OtherConst>
4780 requires (sized_sentinel_for<sentinel_t<__detail::__maybe_const_t<_Const, _Vs>>,
4781 iterator_t<__detail::__maybe_const_t<_OtherConst, _Vs>>> && ...)
4782 friend constexpr auto
4783 operator-(const _Sentinel& __y, const _Iterator<_OtherConst>& __x)
4784 { return -(__x - __y); }
4791 template<typename... _Ts>
4792 concept __can_zip_view
4793 = requires { zip_view<all_t<_Ts>...>(std::declval<_Ts>()...); };
4798 template<typename... _Ts>
4799 requires (sizeof...(_Ts) == 0 || __detail::__can_zip_view<_Ts...>)
4801 operator() [[nodiscard]] (_Ts&&... __ts) const
4803 if constexpr (sizeof...(_Ts) == 0)
4804 return views::empty<tuple<>>;
4806 return zip_view<all_t<_Ts>...>(std::forward<_Ts>(__ts)...);
4810 inline constexpr _Zip zip;
4815 template<typename _Range, bool _Const>
4816 using __range_iter_cat
4817 = typename iterator_traits<iterator_t<__maybe_const_t<_Const, _Range>>>::iterator_category;
4820 template<copy_constructible _Fp, input_range... _Vs>
4821 requires (view<_Vs> && ...) && (sizeof...(_Vs) > 0) && is_object_v<_Fp>
4822 && regular_invocable<_Fp&, range_reference_t<_Vs>...>
4823 && std::__detail::__can_reference<invoke_result_t<_Fp&, range_reference_t<_Vs>...>>
4824 class zip_transform_view : public view_interface<zip_transform_view<_Fp, _Vs...>>
4826 [[no_unique_address]] __detail::__box<_Fp> _M_fun;
4827 zip_view<_Vs...> _M_zip;
4829 using _InnerView = zip_view<_Vs...>;
4831 template<bool _Const>
4832 using __ziperator = iterator_t<__detail::__maybe_const_t<_Const, _InnerView>>;
4834 template<bool _Const>
4835 using __zentinel = sentinel_t<__detail::__maybe_const_t<_Const, _InnerView>>;
4837 template<bool _Const>
4838 using _Base = __detail::__maybe_const_t<_Const, _InnerView>;
4840 template<bool _Const>
4844 template<bool _Const>
4845 requires forward_range<_Base<_Const>>
4846 struct __iter_cat<_Const>
4852 using __detail::__maybe_const_t;
4853 using __detail::__range_iter_cat;
4854 using _Res = invoke_result_t<__maybe_const_t<_Const, _Fp>&,
4855 range_reference_t<__maybe_const_t<_Const, _Vs>>...>;
4856 if constexpr (!is_lvalue_reference_v<_Res>)
4857 return input_iterator_tag{};
4858 else if constexpr ((derived_from<__range_iter_cat<_Vs, _Const>,
4859 random_access_iterator_tag> && ...))
4860 return random_access_iterator_tag{};
4861 else if constexpr ((derived_from<__range_iter_cat<_Vs, _Const>,
4862 bidirectional_iterator_tag> && ...))
4863 return bidirectional_iterator_tag{};
4864 else if constexpr ((derived_from<__range_iter_cat<_Vs, _Const>,
4865 forward_iterator_tag> && ...))
4866 return forward_iterator_tag{};
4868 return input_iterator_tag{};
4871 using iterator_category = decltype(_S_iter_cat());
4874 template<bool> class _Iterator;
4875 template<bool> class _Sentinel;
4878 zip_transform_view() = default;
4881 zip_transform_view(_Fp __fun, _Vs... __views)
4882 : _M_fun(std::move(__fun)), _M_zip(std::move(__views)...)
4887 { return _Iterator<false>(*this, _M_zip.begin()); }
4891 requires range<const _InnerView>
4892 && regular_invocable<const _Fp&, range_reference_t<const _Vs>...>
4893 { return _Iterator<true>(*this, _M_zip.begin()); }
4898 if constexpr (common_range<_InnerView>)
4899 return _Iterator<false>(*this, _M_zip.end());
4901 return _Sentinel<false>(_M_zip.end());
4906 requires range<const _InnerView>
4907 && regular_invocable<const _Fp&, range_reference_t<const _Vs>...>
4909 if constexpr (common_range<const _InnerView>)
4910 return _Iterator<true>(*this, _M_zip.end());
4912 return _Sentinel<true>(_M_zip.end());
4916 size() requires sized_range<_InnerView>
4917 { return _M_zip.size(); }
4920 size() const requires sized_range<const _InnerView>
4921 { return _M_zip.size(); }
4924 template<class _Fp, class... Rs>
4925 zip_transform_view(_Fp, Rs&&...) -> zip_transform_view<_Fp, views::all_t<Rs>...>;
4927 template<copy_constructible _Fp, input_range... _Vs>
4928 requires (view<_Vs> && ...) && (sizeof...(_Vs) > 0) && is_object_v<_Fp>
4929 && regular_invocable<_Fp&, range_reference_t<_Vs>...>
4930 && std::__detail::__can_reference<invoke_result_t<_Fp&, range_reference_t<_Vs>...>>
4931 template<bool _Const>
4932 class zip_transform_view<_Fp, _Vs...>::_Iterator : public __iter_cat<_Const>
4934 using _Parent = __detail::__maybe_const_t<_Const, zip_transform_view>;
4936 _Parent* _M_parent = nullptr;
4937 __ziperator<_Const> _M_inner;
4940 _Iterator(_Parent& __parent, __ziperator<_Const> __inner)
4941 : _M_parent(std::__addressof(__parent)), _M_inner(std::move(__inner))
4944 friend class zip_transform_view;
4947 // iterator_category defined in zip_transform_view::__iter_cat
4948 using iterator_concept = typename __ziperator<_Const>::iterator_concept;
4950 = remove_cvref_t<invoke_result_t<__detail::__maybe_const_t<_Const, _Fp>&,
4951 range_reference_t<__detail::__maybe_const_t<_Const, _Vs>>...>>;
4952 using difference_type = range_difference_t<_Base<_Const>>;
4954 _Iterator() = default;
4957 _Iterator(_Iterator<!_Const> __i)
4958 requires _Const && convertible_to<__ziperator<false>, __ziperator<_Const>>
4959 : _M_parent(__i._M_parent), _M_inner(std::move(__i._M_inner))
4962 constexpr decltype(auto)
4965 return std::apply([&](const auto&... __iters) -> decltype(auto) {
4966 return std::__invoke(*_M_parent->_M_fun, *__iters...);
4967 }, _M_inner._M_current);
4970 constexpr _Iterator&
4982 operator++(int) requires forward_range<_Base<_Const>>
4989 constexpr _Iterator&
4990 operator--() requires bidirectional_range<_Base<_Const>>
4997 operator--(int) requires bidirectional_range<_Base<_Const>>
5004 constexpr _Iterator&
5005 operator+=(difference_type __x) requires random_access_range<_Base<_Const>>
5011 constexpr _Iterator&
5012 operator-=(difference_type __x) requires random_access_range<_Base<_Const>>
5018 constexpr decltype(auto)
5019 operator[](difference_type __n) const requires random_access_range<_Base<_Const>>
5021 return std::apply([&]<typename... _Is>(const _Is&... __iters) -> decltype(auto) {
5022 return std::__invoke(*_M_parent->_M_fun, __iters[iter_difference_t<_Is>(__n)]...);
5023 }, _M_inner._M_current);
5026 friend constexpr bool
5027 operator==(const _Iterator& __x, const _Iterator& __y)
5028 requires equality_comparable<__ziperator<_Const>>
5029 { return __x._M_inner == __y._M_inner; }
5031 friend constexpr auto
5032 operator<=>(const _Iterator& __x, const _Iterator& __y)
5033 requires random_access_range<_Base<_Const>>
5034 { return __x._M_inner <=> __y._M_inner; }
5036 friend constexpr _Iterator
5037 operator+(const _Iterator& __i, difference_type __n)
5038 requires random_access_range<_Base<_Const>>
5039 { return _Iterator(*__i._M_parent, __i._M_inner + __n); }
5041 friend constexpr _Iterator
5042 operator+(difference_type __n, const _Iterator& __i)
5043 requires random_access_range<_Base<_Const>>
5044 { return _Iterator(*__i._M_parent, __i._M_inner + __n); }
5046 friend constexpr _Iterator
5047 operator-(const _Iterator& __i, difference_type __n)
5048 requires random_access_range<_Base<_Const>>
5049 { return _Iterator(*__i._M_parent, __i._M_inner - __n); }
5051 friend constexpr difference_type
5052 operator-(const _Iterator& __x, const _Iterator& __y)
5053 requires sized_sentinel_for<__ziperator<_Const>, __ziperator<_Const>>
5054 { return __x._M_inner - __y._M_inner; }
5057 template<copy_constructible _Fp, input_range... _Vs>
5058 requires (view<_Vs> && ...) && (sizeof...(_Vs) > 0) && is_object_v<_Fp>
5059 && regular_invocable<_Fp&, range_reference_t<_Vs>...>
5060 && std::__detail::__can_reference<invoke_result_t<_Fp&, range_reference_t<_Vs>...>>
5061 template<bool _Const>
5062 class zip_transform_view<_Fp, _Vs...>::_Sentinel
5064 __zentinel<_Const> _M_inner;
5067 _Sentinel(__zentinel<_Const> __inner)
5071 friend class zip_transform_view;
5074 _Sentinel() = default;
5077 _Sentinel(_Sentinel<!_Const> __i)
5078 requires _Const && convertible_to<__zentinel<false>, __zentinel<_Const>>
5079 : _M_inner(std::move(__i._M_inner))
5082 template<bool _OtherConst>
5083 requires sentinel_for<__zentinel<_Const>, __ziperator<_OtherConst>>
5084 friend constexpr bool
5085 operator==(const _Iterator<_OtherConst>& __x, const _Sentinel& __y)
5086 { return __x._M_inner == __y._M_inner; }
5088 template<bool _OtherConst>
5089 requires sized_sentinel_for<__zentinel<_Const>, __ziperator<_OtherConst>>
5090 friend constexpr range_difference_t<__detail::__maybe_const_t<_OtherConst, _InnerView>>
5091 operator-(const _Iterator<_OtherConst>& __x, const _Sentinel& __y)
5092 { return __x._M_inner - __y._M_inner; }
5094 template<bool _OtherConst>
5095 requires sized_sentinel_for<__zentinel<_Const>, __ziperator<_OtherConst>>
5096 friend constexpr range_difference_t<__detail::__maybe_const_t<_OtherConst, _InnerView>>
5097 operator-(const _Sentinel& __x, const _Iterator<_OtherConst>& __y)
5098 { return __x._M_inner - __y._M_inner; }
5105 template<typename _Fp, typename... _Ts>
5106 concept __can_zip_transform_view
5107 = requires { zip_transform_view(std::declval<_Fp>(), std::declval<_Ts>()...); };
5110 struct _ZipTransform
5112 template<typename _Fp, typename... _Ts>
5113 requires (sizeof...(_Ts) == 0) || __detail::__can_zip_transform_view<_Fp, _Ts...>
5115 operator() [[nodiscard]] (_Fp&& __f, _Ts&&... __ts) const
5117 if constexpr (sizeof...(_Ts) == 0)
5118 return views::empty<decay_t<invoke_result_t<decay_t<_Fp>&>>>;
5120 return zip_transform_view(std::forward<_Fp>(__f), std::forward<_Ts>(__ts)...);
5124 inline constexpr _ZipTransform zip_transform;
5127 template<forward_range _Vp, size_t _Nm>
5128 requires view<_Vp> && (_Nm > 0)
5129 class adjacent_view : public view_interface<adjacent_view<_Vp, _Nm>>
5131 _Vp _M_base = _Vp();
5133 template<bool> class _Iterator;
5134 template<bool> class _Sentinel;
5136 struct __as_sentinel
5140 adjacent_view() requires default_initializable<_Vp> = default;
5143 adjacent_view(_Vp __base)
5144 : _M_base(std::move(__base))
5148 begin() requires (!__detail::__simple_view<_Vp>)
5149 { return _Iterator<false>(ranges::begin(_M_base), ranges::end(_M_base)); }
5152 begin() const requires range<const _Vp>
5153 { return _Iterator<true>(ranges::begin(_M_base), ranges::end(_M_base)); }
5156 end() requires (!__detail::__simple_view<_Vp>)
5158 if constexpr (common_range<_Vp>)
5159 return _Iterator<false>(__as_sentinel{}, ranges::begin(_M_base), ranges::end(_M_base));
5161 return _Sentinel<false>(ranges::end(_M_base));
5165 end() const requires range<const _Vp>
5167 if constexpr (common_range<const _Vp>)
5168 return _Iterator<true>(__as_sentinel{}, ranges::begin(_M_base), ranges::end(_M_base));
5170 return _Sentinel<true>(ranges::end(_M_base));
5174 size() requires sized_range<_Vp>
5176 using _ST = decltype(ranges::size(_M_base));
5177 using _CT = common_type_t<_ST, size_t>;
5178 auto __sz = static_cast<_CT>(ranges::size(_M_base));
5179 __sz -= std::min<_CT>(__sz, _Nm - 1);
5180 return static_cast<_ST>(__sz);
5184 size() const requires sized_range<const _Vp>
5186 using _ST = decltype(ranges::size(_M_base));
5187 using _CT = common_type_t<_ST, size_t>;
5188 auto __sz = static_cast<_CT>(ranges::size(_M_base));
5189 __sz -= std::min<_CT>(__sz, _Nm - 1);
5190 return static_cast<_ST>(__sz);
5194 template<typename _Vp, size_t _Nm>
5195 inline constexpr bool enable_borrowed_range<adjacent_view<_Vp, _Nm>>
5196 = enable_borrowed_range<_Vp>;
5200 // Yields tuple<_Tp, ..., _Tp> with _Nm elements.
5201 template<typename _Tp, size_t _Nm>
5202 using __repeated_tuple = decltype(std::tuple_cat(std::declval<array<_Tp, _Nm>>()));
5204 // For a functor F that is callable with N arguments, the expression
5205 // declval<__unarize<F, N>>(x) is equivalent to declval<F>(x, ..., x).
5206 template<typename _Fp, size_t _Nm>
5209 template<typename... _Ts>
5210 static invoke_result_t<_Fp, _Ts...>
5211 __tuple_apply(const tuple<_Ts...>&); // not defined
5213 template<typename _Tp>
5214 decltype(__tuple_apply(std::declval<__repeated_tuple<_Tp, _Nm>>()))
5215 operator()(_Tp&&); // not defined
5219 template<forward_range _Vp, size_t _Nm>
5220 requires view<_Vp> && (_Nm > 0)
5221 template<bool _Const>
5222 class adjacent_view<_Vp, _Nm>::_Iterator
5224 using _Base = __detail::__maybe_const_t<_Const, _Vp>;
5225 array<iterator_t<_Base>, _Nm> _M_current = array<iterator_t<_Base>, _Nm>();
5228 _Iterator(iterator_t<_Base> __first, sentinel_t<_Base> __last)
5230 for (auto& __i : _M_current)
5233 ranges::advance(__first, 1, __last);
5238 _Iterator(__as_sentinel, iterator_t<_Base> __first, iterator_t<_Base> __last)
5240 if constexpr (!bidirectional_range<_Base>)
5241 for (auto& __it : _M_current)
5244 for (size_t __i = 0; __i < _Nm; ++__i)
5246 _M_current[_Nm - 1 - __i] = __last;
5247 ranges::advance(__last, -1, __first);
5254 if constexpr (random_access_range<_Base>)
5255 return random_access_iterator_tag{};
5256 else if constexpr (bidirectional_range<_Base>)
5257 return bidirectional_iterator_tag{};
5259 return forward_iterator_tag{};
5262 friend class adjacent_view;
5264 template<forward_range _Wp, copy_constructible _Fp, size_t _Mm>
5265 requires view<_Wp> && (_Mm > 0) && is_object_v<_Fp>
5266 && regular_invocable<__detail::__unarize<_Fp&, _Mm>, range_reference_t<_Wp>>
5267 && std::__detail::__can_reference<invoke_result_t<__detail::__unarize<_Fp&, _Mm>,
5268 range_reference_t<_Wp>>>
5269 friend class adjacent_transform_view;
5272 using iterator_category = input_iterator_tag;
5273 using iterator_concept = decltype(_S_iter_concept());
5274 using value_type = conditional_t<_Nm == 2,
5275 pair<range_value_t<_Base>, range_value_t<_Base>>,
5276 __detail::__repeated_tuple<range_value_t<_Base>, _Nm>>;
5277 using difference_type = range_difference_t<_Base>;
5279 _Iterator() = default;
5282 _Iterator(_Iterator<!_Const> __i)
5283 requires _Const && convertible_to<iterator_t<_Vp>, iterator_t<_Base>>
5285 for (size_t __j = 0; __j < _Nm; ++__j)
5286 _M_current[__j] = std::move(__i._M_current[__j]);
5292 auto __f = [](auto& __i) -> decltype(auto) { return *__i; };
5293 return __detail::__tuple_transform(__f, _M_current);
5296 constexpr _Iterator&
5299 for (auto& __i : _M_current)
5312 constexpr _Iterator&
5313 operator--() requires bidirectional_range<_Base>
5315 for (auto& __i : _M_current)
5321 operator--(int) requires bidirectional_range<_Base>
5328 constexpr _Iterator&
5329 operator+=(difference_type __x)
5330 requires random_access_range<_Base>
5332 for (auto& __i : _M_current)
5337 constexpr _Iterator&
5338 operator-=(difference_type __x)
5339 requires random_access_range<_Base>
5341 for (auto& __i : _M_current)
5347 operator[](difference_type __n) const
5348 requires random_access_range<_Base>
5350 auto __f = [&](auto& __i) -> decltype(auto) { return __i[__n]; };
5351 return __detail::__tuple_transform(__f, _M_current);
5354 friend constexpr bool
5355 operator==(const _Iterator& __x, const _Iterator& __y)
5356 { return __x._M_current.back() == __y._M_current.back(); }
5358 friend constexpr bool
5359 operator<(const _Iterator& __x, const _Iterator& __y)
5360 requires random_access_range<_Base>
5361 { return __x._M_current.back() < __y._M_current.back(); }
5363 friend constexpr bool
5364 operator>(const _Iterator& __x, const _Iterator& __y)
5365 requires random_access_range<_Base>
5366 { return __y < __x; }
5368 friend constexpr bool
5369 operator<=(const _Iterator& __x, const _Iterator& __y)
5370 requires random_access_range<_Base>
5371 { return !(__y < __x); }
5373 friend constexpr bool
5374 operator>=(const _Iterator& __x, const _Iterator& __y)
5375 requires random_access_range<_Base>
5376 { return !(__x < __y); }
5378 friend constexpr auto
5379 operator<=>(const _Iterator& __x, const _Iterator& __y)
5380 requires random_access_range<_Base>
5381 && three_way_comparable<iterator_t<_Base>>
5382 { return __x._M_current.back() <=> __y._M_current.back(); }
5384 friend constexpr _Iterator
5385 operator+(const _Iterator& __i, difference_type __n)
5386 requires random_access_range<_Base>
5393 friend constexpr _Iterator
5394 operator+(difference_type __n, const _Iterator& __i)
5395 requires random_access_range<_Base>
5402 friend constexpr _Iterator
5403 operator-(const _Iterator& __i, difference_type __n)
5404 requires random_access_range<_Base>
5411 friend constexpr difference_type
5412 operator-(const _Iterator& __x, const _Iterator& __y)
5413 requires sized_sentinel_for<iterator_t<_Base>, iterator_t<_Base>>
5414 { return __x._M_current.back() - __y._M_current.back(); }
5416 friend constexpr auto
5417 iter_move(const _Iterator& __i)
5418 { return __detail::__tuple_transform(ranges::iter_move, __i._M_current); }
5420 friend constexpr void
5421 iter_swap(const _Iterator& __l, const _Iterator& __r)
5422 requires indirectly_swappable<iterator_t<_Base>>
5424 for (size_t __i = 0; __i < _Nm; __i++)
5425 ranges::iter_swap(__l._M_current[__i], __r._M_current[__i]);
5429 template<forward_range _Vp, size_t _Nm>
5430 requires view<_Vp> && (_Nm > 0)
5431 template<bool _Const>
5432 class adjacent_view<_Vp, _Nm>::_Sentinel
5434 using _Base = __detail::__maybe_const_t<_Const, _Vp>;
5436 sentinel_t<_Base> _M_end = sentinel_t<_Base>();
5439 _Sentinel(sentinel_t<_Base> __end)
5443 friend class adjacent_view;
5446 _Sentinel() = default;
5449 _Sentinel(_Sentinel<!_Const> __i)
5450 requires _Const && convertible_to<sentinel_t<_Vp>, sentinel_t<_Base>>
5451 : _M_end(std::move(__i._M_end))
5454 template<bool _OtherConst>
5455 requires sentinel_for<sentinel_t<_Base>,
5456 iterator_t<__detail::__maybe_const_t<_OtherConst, _Vp>>>
5457 friend constexpr bool
5458 operator==(const _Iterator<_OtherConst>& __x, const _Sentinel& __y)
5459 { return __x._M_current.back() == __y._M_end; }
5461 template<bool _OtherConst>
5462 requires sized_sentinel_for<sentinel_t<_Base>,
5463 iterator_t<__detail::__maybe_const_t<_OtherConst, _Vp>>>
5464 friend constexpr range_difference_t<__detail::__maybe_const_t<_OtherConst, _Vp>>
5465 operator-(const _Iterator<_OtherConst>& __x, const _Sentinel& __y)
5466 { return __x._M_current.back() - __y._M_end; }
5468 template<bool _OtherConst>
5469 requires sized_sentinel_for<sentinel_t<_Base>,
5470 iterator_t<__detail::__maybe_const_t<_OtherConst, _Vp>>>
5471 friend constexpr range_difference_t<__detail::__maybe_const_t<_OtherConst, _Vp>>
5472 operator-(const _Sentinel& __y, const _Iterator<_OtherConst>& __x)
5473 { return __y._M_end - __x._M_current.back(); }
5480 template<size_t _Nm, typename _Range>
5481 concept __can_adjacent_view
5482 = requires { adjacent_view<all_t<_Range>, _Nm>(std::declval<_Range>()); };
5485 template<size_t _Nm>
5486 struct _Adjacent : __adaptor::_RangeAdaptorClosure
5488 template<viewable_range _Range>
5489 requires (_Nm == 0) || __detail::__can_adjacent_view<_Nm, _Range>
5491 operator() [[nodiscard]] (_Range&& __r) const
5493 if constexpr (_Nm == 0)
5494 return views::empty<tuple<>>;
5496 return adjacent_view<all_t<_Range>, _Nm>(std::forward<_Range>(__r));
5500 template<size_t _Nm>
5501 inline constexpr _Adjacent<_Nm> adjacent;
5503 inline constexpr auto pairwise = adjacent<2>;
5506 template<forward_range _Vp, copy_constructible _Fp, size_t _Nm>
5507 requires view<_Vp> && (_Nm > 0) && is_object_v<_Fp>
5508 && regular_invocable<__detail::__unarize<_Fp&, _Nm>, range_reference_t<_Vp>>
5509 && std::__detail::__can_reference<invoke_result_t<__detail::__unarize<_Fp&, _Nm>,
5510 range_reference_t<_Vp>>>
5511 class adjacent_transform_view : public view_interface<adjacent_transform_view<_Vp, _Fp, _Nm>>
5513 [[no_unique_address]] __detail::__box<_Fp> _M_fun;
5514 adjacent_view<_Vp, _Nm> _M_inner;
5516 using _InnerView = adjacent_view<_Vp, _Nm>;
5518 template<bool _Const>
5519 using _InnerIter = iterator_t<__detail::__maybe_const_t<_Const, _InnerView>>;
5521 template<bool _Const>
5522 using _InnerSent = sentinel_t<__detail::__maybe_const_t<_Const, _InnerView>>;
5524 template<bool> class _Iterator;
5525 template<bool> class _Sentinel;
5528 adjacent_transform_view() = default;
5531 adjacent_transform_view(_Vp __base, _Fp __fun)
5532 : _M_fun(std::move(__fun)), _M_inner(std::move(__base))
5537 { return _Iterator<false>(*this, _M_inner.begin()); }
5541 requires range<const _InnerView>
5542 && regular_invocable<__detail::__unarize<const _Fp&, _Nm>,
5543 range_reference_t<const _Vp>>
5544 { return _Iterator<true>(*this, _M_inner.begin()); }
5549 if constexpr (common_range<_InnerView>)
5550 return _Iterator<false>(*this, _M_inner.end());
5552 return _Sentinel<false>(_M_inner.end());
5557 requires range<const _InnerView>
5558 && regular_invocable<__detail::__unarize<const _Fp&, _Nm>,
5559 range_reference_t<const _Vp>>
5561 if constexpr (common_range<const _InnerView>)
5562 return _Iterator<true>(*this, _M_inner.end());
5564 return _Sentinel<true>(_M_inner.end());
5568 size() requires sized_range<_InnerView>
5569 { return _M_inner.size(); }
5572 size() const requires sized_range<const _InnerView>
5573 { return _M_inner.size(); }
5576 template<forward_range _Vp, copy_constructible _Fp, size_t _Nm>
5577 requires view<_Vp> && (_Nm > 0) && is_object_v<_Fp>
5578 && regular_invocable<__detail::__unarize<_Fp&, _Nm>, range_reference_t<_Vp>>
5579 && std::__detail::__can_reference<invoke_result_t<__detail::__unarize<_Fp&, _Nm>,
5580 range_reference_t<_Vp>>>
5581 template<bool _Const>
5582 class adjacent_transform_view<_Vp, _Fp, _Nm>::_Iterator
5584 using _Parent = __detail::__maybe_const_t<_Const, adjacent_transform_view>;
5585 using _Base = __detail::__maybe_const_t<_Const, _Vp>;
5587 _Parent* _M_parent = nullptr;
5588 _InnerIter<_Const> _M_inner;
5591 _Iterator(_Parent& __parent, _InnerIter<_Const> __inner)
5592 : _M_parent(std::__addressof(__parent)), _M_inner(std::move(__inner))
5598 using __detail::__maybe_const_t;
5599 using __detail::__unarize;
5600 using _Res = invoke_result_t<__unarize<__maybe_const_t<_Const, _Fp>&, _Nm>,
5601 range_reference_t<_Base>>;
5602 using _Cat = typename iterator_traits<iterator_t<_Base>>::iterator_category;
5603 if constexpr (!is_lvalue_reference_v<_Res>)
5604 return input_iterator_tag{};
5605 else if constexpr (derived_from<_Cat, random_access_iterator_tag>)
5606 return random_access_iterator_tag{};
5607 else if constexpr (derived_from<_Cat, bidirectional_iterator_tag>)
5608 return bidirectional_iterator_tag{};
5609 else if constexpr (derived_from<_Cat, forward_iterator_tag>)
5610 return forward_iterator_tag{};
5612 return input_iterator_tag{};
5615 friend class adjacent_transform_view;
5618 using iterator_category = decltype(_S_iter_cat());
5619 using iterator_concept = typename _InnerIter<_Const>::iterator_concept;
5621 = remove_cvref_t<invoke_result_t
5622 <__detail::__unarize<__detail::__maybe_const_t<_Const, _Fp>&, _Nm>,
5623 range_reference_t<_Base>>>;
5624 using difference_type = range_difference_t<_Base>;
5626 _Iterator() = default;
5629 _Iterator(_Iterator<!_Const> __i)
5630 requires _Const && convertible_to<_InnerIter<false>, _InnerIter<_Const>>
5631 : _M_parent(__i._M_parent), _M_inner(std::move(__i._M_inner))
5634 constexpr decltype(auto)
5637 return std::apply([&](const auto&... __iters) -> decltype(auto) {
5638 return std::__invoke(*_M_parent->_M_fun, *__iters...);
5639 }, _M_inner._M_current);
5642 constexpr _Iterator&
5657 constexpr _Iterator&
5658 operator--() requires bidirectional_range<_Base>
5665 operator--(int) requires bidirectional_range<_Base>
5672 constexpr _Iterator&
5673 operator+=(difference_type __x) requires random_access_range<_Base>
5679 constexpr _Iterator&
5680 operator-=(difference_type __x) requires random_access_range<_Base>
5686 constexpr decltype(auto)
5687 operator[](difference_type __n) const requires random_access_range<_Base>
5689 return std::apply([&](const auto&... __iters) -> decltype(auto) {
5690 return std::__invoke(*_M_parent->_M_fun, __iters[__n]...);
5691 }, _M_inner._M_current);
5694 friend constexpr bool
5695 operator==(const _Iterator& __x, const _Iterator& __y)
5696 { return __x._M_inner == __y._M_inner; }
5698 friend constexpr bool
5699 operator<(const _Iterator& __x, const _Iterator& __y)
5700 requires random_access_range<_Base>
5701 { return __x._M_inner < __y._M_inner; }
5703 friend constexpr bool
5704 operator>(const _Iterator& __x, const _Iterator& __y)
5705 requires random_access_range<_Base>
5706 { return __x._M_inner > __y._M_inner; }
5708 friend constexpr bool
5709 operator<=(const _Iterator& __x, const _Iterator& __y)
5710 requires random_access_range<_Base>
5711 { return __x._M_inner <= __y._M_inner; }
5713 friend constexpr bool
5714 operator>=(const _Iterator& __x, const _Iterator& __y)
5715 requires random_access_range<_Base>
5716 { return __x._M_inner >= __y._M_inner; }
5718 friend constexpr auto
5719 operator<=>(const _Iterator& __x, const _Iterator& __y)
5720 requires random_access_range<_Base> &&
5721 three_way_comparable<_InnerIter<_Const>>
5722 { return __x._M_inner <=> __y._M_inner; }
5724 friend constexpr _Iterator
5725 operator+(const _Iterator& __i, difference_type __n)
5726 requires random_access_range<_Base>
5727 { return _Iterator(*__i._M_parent, __i._M_inner + __n); }
5729 friend constexpr _Iterator
5730 operator+(difference_type __n, const _Iterator& __i)
5731 requires random_access_range<_Base>
5732 { return _Iterator(*__i._M_parent, __i._M_inner + __n); }
5734 friend constexpr _Iterator
5735 operator-(const _Iterator& __i, difference_type __n)
5736 requires random_access_range<_Base>
5737 { return _Iterator(*__i._M_parent, __i._M_inner - __n); }
5739 friend constexpr difference_type
5740 operator-(const _Iterator& __x, const _Iterator& __y)
5741 requires sized_sentinel_for<_InnerIter<_Const>, _InnerIter<_Const>>
5742 { return __x._M_inner - __y._M_inner; }
5745 template<forward_range _Vp, copy_constructible _Fp, size_t _Nm>
5746 requires view<_Vp> && (_Nm > 0) && is_object_v<_Fp>
5747 && regular_invocable<__detail::__unarize<_Fp&, _Nm>, range_reference_t<_Vp>>
5748 && std::__detail::__can_reference<invoke_result_t<__detail::__unarize<_Fp&, _Nm>,
5749 range_reference_t<_Vp>>>
5750 template<bool _Const>
5751 class adjacent_transform_view<_Vp, _Fp, _Nm>::_Sentinel
5753 _InnerSent<_Const> _M_inner;
5756 _Sentinel(_InnerSent<_Const> __inner)
5760 friend class adjacent_transform_view;
5763 _Sentinel() = default;
5766 _Sentinel(_Sentinel<!_Const> __i)
5767 requires _Const && convertible_to<_InnerSent<false>, _InnerSent<_Const>>
5768 : _M_inner(std::move(__i._M_inner))
5771 template<bool _OtherConst>
5772 requires sentinel_for<_InnerSent<_Const>, _InnerIter<_OtherConst>>
5773 friend constexpr bool
5774 operator==(const _Iterator<_OtherConst>& __x, const _Sentinel& __y)
5775 { return __x._M_inner == __y._M_inner; }
5777 template<bool _OtherConst>
5778 requires sized_sentinel_for<_InnerSent<_Const>, _InnerIter<_OtherConst>>
5779 friend constexpr range_difference_t<__detail::__maybe_const_t<_OtherConst, _InnerView>>
5780 operator-(const _Iterator<_OtherConst>& __x, const _Sentinel& __y)
5781 { return __x._M_inner - __y._M_inner; }
5783 template<bool _OtherConst>
5784 requires sized_sentinel_for<_InnerSent<_Const>, _InnerIter<_OtherConst>>
5785 friend constexpr range_difference_t<__detail::__maybe_const_t<_OtherConst, _InnerView>>
5786 operator-(const _Sentinel& __x, const _Iterator<_OtherConst>& __y)
5787 { return __x._M_inner - __y._M_inner; }
5794 template<size_t _Nm, typename _Range, typename _Fp>
5795 concept __can_adjacent_transform_view
5796 = requires { adjacent_transform_view<all_t<_Range>, decay_t<_Fp>, _Nm>
5797 (std::declval<_Range>(), std::declval<_Fp>()); };
5800 template<size_t _Nm>
5801 struct _AdjacentTransform : __adaptor::_RangeAdaptor<_AdjacentTransform<_Nm>>
5803 template<viewable_range _Range, typename _Fp>
5804 requires (_Nm == 0) || __detail::__can_adjacent_transform_view<_Nm, _Range, _Fp>
5806 operator() [[nodiscard]] (_Range&& __r, _Fp&& __f) const
5808 if constexpr (_Nm == 0)
5809 return zip_transform(std::forward<_Fp>(__f));
5811 return adjacent_transform_view<all_t<_Range>, decay_t<_Fp>, _Nm>
5812 (std::forward<_Range>(__r), std::forward<_Fp>(__f));
5815 using __adaptor::_RangeAdaptor<_AdjacentTransform>::operator();
5816 static constexpr int _S_arity = 2;
5817 static constexpr bool _S_has_simple_extra_args = true;
5820 template<size_t _Nm>
5821 inline constexpr _AdjacentTransform<_Nm> adjacent_transform;
5823 inline constexpr auto pairwise_transform = adjacent_transform<2>;
5826#define __cpp_lib_ranges_chunk 202202L
5830 template<typename _Tp>
5831 constexpr _Tp __div_ceil(_Tp __num, _Tp __denom)
5833 _Tp __r = __num / __denom;
5834 if (__num % __denom)
5841 requires input_range<_Vp>
5842 class chunk_view : public view_interface<chunk_view<_Vp>>
5845 range_difference_t<_Vp> _M_n;
5846 range_difference_t<_Vp> _M_remainder = 0;
5847 __detail::__non_propagating_cache<iterator_t<_Vp>> _M_current;
5854 chunk_view(_Vp __base, range_difference_t<_Vp> __n)
5855 : _M_base(std::move(__base)), _M_n(__n)
5856 { __glibcxx_assert(__n >= 0); }
5859 base() const & requires copy_constructible<_Vp>
5864 { return std::move(_M_base); }
5866 constexpr _OuterIter
5869 _M_current = ranges::begin(_M_base);
5870 _M_remainder = _M_n;
5871 return _OuterIter(*this);
5874 constexpr default_sentinel_t
5875 end() const noexcept
5876 { return default_sentinel; }
5879 size() requires sized_range<_Vp>
5881 return __detail::__to_unsigned_like(__detail::__div_ceil
5882 (ranges::distance(_M_base), _M_n));
5886 size() const requires sized_range<const _Vp>
5888 return __detail::__to_unsigned_like(__detail::__div_ceil
5889 (ranges::distance(_M_base), _M_n));
5893 template<typename _Range>
5894 chunk_view(_Range&&, range_difference_t<_Range>) -> chunk_view<views::all_t<_Range>>;
5897 requires input_range<_Vp>
5898 class chunk_view<_Vp>::_OuterIter
5900 chunk_view* _M_parent;
5903 _OuterIter(chunk_view& __parent) noexcept
5904 : _M_parent(std::__addressof(__parent))
5910 using iterator_concept = input_iterator_tag;
5911 using difference_type = range_difference_t<_Vp>;
5915 _OuterIter(_OuterIter&&) = default;
5916 _OuterIter& operator=(_OuterIter&&) = default;
5918 constexpr value_type
5921 __glibcxx_assert(*this != default_sentinel);
5922 return value_type(*_M_parent);
5925 constexpr _OuterIter&
5928 __glibcxx_assert(*this != default_sentinel);
5929 ranges::advance(*_M_parent->_M_current, _M_parent->_M_remainder,
5930 ranges::end(_M_parent->_M_base));
5931 _M_parent->_M_remainder = _M_parent->_M_n;
5939 friend constexpr bool
5940 operator==(const _OuterIter& __x, default_sentinel_t)
5942 return *__x._M_parent->_M_current == ranges::end(__x._M_parent->_M_base)
5943 && __x._M_parent->_M_remainder != 0;
5946 friend constexpr difference_type
5947 operator-(default_sentinel_t, const _OuterIter& __x)
5948 requires sized_sentinel_for<sentinel_t<_Vp>, iterator_t<_Vp>>
5950 const auto __dist = ranges::end(__x._M_parent->_M_base) - *__x._M_parent->_M_current;
5952 if (__dist < __x._M_parent->_M_remainder)
5953 return __dist == 0 ? 0 : 1;
5955 return 1 + __detail::__div_ceil(__dist - __x._M_parent->_M_remainder,
5956 __x._M_parent->_M_n);
5959 friend constexpr difference_type
5960 operator-(const _OuterIter& __x, default_sentinel_t __y)
5961 requires sized_sentinel_for<sentinel_t<_Vp>, iterator_t<_Vp>>
5962 { return -(__y - __x); }
5966 requires input_range<_Vp>
5967 struct chunk_view<_Vp>::_OuterIter::value_type : view_interface<value_type>
5970 chunk_view* _M_parent;
5973 value_type(chunk_view& __parent) noexcept
5974 : _M_parent(std::__addressof(__parent))
5980 constexpr _InnerIter
5981 begin() const noexcept
5982 { return _InnerIter(*_M_parent); }
5984 constexpr default_sentinel_t
5985 end() const noexcept
5986 { return default_sentinel; }
5990 requires sized_sentinel_for<sentinel_t<_Vp>, iterator_t<_Vp>>
5992 return __detail::__to_unsigned_like
5993 (ranges::min(_M_parent->_M_remainder,
5994 ranges::end(_M_parent->_M_base) - *_M_parent->_M_current));
5999 requires input_range<_Vp>
6000 class chunk_view<_Vp>::_InnerIter
6002 chunk_view* _M_parent;
6005 _InnerIter(chunk_view& __parent) noexcept
6006 : _M_parent(std::__addressof(__parent))
6009 friend _OuterIter::value_type;
6012 using iterator_concept = input_iterator_tag;
6013 using difference_type = range_difference_t<_Vp>;
6014 using value_type = range_value_t<_Vp>;
6016 _InnerIter(_InnerIter&&) = default;
6017 _InnerIter& operator=(_InnerIter&&) = default;
6019 constexpr const iterator_t<_Vp>&
6021 { return *_M_parent->_M_current; }
6023 constexpr range_reference_t<_Vp>
6026 __glibcxx_assert(*this != default_sentinel);
6027 return **_M_parent->_M_current;
6030 constexpr _InnerIter&
6033 __glibcxx_assert(*this != default_sentinel);
6034 ++*_M_parent->_M_current;
6035 if (*_M_parent->_M_current == ranges::end(_M_parent->_M_base))
6036 _M_parent->_M_remainder = 0;
6038 --_M_parent->_M_remainder;
6046 friend constexpr bool
6047 operator==(const _InnerIter& __x, default_sentinel_t) noexcept
6048 { return __x._M_parent->_M_remainder == 0; }
6050 friend constexpr difference_type
6051 operator-(default_sentinel_t, const _InnerIter& __x)
6052 requires sized_sentinel_for<sentinel_t<_Vp>, iterator_t<_Vp>>
6054 return ranges::min(__x._M_parent->_M_remainder,
6055 ranges::end(__x._M_parent->_M_base) - *__x._M_parent->_M_current);
6058 friend constexpr difference_type
6059 operator-(const _InnerIter& __x, default_sentinel_t __y)
6060 requires sized_sentinel_for<sentinel_t<_Vp>, iterator_t<_Vp>>
6061 { return -(__y - __x); }
6065 requires forward_range<_Vp>
6066 class chunk_view<_Vp> : public view_interface<chunk_view<_Vp>>
6069 range_difference_t<_Vp> _M_n;
6070 template<bool> class _Iterator;
6074 chunk_view(_Vp __base, range_difference_t<_Vp> __n)
6075 : _M_base(std::move(__base)), _M_n(__n)
6076 { __glibcxx_assert(__n > 0); }
6079 base() const & requires copy_constructible<_Vp>
6084 { return std::move(_M_base); }
6087 begin() requires (!__detail::__simple_view<_Vp>)
6088 { return _Iterator<false>(this, ranges::begin(_M_base)); }
6091 begin() const requires forward_range<const _Vp>
6092 { return _Iterator<true>(this, ranges::begin(_M_base)); }
6095 end() requires (!__detail::__simple_view<_Vp>)
6097 if constexpr (common_range<_Vp> && sized_range<_Vp>)
6099 auto __missing = (_M_n - ranges::distance(_M_base) % _M_n) % _M_n;
6100 return _Iterator<false>(this, ranges::end(_M_base), __missing);
6102 else if constexpr (common_range<_Vp> && !bidirectional_range<_Vp>)
6103 return _Iterator<false>(this, ranges::end(_M_base));
6105 return default_sentinel;
6109 end() const requires forward_range<const _Vp>
6111 if constexpr (common_range<const _Vp> && sized_range<const _Vp>)
6113 auto __missing = (_M_n - ranges::distance(_M_base) % _M_n) % _M_n;
6114 return _Iterator<true>(this, ranges::end(_M_base), __missing);
6116 else if constexpr (common_range<const _Vp> && !bidirectional_range<const _Vp>)
6117 return _Iterator<true>(this, ranges::end(_M_base));
6119 return default_sentinel;
6123 size() requires sized_range<_Vp>
6125 return __detail::__to_unsigned_like(__detail::__div_ceil
6126 (ranges::distance(_M_base), _M_n));
6130 size() const requires sized_range<const _Vp>
6132 return __detail::__to_unsigned_like(__detail::__div_ceil
6133 (ranges::distance(_M_base), _M_n));
6137 template<typename _Vp>
6138 inline constexpr bool enable_borrowed_range<chunk_view<_Vp>>
6139 = forward_range<_Vp> && enable_borrowed_range<_Vp>;
6142 requires forward_range<_Vp>
6143 template<bool _Const>
6144 class chunk_view<_Vp>::_Iterator
6146 using _Parent = __detail::__maybe_const_t<_Const, chunk_view>;
6147 using _Base = __detail::__maybe_const_t<_Const, _Vp>;
6149 iterator_t<_Base> _M_current = iterator_t<_Base>();
6150 sentinel_t<_Base> _M_end = sentinel_t<_Base>();
6151 range_difference_t<_Base> _M_n = 0;
6152 range_difference_t<_Base> _M_missing = 0;
6155 _Iterator(_Parent* __parent, iterator_t<_Base> __current,
6156 range_difference_t<_Base> __missing = 0)
6157 : _M_current(__current), _M_end(ranges::end(__parent->_M_base)),
6158 _M_n(__parent->_M_n), _M_missing(__missing)
6164 if constexpr (random_access_range<_Base>)
6165 return random_access_iterator_tag{};
6166 else if constexpr (bidirectional_range<_Base>)
6167 return bidirectional_iterator_tag{};
6169 return forward_iterator_tag{};
6175 using iterator_category = input_iterator_tag;
6176 using iterator_concept = decltype(_S_iter_cat());
6177 using value_type = decltype(views::take(subrange(_M_current, _M_end), _M_n));
6178 using difference_type = range_difference_t<_Base>;
6180 _Iterator() = default;
6182 constexpr _Iterator(_Iterator<!_Const> __i)
6184 && convertible_to<iterator_t<_Vp>, iterator_t<_Base>>
6185 && convertible_to<sentinel_t<_Vp>, sentinel_t<_Base>>
6186 : _M_current(std::move(__i._M_current)), _M_end(std::move(__i._M_end)),
6187 _M_n(__i._M_n), _M_missing(__i._M_missing)
6190 constexpr iterator_t<_Base>
6192 { return _M_current; }
6194 constexpr value_type
6197 __glibcxx_assert(_M_current != _M_end);
6198 return views::take(subrange(_M_current, _M_end), _M_n);
6201 constexpr _Iterator&
6204 __glibcxx_assert(_M_current != _M_end);
6205 _M_missing = ranges::advance(_M_current, _M_n, _M_end);
6217 constexpr _Iterator&
6218 operator--() requires bidirectional_range<_Base>
6220 ranges::advance(_M_current, _M_missing - _M_n);
6226 operator--(int) requires bidirectional_range<_Base>
6233 constexpr _Iterator&
6234 operator+=(difference_type __x)
6235 requires random_access_range<_Base>
6239 __glibcxx_assert(ranges::distance(_M_current, _M_end) > _M_n * (__x - 1));
6240 _M_missing = ranges::advance(_M_current, _M_n * __x, _M_end);
6244 ranges::advance(_M_current, _M_n * __x + _M_missing);
6250 constexpr _Iterator&
6251 operator-=(difference_type __x)
6252 requires random_access_range<_Base>
6253 { return *this += -__x; }
6255 constexpr value_type
6256 operator[](difference_type __n) const
6257 requires random_access_range<_Base>
6258 { return *(*this + __n); }
6260 friend constexpr bool
6261 operator==(const _Iterator& __x, const _Iterator& __y)
6262 { return __x._M_current == __y._M_current; }
6264 friend constexpr bool
6265 operator==(const _Iterator& __x, default_sentinel_t)
6266 { return __x._M_current == __x._M_end; }
6268 friend constexpr bool
6269 operator<(const _Iterator& __x, const _Iterator& __y)
6270 requires random_access_range<_Base>
6271 { return __x._M_current > __y._M_current; }
6273 friend constexpr bool
6274 operator>(const _Iterator& __x, const _Iterator& __y)
6275 requires random_access_range<_Base>
6276 { return __y < __x; }
6278 friend constexpr bool
6279 operator<=(const _Iterator& __x, const _Iterator& __y)
6280 requires random_access_range<_Base>
6281 { return !(__y < __x); }
6283 friend constexpr bool
6284 operator>=(const _Iterator& __x, const _Iterator& __y)
6285 requires random_access_range<_Base>
6286 { return !(__x < __y); }
6288 friend constexpr auto
6289 operator<=>(const _Iterator& __x, const _Iterator& __y)
6290 requires random_access_range<_Base>
6291 && three_way_comparable<iterator_t<_Base>>
6292 { return __x._M_current <=> __y._M_current; }
6294 friend constexpr _Iterator
6295 operator+(const _Iterator& __i, difference_type __n)
6296 requires random_access_range<_Base>
6303 friend constexpr _Iterator
6304 operator+(difference_type __n, const _Iterator& __i)
6305 requires random_access_range<_Base>
6312 friend constexpr _Iterator
6313 operator-(const _Iterator& __i, difference_type __n)
6314 requires random_access_range<_Base>
6321 friend constexpr difference_type
6322 operator-(const _Iterator& __x, const _Iterator& __y)
6323 requires sized_sentinel_for<iterator_t<_Base>, iterator_t<_Base>>
6325 return (__x._M_current - __y._M_current
6326 + __x._M_missing - __y._M_missing) / __x._M_n;
6329 friend constexpr difference_type
6330 operator-(default_sentinel_t __y, const _Iterator& __x)
6331 requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<_Base>>
6332 { return __detail::__div_ceil(__x._M_end - __x._M_current, __x._M_n); }
6334 friend constexpr difference_type
6335 operator-(const _Iterator& __x, default_sentinel_t __y)
6336 requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<_Base>>
6337 { return -(__y - __x); }
6344 template<typename _Range, typename _Dp>
6345 concept __can_chunk_view
6346 = requires { chunk_view(std::declval<_Range>(), std::declval<_Dp>()); };
6349 struct _Chunk : __adaptor::_RangeAdaptor<_Chunk>
6351 template<viewable_range _Range, typename _Dp = range_difference_t<_Range>>
6352 requires __detail::__can_chunk_view<_Range, _Dp>
6354 operator() [[nodiscard]] (_Range&& __r, type_identity_t<_Dp> __n) const
6355 { return chunk_view(std::forward<_Range>(__r), __n); }
6357 using __adaptor::_RangeAdaptor<_Chunk>::operator();
6358 static constexpr int _S_arity = 2;
6359 static constexpr bool _S_has_simple_extra_args = true;
6362 inline constexpr _Chunk chunk;
6365#define __cpp_lib_ranges_slide 202202L
6369 template<typename _Vp>
6370 concept __slide_caches_nothing = random_access_range<_Vp> && sized_range<_Vp>;
6372 template<typename _Vp>
6373 concept __slide_caches_last
6374 = !__slide_caches_nothing<_Vp> && bidirectional_range<_Vp> && common_range<_Vp>;
6376 template<typename _Vp>
6377 concept __slide_caches_first
6378 = !__slide_caches_nothing<_Vp> && !__slide_caches_last<_Vp>;
6381 template<forward_range _Vp>
6383 class slide_view : public view_interface<slide_view<_Vp>>
6386 range_difference_t<_Vp> _M_n;
6387 [[no_unique_address]]
6388 __detail::__maybe_present_t<__detail::__slide_caches_first<_Vp>,
6389 __detail::_CachedPosition<_Vp>> _M_cached_begin;
6390 [[no_unique_address]]
6391 __detail::__maybe_present_t<__detail::__slide_caches_last<_Vp>,
6392 __detail::_CachedPosition<_Vp>> _M_cached_end;
6394 template<bool> class _Iterator;
6399 slide_view(_Vp __base, range_difference_t<_Vp> __n)
6400 : _M_base(std::move(__base)), _M_n(__n)
6401 { __glibcxx_assert(__n > 0); }
6404 begin() requires (!(__detail::__simple_view<_Vp>
6405 && __detail::__slide_caches_nothing<const _Vp>))
6407 if constexpr (__detail::__slide_caches_first<_Vp>)
6409 iterator_t<_Vp> __it;
6410 if (_M_cached_begin._M_has_value())
6411 __it = _M_cached_begin._M_get(_M_base);
6414 __it = ranges::next(ranges::begin(_M_base), _M_n - 1, ranges::end(_M_base));
6415 _M_cached_begin._M_set(_M_base, __it);
6417 return _Iterator<false>(ranges::begin(_M_base), std::move(__it), _M_n);
6420 return _Iterator<false>(ranges::begin(_M_base), _M_n);
6424 begin() const requires __detail::__slide_caches_nothing<const _Vp>
6425 { return _Iterator<true>(ranges::begin(_M_base), _M_n); }
6428 end() requires (!(__detail::__simple_view<_Vp>
6429 && __detail::__slide_caches_nothing<const _Vp>))
6431 if constexpr (__detail::__slide_caches_nothing<_Vp>)
6432 return _Iterator<false>(ranges::begin(_M_base) + range_difference_t<_Vp>(size()),
6434 else if constexpr (__detail::__slide_caches_last<_Vp>)
6436 iterator_t<_Vp> __it;
6437 if (_M_cached_end._M_has_value())
6438 __it = _M_cached_end._M_get(_M_base);
6441 __it = ranges::prev(ranges::end(_M_base), _M_n - 1, ranges::begin(_M_base));
6442 _M_cached_end._M_set(_M_base, __it);
6444 return _Iterator<false>(std::move(__it), _M_n);
6446 else if constexpr (common_range<_Vp>)
6447 return _Iterator<false>(ranges::end(_M_base), ranges::end(_M_base), _M_n);
6449 return _Sentinel(ranges::end(_M_base));
6453 end() const requires __detail::__slide_caches_nothing<const _Vp>
6454 { return begin() + range_difference_t<const _Vp>(size()); }
6457 size() requires sized_range<_Vp>
6459 auto __sz = ranges::distance(_M_base) - _M_n + 1;
6462 return __detail::__to_unsigned_like(__sz);
6466 size() const requires sized_range<const _Vp>
6468 auto __sz = ranges::distance(_M_base) - _M_n + 1;
6471 return __detail::__to_unsigned_like(__sz);
6475 template<typename _Range>
6476 slide_view(_Range&&, range_difference_t<_Range>) -> slide_view<views::all_t<_Range>>;
6478 template<typename _Vp>
6479 inline constexpr bool enable_borrowed_range<slide_view<_Vp>>
6480 = enable_borrowed_range<_Vp>;
6482 template<forward_range _Vp>
6484 template<bool _Const>
6485 class slide_view<_Vp>::_Iterator
6487 using _Base = __detail::__maybe_const_t<_Const, _Vp>;
6488 static constexpr bool _S_last_elt_present
6489 = __detail::__slide_caches_first<_Base>;
6491 iterator_t<_Base> _M_current = iterator_t<_Base>();
6492 [[no_unique_address]]
6493 __detail::__maybe_present_t<_S_last_elt_present, iterator_t<_Base>>
6494 _M_last_elt = decltype(_M_last_elt)();
6495 range_difference_t<_Base> _M_n = 0;
6498 _Iterator(iterator_t<_Base> __current, range_difference_t<_Base> __n)
6499 requires (!_S_last_elt_present)
6500 : _M_current(__current), _M_n(__n)
6504 _Iterator(iterator_t<_Base> __current, iterator_t<_Base> __last_elt,
6505 range_difference_t<_Base> __n)
6506 requires _S_last_elt_present
6507 : _M_current(__current), _M_last_elt(__last_elt), _M_n(__n)
6513 if constexpr (random_access_range<_Base>)
6514 return random_access_iterator_tag{};
6515 else if constexpr (bidirectional_range<_Base>)
6516 return bidirectional_iterator_tag{};
6518 return forward_iterator_tag{};
6522 friend slide_view::_Sentinel;
6525 using iterator_category = input_iterator_tag;
6526 using iterator_concept = decltype(_S_iter_concept());
6527 using value_type = decltype(views::counted(_M_current, _M_n));
6528 using difference_type = range_difference_t<_Base>;
6530 _Iterator() = default;
6533 _Iterator(_Iterator<!_Const> __i)
6534 requires _Const && convertible_to<iterator_t<_Vp>, iterator_t<_Base>>
6535 : _M_current(std::move(__i._M_current)), _M_n(__i._M_n)
6540 { return views::counted(_M_current, _M_n); }
6542 constexpr _Iterator&
6546 if constexpr (_S_last_elt_present)
6559 constexpr _Iterator&
6560 operator--() requires bidirectional_range<_Base>
6563 if constexpr (_S_last_elt_present)
6569 operator--(int) requires bidirectional_range<_Base>
6576 constexpr _Iterator&
6577 operator+=(difference_type __x)
6578 requires random_access_range<_Base>
6581 if constexpr (_S_last_elt_present)
6586 constexpr _Iterator&
6587 operator-=(difference_type __x)
6588 requires random_access_range<_Base>
6591 if constexpr (_S_last_elt_present)
6597 operator[](difference_type __n) const
6598 requires random_access_range<_Base>
6599 { return views::counted(_M_current + __n, _M_n); }
6601 friend constexpr bool
6602 operator==(const _Iterator& __x, const _Iterator& __y)
6604 if constexpr (_S_last_elt_present)
6605 return __x._M_last_elt == __y._M_last_elt;
6607 return __x._M_current == __y._M_current;
6610 friend constexpr bool
6611 operator<(const _Iterator& __x, const _Iterator& __y)
6612 requires random_access_range<_Base>
6613 { return __x._M_current < __y._M_current; }
6615 friend constexpr bool
6616 operator>(const _Iterator& __x, const _Iterator& __y)
6617 requires random_access_range<_Base>
6618 { return __y < __x; }
6620 friend constexpr bool
6621 operator<=(const _Iterator& __x, const _Iterator& __y)
6622 requires random_access_range<_Base>
6623 { return !(__y < __x); }
6625 friend constexpr bool
6626 operator>=(const _Iterator& __x, const _Iterator& __y)
6627 requires random_access_range<_Base>
6628 { return !(__x < __y); }
6630 friend constexpr auto
6631 operator<=>(const _Iterator& __x, const _Iterator& __y)
6632 requires random_access_range<_Base>
6633 && three_way_comparable<iterator_t<_Base>>
6634 { return __x._M_current <=> __y._M_current; }
6636 friend constexpr _Iterator
6637 operator+(const _Iterator& __i, difference_type __n)
6638 requires random_access_range<_Base>
6645 friend constexpr _Iterator
6646 operator+(difference_type __n, const _Iterator& __i)
6647 requires random_access_range<_Base>
6654 friend constexpr _Iterator
6655 operator-(const _Iterator& __i, difference_type __n)
6656 requires random_access_range<_Base>
6663 friend constexpr difference_type
6664 operator-(const _Iterator& __x, const _Iterator& __y)
6665 requires sized_sentinel_for<iterator_t<_Base>, iterator_t<_Base>>
6667 if constexpr (_S_last_elt_present)
6668 return __x._M_last_elt - __y._M_last_elt;
6670 return __x._M_current - __y._M_current;
6674 template<forward_range _Vp>
6676 class slide_view<_Vp>::_Sentinel
6678 sentinel_t<_Vp> _M_end = sentinel_t<_Vp>();
6681 _Sentinel(sentinel_t<_Vp> __end)
6688 _Sentinel() = default;
6690 friend constexpr bool
6691 operator==(const _Iterator<false>& __x, const _Sentinel& __y)
6692 { return __x._M_last_elt == __y._M_end; }
6694 friend constexpr range_difference_t<_Vp>
6695 operator-(const _Iterator<false>& __x, const _Sentinel& __y)
6696 requires sized_sentinel_for<sentinel_t<_Vp>, iterator_t<_Vp>>
6697 { return __x._M_last_elt - __y._M_end; }
6699 friend constexpr range_difference_t<_Vp>
6700 operator-(const _Sentinel& __y, const _Iterator<false>& __x)
6701 requires sized_sentinel_for<sentinel_t<_Vp>, iterator_t<_Vp>>
6702 { return __y._M_end -__x._M_last_elt; }
6709 template<typename _Range, typename _Dp>
6710 concept __can_slide_view
6711 = requires { slide_view(std::declval<_Range>(), std::declval<_Dp>()); };
6714 struct _Slide : __adaptor::_RangeAdaptor<_Slide>
6716 template<viewable_range _Range, typename _Dp = range_difference_t<_Range>>
6717 requires __detail::__can_slide_view<_Range, _Dp>
6719 operator() [[nodiscard]] (_Range&& __r, type_identity_t<_Dp> __n) const
6720 { return slide_view(std::forward<_Range>(__r), __n); }
6722 using __adaptor::_RangeAdaptor<_Slide>::operator();
6723 static constexpr int _S_arity = 2;
6724 static constexpr bool _S_has_simple_extra_args = true;
6727 inline constexpr _Slide slide;
6730#define __cpp_lib_ranges_chunk_by 202202L
6732 template<forward_range _Vp,
6733 indirect_binary_predicate<iterator_t<_Vp>, iterator_t<_Vp>> _Pred>
6734 requires view<_Vp> && is_object_v<_Pred>
6735 class chunk_by_view : public view_interface<chunk_by_view<_Vp, _Pred>>
6737 _Vp _M_base = _Vp();
6738 __detail::__box<_Pred> _M_pred;
6739 __detail::_CachedPosition<_Vp> _M_cached_begin;
6741 constexpr iterator_t<_Vp>
6742 _M_find_next(iterator_t<_Vp> __current)
6744 __glibcxx_assert(_M_pred.has_value());
6745 auto __pred = [this]<typename _Tp>(_Tp&& __x, _Tp&& __y) {
6746 return !bool((*_M_pred)(std::forward<_Tp>(__x), std::forward<_Tp>(__y)));
6748 auto __it = ranges::adjacent_find(__current, ranges::end(_M_base), __pred);
6749 return ranges::next(__it, 1, ranges::end(_M_base));
6752 constexpr iterator_t<_Vp>
6753 _M_find_prev(iterator_t<_Vp> __current) requires bidirectional_range<_Vp>
6755 __glibcxx_assert(_M_pred.has_value());
6756 auto __pred = [this]<typename _Tp>(_Tp&& __x, _Tp&& __y) {
6757 return !bool((*_M_pred)(std::forward<_Tp>(__y), std::forward<_Tp>(__x)));
6759 auto __rbegin = std::make_reverse_iterator(__current);
6760 auto __rend = std::make_reverse_iterator(ranges::begin(_M_base));
6761 __glibcxx_assert(__rbegin != __rend);
6762 auto __it = ranges::adjacent_find(__rbegin, __rend, __pred).base();
6763 return ranges::prev(__it, 1, ranges::begin(_M_base));
6769 chunk_by_view() requires (default_initializable<_Vp>
6770 && default_initializable<_Pred>)
6774 chunk_by_view(_Vp __base, _Pred __pred)
6775 : _M_base(std::move(__base)), _M_pred(std::move(__pred))
6779 base() const & requires copy_constructible<_Vp>
6784 { return std::move(_M_base); }
6786 constexpr const _Pred&
6788 { return *_M_pred; }
6793 __glibcxx_assert(_M_pred.has_value());
6794 iterator_t<_Vp> __it;
6795 if (_M_cached_begin._M_has_value())
6796 __it = _M_cached_begin._M_get(_M_base);
6799 __it = _M_find_next(ranges::begin(_M_base));
6800 _M_cached_begin._M_set(_M_base, __it);
6802 return _Iterator(*this, ranges::begin(_M_base), __it);
6808 if constexpr (common_range<_Vp>)
6809 return _Iterator(*this, ranges::end(_M_base), ranges::end(_M_base));
6811 return default_sentinel;
6815 template<typename _Range, typename _Pred>
6816 chunk_by_view(_Range&&, _Pred) -> chunk_by_view<views::all_t<_Range>, _Pred>;
6818 template<forward_range _Vp,
6819 indirect_binary_predicate<iterator_t<_Vp>, iterator_t<_Vp>> _Pred>
6820 requires view<_Vp> && is_object_v<_Pred>
6821 class chunk_by_view<_Vp, _Pred>::_Iterator
6823 chunk_by_view* _M_parent = nullptr;
6824 iterator_t<_Vp> _M_current = iterator_t<_Vp>();
6825 iterator_t<_Vp> _M_next = iterator_t<_Vp>();
6828 _Iterator(chunk_by_view& __parent, iterator_t<_Vp> __current, iterator_t<_Vp> __next)
6829 : _M_parent(std::__addressof(__parent)), _M_current(__current), _M_next(__next)
6835 if constexpr (bidirectional_range<_Vp>)
6836 return bidirectional_iterator_tag{};
6838 return forward_iterator_tag{};
6841 friend chunk_by_view;
6844 using value_type = subrange<iterator_t<_Vp>>;
6845 using difference_type = range_difference_t<_Vp>;
6846 using iterator_category = input_iterator_tag;
6847 using iterator_concept = decltype(_S_iter_concept());
6849 _Iterator() = default;
6851 constexpr value_type
6854 __glibcxx_assert(_M_current != _M_next);
6855 return ranges::subrange(_M_current, _M_next);
6858 constexpr _Iterator&
6861 __glibcxx_assert(_M_current != _M_next);
6862 _M_current = _M_next;
6863 _M_next = _M_parent->_M_find_next(_M_current);
6875 constexpr _Iterator&
6876 operator--() requires bidirectional_range<_Vp>
6878 _M_next = _M_current;
6879 _M_current = _M_parent->_M_find_prev(_M_next);
6884 operator--(int) requires bidirectional_range<_Vp>
6891 friend constexpr bool
6892 operator==(const _Iterator& __x, const _Iterator& __y)
6893 { return __x._M_current == __y._M_current; }
6895 friend constexpr bool
6896 operator==(const _Iterator& __x, default_sentinel_t)
6897 { return __x._M_current == __x._M_next; }
6904 template<typename _Range, typename _Pred>
6905 concept __can_chunk_by_view
6906 = requires { chunk_by_view(std::declval<_Range>(), std::declval<_Pred>()); };
6909 struct _ChunkBy : __adaptor::_RangeAdaptor<_ChunkBy>
6911 template<viewable_range _Range, typename _Pred>
6912 requires __detail::__can_chunk_by_view<_Range, _Pred>
6914 operator() [[nodiscard]] (_Range&& __r, _Pred&& __pred) const
6915 { return chunk_by_view(std::forward<_Range>(__r), std::forward<_Pred>(__pred)); }
6917 using __adaptor::_RangeAdaptor<_ChunkBy>::operator();
6918 static constexpr int _S_arity = 2;
6919 static constexpr bool _S_has_simple_extra_args = true;
6922 inline constexpr _ChunkBy chunk_by;
6925#define __cpp_lib_ranges_join_with 202202L
6929 template<typename _Range, typename _Pattern>
6930 concept __compatible_joinable_ranges
6931 = common_with<range_value_t<_Range>, range_value_t<_Pattern>>
6932 && common_reference_with<range_reference_t<_Range>,
6933 range_reference_t<_Pattern>>
6934 && common_reference_with<range_rvalue_reference_t<_Range>,
6935 range_rvalue_reference_t<_Pattern>>;
6937 template<typename _Range>
6938 concept __bidirectional_common = bidirectional_range<_Range> && common_range<_Range>;
6941 template<input_range _Vp, forward_range _Pattern>
6942 requires view<_Vp> && view<_Pattern>
6943 && input_range<range_reference_t<_Vp>>
6944 && __detail::__compatible_joinable_ranges<range_reference_t<_Vp>, _Pattern>
6945 class join_with_view : public view_interface<join_with_view<_Vp, _Pattern>>
6947 using _InnerRange = range_reference_t<_Vp>;
6949 _Vp _M_base = _Vp();
6950 __detail::__non_propagating_cache<remove_cv_t<_InnerRange>> _M_inner;
6951 _Pattern _M_pattern = _Pattern();
6953 template<bool _Const> using _Base = __detail::__maybe_const_t<_Const, _Vp>;
6954 template<bool _Const> using _InnerBase = range_reference_t<_Base<_Const>>;
6955 template<bool _Const> using _PatternBase = __detail::__maybe_const_t<_Const, _Pattern>;
6957 template<bool _Const> using _OuterIter = iterator_t<_Base<_Const>>;
6958 template<bool _Const> using _InnerIter = iterator_t<_InnerBase<_Const>>;
6959 template<bool _Const> using _PatternIter = iterator_t<_PatternBase<_Const>>;
6961 template<bool _Const>
6962 static constexpr bool _S_ref_is_glvalue = is_reference_v<_InnerBase<_Const>>;
6964 template<bool _Const>
6968 template<bool _Const>
6969 requires _S_ref_is_glvalue<_Const>
6970 && forward_range<_Base<_Const>>
6971 && forward_range<_InnerBase<_Const>>
6972 struct __iter_cat<_Const>
6978 using _OuterIter = join_with_view::_OuterIter<_Const>;
6979 using _InnerIter = join_with_view::_InnerIter<_Const>;
6980 using _PatternIter = join_with_view::_PatternIter<_Const>;
6981 using _OuterCat = typename iterator_traits<_OuterIter>::iterator_category;
6982 using _InnerCat = typename iterator_traits<_InnerIter>::iterator_category;
6983 using _PatternCat = typename iterator_traits<_PatternIter>::iterator_category;
6984 if constexpr (!is_lvalue_reference_v<common_reference_t<iter_reference_t<_InnerIter>,
6985 iter_reference_t<_PatternIter>>>)
6986 return input_iterator_tag{};
6987 else if constexpr (derived_from<_OuterCat, bidirectional_iterator_tag>
6988 && derived_from<_InnerCat, bidirectional_iterator_tag>
6989 && derived_from<_PatternCat, bidirectional_iterator_tag>
6990 && common_range<_InnerBase<_Const>>
6991 && common_range<_PatternBase<_Const>>)
6992 return bidirectional_iterator_tag{};
6993 else if constexpr (derived_from<_OuterCat, forward_iterator_tag>
6994 && derived_from<_InnerCat, forward_iterator_tag>
6995 && derived_from<_PatternCat, forward_iterator_tag>)
6996 return forward_iterator_tag{};
6998 return input_iterator_tag{};
7001 using iterator_category = decltype(_S_iter_cat());
7004 template<bool> struct _Iterator;
7005 template<bool> struct _Sentinel;
7008 join_with_view() requires (default_initializable<_Vp>
7009 && default_initializable<_Pattern>)
7013 join_with_view(_Vp __base, _Pattern __pattern)
7014 : _M_base(std::move(__base)), _M_pattern(std::move(__pattern))
7017 template<input_range _Range>
7018 requires constructible_from<_Vp, views::all_t<_Range>>
7019 && constructible_from<_Pattern, single_view<range_value_t<_InnerRange>>>
7021 join_with_view(_Range&& __r, range_value_t<_InnerRange> __e)
7022 : _M_base(views::all(std::forward<_Range>(__r))),
7023 _M_pattern(views::single(std::move(__e)))
7027 base() const& requires copy_constructible<_Vp>
7032 { return std::move(_M_base); }
7037 constexpr bool __use_const = is_reference_v<_InnerRange>
7038 && __detail::__simple_view<_Vp> && __detail::__simple_view<_Pattern>;
7039 return _Iterator<__use_const>{*this, ranges::begin(_M_base)};
7044 requires input_range<const _Vp>
7045 && forward_range<const _Pattern>
7046 && is_reference_v<range_reference_t<const _Vp>>
7047 { return _Iterator<true>{*this, ranges::begin(_M_base)}; }
7052 constexpr bool __use_const
7053 = __detail::__simple_view<_Vp> && __detail::__simple_view<_Pattern>;
7054 if constexpr (is_reference_v<_InnerRange>
7055 && forward_range<_Vp> && common_range<_Vp>
7056 && forward_range<_InnerRange> && common_range<_InnerRange>)
7057 return _Iterator<__use_const>{*this, ranges::end(_M_base)};
7059 return _Sentinel<__use_const>{*this};
7064 requires input_range<const _Vp>
7065 && forward_range<const _Pattern>
7066 && is_reference_v<range_reference_t<const _Vp>>
7068 using _InnerConstRange = range_reference_t<const _Vp>;
7069 if constexpr (forward_range<const _Vp>
7070 && forward_range<_InnerConstRange>
7071 && common_range<const _Vp>
7072 && common_range<_InnerConstRange>)
7073 return _Iterator<true>{*this, ranges::end(_M_base)};
7075 return _Sentinel<true>{*this};
7079 template<typename _Range, typename _Pattern>
7080 join_with_view(_Range&&, _Pattern&&)
7081 -> join_with_view<views::all_t<_Range>, views::all_t<_Pattern>>;
7083 template<input_range _Range>
7084 join_with_view(_Range&&, range_value_t<range_reference_t<_Range>>)
7085 -> join_with_view<views::all_t<_Range>,
7086 single_view<range_value_t<range_reference_t<_Range>>>>;
7088 template<input_range _Vp, forward_range _Pattern>
7089 requires view<_Vp> && view<_Pattern>
7090 && input_range<range_reference_t<_Vp>>
7091 && __detail::__compatible_joinable_ranges<range_reference_t<_Vp>, _Pattern>
7092 template<bool _Const>
7093 class join_with_view<_Vp, _Pattern>::_Iterator : public __iter_cat<_Const>
7095 using _Parent = __detail::__maybe_const_t<_Const, join_with_view>;
7096 using _Base = join_with_view::_Base<_Const>;
7097 using _InnerBase = join_with_view::_InnerBase<_Const>;
7098 using _PatternBase = join_with_view::_PatternBase<_Const>;
7100 using _OuterIter = join_with_view::_OuterIter<_Const>;
7101 using _InnerIter = join_with_view::_InnerIter<_Const>;
7102 using _PatternIter = join_with_view::_PatternIter<_Const>;
7104 static constexpr bool _S_ref_is_glvalue = join_with_view::_S_ref_is_glvalue<_Const>;
7106 _Parent* _M_parent = nullptr;
7107 _OuterIter _M_outer_it = _OuterIter();
7108 variant<_PatternIter, _InnerIter> _M_inner_it;
7111 _Iterator(_Parent& __parent, iterator_t<_Base> __outer)
7112 : _M_parent(std::__addressof(__parent)), _M_outer_it(std::move(__outer))
7114 if (_M_outer_it != ranges::end(_M_parent->_M_base))
7116 auto&& __inner = _M_update_inner(_M_outer_it);
7117 _M_inner_it.template emplace<1>(ranges::begin(__inner));
7123 _M_update_inner(const _OuterIter& __x)
7125 if constexpr (_S_ref_is_glvalue)
7128 return _M_parent->_M_inner._M_emplace_deref(__x);
7132 _M_get_inner(const _OuterIter& __x)
7134 if constexpr (_S_ref_is_glvalue)
7137 return *_M_parent->_M_inner;
7145 if (_M_inner_it.index() == 0)
7147 if (std::get<0>(_M_inner_it) != ranges::end(_M_parent->_M_pattern))
7150 auto&& __inner = _M_update_inner(_M_outer_it);
7151 _M_inner_it.template emplace<1>(ranges::begin(__inner));
7155 auto&& __inner = _M_get_inner(_M_outer_it);
7156 if (std::get<1>(_M_inner_it) != ranges::end(__inner))
7159 if (++_M_outer_it == ranges::end(_M_parent->_M_base))
7161 if constexpr (_S_ref_is_glvalue)
7162 _M_inner_it.template emplace<0>();
7166 _M_inner_it.template emplace<0>(ranges::begin(_M_parent->_M_pattern));
7174 if constexpr (_S_ref_is_glvalue
7175 && bidirectional_range<_Base>
7176 && __detail::__bidirectional_common<_InnerBase>
7177 && __detail::__bidirectional_common<_PatternBase>)
7178 return bidirectional_iterator_tag{};
7179 else if constexpr (_S_ref_is_glvalue
7180 && forward_range<_Base>
7181 && forward_range<_InnerBase>)
7182 return forward_iterator_tag{};
7184 return input_iterator_tag{};
7187 friend join_with_view;
7190 using iterator_concept = decltype(_S_iter_concept());
7191 // iterator_category defined in join_with_view::__iter_cat
7192 using value_type = common_type_t<iter_value_t<_InnerIter>,
7193 iter_value_t<_PatternIter>>;
7194 using difference_type = common_type_t<iter_difference_t<_OuterIter>,
7195 iter_difference_t<_InnerIter>,
7196 iter_difference_t<_PatternIter>>;
7198 _Iterator() requires default_initializable<_OuterIter> = default;
7201 _Iterator(_Iterator<!_Const> __i)
7203 && convertible_to<iterator_t<_Vp>, _OuterIter>
7204 && convertible_to<iterator_t<_InnerRange>, _InnerIter>
7205 && convertible_to<iterator_t<_Pattern>, _PatternIter>
7206 : _M_parent(__i._M_parent),
7207 _M_outer_it(std::move(__i._M_outer_it))
7209 if (__i._M_inner_it.index() == 0)
7210 _M_inner_it.template emplace<0>(std::get<0>(std::move(__i._M_inner_it)));
7212 _M_inner_it.template emplace<1>(std::get<1>(std::move(__i._M_inner_it)));
7215 constexpr common_reference_t<iter_reference_t<_InnerIter>,
7216 iter_reference_t<_PatternIter>>
7219 if (_M_inner_it.index() == 0)
7220 return *std::get<0>(_M_inner_it);
7222 return *std::get<1>(_M_inner_it);
7225 constexpr _Iterator&
7228 if (_M_inner_it.index() == 0)
7229 ++std::get<0>(_M_inner_it);
7231 ++std::get<1>(_M_inner_it);
7242 requires _S_ref_is_glvalue
7243 && forward_iterator<_OuterIter> && forward_iterator<_InnerIter>
7245 _Iterator __tmp = *this;
7250 constexpr _Iterator&
7252 requires _S_ref_is_glvalue
7253 && bidirectional_range<_Base>
7254 && __detail::__bidirectional_common<_InnerBase>
7255 && __detail::__bidirectional_common<_PatternBase>
7257 if (_M_outer_it == ranges::end(_M_parent->_M_base))
7259 auto&& __inner = *--_M_outer_it;
7260 _M_inner_it.template emplace<1>(ranges::end(__inner));
7265 if (_M_inner_it.index() == 0)
7267 auto& __it = std::get<0>(_M_inner_it);
7268 if (__it == ranges::begin(_M_parent->_M_pattern))
7270 auto&& __inner = *--_M_outer_it;
7271 _M_inner_it.template emplace<1>(ranges::end(__inner));
7278 auto& __it = std::get<1>(_M_inner_it);
7279 auto&& __inner = *_M_outer_it;
7280 if (__it == ranges::begin(__inner))
7281 _M_inner_it.template emplace<0>(ranges::end(_M_parent->_M_pattern));
7287 if (_M_inner_it.index() == 0)
7288 --std::get<0>(_M_inner_it);
7290 --std::get<1>(_M_inner_it);
7296 requires _S_ref_is_glvalue && bidirectional_range<_Base>
7297 && __detail::__bidirectional_common<_InnerBase>
7298 && __detail::__bidirectional_common<_PatternBase>
7300 _Iterator __tmp = *this;
7305 friend constexpr bool
7306 operator==(const _Iterator& __x, const _Iterator& __y)
7307 requires _S_ref_is_glvalue
7308 && equality_comparable<_OuterIter> && equality_comparable<_InnerIter>
7309 { return __x._M_outer_it == __y._M_outer_it && __x._M_inner_it ==__y._M_inner_it; }
7311 friend constexpr common_reference_t<iter_rvalue_reference_t<_InnerIter>,
7312 iter_rvalue_reference_t<_PatternIter>>
7313 iter_move(const _Iterator& __x)
7315 if (__x._M_inner_it.index() == 0)
7316 return ranges::iter_move(std::get<0>(__x._M_inner_it));
7318 return ranges::iter_move(std::get<1>(__x._M_inner_it));
7321 friend constexpr void
7322 iter_swap(const _Iterator& __x, const _Iterator& __y)
7323 requires indirectly_swappable<_InnerIter, _PatternIter>
7325 if (__x._M_inner_it.index() == 0)
7327 if (__y._M_inner_it.index() == 0)
7328 ranges::iter_swap(std::get<0>(__x._M_inner_it), std::get<0>(__y._M_inner_it));
7330 ranges::iter_swap(std::get<0>(__x._M_inner_it), std::get<1>(__y._M_inner_it));
7334 if (__y._M_inner_it.index() == 0)
7335 ranges::iter_swap(std::get<1>(__x._M_inner_it), std::get<0>(__y._M_inner_it));
7337 ranges::iter_swap(std::get<1>(__x._M_inner_it), std::get<1>(__y._M_inner_it));
7342 template<input_range _Vp, forward_range _Pattern>
7343 requires view<_Vp> && view<_Pattern>
7344 && input_range<range_reference_t<_Vp>>
7345 && __detail::__compatible_joinable_ranges<range_reference_t<_Vp>, _Pattern>
7346 template<bool _Const>
7347 class join_with_view<_Vp, _Pattern>::_Sentinel
7349 using _Parent = __detail::__maybe_const_t<_Const, join_with_view>;
7350 using _Base = join_with_view::_Base<_Const>;
7352 sentinel_t<_Base> _M_end = sentinel_t<_Base>();
7355 _Sentinel(_Parent& __parent)
7356 : _M_end(ranges::end(__parent._M_base))
7359 friend join_with_view;
7362 _Sentinel() = default;
7365 _Sentinel(_Sentinel<!_Const> __s)
7366 requires _Const && convertible_to<sentinel_t<_Vp>, sentinel_t<_Base>>
7367 : _M_end(std::move(__s._M_end))
7370 template<bool _OtherConst>
7371 requires sentinel_for<sentinel_t<_Base>,
7372 iterator_t<__detail::__maybe_const_t<_OtherConst, _Vp>>>
7373 friend constexpr bool
7374 operator==(const _Iterator<_OtherConst>& __x, const _Sentinel& __y)
7375 { return __x._M_outer_it == __y._M_end; }
7382 template<typename _Range, typename _Pattern>
7383 concept __can_join_with_view
7384 = requires { join_with_view(std::declval<_Range>(), std::declval<_Pattern>()); };
7385 } // namespace __detail
7387 struct _JoinWith : __adaptor::_RangeAdaptor<_JoinWith>
7389 template<viewable_range _Range, typename _Pattern>
7390 requires __detail::__can_join_with_view<_Range, _Pattern>
7392 operator() [[nodiscard]] (_Range&& __r, _Pattern&& __f) const
7394 return join_with_view(std::forward<_Range>(__r), std::forward<_Pattern>(__f));
7397 using _RangeAdaptor<_JoinWith>::operator();
7398 static constexpr int _S_arity = 2;
7399 template<typename _Pattern>
7400 static constexpr bool _S_has_simple_extra_args
7401 = _LazySplit::_S_has_simple_extra_args<_Pattern>;
7404 inline constexpr _JoinWith join_with;
7405 } // namespace views
7407#define __cpp_lib_ranges_repeat 202207L
7409 template<copy_constructible _Tp, semiregular _Bound = unreachable_sentinel_t>
7410 requires is_object_v<_Tp> && same_as<_Tp, remove_cv_t<_Tp>>
7411 && (__detail::__is_integer_like<_Bound> || same_as<_Bound, unreachable_sentinel_t>)
7412 class repeat_view : public view_interface<repeat_view<_Tp, _Bound>>
7414 __detail::__box<_Tp> _M_value;
7415 [[no_unique_address]] _Bound _M_bound = _Bound();
7419 template<typename _Range>
7420 friend constexpr auto
7421 views::__detail::__take_of_repeat_view(_Range&&, range_difference_t<_Range>);
7423 template<typename _Range>
7424 friend constexpr auto
7425 views::__detail::__drop_of_repeat_view(_Range&&, range_difference_t<_Range>);
7428 repeat_view() requires default_initializable<_Tp> = default;
7431 repeat_view(const _Tp& __value, _Bound __bound = _Bound())
7432 : _M_value(__value), _M_bound(__bound)
7434 if constexpr (!same_as<_Bound, unreachable_sentinel_t>)
7435 __glibcxx_assert(__bound >= 0);
7439 repeat_view(_Tp&& __value, _Bound __bound = _Bound())
7440 : _M_value(std::move(__value)), _M_bound(__bound)
7443 template<typename... _Args, typename... _BoundArgs>
7444 requires constructible_from<_Tp, _Args...>
7445 && constructible_from<_Bound, _BoundArgs...>
7447 repeat_view(piecewise_construct_t,
7448 tuple<_Args...> __args,
7449 tuple<_BoundArgs...> __bound_args = tuple<>{})
7450 : _M_value(std::make_from_tuple<_Tp>(std::move(__args))),
7451 _M_bound(std::make_from_tuple<_Bound>(std::move(__bound_args)))
7456 { return _Iterator(std::__addressof(*_M_value)); }
7459 end() const requires (!same_as<_Bound, unreachable_sentinel_t>)
7460 { return _Iterator(std::__addressof(*_M_value), _M_bound); }
7462 constexpr unreachable_sentinel_t
7463 end() const noexcept
7464 { return unreachable_sentinel; }
7467 size() const requires (!same_as<_Bound, unreachable_sentinel_t>)
7468 { return __detail::__to_unsigned_like(_M_bound); }
7471 template<typename _Tp, typename _Bound>
7472 repeat_view(_Tp, _Bound) -> repeat_view<_Tp, _Bound>;
7474 template<copy_constructible _Tp, semiregular _Bound>
7475 requires is_object_v<_Tp> && same_as<_Tp, remove_cv_t<_Tp>>
7476 && (__detail::__is_integer_like<_Bound> || same_as<_Bound, unreachable_sentinel_t>)
7477 class repeat_view<_Tp, _Bound>::_Iterator
7480 = __conditional_t<same_as<_Bound, unreachable_sentinel_t>, ptrdiff_t, _Bound>;
7482 const _Tp* _M_value = nullptr;
7483 __index_type _M_current = __index_type();
7486 _Iterator(const _Tp* __value, __index_type __bound = __index_type())
7487 : _M_value(__value), _M_current(__bound)
7489 if constexpr (!same_as<_Bound, unreachable_sentinel_t>)
7490 __glibcxx_assert(__bound >= 0);
7496 using iterator_concept = random_access_iterator_tag;
7497 using iterator_category = random_access_iterator_tag;
7498 using value_type = _Tp;
7499 using difference_type = __conditional_t<__detail::__is_signed_integer_like<__index_type>,
7501 __detail::__iota_diff_t<__index_type>>;
7503 _Iterator() = default;
7505 constexpr const _Tp&
7506 operator*() const noexcept
7507 { return *_M_value; }
7509 constexpr _Iterator&
7524 constexpr _Iterator&
7527 if constexpr (!same_as<_Bound, unreachable_sentinel_t>)
7528 __glibcxx_assert(_M_current > 0);
7541 constexpr _Iterator&
7542 operator+=(difference_type __n)
7544 if constexpr (!same_as<_Bound, unreachable_sentinel_t>)
7545 __glibcxx_assert(_M_current + __n >= 0);
7550 constexpr _Iterator&
7551 operator-=(difference_type __n)
7553 if constexpr (!same_as<_Bound, unreachable_sentinel_t>)
7554 __glibcxx_assert(_M_current - __n >= 0);
7559 constexpr const _Tp&
7560 operator[](difference_type __n) const noexcept
7561 { return *(*this + __n); }
7563 friend constexpr bool
7564 operator==(const _Iterator& __x, const _Iterator& __y)
7565 { return __x._M_current == __y._M_current; }
7567 friend constexpr auto
7568 operator<=>(const _Iterator& __x, const _Iterator& __y)
7569 { return __x._M_current <=> __y._M_current; }
7571 friend constexpr _Iterator
7572 operator+(_Iterator __i, difference_type __n)
7578 friend constexpr _Iterator
7579 operator+(difference_type __n, _Iterator __i)
7580 { return __i + __n; }
7582 friend constexpr _Iterator
7583 operator-(_Iterator __i, difference_type __n)
7589 friend constexpr difference_type
7590 operator-(const _Iterator& __x, const _Iterator& __y)
7592 return (static_cast<difference_type>(__x._M_current)
7593 - static_cast<difference_type>(__y._M_current));
7601 template<typename _Tp, typename _Bound>
7602 inline constexpr bool __is_repeat_view<repeat_view<_Tp, _Bound>> = true;
7604 template<typename _Tp>
7605 concept __can_repeat_view
7606 = requires { repeat_view(std::declval<_Tp>()); };
7608 template<typename _Tp, typename _Bound>
7609 concept __can_bounded_repeat_view
7610 = requires { repeat_view(std::declval<_Tp>(), std::declval<_Bound>()); };
7615 template<typename _Tp>
7616 requires __detail::__can_repeat_view<_Tp>
7618 operator() [[nodiscard]] (_Tp&& __value) const
7619 { return repeat_view(std::forward<_Tp>(__value)); }
7621 template<typename _Tp, typename _Bound>
7622 requires __detail::__can_bounded_repeat_view<_Tp, _Bound>
7624 operator() [[nodiscard]] (_Tp&& __value, _Bound __bound) const
7625 { return repeat_view(std::forward<_Tp>(__value), __bound); }
7628 inline constexpr _Repeat repeat;
7632 template<typename _Range>
7634 __take_of_repeat_view(_Range&& __r, range_difference_t<_Range> __n)
7636 using _Tp = remove_cvref_t<_Range>;
7637 static_assert(__is_repeat_view<_Tp>);
7638 if constexpr (sized_range<_Tp>)
7639 return views::repeat(*__r._M_value, std::min(ranges::distance(__r), __n));
7641 return views::repeat(*__r._M_value, __n);
7644 template<typename _Range>
7646 __drop_of_repeat_view(_Range&& __r, range_difference_t<_Range> __n)
7648 using _Tp = remove_cvref_t<_Range>;
7649 static_assert(__is_repeat_view<_Tp>);
7650 if constexpr (sized_range<_Tp>)
7652 auto __sz = ranges::distance(__r);
7653 return views::repeat(*__r._M_value, __sz - std::min(__sz, __n));
7661#define __cpp_lib_ranges_stride 202207L
7663 template<input_range _Vp>
7665 class stride_view : public view_interface<stride_view<_Vp>>
7668 range_difference_t<_Vp> _M_stride;
7670 template<bool _Const> using _Base = __detail::__maybe_const_t<_Const, _Vp>;
7672 template<bool _Const>
7676 template<bool _Const>
7677 requires forward_range<_Base<_Const>>
7678 struct __iter_cat<_Const>
7684 using _Cat = typename iterator_traits<iterator_t<_Base<_Const>>>::iterator_category;
7685 if constexpr (derived_from<_Cat, random_access_iterator_tag>)
7686 return random_access_iterator_tag{};
7691 using iterator_category = decltype(_S_iter_cat());
7694 template<bool> class _Iterator;
7698 stride_view(_Vp __base, range_difference_t<_Vp> __stride)
7699 : _M_base(std::move(__base)), _M_stride(__stride)
7700 { __glibcxx_assert(__stride > 0); }
7703 base() const& requires copy_constructible<_Vp>
7708 { return std::move(_M_base); }
7710 constexpr range_difference_t<_Vp>
7711 stride() const noexcept
7712 { return _M_stride; }
7715 begin() requires (!__detail::__simple_view<_Vp>)
7716 { return _Iterator<false>(this, ranges::begin(_M_base)); }
7719 begin() const requires range<const _Vp>
7720 { return _Iterator<true>(this, ranges::begin(_M_base)); }
7723 end() requires (!__detail::__simple_view<_Vp>)
7725 if constexpr (common_range<_Vp> && sized_range<_Vp> && forward_range<_Vp>)
7727 auto __missing = (_M_stride - ranges::distance(_M_base) % _M_stride) % _M_stride;
7728 return _Iterator<false>(this, ranges::end(_M_base), __missing);
7730 else if constexpr (common_range<_Vp> && !bidirectional_range<_Vp>)
7731 return _Iterator<false>(this, ranges::end(_M_base));
7733 return default_sentinel;
7737 end() const requires range<const _Vp>
7739 if constexpr (common_range<const _Vp> && sized_range<const _Vp>
7740 && forward_range<const _Vp>)
7742 auto __missing = (_M_stride - ranges::distance(_M_base) % _M_stride) % _M_stride;
7743 return _Iterator<true>(this, ranges::end(_M_base), __missing);
7745 else if constexpr (common_range<const _Vp> && !bidirectional_range<const _Vp>)
7746 return _Iterator<true>(this, ranges::end(_M_base));
7748 return default_sentinel;
7752 size() requires sized_range<_Vp>
7754 return __detail::__to_unsigned_like
7755 (__detail::__div_ceil(ranges::distance(_M_base), _M_stride));
7759 size() const requires sized_range<const _Vp>
7761 return __detail::__to_unsigned_like
7762 (__detail::__div_ceil(ranges::distance(_M_base), _M_stride));
7766 template<typename _Range>
7767 stride_view(_Range&&, range_difference_t<_Range>) -> stride_view<views::all_t<_Range>>;
7769 template<typename _Vp>
7770 inline constexpr bool enable_borrowed_range<stride_view<_Vp>>
7771 = enable_borrowed_range<_Vp>;
7773 template<input_range _Vp>
7775 template<bool _Const>
7776 class stride_view<_Vp>::_Iterator : public __iter_cat<_Const>
7778 using _Parent = __detail::__maybe_const_t<_Const, stride_view>;
7779 using _Base = stride_view::_Base<_Const>;
7781 iterator_t<_Base> _M_current = iterator_t<_Base>();
7782 sentinel_t<_Base> _M_end = sentinel_t<_Base>();
7783 range_difference_t<_Base> _M_stride = 0;
7784 range_difference_t<_Base> _M_missing = 0;
7787 _Iterator(_Parent* __parent, iterator_t<_Base> __current,
7788 range_difference_t<_Base> __missing = 0)
7789 : _M_current(std::move(__current)), _M_end(ranges::end(__parent->_M_base)),
7790 _M_stride(__parent->_M_stride), _M_missing(__missing)
7796 if constexpr (random_access_range<_Base>)
7797 return random_access_iterator_tag{};
7798 else if constexpr (bidirectional_range<_Base>)
7799 return bidirectional_iterator_tag{};
7800 else if constexpr (forward_range<_Base>)
7801 return forward_iterator_tag{};
7803 return input_iterator_tag{};
7809 using difference_type = range_difference_t<_Base>;
7810 using value_type = range_value_t<_Base>;
7811 using iterator_concept = decltype(_S_iter_concept());
7812 // iterator_category defined in stride_view::__iter_cat
7814 _Iterator() requires default_initializable<iterator_t<_Base>> = default;
7817 _Iterator(_Iterator<!_Const> __other)
7819 && convertible_to<iterator_t<_Vp>, iterator_t<_Base>>
7820 && convertible_to<sentinel_t<_Vp>, sentinel_t<_Base>>
7821 : _M_current(std::move(__other._M_current)), _M_end(std::move(__other._M_end)),
7822 _M_stride(__other._M_stride), _M_missing(__other._M_missing)
7825 constexpr iterator_t<_Base>
7827 { return std::move(_M_current); }
7829 constexpr const iterator_t<_Base>&
7830 base() const & noexcept
7831 { return _M_current; }
7833 constexpr decltype(auto)
7835 { return *_M_current; }
7837 constexpr _Iterator&
7840 __glibcxx_assert(_M_current != _M_end);
7841 _M_missing = ranges::advance(_M_current, _M_stride, _M_end);
7850 operator++(int) requires forward_range<_Base>
7857 constexpr _Iterator&
7858 operator--() requires bidirectional_range<_Base>
7860 ranges::advance(_M_current, _M_missing - _M_stride);
7866 operator--(int) requires bidirectional_range<_Base>
7873 constexpr _Iterator&
7874 operator+=(difference_type __n) requires random_access_range<_Base>
7878 __glibcxx_assert(ranges::distance(_M_current, _M_end) > _M_stride * (__n - 1));
7879 _M_missing = ranges::advance(_M_current, _M_stride * __n, _M_end);
7883 ranges::advance(_M_current, _M_stride * __n + _M_missing);
7889 constexpr _Iterator&
7890 operator-=(difference_type __n) requires random_access_range<_Base>
7891 { return *this += -__n; }
7893 constexpr decltype(auto) operator[](difference_type __n) const
7894 requires random_access_range<_Base>
7895 { return *(*this + __n); }
7897 friend constexpr bool
7898 operator==(const _Iterator& __x, default_sentinel_t)
7899 { return __x._M_current == __x._M_end; }
7901 friend constexpr bool
7902 operator==(const _Iterator& __x, const _Iterator& __y)
7903 requires equality_comparable<iterator_t<_Base>>
7904 { return __x._M_current == __y._M_current; }
7906 friend constexpr bool
7907 operator<(const _Iterator& __x, const _Iterator& __y)
7908 requires random_access_range<_Base>
7909 { return __x._M_current < __y._M_current; }
7911 friend constexpr bool
7912 operator>(const _Iterator& __x, const _Iterator& __y)
7913 requires random_access_range<_Base>
7914 { return __y._M_current < __x._M_current; }
7916 friend constexpr bool
7917 operator<=(const _Iterator& __x, const _Iterator& __y)
7918 requires random_access_range<_Base>
7919 { return !(__y._M_current < __x._M_current); }
7921 friend constexpr bool
7922 operator>=(const _Iterator& __x, const _Iterator& __y)
7923 requires random_access_range<_Base>
7924 { return !(__x._M_current < __y._M_current); }
7926 friend constexpr auto
7927 operator<=>(const _Iterator& __x, const _Iterator& __y)
7928 requires random_access_range<_Base> && three_way_comparable<iterator_t<_Base>>
7929 { return __x._M_current <=> __y._M_current; }
7931 friend constexpr _Iterator
7932 operator+(const _Iterator& __i, difference_type __n)
7933 requires random_access_range<_Base>
7940 friend constexpr _Iterator
7941 operator+(difference_type __n, const _Iterator& __i)
7942 requires random_access_range<_Base>
7943 { return __i + __n; }
7945 friend constexpr _Iterator
7946 operator-(const _Iterator& __i, difference_type __n)
7947 requires random_access_range<_Base>
7954 friend constexpr difference_type
7955 operator-(const _Iterator& __x, const _Iterator& __y)
7956 requires sized_sentinel_for<iterator_t<_Base>, iterator_t<_Base>>
7958 auto __n = __x._M_current - __y._M_current;
7959 if constexpr (forward_range<_Base>)
7960 return (__n + __x._M_missing - __y._M_missing) / __x._M_stride;
7962 return -__detail::__div_ceil(-__n, __x._M_stride);
7964 return __detail::__div_ceil(__n, __x._M_stride);
7967 friend constexpr difference_type
7968 operator-(default_sentinel_t __y, const _Iterator& __x)
7969 requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<_Base>>
7970 { return __detail::__div_ceil(__x._M_end - __x._M_current, __x._M_stride); }
7972 friend constexpr difference_type
7973 operator-(const _Iterator& __x, default_sentinel_t __y)
7974 requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<_Base>>
7975 { return -(__y - __x); }
7977 friend constexpr range_rvalue_reference_t<_Base>
7978 iter_move(const _Iterator& __i)
7979 noexcept(noexcept(ranges::iter_move(__i._M_current)))
7980 { return ranges::iter_move(__i._M_current); }
7982 friend constexpr void
7983 iter_swap(const _Iterator& __x, const _Iterator& __y)
7984 noexcept(noexcept(ranges::iter_swap(__x._M_current, __y._M_current)))
7985 requires indirectly_swappable<iterator_t<_Base>>
7986 { ranges::iter_swap(__x._M_current, __y._M_current); }
7993 template<typename _Range, typename _Dp>
7994 concept __can_stride_view
7995 = requires { stride_view(std::declval<_Range>(), std::declval<_Dp>()); };
7998 struct _Stride : __adaptor::_RangeAdaptor<_Stride>
8000 template<viewable_range _Range, typename _Dp = range_difference_t<_Range>>
8001 requires __detail::__can_stride_view<_Range, _Dp>
8003 operator() [[nodiscard]] (_Range&& __r, type_identity_t<_Dp> __n) const
8004 { return stride_view(std::forward<_Range>(__r), __n); }
8006 using __adaptor::_RangeAdaptor<_Stride>::operator();
8007 static constexpr int _S_arity = 2;
8008 static constexpr bool _S_has_simple_extra_args = true;
8011 inline constexpr _Stride stride;
8014#define __cpp_lib_ranges_cartesian_product 202207L
8018 template<bool _Const, typename _First, typename... _Vs>
8019 concept __cartesian_product_is_random_access
8020 = (random_access_range<__maybe_const_t<_Const, _First>>
8022 && (random_access_range<__maybe_const_t<_Const, _Vs>>
8023 && sized_range<__maybe_const_t<_Const, _Vs>>));
8025 template<typename _Range>
8026 concept __cartesian_product_common_arg
8027 = common_range<_Range> || (sized_range<_Range> && random_access_range<_Range>);
8029 template<bool _Const, typename _First, typename... _Vs>
8030 concept __cartesian_product_is_bidirectional
8031 = (bidirectional_range<__maybe_const_t<_Const, _First>>
8033 && (bidirectional_range<__maybe_const_t<_Const, _Vs>>
8034 && __cartesian_product_common_arg<__maybe_const_t<_Const, _Vs>>));
8036 template<typename _First, typename... _Vs>
8037 concept __cartesian_product_is_common = __cartesian_product_common_arg<_First>;
8039 template<typename... _Vs>
8040 concept __cartesian_product_is_sized = (sized_range<_Vs> && ...);
8042 template<bool _Const, template<typename> class FirstSent, typename _First, typename... _Vs>
8043 concept __cartesian_is_sized_sentinel
8044 = (sized_sentinel_for<FirstSent<__maybe_const_t<_Const, _First>>,
8045 iterator_t<__maybe_const_t<_Const, _First>>>
8047 && (sized_range<__maybe_const_t<_Const, _Vs>>
8048 && sized_sentinel_for<iterator_t<__maybe_const_t<_Const, _Vs>>,
8049 iterator_t<__maybe_const_t<_Const, _Vs>>>));
8051 template<__cartesian_product_common_arg _Range>
8053 __cartesian_common_arg_end(_Range& __r)
8055 if constexpr (common_range<_Range>)
8056 return ranges::end(__r);
8058 return ranges::begin(__r) + ranges::distance(__r);
8060 } // namespace __detail
8062 template<input_range _First, forward_range... _Vs>
8063 requires (view<_First> && ... && view<_Vs>)
8064 class cartesian_product_view : public view_interface<cartesian_product_view<_First, _Vs...>>
8066 tuple<_First, _Vs...> _M_bases;
8068 template<bool> class _Iterator;
8071 _S_difference_type()
8073 // TODO: Implement the recommended practice of using the smallest
8074 // sufficiently wide type according to the maximum sizes of the
8075 // underlying ranges?
8076 return common_type_t<ptrdiff_t,
8077 range_difference_t<_First>,
8078 range_difference_t<_Vs>...>{};
8082 cartesian_product_view() = default;
8085 cartesian_product_view(_First __first, _Vs... __rest)
8086 : _M_bases(std::move(__first), std::move(__rest)...)
8089 constexpr _Iterator<false>
8090 begin() requires (!__detail::__simple_view<_First> || ... || !__detail::__simple_view<_Vs>)
8091 { return _Iterator<false>(*this, __detail::__tuple_transform(ranges::begin, _M_bases)); }
8093 constexpr _Iterator<true>
8094 begin() const requires (range<const _First> && ... && range<const _Vs>)
8095 { return _Iterator<true>(*this, __detail::__tuple_transform(ranges::begin, _M_bases)); }
8097 constexpr _Iterator<false>
8098 end() requires ((!__detail::__simple_view<_First> || ... || !__detail::__simple_view<_Vs>)
8099 && __detail::__cartesian_product_is_common<_First, _Vs...>)
8101 auto __its = [this]<size_t... _Is>(index_sequence<_Is...>) {
8102 using _Ret = __detail::__tuple_or_pair_t<iterator_t<_First>,
8103 iterator_t<_Vs>...>;
8104 bool __empty_tail = (ranges::empty(std::get<1 + _Is>(_M_bases)) || ...);
8105 auto& __first = std::get<0>(_M_bases);
8106 return _Ret{(__empty_tail
8107 ? ranges::begin(__first)
8108 : __detail::__cartesian_common_arg_end(__first)),
8109 ranges::begin(std::get<1 + _Is>(_M_bases))...};
8110 }(make_index_sequence<sizeof...(_Vs)>{});
8112 return _Iterator<false>{*this, std::move(__its)};
8115 constexpr _Iterator<true>
8116 end() const requires __detail::__cartesian_product_is_common<const _First, const _Vs...>
8118 auto __its = [this]<size_t... _Is>(index_sequence<_Is...>) {
8119 using _Ret = __detail::__tuple_or_pair_t<iterator_t<const _First>,
8120 iterator_t<const _Vs>...>;
8121 bool __empty_tail = (ranges::empty(std::get<1 + _Is>(_M_bases)) || ...);
8122 auto& __first = std::get<0>(_M_bases);
8123 return _Ret{(__empty_tail
8124 ? ranges::begin(__first)
8125 : __detail::__cartesian_common_arg_end(__first)),
8126 ranges::begin(std::get<1 + _Is>(_M_bases))...};
8127 }(make_index_sequence<sizeof...(_Vs)>{});
8129 return _Iterator<true>{*this, std::move(__its)};
8132 constexpr default_sentinel_t
8133 end() const noexcept
8134 { return default_sentinel; }
8137 size() requires __detail::__cartesian_product_is_sized<_First, _Vs...>
8139 using _ST = __detail::__make_unsigned_like_t<decltype(_S_difference_type())>;
8140 return [&]<size_t... _Is>(index_sequence<_Is...>) {
8141 auto __size = static_cast<_ST>(1);
8142#ifdef _GLIBCXX_ASSERTIONS
8143 if constexpr (integral<_ST>)
8146 = (__builtin_mul_overflow(__size,
8147 static_cast<_ST>(ranges::size(std::get<_Is>(_M_bases))),
8150 __glibcxx_assert(!__overflow);
8154 __size = (static_cast<_ST>(ranges::size(std::get<_Is>(_M_bases))) * ...);
8156 }(make_index_sequence<1 + sizeof...(_Vs)>{});
8160 size() const requires __detail::__cartesian_product_is_sized<const _First, const _Vs...>
8162 using _ST = __detail::__make_unsigned_like_t<decltype(_S_difference_type())>;
8163 return [&]<size_t... _Is>(index_sequence<_Is...>) {
8164 auto __size = static_cast<_ST>(1);
8165#ifdef _GLIBCXX_ASSERTIONS
8166 if constexpr (integral<_ST>)
8169 = (__builtin_mul_overflow(__size,
8170 static_cast<_ST>(ranges::size(std::get<_Is>(_M_bases))),
8173 __glibcxx_assert(!__overflow);
8177 __size = (static_cast<_ST>(ranges::size(std::get<_Is>(_M_bases))) * ...);
8179 }(make_index_sequence<1 + sizeof...(_Vs)>{});
8183 template<typename... _Vs>
8184 cartesian_product_view(_Vs&&...) -> cartesian_product_view<views::all_t<_Vs>...>;
8186 template<input_range _First, forward_range... _Vs>
8187 requires (view<_First> && ... && view<_Vs>)
8188 template<bool _Const>
8189 class cartesian_product_view<_First, _Vs...>::_Iterator
8191 using _Parent = __maybe_const_t<_Const, cartesian_product_view>;
8192 _Parent* _M_parent = nullptr;
8193 __detail::__tuple_or_pair_t<iterator_t<__maybe_const_t<_Const, _First>>,
8194 iterator_t<__maybe_const_t<_Const, _Vs>>...> _M_current;
8197 _Iterator(_Parent& __parent, decltype(_M_current) __current)
8198 : _M_parent(std::__addressof(__parent)),
8199 _M_current(std::move(__current))
8205 if constexpr (__detail::__cartesian_product_is_random_access<_Const, _First, _Vs...>)
8206 return random_access_iterator_tag{};
8207 else if constexpr (__detail::__cartesian_product_is_bidirectional<_Const, _First, _Vs...>)
8208 return bidirectional_iterator_tag{};
8209 else if constexpr (forward_range<__maybe_const_t<_Const, _First>>)
8210 return forward_iterator_tag{};
8212 return input_iterator_tag{};
8215 friend cartesian_product_view;
8218 using iterator_category = input_iterator_tag;
8219 using iterator_concept = decltype(_S_iter_concept());
8221 = __detail::__tuple_or_pair_t<range_value_t<__maybe_const_t<_Const, _First>>,
8222 range_value_t<__maybe_const_t<_Const, _Vs>>...>;
8224 = __detail::__tuple_or_pair_t<range_reference_t<__maybe_const_t<_Const, _First>>,
8225 range_reference_t<__maybe_const_t<_Const, _Vs>>...>;
8226 using difference_type = decltype(cartesian_product_view::_S_difference_type());
8228 _Iterator() = default;
8231 _Iterator(_Iterator<!_Const> __i)
8233 && (convertible_to<iterator_t<_First>, iterator_t<const _First>>
8234 && ... && convertible_to<iterator_t<_Vs>, iterator_t<const _Vs>>)
8235 : _M_parent(std::__addressof(__i._M_parent)),
8236 _M_current(std::move(__i._M_current))
8242 auto __f = [](auto& __i) -> decltype(auto) {
8245 return __detail::__tuple_transform(__f, _M_current);
8248 constexpr _Iterator&
8260 operator++(int) requires forward_range<__maybe_const_t<_Const, _First>>
8267 constexpr _Iterator&
8269 requires __detail::__cartesian_product_is_bidirectional<_Const, _First, _Vs...>
8277 requires __detail::__cartesian_product_is_bidirectional<_Const, _First, _Vs...>
8284 constexpr _Iterator&
8285 operator+=(difference_type __x)
8286 requires __detail::__cartesian_product_is_random_access<_Const, _First, _Vs...>
8292 constexpr _Iterator&
8293 operator-=(difference_type __x)
8294 requires __detail::__cartesian_product_is_random_access<_Const, _First, _Vs...>
8295 { return *this += -__x; }
8298 operator[](difference_type __n) const
8299 requires __detail::__cartesian_product_is_random_access<_Const, _First, _Vs...>
8300 { return *((*this) + __n); }
8302 friend constexpr bool
8303 operator==(const _Iterator& __x, const _Iterator& __y)
8304 requires equality_comparable<iterator_t<__maybe_const_t<_Const, _First>>>
8305 { return __x._M_current == __y._M_current; }
8307 friend constexpr bool
8308 operator==(const _Iterator& __x, default_sentinel_t)
8310 return [&]<size_t... _Is>(index_sequence<_Is...>) {
8311 return ((std::get<_Is>(__x._M_current)
8312 == ranges::end(std::get<_Is>(__x._M_parent->_M_bases)))
8314 }(make_index_sequence<1 + sizeof...(_Vs)>{});
8317 friend constexpr auto
8318 operator<=>(const _Iterator& __x, const _Iterator& __y)
8319 requires __detail::__all_random_access<_Const, _First, _Vs...>
8320 { return __x._M_current <=> __y._M_current; }
8322 friend constexpr _Iterator
8323 operator+(_Iterator __x, difference_type __y)
8324 requires __detail::__cartesian_product_is_random_access<_Const, _First, _Vs...>
8325 { return __x += __y; }
8327 friend constexpr _Iterator
8328 operator+(difference_type __x, _Iterator __y)
8329 requires __detail::__cartesian_product_is_random_access<_Const, _First, _Vs...>
8330 { return __y += __x; }
8332 friend constexpr _Iterator
8333 operator-(_Iterator __x, difference_type __y)
8334 requires __detail::__cartesian_product_is_random_access<_Const, _First, _Vs...>
8335 { return __x -= __y; }
8337 friend constexpr difference_type
8338 operator-(const _Iterator& __x, const _Iterator& __y)
8339 requires __detail::__cartesian_is_sized_sentinel<_Const, iterator_t, _First, _Vs...>
8340 { return __x._M_distance_from(__y._M_current); }
8342 friend constexpr difference_type
8343 operator-(const _Iterator& __i, default_sentinel_t)
8344 requires __detail::__cartesian_is_sized_sentinel<_Const, sentinel_t, _First, _Vs...>
8346 tuple __end_tuple = [&]<size_t... _Is>(index_sequence<_Is...>) {
8347 return tuple{ranges::end(std::get<0>(__i._M_parent->_M_bases)),
8348 ranges::begin(std::get<1 + _Is>(__i._M_parent->_M_bases))...};
8349 }(make_index_sequence<sizeof...(_Vs)>{});
8350 return __i._M_distance_from(__end_tuple);
8353 friend constexpr difference_type
8354 operator-(default_sentinel_t, const _Iterator& __i)
8355 requires __detail::__cartesian_is_sized_sentinel<_Const, sentinel_t, _First, _Vs...>
8356 { return -(__i - default_sentinel); }
8358 friend constexpr auto
8359 iter_move(const _Iterator& __i)
8360 { return __detail::__tuple_transform(ranges::iter_move, __i._M_current); }
8362 friend constexpr void
8363 iter_swap(const _Iterator& __l, const _Iterator& __r)
8364 requires (indirectly_swappable<iterator_t<__maybe_const_t<_Const, _First>>>
8366 && indirectly_swappable<iterator_t<__maybe_const_t<_Const, _Vs>>>)
8368 [&]<size_t... _Is>(index_sequence<_Is...>) {
8369 (ranges::iter_swap(std::get<_Is>(__l._M_current), std::get<_Is>(__r._M_current)), ...);
8370 }(make_index_sequence<1 + sizeof...(_Vs)>{});
8374 template<size_t _Nm = sizeof...(_Vs)>
8378 auto& __it = std::get<_Nm>(_M_current);
8380 if constexpr (_Nm > 0)
8381 if (__it == ranges::end(std::get<_Nm>(_M_parent->_M_bases)))
8383 __it = ranges::begin(std::get<_Nm>(_M_parent->_M_bases));
8388 template<size_t _Nm = sizeof...(_Vs)>
8392 auto& __it = std::get<_Nm>(_M_current);
8393 if constexpr (_Nm > 0)
8394 if (__it == ranges::begin(std::get<_Nm>(_M_parent->_M_bases)))
8396 __it = __detail::__cartesian_common_arg_end(std::get<_Nm>(_M_parent->_M_bases));
8402 template<size_t _Nm = sizeof...(_Vs)>
8404 _M_advance(difference_type __x)
8405 requires __detail::__cartesian_product_is_random_access<_Const, _First, _Vs...>
8413 // Constant time iterator advancement.
8414 auto& __r = std::get<_Nm>(_M_parent->_M_bases);
8415 auto& __it = std::get<_Nm>(_M_current);
8416 if constexpr (_Nm == 0)
8418#ifdef _GLIBCXX_ASSERTIONS
8419 if constexpr (sized_range<__maybe_const_t<_Const, _First>>)
8421 auto __size = ranges::ssize(__r);
8422 auto __begin = ranges::begin(__r);
8423 auto __offset = __it - __begin;
8424 __glibcxx_assert(__offset + __x >= 0 && __offset + __x <= __size);
8431 auto __size = ranges::ssize(__r);
8432 auto __begin = ranges::begin(__r);
8433 auto __offset = __it - __begin;
8435 __x = __offset / __size;
8439 __offset = __size + __offset;
8442 __it = __begin + __offset;
8443 _M_advance<_Nm - 1>(__x);
8448 template<typename _Tuple>
8449 constexpr difference_type
8450 _M_distance_from(const _Tuple& __t) const
8452 return [&]<size_t... _Is>(index_sequence<_Is...>) {
8453 auto __sum = static_cast<difference_type>(0);
8454#ifdef _GLIBCXX_ASSERTIONS
8455 if constexpr (integral<difference_type>)
8458 = (__builtin_add_overflow(__sum, _M_scaled_distance<_Is>(__t), &__sum)
8460 __glibcxx_assert(!__overflow);
8464 __sum = (_M_scaled_distance<_Is>(__t) + ...);
8466 }(make_index_sequence<1 + sizeof...(_Vs)>{});
8469 template<size_t _Nm, typename _Tuple>
8470 constexpr difference_type
8471 _M_scaled_distance(const _Tuple& __t) const
8473 auto __dist = static_cast<difference_type>(std::get<_Nm>(_M_current)
8474 - std::get<_Nm>(__t));
8475#ifdef _GLIBCXX_ASSERTIONS
8476 if constexpr (integral<difference_type>)
8478 bool __overflow = __builtin_mul_overflow(__dist, _M_scaled_size<_Nm+1>(), &__dist);
8479 __glibcxx_assert(!__overflow);
8483 __dist *= _M_scaled_size<_Nm+1>();
8487 template<size_t _Nm>
8488 constexpr difference_type
8489 _M_scaled_size() const
8491 if constexpr (_Nm <= sizeof...(_Vs))
8493 auto __size = static_cast<difference_type>(ranges::size
8494 (std::get<_Nm>(_M_parent->_M_bases)));
8495#ifdef _GLIBCXX_ASSERTIONS
8496 if constexpr (integral<difference_type>)
8498 bool __overflow = __builtin_mul_overflow(__size, _M_scaled_size<_Nm+1>(), &__size);
8499 __glibcxx_assert(!__overflow);
8503 __size *= _M_scaled_size<_Nm+1>();
8507 return static_cast<difference_type>(1);
8515 template<typename... _Ts>
8516 concept __can_cartesian_product_view
8517 = requires { cartesian_product_view<all_t<_Ts>...>(std::declval<_Ts>()...); };
8520 struct _CartesianProduct
8522 template<typename... _Ts>
8523 requires (sizeof...(_Ts) == 0 || __detail::__can_cartesian_product_view<_Ts...>)
8525 operator() [[nodiscard]] (_Ts&&... __ts) const
8527 if constexpr (sizeof...(_Ts) == 0)
8528 return views::empty<tuple<>>;
8530 return cartesian_product_view<all_t<_Ts>...>(std::forward<_Ts>(__ts)...);
8534 inline constexpr _CartesianProduct cartesian_product;
8537#define __cpp_lib_ranges_as_rvalue 202207L
8539 template<input_range _Vp>
8541 class as_rvalue_view : public view_interface<as_rvalue_view<_Vp>>
8543 _Vp _M_base = _Vp();
8546 as_rvalue_view() requires default_initializable<_Vp> = default;
8549 as_rvalue_view(_Vp __base)
8550 : _M_base(std::move(__base))
8554 base() const& requires copy_constructible<_Vp>
8559 { return std::move(_M_base); }
8562 begin() requires (!__detail::__simple_view<_Vp>)
8563 { return move_iterator(ranges::begin(_M_base)); }
8566 begin() const requires range<const _Vp>
8567 { return move_iterator(ranges::begin(_M_base)); }
8570 end() requires (!__detail::__simple_view<_Vp>)
8572 if constexpr (common_range<_Vp>)
8573 return move_iterator(ranges::end(_M_base));
8575 return move_sentinel(ranges::end(_M_base));
8579 end() const requires range<const _Vp>
8581 if constexpr (common_range<const _Vp>)
8582 return move_iterator(ranges::end(_M_base));
8584 return move_sentinel(ranges::end(_M_base));
8588 size() requires sized_range<_Vp>
8589 { return ranges::size(_M_base); }
8592 size() const requires sized_range<const _Vp>
8593 { return ranges::size(_M_base); }
8596 template<typename _Range>
8597 as_rvalue_view(_Range&&) -> as_rvalue_view<views::all_t<_Range>>;
8599 template<typename _Tp>
8600 inline constexpr bool enable_borrowed_range<as_rvalue_view<_Tp>>
8601 = enable_borrowed_range<_Tp>;
8607 template<typename _Tp>
8608 concept __can_as_rvalue_view = requires { as_rvalue_view(std::declval<_Tp>()); };
8611 struct _AsRvalue : __adaptor::_RangeAdaptorClosure
8613 template<viewable_range _Range>
8614 requires __detail::__can_as_rvalue_view<_Range>
8616 operator() [[nodiscard]] (_Range&& __r) const
8618 if constexpr (same_as<range_rvalue_reference_t<_Range>,
8619 range_reference_t<_Range>>)
8620 return views::all(std::forward<_Range>(__r));
8622 return as_rvalue_view(std::forward<_Range>(__r));
8626 inline constexpr _AsRvalue as_rvalue;
8629} // namespace ranges
8631 namespace views = ranges::views;
8633_GLIBCXX_END_NAMESPACE_VERSION
8635#endif // library concepts
8637#endif /* _GLIBCXX_RANGES */