1349cc55cSDimitry Andric // -*- C++ -*- 2349cc55cSDimitry Andric //===----------------------------------------------------------------------===// 3349cc55cSDimitry Andric // 4349cc55cSDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5349cc55cSDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 6349cc55cSDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7349cc55cSDimitry Andric // 8349cc55cSDimitry Andric //===----------------------------------------------------------------------===// 9bdd1243dSDimitry Andric 10349cc55cSDimitry Andric #ifndef _LIBCPP___RANGES_IOTA_VIEW_H 11349cc55cSDimitry Andric #define _LIBCPP___RANGES_IOTA_VIEW_H 12349cc55cSDimitry Andric 1381ad6265SDimitry Andric #include <__assert> 14349cc55cSDimitry Andric #include <__compare/three_way_comparable.h> 15349cc55cSDimitry Andric #include <__concepts/arithmetic.h> 16349cc55cSDimitry Andric #include <__concepts/constructible.h> 17349cc55cSDimitry Andric #include <__concepts/convertible_to.h> 18349cc55cSDimitry Andric #include <__concepts/copyable.h> 19349cc55cSDimitry Andric #include <__concepts/equality_comparable.h> 20349cc55cSDimitry Andric #include <__concepts/invocable.h> 21349cc55cSDimitry Andric #include <__concepts/same_as.h> 22349cc55cSDimitry Andric #include <__concepts/semiregular.h> 23349cc55cSDimitry Andric #include <__concepts/totally_ordered.h> 24349cc55cSDimitry Andric #include <__config> 25349cc55cSDimitry Andric #include <__iterator/concepts.h> 26349cc55cSDimitry Andric #include <__iterator/incrementable_traits.h> 27349cc55cSDimitry Andric #include <__iterator/iterator_traits.h> 28349cc55cSDimitry Andric #include <__iterator/unreachable_sentinel.h> 29349cc55cSDimitry Andric #include <__ranges/enable_borrowed_range.h> 3006c3fb27SDimitry Andric #include <__ranges/movable_box.h> 31349cc55cSDimitry Andric #include <__ranges/view_interface.h> 3206c3fb27SDimitry Andric #include <__type_traits/conditional.h> 33*0fca6ea1SDimitry Andric #include <__type_traits/is_nothrow_constructible.h> 3406c3fb27SDimitry Andric #include <__type_traits/make_unsigned.h> 3506c3fb27SDimitry Andric #include <__type_traits/type_identity.h> 36349cc55cSDimitry Andric #include <__utility/forward.h> 37349cc55cSDimitry Andric #include <__utility/move.h> 38349cc55cSDimitry Andric 39349cc55cSDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 40349cc55cSDimitry Andric # pragma GCC system_header 41349cc55cSDimitry Andric #endif 42349cc55cSDimitry Andric 43b3edf446SDimitry Andric _LIBCPP_PUSH_MACROS 44b3edf446SDimitry Andric #include <__undef_macros> 45b3edf446SDimitry Andric 46349cc55cSDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD 47349cc55cSDimitry Andric 4806c3fb27SDimitry Andric #if _LIBCPP_STD_VER >= 20 49349cc55cSDimitry Andric 50349cc55cSDimitry Andric namespace ranges { 51349cc55cSDimitry Andric template <class _Int> 52349cc55cSDimitry Andric struct __get_wider_signed { 5306c3fb27SDimitry Andric consteval static auto __call() { 54cb14a3feSDimitry Andric if constexpr (sizeof(_Int) < sizeof(short)) 55cb14a3feSDimitry Andric return type_identity<short>{}; 56cb14a3feSDimitry Andric else if constexpr (sizeof(_Int) < sizeof(int)) 57cb14a3feSDimitry Andric return type_identity<int>{}; 58cb14a3feSDimitry Andric else if constexpr (sizeof(_Int) < sizeof(long)) 59cb14a3feSDimitry Andric return type_identity<long>{}; 60cb14a3feSDimitry Andric else 61cb14a3feSDimitry Andric return type_identity<long long>{}; 62349cc55cSDimitry Andric 63cb14a3feSDimitry Andric static_assert( 64cb14a3feSDimitry Andric sizeof(_Int) <= sizeof(long long), "Found integer-like type that is bigger than largest integer like type."); 65349cc55cSDimitry Andric } 66349cc55cSDimitry Andric 67349cc55cSDimitry Andric using type = typename decltype(__call())::type; 68349cc55cSDimitry Andric }; 69349cc55cSDimitry Andric 70349cc55cSDimitry Andric template <class _Start> 71cb14a3feSDimitry Andric using _IotaDiffT = 72cb14a3feSDimitry Andric typename _If< (!integral<_Start> || sizeof(iter_difference_t<_Start>) > sizeof(_Start)), 73349cc55cSDimitry Andric type_identity<iter_difference_t<_Start>>, 74cb14a3feSDimitry Andric __get_wider_signed<_Start> >::type; 75349cc55cSDimitry Andric 76349cc55cSDimitry Andric template <class _Iter> 77349cc55cSDimitry Andric concept __decrementable = incrementable<_Iter> && requires(_Iter __i) { 78349cc55cSDimitry Andric { --__i } -> same_as<_Iter&>; 79349cc55cSDimitry Andric { __i-- } -> same_as<_Iter>; 80349cc55cSDimitry Andric }; 81349cc55cSDimitry Andric 82349cc55cSDimitry Andric template <class _Iter> 83349cc55cSDimitry Andric concept __advanceable = 84349cc55cSDimitry Andric __decrementable<_Iter> && totally_ordered<_Iter> && 85349cc55cSDimitry Andric requires(_Iter __i, const _Iter __j, const _IotaDiffT<_Iter> __n) { 86349cc55cSDimitry Andric { __i += __n } -> same_as<_Iter&>; 87349cc55cSDimitry Andric { __i -= __n } -> same_as<_Iter&>; 88349cc55cSDimitry Andric _Iter(__j + __n); 89349cc55cSDimitry Andric _Iter(__n + __j); 90349cc55cSDimitry Andric _Iter(__j - __n); 91349cc55cSDimitry Andric { __j - __j } -> convertible_to<_IotaDiffT<_Iter>>; 92349cc55cSDimitry Andric }; 93349cc55cSDimitry Andric 94349cc55cSDimitry Andric template <class> 95349cc55cSDimitry Andric struct __iota_iterator_category {}; 96349cc55cSDimitry Andric 97349cc55cSDimitry Andric template <incrementable _Tp> 98349cc55cSDimitry Andric struct __iota_iterator_category<_Tp> { 99349cc55cSDimitry Andric using iterator_category = input_iterator_tag; 100349cc55cSDimitry Andric }; 101349cc55cSDimitry Andric 10281ad6265SDimitry Andric template <weakly_incrementable _Start, semiregular _BoundSentinel = unreachable_sentinel_t> 10381ad6265SDimitry Andric requires __weakly_equality_comparable_with<_Start, _BoundSentinel> && copyable<_Start> 10481ad6265SDimitry Andric class iota_view : public view_interface<iota_view<_Start, _BoundSentinel>> { 1051ac55f4cSDimitry Andric struct __iterator : public __iota_iterator_category<_Start> { 1061ac55f4cSDimitry Andric friend class iota_view; 107349cc55cSDimitry Andric 1081ac55f4cSDimitry Andric using iterator_concept = 109cb14a3feSDimitry Andric _If<__advanceable<_Start>, 110cb14a3feSDimitry Andric random_access_iterator_tag, 111cb14a3feSDimitry Andric _If<__decrementable<_Start>, 112cb14a3feSDimitry Andric bidirectional_iterator_tag, 113cb14a3feSDimitry Andric _If<incrementable<_Start>, 114cb14a3feSDimitry Andric forward_iterator_tag, 1151ac55f4cSDimitry Andric /*Else*/ input_iterator_tag>>>; 1161ac55f4cSDimitry Andric 1171ac55f4cSDimitry Andric using value_type = _Start; 1181ac55f4cSDimitry Andric using difference_type = _IotaDiffT<_Start>; 1191ac55f4cSDimitry Andric 1201ac55f4cSDimitry Andric _Start __value_ = _Start(); 1211ac55f4cSDimitry Andric 122cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI __iterator() 123cb14a3feSDimitry Andric requires default_initializable<_Start> 124cb14a3feSDimitry Andric = default; 1251ac55f4cSDimitry Andric 126cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr explicit __iterator(_Start __value) : __value_(std::move(__value)) {} 1271ac55f4cSDimitry Andric 128cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr _Start operator*() const noexcept(is_nothrow_copy_constructible_v<_Start>) { 1291ac55f4cSDimitry Andric return __value_; 1301ac55f4cSDimitry Andric } 1311ac55f4cSDimitry Andric 132cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator++() { 1331ac55f4cSDimitry Andric ++__value_; 1341ac55f4cSDimitry Andric return *this; 1351ac55f4cSDimitry Andric } 1361ac55f4cSDimitry Andric 137cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr void operator++(int) { ++*this; } 1381ac55f4cSDimitry Andric 139cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr __iterator operator++(int) 140cb14a3feSDimitry Andric requires incrementable<_Start> 141cb14a3feSDimitry Andric { 1421ac55f4cSDimitry Andric auto __tmp = *this; 1431ac55f4cSDimitry Andric ++*this; 1441ac55f4cSDimitry Andric return __tmp; 1451ac55f4cSDimitry Andric } 1461ac55f4cSDimitry Andric 147cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator--() 148cb14a3feSDimitry Andric requires __decrementable<_Start> 149cb14a3feSDimitry Andric { 1501ac55f4cSDimitry Andric --__value_; 1511ac55f4cSDimitry Andric return *this; 1521ac55f4cSDimitry Andric } 1531ac55f4cSDimitry Andric 154cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr __iterator operator--(int) 155cb14a3feSDimitry Andric requires __decrementable<_Start> 156cb14a3feSDimitry Andric { 1571ac55f4cSDimitry Andric auto __tmp = *this; 1581ac55f4cSDimitry Andric --*this; 1591ac55f4cSDimitry Andric return __tmp; 1601ac55f4cSDimitry Andric } 1611ac55f4cSDimitry Andric 162cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator+=(difference_type __n) 1631ac55f4cSDimitry Andric requires __advanceable<_Start> 1641ac55f4cSDimitry Andric { 1651ac55f4cSDimitry Andric if constexpr (__integer_like<_Start> && !__signed_integer_like<_Start>) { 1661ac55f4cSDimitry Andric if (__n >= difference_type(0)) { 1671ac55f4cSDimitry Andric __value_ += static_cast<_Start>(__n); 1681ac55f4cSDimitry Andric } else { 1691ac55f4cSDimitry Andric __value_ -= static_cast<_Start>(-__n); 1701ac55f4cSDimitry Andric } 1711ac55f4cSDimitry Andric } else { 1721ac55f4cSDimitry Andric __value_ += __n; 1731ac55f4cSDimitry Andric } 1741ac55f4cSDimitry Andric return *this; 1751ac55f4cSDimitry Andric } 1761ac55f4cSDimitry Andric 177cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator-=(difference_type __n) 1781ac55f4cSDimitry Andric requires __advanceable<_Start> 1791ac55f4cSDimitry Andric { 1801ac55f4cSDimitry Andric if constexpr (__integer_like<_Start> && !__signed_integer_like<_Start>) { 1811ac55f4cSDimitry Andric if (__n >= difference_type(0)) { 1821ac55f4cSDimitry Andric __value_ -= static_cast<_Start>(__n); 1831ac55f4cSDimitry Andric } else { 1841ac55f4cSDimitry Andric __value_ += static_cast<_Start>(-__n); 1851ac55f4cSDimitry Andric } 1861ac55f4cSDimitry Andric } else { 1871ac55f4cSDimitry Andric __value_ -= __n; 1881ac55f4cSDimitry Andric } 1891ac55f4cSDimitry Andric return *this; 1901ac55f4cSDimitry Andric } 1911ac55f4cSDimitry Andric 192cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr _Start operator[](difference_type __n) const 1931ac55f4cSDimitry Andric requires __advanceable<_Start> 1941ac55f4cSDimitry Andric { 1951ac55f4cSDimitry Andric return _Start(__value_ + __n); 1961ac55f4cSDimitry Andric } 1971ac55f4cSDimitry Andric 198cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const __iterator& __x, const __iterator& __y) 1991ac55f4cSDimitry Andric requires equality_comparable<_Start> 2001ac55f4cSDimitry Andric { 2011ac55f4cSDimitry Andric return __x.__value_ == __y.__value_; 2021ac55f4cSDimitry Andric } 2031ac55f4cSDimitry Andric 204cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<(const __iterator& __x, const __iterator& __y) 2051ac55f4cSDimitry Andric requires totally_ordered<_Start> 2061ac55f4cSDimitry Andric { 2071ac55f4cSDimitry Andric return __x.__value_ < __y.__value_; 2081ac55f4cSDimitry Andric } 2091ac55f4cSDimitry Andric 210cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>(const __iterator& __x, const __iterator& __y) 2111ac55f4cSDimitry Andric requires totally_ordered<_Start> 2121ac55f4cSDimitry Andric { 2131ac55f4cSDimitry Andric return __y < __x; 2141ac55f4cSDimitry Andric } 2151ac55f4cSDimitry Andric 216cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<=(const __iterator& __x, const __iterator& __y) 2171ac55f4cSDimitry Andric requires totally_ordered<_Start> 2181ac55f4cSDimitry Andric { 2191ac55f4cSDimitry Andric return !(__y < __x); 2201ac55f4cSDimitry Andric } 2211ac55f4cSDimitry Andric 222cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>=(const __iterator& __x, const __iterator& __y) 2231ac55f4cSDimitry Andric requires totally_ordered<_Start> 2241ac55f4cSDimitry Andric { 2251ac55f4cSDimitry Andric return !(__x < __y); 2261ac55f4cSDimitry Andric } 2271ac55f4cSDimitry Andric 228cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI friend constexpr auto operator<=>(const __iterator& __x, const __iterator& __y) 2291ac55f4cSDimitry Andric requires totally_ordered<_Start> && three_way_comparable<_Start> 2301ac55f4cSDimitry Andric { 2311ac55f4cSDimitry Andric return __x.__value_ <=> __y.__value_; 2321ac55f4cSDimitry Andric } 2331ac55f4cSDimitry Andric 234cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI friend constexpr __iterator operator+(__iterator __i, difference_type __n) 2351ac55f4cSDimitry Andric requires __advanceable<_Start> 2361ac55f4cSDimitry Andric { 2371ac55f4cSDimitry Andric __i += __n; 2381ac55f4cSDimitry Andric return __i; 2391ac55f4cSDimitry Andric } 2401ac55f4cSDimitry Andric 241cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI friend constexpr __iterator operator+(difference_type __n, __iterator __i) 2421ac55f4cSDimitry Andric requires __advanceable<_Start> 2431ac55f4cSDimitry Andric { 2441ac55f4cSDimitry Andric return __i + __n; 2451ac55f4cSDimitry Andric } 2461ac55f4cSDimitry Andric 247cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI friend constexpr __iterator operator-(__iterator __i, difference_type __n) 2481ac55f4cSDimitry Andric requires __advanceable<_Start> 2491ac55f4cSDimitry Andric { 2501ac55f4cSDimitry Andric __i -= __n; 2511ac55f4cSDimitry Andric return __i; 2521ac55f4cSDimitry Andric } 2531ac55f4cSDimitry Andric 254cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI friend constexpr difference_type operator-(const __iterator& __x, const __iterator& __y) 2551ac55f4cSDimitry Andric requires __advanceable<_Start> 2561ac55f4cSDimitry Andric { 2571ac55f4cSDimitry Andric if constexpr (__integer_like<_Start>) { 2581ac55f4cSDimitry Andric if constexpr (__signed_integer_like<_Start>) { 2591ac55f4cSDimitry Andric return difference_type(difference_type(__x.__value_) - difference_type(__y.__value_)); 2601ac55f4cSDimitry Andric } 2611ac55f4cSDimitry Andric if (__y.__value_ > __x.__value_) { 2621ac55f4cSDimitry Andric return difference_type(-difference_type(__y.__value_ - __x.__value_)); 2631ac55f4cSDimitry Andric } 2641ac55f4cSDimitry Andric return difference_type(__x.__value_ - __y.__value_); 2651ac55f4cSDimitry Andric } 2661ac55f4cSDimitry Andric return __x.__value_ - __y.__value_; 2671ac55f4cSDimitry Andric } 2681ac55f4cSDimitry Andric }; 2691ac55f4cSDimitry Andric 2701ac55f4cSDimitry Andric struct __sentinel { 2711ac55f4cSDimitry Andric friend class iota_view; 2721ac55f4cSDimitry Andric 2731ac55f4cSDimitry Andric private: 2741ac55f4cSDimitry Andric _BoundSentinel __bound_sentinel_ = _BoundSentinel(); 2751ac55f4cSDimitry Andric 2761ac55f4cSDimitry Andric public: 277cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI __sentinel() = default; 27806c3fb27SDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr explicit __sentinel(_BoundSentinel __bound_sentinel) 27906c3fb27SDimitry Andric : __bound_sentinel_(std::move(__bound_sentinel)) {} 2801ac55f4cSDimitry Andric 281cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const __iterator& __x, const __sentinel& __y) { 2821ac55f4cSDimitry Andric return __x.__value_ == __y.__bound_sentinel_; 2831ac55f4cSDimitry Andric } 2841ac55f4cSDimitry Andric 285cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI friend constexpr iter_difference_t<_Start> 286cb14a3feSDimitry Andric operator-(const __iterator& __x, const __sentinel& __y) 2871ac55f4cSDimitry Andric requires sized_sentinel_for<_BoundSentinel, _Start> 2881ac55f4cSDimitry Andric { 2891ac55f4cSDimitry Andric return __x.__value_ - __y.__bound_sentinel_; 2901ac55f4cSDimitry Andric } 2911ac55f4cSDimitry Andric 292cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI friend constexpr iter_difference_t<_Start> 293cb14a3feSDimitry Andric operator-(const __sentinel& __x, const __iterator& __y) 2941ac55f4cSDimitry Andric requires sized_sentinel_for<_BoundSentinel, _Start> 2951ac55f4cSDimitry Andric { 2961ac55f4cSDimitry Andric return -(__y - __x); 2971ac55f4cSDimitry Andric } 2981ac55f4cSDimitry Andric }; 299349cc55cSDimitry Andric 300349cc55cSDimitry Andric _Start __value_ = _Start(); 30181ad6265SDimitry Andric _BoundSentinel __bound_sentinel_ = _BoundSentinel(); 302349cc55cSDimitry Andric 303349cc55cSDimitry Andric public: 304cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI iota_view() 305cb14a3feSDimitry Andric requires default_initializable<_Start> 306cb14a3feSDimitry Andric = default; 307349cc55cSDimitry Andric 308cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr explicit iota_view(_Start __value) : __value_(std::move(__value)) {} 309349cc55cSDimitry Andric 310cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr _LIBCPP_EXPLICIT_SINCE_CXX23 311cb14a3feSDimitry Andric iota_view(type_identity_t<_Start> __value, type_identity_t<_BoundSentinel> __bound_sentinel) 31281ad6265SDimitry Andric : __value_(std::move(__value)), __bound_sentinel_(std::move(__bound_sentinel)) { 313349cc55cSDimitry Andric // Validate the precondition if possible. 31481ad6265SDimitry Andric if constexpr (totally_ordered_with<_Start, _BoundSentinel>) { 315*0fca6ea1SDimitry Andric _LIBCPP_ASSERT_VALID_INPUT_RANGE( 316*0fca6ea1SDimitry Andric bool(__value_ <= __bound_sentinel_), "iota_view: bound must be reachable from value"); 317349cc55cSDimitry Andric } 318349cc55cSDimitry Andric } 319349cc55cSDimitry Andric 320cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr _LIBCPP_EXPLICIT_SINCE_CXX23 iota_view(__iterator __first, __iterator __last) 32181ad6265SDimitry Andric requires same_as<_Start, _BoundSentinel> 32281ad6265SDimitry Andric : iota_view(std::move(__first.__value_), std::move(__last.__value_)) {} 323349cc55cSDimitry Andric 324cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr _LIBCPP_EXPLICIT_SINCE_CXX23 iota_view(__iterator __first, _BoundSentinel __last) 32581ad6265SDimitry Andric requires same_as<_BoundSentinel, unreachable_sentinel_t> 32681ad6265SDimitry Andric : iota_view(std::move(__first.__value_), std::move(__last)) {} 327349cc55cSDimitry Andric 328cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr _LIBCPP_EXPLICIT_SINCE_CXX23 iota_view(__iterator __first, __sentinel __last) 32906c3fb27SDimitry Andric requires(!same_as<_Start, _BoundSentinel> && !same_as<_BoundSentinel, unreachable_sentinel_t>) 33081ad6265SDimitry Andric : iota_view(std::move(__first.__value_), std::move(__last.__bound_sentinel_)) {} 331349cc55cSDimitry Andric 332cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr __iterator begin() const { return __iterator{__value_}; } 333349cc55cSDimitry Andric 334cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr auto end() const { 33581ad6265SDimitry Andric if constexpr (same_as<_BoundSentinel, unreachable_sentinel_t>) 336349cc55cSDimitry Andric return unreachable_sentinel; 337349cc55cSDimitry Andric else 33881ad6265SDimitry Andric return __sentinel{__bound_sentinel_}; 339349cc55cSDimitry Andric } 340349cc55cSDimitry Andric 341cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr __iterator end() const 34281ad6265SDimitry Andric requires same_as<_Start, _BoundSentinel> 34381ad6265SDimitry Andric { 34481ad6265SDimitry Andric return __iterator{__bound_sentinel_}; 345349cc55cSDimitry Andric } 346349cc55cSDimitry Andric 347*0fca6ea1SDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr bool empty() const { return __value_ == __bound_sentinel_; } 348*0fca6ea1SDimitry Andric 349cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr auto size() const 35081ad6265SDimitry Andric requires(same_as<_Start, _BoundSentinel> && __advanceable<_Start>) || 35181ad6265SDimitry Andric (integral<_Start> && integral<_BoundSentinel>) || sized_sentinel_for<_BoundSentinel, _Start> 352349cc55cSDimitry Andric { 35381ad6265SDimitry Andric if constexpr (__integer_like<_Start> && __integer_like<_BoundSentinel>) { 3545f757f3fSDimitry Andric return (__value_ < 0) 3555f757f3fSDimitry Andric ? ((__bound_sentinel_ < 0) 3565f757f3fSDimitry Andric ? std::__to_unsigned_like(-__value_) - std::__to_unsigned_like(-__bound_sentinel_) 3575f757f3fSDimitry Andric : std::__to_unsigned_like(__bound_sentinel_) + std::__to_unsigned_like(-__value_)) 3585f757f3fSDimitry Andric : std::__to_unsigned_like(__bound_sentinel_) - std::__to_unsigned_like(__value_); 3595f757f3fSDimitry Andric } else { 36081ad6265SDimitry Andric return std::__to_unsigned_like(__bound_sentinel_ - __value_); 361349cc55cSDimitry Andric } 3625f757f3fSDimitry Andric } 363349cc55cSDimitry Andric }; 364349cc55cSDimitry Andric 36581ad6265SDimitry Andric template <class _Start, class _BoundSentinel> 36681ad6265SDimitry Andric requires(!__integer_like<_Start> || !__integer_like<_BoundSentinel> || 36781ad6265SDimitry Andric (__signed_integer_like<_Start> == __signed_integer_like<_BoundSentinel>)) 36881ad6265SDimitry Andric iota_view(_Start, _BoundSentinel) -> iota_view<_Start, _BoundSentinel>; 369349cc55cSDimitry Andric 37081ad6265SDimitry Andric template <class _Start, class _BoundSentinel> 37181ad6265SDimitry Andric inline constexpr bool enable_borrowed_range<iota_view<_Start, _BoundSentinel>> = true; 372349cc55cSDimitry Andric 373349cc55cSDimitry Andric namespace views { 374349cc55cSDimitry Andric namespace __iota { 375349cc55cSDimitry Andric struct __fn { 376349cc55cSDimitry Andric template <class _Start> 377cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Start&& __start) const 37881ad6265SDimitry Andric noexcept(noexcept(ranges::iota_view(std::forward<_Start>(__start)))) 379cb14a3feSDimitry Andric -> decltype(ranges::iota_view(std::forward<_Start>(__start))) { 380cb14a3feSDimitry Andric return ranges::iota_view(std::forward<_Start>(__start)); 381cb14a3feSDimitry Andric } 382349cc55cSDimitry Andric 38381ad6265SDimitry Andric template <class _Start, class _BoundSentinel> 384cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Start&& __start, _BoundSentinel&& __bound_sentinel) const noexcept( 385cb14a3feSDimitry Andric noexcept(ranges::iota_view(std::forward<_Start>(__start), std::forward<_BoundSentinel>(__bound_sentinel)))) 386cb14a3feSDimitry Andric -> decltype(ranges::iota_view(std::forward<_Start>(__start), std::forward<_BoundSentinel>(__bound_sentinel))) { 387cb14a3feSDimitry Andric return ranges::iota_view(std::forward<_Start>(__start), std::forward<_BoundSentinel>(__bound_sentinel)); 388cb14a3feSDimitry Andric } 389349cc55cSDimitry Andric }; 390349cc55cSDimitry Andric } // namespace __iota 391349cc55cSDimitry Andric 392349cc55cSDimitry Andric inline namespace __cpo { 393349cc55cSDimitry Andric inline constexpr auto iota = __iota::__fn{}; 3941fd87a68SDimitry Andric } // namespace __cpo 395349cc55cSDimitry Andric } // namespace views 396349cc55cSDimitry Andric } // namespace ranges 397349cc55cSDimitry Andric 39806c3fb27SDimitry Andric #endif // _LIBCPP_STD_VER >= 20 399349cc55cSDimitry Andric 400349cc55cSDimitry Andric _LIBCPP_END_NAMESPACE_STD 401349cc55cSDimitry Andric 402b3edf446SDimitry Andric _LIBCPP_POP_MACROS 403b3edf446SDimitry Andric 404349cc55cSDimitry Andric #endif // _LIBCPP___RANGES_IOTA_VIEW_H 405