1 // -*- C++ -*- 2 //===----------------------------------------------------------------------===// 3 // 4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5 // See https://llvm.org/LICENSE.txt for license information. 6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7 // 8 //===----------------------------------------------------------------------===// 9 10 #ifndef _LIBCPP___RANGES_TAKE_WHILE_VIEW_H 11 #define _LIBCPP___RANGES_TAKE_WHILE_VIEW_H 12 13 #include <__concepts/constructible.h> 14 #include <__concepts/convertible_to.h> 15 #include <__config> 16 #include <__functional/bind_back.h> 17 #include <__functional/invoke.h> 18 #include <__iterator/concepts.h> 19 #include <__memory/addressof.h> 20 #include <__ranges/access.h> 21 #include <__ranges/all.h> 22 #include <__ranges/concepts.h> 23 #include <__ranges/movable_box.h> 24 #include <__ranges/range_adaptor.h> 25 #include <__ranges/view_interface.h> 26 #include <__type_traits/decay.h> 27 #include <__type_traits/is_nothrow_constructible.h> 28 #include <__type_traits/is_object.h> 29 #include <__type_traits/maybe_const.h> 30 #include <__utility/forward.h> 31 #include <__utility/in_place.h> 32 #include <__utility/move.h> 33 34 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 35 # pragma GCC system_header 36 #endif 37 38 _LIBCPP_BEGIN_NAMESPACE_STD 39 40 #if _LIBCPP_STD_VER >= 20 41 42 namespace ranges { 43 44 template <view _View, class _Pred> 45 requires input_range<_View> && is_object_v<_Pred> && indirect_unary_predicate<const _Pred, iterator_t<_View>> 46 class _LIBCPP_ABI_2023_OVERLAPPING_SUBOBJECT_FIX_TAG take_while_view 47 : public view_interface<take_while_view<_View, _Pred>> { 48 template <bool> 49 class __sentinel; 50 51 _LIBCPP_NO_UNIQUE_ADDRESS _View __base_ = _View(); 52 _LIBCPP_NO_UNIQUE_ADDRESS __movable_box<_Pred> __pred_; 53 54 public: 55 _LIBCPP_HIDE_FROM_ABI take_while_view() 56 requires default_initializable<_View> && default_initializable<_Pred> 57 = default; 58 59 _LIBCPP_HIDE_FROM_ABI constexpr _LIBCPP_EXPLICIT_SINCE_CXX23 take_while_view(_View __base, _Pred __pred) 60 : __base_(std::move(__base)), __pred_(std::in_place, std::move(__pred)) {} 61 62 _LIBCPP_HIDE_FROM_ABI constexpr _View base() const& 63 requires copy_constructible<_View> 64 { 65 return __base_; 66 } 67 68 _LIBCPP_HIDE_FROM_ABI constexpr _View base() && { return std::move(__base_); } 69 70 _LIBCPP_HIDE_FROM_ABI constexpr const _Pred& pred() const { return *__pred_; } 71 72 _LIBCPP_HIDE_FROM_ABI constexpr auto begin() 73 requires(!__simple_view<_View>) 74 { 75 return ranges::begin(__base_); 76 } 77 78 _LIBCPP_HIDE_FROM_ABI constexpr auto begin() const 79 requires range<const _View> && indirect_unary_predicate<const _Pred, iterator_t<const _View>> 80 { 81 return ranges::begin(__base_); 82 } 83 84 _LIBCPP_HIDE_FROM_ABI constexpr auto end() 85 requires(!__simple_view<_View>) 86 { 87 return __sentinel</*_Const=*/false>(ranges::end(__base_), std::addressof(*__pred_)); 88 } 89 90 _LIBCPP_HIDE_FROM_ABI constexpr auto end() const 91 requires range<const _View> && indirect_unary_predicate<const _Pred, iterator_t<const _View>> 92 { 93 return __sentinel</*_Const=*/true>(ranges::end(__base_), std::addressof(*__pred_)); 94 } 95 }; 96 97 template <class _Range, class _Pred> 98 take_while_view(_Range&&, _Pred) -> take_while_view<views::all_t<_Range>, _Pred>; 99 100 template <view _View, class _Pred> 101 requires input_range<_View> && is_object_v<_Pred> && indirect_unary_predicate<const _Pred, iterator_t<_View>> 102 template <bool _Const> 103 class take_while_view<_View, _Pred>::__sentinel { 104 using _Base = __maybe_const<_Const, _View>; 105 106 sentinel_t<_Base> __end_ = sentinel_t<_Base>(); 107 const _Pred* __pred_ = nullptr; 108 109 friend class __sentinel<!_Const>; 110 111 public: 112 _LIBCPP_HIDE_FROM_ABI __sentinel() = default; 113 114 _LIBCPP_HIDE_FROM_ABI constexpr explicit __sentinel(sentinel_t<_Base> __end, const _Pred* __pred) 115 : __end_(std::move(__end)), __pred_(__pred) {} 116 117 _LIBCPP_HIDE_FROM_ABI constexpr __sentinel(__sentinel<!_Const> __s) 118 requires _Const && convertible_to<sentinel_t<_View>, sentinel_t<_Base>> 119 : __end_(std::move(__s.__end_)), __pred_(__s.__pred_) {} 120 121 _LIBCPP_HIDE_FROM_ABI constexpr sentinel_t<_Base> base() const { return __end_; } 122 123 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const iterator_t<_Base>& __x, const __sentinel& __y) { 124 return __x == __y.__end_ || !std::invoke(*__y.__pred_, *__x); 125 } 126 127 template <bool _OtherConst = !_Const> 128 requires sentinel_for<sentinel_t<_Base>, iterator_t<__maybe_const<_OtherConst, _View>>> 129 _LIBCPP_HIDE_FROM_ABI friend constexpr bool 130 operator==(const iterator_t<__maybe_const<_OtherConst, _View>>& __x, const __sentinel& __y) { 131 return __x == __y.__end_ || !std::invoke(*__y.__pred_, *__x); 132 } 133 }; 134 135 namespace views { 136 namespace __take_while { 137 138 struct __fn { 139 template <class _Range, class _Pred> 140 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Range&& __range, _Pred&& __pred) const 141 noexcept(noexcept(/**/ take_while_view(std::forward<_Range>(__range), std::forward<_Pred>(__pred)))) 142 -> decltype(/*--*/ take_while_view(std::forward<_Range>(__range), std::forward<_Pred>(__pred))) { 143 return /*-------------*/ take_while_view(std::forward<_Range>(__range), std::forward<_Pred>(__pred)); 144 } 145 146 template <class _Pred> 147 requires constructible_from<decay_t<_Pred>, _Pred> 148 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Pred&& __pred) const 149 noexcept(is_nothrow_constructible_v<decay_t<_Pred>, _Pred>) { 150 return __range_adaptor_closure_t(std::__bind_back(*this, std::forward<_Pred>(__pred))); 151 } 152 }; 153 154 } // namespace __take_while 155 156 inline namespace __cpo { 157 inline constexpr auto take_while = __take_while::__fn{}; 158 } // namespace __cpo 159 } // namespace views 160 } // namespace ranges 161 162 #endif // _LIBCPP_STD_VER >= 20 163 164 _LIBCPP_END_NAMESPACE_STD 165 166 #endif // _LIBCPP___RANGES_TAKE_WHILE_VIEW_H 167