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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-exception7//8//===----------------------------------------------------------------------===//9 10#ifndef _LIBCPP___RANGES_DROP_WHILE_VIEW_H11#define _LIBCPP___RANGES_DROP_WHILE_VIEW_H12 13#include <__algorithm/ranges_find_if_not.h>14#include <__assert>15#include <__concepts/constructible.h>16#include <__config>17#include <__functional/bind_back.h>18#include <__functional/reference_wrapper.h>19#include <__iterator/concepts.h>20#include <__ranges/access.h>21#include <__ranges/all.h>22#include <__ranges/concepts.h>23#include <__ranges/enable_borrowed_range.h>24#include <__ranges/movable_box.h>25#include <__ranges/non_propagating_cache.h>26#include <__ranges/range_adaptor.h>27#include <__ranges/view_interface.h>28#include <__type_traits/conditional.h>29#include <__type_traits/decay.h>30#include <__type_traits/is_nothrow_constructible.h>31#include <__type_traits/is_object.h>32#include <__utility/forward.h>33#include <__utility/in_place.h>34#include <__utility/move.h>35 36#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)37# pragma GCC system_header38#endif39 40_LIBCPP_PUSH_MACROS41#include <__undef_macros>42 43_LIBCPP_BEGIN_NAMESPACE_STD44 45#if _LIBCPP_STD_VER >= 2046 47namespace ranges {48 49template <view _View, class _Pred>50 requires input_range<_View> && is_object_v<_Pred> && indirect_unary_predicate<const _Pred, iterator_t<_View>>51class _LIBCPP_ABI_LLVM18_NO_UNIQUE_ADDRESS drop_while_view : public view_interface<drop_while_view<_View, _Pred>> {52public:53 _LIBCPP_HIDE_FROM_ABI drop_while_view()54 requires default_initializable<_View> && default_initializable<_Pred>55 = default;56 57 _LIBCPP_HIDE_FROM_ABI constexpr _LIBCPP_EXPLICIT_SINCE_CXX23 drop_while_view(_View __base, _Pred __pred)58 : __base_(std::move(__base)), __pred_(std::in_place, std::move(__pred)) {}59 60 _LIBCPP_HIDE_FROM_ABI constexpr _View base() const&61 requires copy_constructible<_View>62 {63 return __base_;64 }65 66 _LIBCPP_HIDE_FROM_ABI constexpr _View base() && { return std::move(__base_); }67 68 _LIBCPP_HIDE_FROM_ABI constexpr const _Pred& pred() const { return *__pred_; }69 70 _LIBCPP_HIDE_FROM_ABI constexpr auto begin() {71 // Note: this duplicates a check in `optional` but provides a better error message.72 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(73 __pred_.__has_value(),74 "drop_while_view needs to have a non-empty predicate before calling begin() -- did a previous "75 "assignment to this drop_while_view fail?");76 if constexpr (_UseCache) {77 if (!__cached_begin_.__has_value()) {78 __cached_begin_.__emplace(ranges::find_if_not(__base_, std::cref(*__pred_)));79 }80 return *__cached_begin_;81 } else {82 return ranges::find_if_not(__base_, std::cref(*__pred_));83 }84 }85 86 _LIBCPP_HIDE_FROM_ABI constexpr auto end() { return ranges::end(__base_); }87 88private:89 _LIBCPP_NO_UNIQUE_ADDRESS _View __base_ = _View();90 _LIBCPP_NO_UNIQUE_ADDRESS __movable_box<_Pred> __pred_;91 92 static constexpr bool _UseCache = forward_range<_View>;93 using _Cache _LIBCPP_NODEBUG = _If<_UseCache, __non_propagating_cache<iterator_t<_View>>, __empty_cache>;94 _LIBCPP_NO_UNIQUE_ADDRESS _Cache __cached_begin_ = _Cache();95};96 97template <class _View, class _Pred>98inline constexpr bool enable_borrowed_range<drop_while_view<_View, _Pred>> = enable_borrowed_range<_View>;99 100template <class _Range, class _Pred>101drop_while_view(_Range&&, _Pred) -> drop_while_view<views::all_t<_Range>, _Pred>;102 103namespace views {104namespace __drop_while {105 106struct __fn {107 template <class _Range, class _Pred>108 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Range&& __range, _Pred&& __pred) const109 noexcept(noexcept(/**/ drop_while_view(std::forward<_Range>(__range), std::forward<_Pred>(__pred))))110 -> decltype(/*--*/ drop_while_view(std::forward<_Range>(__range), std::forward<_Pred>(__pred))) {111 return /*-------------*/ drop_while_view(std::forward<_Range>(__range), std::forward<_Pred>(__pred));112 }113 114 template <class _Pred>115 requires constructible_from<decay_t<_Pred>, _Pred>116 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Pred&& __pred) const117 noexcept(is_nothrow_constructible_v<decay_t<_Pred>, _Pred>) {118 return __pipeable(std::__bind_back(*this, std::forward<_Pred>(__pred)));119 }120};121 122} // namespace __drop_while123 124inline namespace __cpo {125inline constexpr auto drop_while = __drop_while::__fn{};126} // namespace __cpo127} // namespace views128} // namespace ranges129 130#endif // _LIBCPP_STD_VER >= 20131 132_LIBCPP_END_NAMESPACE_STD133 134_LIBCPP_POP_MACROS135 136#endif // _LIBCPP___RANGES_DROP_WHILE_VIEW_H137