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_COMMON_VIEW_H 11#define _LIBCPP___RANGES_COMMON_VIEW_H 12 13#include <__concepts/constructible.h> 14#include <__concepts/copyable.h> 15#include <__config> 16#include <__iterator/common_iterator.h> 17#include <__iterator/iterator_traits.h> 18#include <__ranges/access.h> 19#include <__ranges/all.h> 20#include <__ranges/concepts.h> 21#include <__ranges/enable_borrowed_range.h> 22#include <__ranges/range_adaptor.h> 23#include <__ranges/size.h> 24#include <__ranges/view_interface.h> 25#include <__utility/forward.h> 26#include <__utility/move.h> 27 28#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 29# pragma GCC system_header 30#endif 31 32_LIBCPP_PUSH_MACROS 33#include <__undef_macros> 34 35_LIBCPP_BEGIN_NAMESPACE_STD 36 37#if _LIBCPP_STD_VER >= 20 38 39namespace ranges { 40 41template <view _View> 42 requires(!common_range<_View> && copyable<iterator_t<_View>>) 43class common_view : public view_interface<common_view<_View>> { 44 _View __base_ = _View(); 45 46public: 47 _LIBCPP_HIDE_FROM_ABI common_view() 48 requires default_initializable<_View> 49 = default; 50 51 _LIBCPP_HIDE_FROM_ABI constexpr explicit common_view(_View __v) : __base_(std::move(__v)) {} 52 53 _LIBCPP_HIDE_FROM_ABI constexpr _View base() const& 54 requires copy_constructible<_View> 55 { 56 return __base_; 57 } 58 59 _LIBCPP_HIDE_FROM_ABI constexpr _View base() && { return std::move(__base_); } 60 61 _LIBCPP_HIDE_FROM_ABI constexpr auto begin() { 62 if constexpr (random_access_range<_View> && sized_range<_View>) 63 return ranges::begin(__base_); 64 else 65 return common_iterator<iterator_t<_View>, sentinel_t<_View>>(ranges::begin(__base_)); 66 } 67 68 _LIBCPP_HIDE_FROM_ABI constexpr auto begin() const 69 requires range<const _View> 70 { 71 if constexpr (random_access_range<const _View> && sized_range<const _View>) 72 return ranges::begin(__base_); 73 else 74 return common_iterator<iterator_t<const _View>, sentinel_t<const _View>>(ranges::begin(__base_)); 75 } 76 77 _LIBCPP_HIDE_FROM_ABI constexpr auto end() { 78 if constexpr (random_access_range<_View> && sized_range<_View>) 79 return ranges::begin(__base_) + ranges::size(__base_); 80 else 81 return common_iterator<iterator_t<_View>, sentinel_t<_View>>(ranges::end(__base_)); 82 } 83 84 _LIBCPP_HIDE_FROM_ABI constexpr auto end() const 85 requires range<const _View> 86 { 87 if constexpr (random_access_range<const _View> && sized_range<const _View>) 88 return ranges::begin(__base_) + ranges::size(__base_); 89 else 90 return common_iterator<iterator_t<const _View>, sentinel_t<const _View>>(ranges::end(__base_)); 91 } 92 93 _LIBCPP_HIDE_FROM_ABI constexpr auto size() 94 requires sized_range<_View> 95 { 96 return ranges::size(__base_); 97 } 98 99 _LIBCPP_HIDE_FROM_ABI constexpr auto size() const 100 requires sized_range<const _View> 101 { 102 return ranges::size(__base_); 103 } 104}; 105 106template <class _Range> 107common_view(_Range&&) -> common_view<views::all_t<_Range>>; 108 109template <class _View> 110inline constexpr bool enable_borrowed_range<common_view<_View>> = enable_borrowed_range<_View>; 111 112namespace views { 113namespace __common { 114struct __fn : __range_adaptor_closure<__fn> { 115 template <class _Range> 116 requires common_range<_Range> 117 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Range&& __range) const 118 noexcept(noexcept(views::all(std::forward<_Range>(__range)))) 119 -> decltype(views::all(std::forward<_Range>(__range))) { 120 return views::all(std::forward<_Range>(__range)); 121 } 122 123 template <class _Range> 124 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Range&& __range) const 125 noexcept(noexcept(common_view{std::forward<_Range>(__range)})) 126 -> decltype(common_view{std::forward<_Range>(__range)}) { 127 return common_view{std::forward<_Range>(__range)}; 128 } 129}; 130} // namespace __common 131 132inline namespace __cpo { 133inline constexpr auto common = __common::__fn{}; 134} // namespace __cpo 135} // namespace views 136} // namespace ranges 137 138#endif // _LIBCPP_STD_VER >= 20 139 140_LIBCPP_END_NAMESPACE_STD 141 142_LIBCPP_POP_MACROS 143 144#endif // _LIBCPP___RANGES_COMMON_VIEW_H 145