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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_VIEW_INTERFACE_H11#define _LIBCPP___RANGES_VIEW_INTERFACE_H12 13#include <__assert>14#include <__concepts/derived_from.h>15#include <__concepts/same_as.h>16#include <__config>17#include <__iterator/concepts.h>18#include <__iterator/iterator_traits.h>19#include <__iterator/prev.h>20#include <__memory/pointer_traits.h>21#include <__ranges/access.h>22#include <__ranges/concepts.h>23#include <__ranges/empty.h>24#include <__ranges/size.h>25#include <__type_traits/is_class.h>26#include <__type_traits/make_unsigned.h>27#include <__type_traits/remove_cv.h>28 29#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)30# pragma GCC system_header31#endif32 33_LIBCPP_BEGIN_NAMESPACE_STD34 35#if _LIBCPP_STD_VER >= 2036 37namespace ranges {38 39template <class _Derived>40 requires is_class_v<_Derived> && same_as<_Derived, remove_cv_t<_Derived>>41class view_interface {42 _LIBCPP_HIDE_FROM_ABI constexpr _Derived& __derived() noexcept {43 static_assert(sizeof(_Derived) && derived_from<_Derived, view_interface> && view<_Derived>);44 return static_cast<_Derived&>(*this);45 }46 47 _LIBCPP_HIDE_FROM_ABI constexpr _Derived const& __derived() const noexcept {48 static_assert(sizeof(_Derived) && derived_from<_Derived, view_interface> && view<_Derived>);49 return static_cast<_Derived const&>(*this);50 }51 52public:53 template <class _D2 = _Derived>54 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool empty()55 requires sized_range<_D2> || forward_range<_D2>56 {57 if constexpr (sized_range<_D2>) {58 return ranges::size(__derived()) == 0;59 } else {60 return ranges::begin(__derived()) == ranges::end(__derived());61 }62 }63 64 template <class _D2 = _Derived>65 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool empty() const66 requires sized_range<const _D2> || forward_range<const _D2>67 {68 if constexpr (sized_range<const _D2>) {69 return ranges::size(__derived()) == 0;70 } else {71 return ranges::begin(__derived()) == ranges::end(__derived());72 }73 }74 75 template <class _D2 = _Derived>76 _LIBCPP_HIDE_FROM_ABI constexpr explicit operator bool()77 requires requires(_D2& __t) { ranges::empty(__t); }78 {79 return !ranges::empty(__derived());80 }81 82 template <class _D2 = _Derived>83 _LIBCPP_HIDE_FROM_ABI constexpr explicit operator bool() const84 requires requires(const _D2& __t) { ranges::empty(__t); }85 {86 return !ranges::empty(__derived());87 }88 89 template <class _D2 = _Derived>90 _LIBCPP_HIDE_FROM_ABI constexpr auto data()91 requires contiguous_iterator<iterator_t<_D2>>92 {93 return std::to_address(ranges::begin(__derived()));94 }95 96 template <class _D2 = _Derived>97 _LIBCPP_HIDE_FROM_ABI constexpr auto data() const98 requires range<const _D2> && contiguous_iterator<iterator_t<const _D2>>99 {100 return std::to_address(ranges::begin(__derived()));101 }102 103 template <class _D2 = _Derived>104 _LIBCPP_HIDE_FROM_ABI constexpr auto size()105 requires forward_range<_D2> && sized_sentinel_for<sentinel_t<_D2>, iterator_t<_D2>>106 {107 return std::__to_unsigned_like(ranges::end(__derived()) - ranges::begin(__derived()));108 }109 110 template <class _D2 = _Derived>111 _LIBCPP_HIDE_FROM_ABI constexpr auto size() const112 requires forward_range<const _D2> && sized_sentinel_for<sentinel_t<const _D2>, iterator_t<const _D2>>113 {114 return std::__to_unsigned_like(ranges::end(__derived()) - ranges::begin(__derived()));115 }116 117 template <class _D2 = _Derived>118 _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) front()119 requires forward_range<_D2>120 {121 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(122 !empty(), "Precondition `!empty()` not satisfied. `.front()` called on an empty view.");123 return *ranges::begin(__derived());124 }125 126 template <class _D2 = _Derived>127 _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) front() const128 requires forward_range<const _D2>129 {130 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(131 !empty(), "Precondition `!empty()` not satisfied. `.front()` called on an empty view.");132 return *ranges::begin(__derived());133 }134 135 template <class _D2 = _Derived>136 _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) back()137 requires bidirectional_range<_D2> && common_range<_D2>138 {139 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(140 !empty(), "Precondition `!empty()` not satisfied. `.back()` called on an empty view.");141 return *ranges::prev(ranges::end(__derived()));142 }143 144 template <class _D2 = _Derived>145 _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) back() const146 requires bidirectional_range<const _D2> && common_range<const _D2>147 {148 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(149 !empty(), "Precondition `!empty()` not satisfied. `.back()` called on an empty view.");150 return *ranges::prev(ranges::end(__derived()));151 }152 153 template <random_access_range _RARange = _Derived>154 _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator[](range_difference_t<_RARange> __index) {155 return ranges::begin(__derived())[__index];156 }157 158 template <random_access_range _RARange = const _Derived>159 _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator[](range_difference_t<_RARange> __index) const {160 return ranges::begin(__derived())[__index];161 }162};163 164} // namespace ranges165 166#endif // _LIBCPP_STD_VER >= 20167 168_LIBCPP_END_NAMESPACE_STD169 170#endif // _LIBCPP___RANGES_VIEW_INTERFACE_H171