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 #ifndef _LIBCPP___RANGES_VIEW_INTERFACE_H 10 #define _LIBCPP___RANGES_VIEW_INTERFACE_H 11 12 #include <__config> 13 #include <__iterator/concepts.h> 14 #include <__iterator/iterator_traits.h> 15 #include <__iterator/prev.h> 16 #include <__memory/pointer_traits.h> 17 #include <__ranges/access.h> 18 #include <__ranges/concepts.h> 19 #include <__ranges/empty.h> 20 #include <__ranges/enable_view.h> 21 #include <concepts> 22 #include <type_traits> 23 24 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 25 #pragma GCC system_header 26 #endif 27 28 _LIBCPP_PUSH_MACROS 29 #include <__undef_macros> 30 31 _LIBCPP_BEGIN_NAMESPACE_STD 32 33 #if !defined(_LIBCPP_HAS_NO_RANGES) 34 35 namespace ranges { 36 37 template<class _Tp> 38 concept __can_empty = requires(_Tp __t) { ranges::empty(__t); }; 39 40 template<class _Tp> 41 void __implicitly_convert_to(type_identity_t<_Tp>) noexcept; 42 43 template<class _Derived> 44 requires is_class_v<_Derived> && same_as<_Derived, remove_cv_t<_Derived>> 45 class view_interface : public view_base { 46 _LIBCPP_HIDE_FROM_ABI 47 constexpr _Derived& __derived() noexcept { 48 return static_cast<_Derived&>(*this); 49 } 50 51 _LIBCPP_HIDE_FROM_ABI 52 constexpr _Derived const& __derived() const noexcept { 53 return static_cast<_Derived const&>(*this); 54 } 55 56 public: 57 template<class _D2 = _Derived> 58 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool empty() 59 noexcept(noexcept(__implicitly_convert_to<bool>(ranges::begin(__derived()) == ranges::end(__derived())))) 60 requires forward_range<_D2> 61 { 62 return ranges::begin(__derived()) == ranges::end(__derived()); 63 } 64 65 template<class _D2 = _Derived> 66 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool empty() const 67 noexcept(noexcept(__implicitly_convert_to<bool>(ranges::begin(__derived()) == ranges::end(__derived())))) 68 requires forward_range<const _D2> 69 { 70 return ranges::begin(__derived()) == ranges::end(__derived()); 71 } 72 73 template<class _D2 = _Derived> 74 _LIBCPP_HIDE_FROM_ABI 75 constexpr explicit operator bool() 76 noexcept(noexcept(ranges::empty(declval<_D2>()))) 77 requires __can_empty<_D2> 78 { 79 return !ranges::empty(__derived()); 80 } 81 82 template<class _D2 = _Derived> 83 _LIBCPP_HIDE_FROM_ABI 84 constexpr explicit operator bool() const 85 noexcept(noexcept(ranges::empty(declval<const _D2>()))) 86 requires __can_empty<const _D2> 87 { 88 return !ranges::empty(__derived()); 89 } 90 91 template<class _D2 = _Derived> 92 _LIBCPP_HIDE_FROM_ABI 93 constexpr auto data() 94 noexcept(noexcept(_VSTD::to_address(ranges::begin(__derived())))) 95 requires contiguous_iterator<iterator_t<_D2>> 96 { 97 return _VSTD::to_address(ranges::begin(__derived())); 98 } 99 100 template<class _D2 = _Derived> 101 _LIBCPP_HIDE_FROM_ABI 102 constexpr auto data() const 103 noexcept(noexcept(_VSTD::to_address(ranges::begin(__derived())))) 104 requires range<const _D2> && contiguous_iterator<iterator_t<const _D2>> 105 { 106 return _VSTD::to_address(ranges::begin(__derived())); 107 } 108 109 template<class _D2 = _Derived> 110 _LIBCPP_HIDE_FROM_ABI 111 constexpr auto size() 112 noexcept(noexcept(ranges::end(__derived()) - ranges::begin(__derived()))) 113 requires forward_range<_D2> 114 && sized_sentinel_for<sentinel_t<_D2>, iterator_t<_D2>> 115 { 116 return ranges::end(__derived()) - ranges::begin(__derived()); 117 } 118 119 template<class _D2 = _Derived> 120 _LIBCPP_HIDE_FROM_ABI 121 constexpr auto size() const 122 noexcept(noexcept(ranges::end(__derived()) - ranges::begin(__derived()))) 123 requires forward_range<const _D2> 124 && sized_sentinel_for<sentinel_t<const _D2>, iterator_t<const _D2>> 125 { 126 return ranges::end(__derived()) - ranges::begin(__derived()); 127 } 128 129 template<class _D2 = _Derived> 130 _LIBCPP_HIDE_FROM_ABI 131 constexpr decltype(auto) front() 132 noexcept(noexcept(*ranges::begin(__derived()))) 133 requires forward_range<_D2> 134 { 135 _LIBCPP_ASSERT(!empty(), 136 "Precondition `!empty()` not satisfied. `.front()` called on an empty view."); 137 return *ranges::begin(__derived()); 138 } 139 140 template<class _D2 = _Derived> 141 _LIBCPP_HIDE_FROM_ABI 142 constexpr decltype(auto) front() const 143 noexcept(noexcept(*ranges::begin(__derived()))) 144 requires forward_range<const _D2> 145 { 146 _LIBCPP_ASSERT(!empty(), 147 "Precondition `!empty()` not satisfied. `.front()` called on an empty view."); 148 return *ranges::begin(__derived()); 149 } 150 151 template<class _D2 = _Derived> 152 _LIBCPP_HIDE_FROM_ABI 153 constexpr decltype(auto) back() 154 noexcept(noexcept(*ranges::prev(ranges::end(__derived())))) 155 requires bidirectional_range<_D2> && common_range<_D2> 156 { 157 _LIBCPP_ASSERT(!empty(), 158 "Precondition `!empty()` not satisfied. `.back()` called on an empty view."); 159 return *ranges::prev(ranges::end(__derived())); 160 } 161 162 template<class _D2 = _Derived> 163 _LIBCPP_HIDE_FROM_ABI 164 constexpr decltype(auto) back() const 165 noexcept(noexcept(*ranges::prev(ranges::end(__derived())))) 166 requires bidirectional_range<const _D2> && common_range<const _D2> 167 { 168 _LIBCPP_ASSERT(!empty(), 169 "Precondition `!empty()` not satisfied. `.back()` called on an empty view."); 170 return *ranges::prev(ranges::end(__derived())); 171 } 172 173 template<random_access_range _RARange = _Derived> 174 _LIBCPP_HIDE_FROM_ABI 175 constexpr decltype(auto) operator[](range_difference_t<_RARange> __index) 176 noexcept(noexcept(ranges::begin(__derived())[__index])) 177 { 178 return ranges::begin(__derived())[__index]; 179 } 180 181 template<random_access_range _RARange = const _Derived> 182 _LIBCPP_HIDE_FROM_ABI 183 constexpr decltype(auto) operator[](range_difference_t<_RARange> __index) const 184 noexcept(noexcept(ranges::begin(__derived())[__index])) 185 { 186 return ranges::begin(__derived())[__index]; 187 } 188 }; 189 190 } 191 192 #endif // !defined(_LIBCPP_HAS_NO_RANGES) 193 194 _LIBCPP_END_NAMESPACE_STD 195 196 _LIBCPP_POP_MACROS 197 198 #endif // _LIBCPP___RANGES_VIEW_INTERFACE_H 199