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 constexpr _Derived& __derived() noexcept { 47 return static_cast<_Derived&>(*this); 48 } 49 50 constexpr _Derived const& __derived() const noexcept { 51 return static_cast<_Derived const&>(*this); 52 } 53 54 public: 55 template<class _D2 = _Derived> 56 [[nodiscard]] constexpr bool empty() 57 noexcept(noexcept(__implicitly_convert_to<bool>(ranges::begin(__derived()) == ranges::end(__derived())))) 58 requires forward_range<_D2> 59 { 60 return ranges::begin(__derived()) == ranges::end(__derived()); 61 } 62 63 template<class _D2 = _Derived> 64 [[nodiscard]] constexpr bool empty() const 65 noexcept(noexcept(__implicitly_convert_to<bool>(ranges::begin(__derived()) == ranges::end(__derived())))) 66 requires forward_range<const _D2> 67 { 68 return ranges::begin(__derived()) == ranges::end(__derived()); 69 } 70 71 template<class _D2 = _Derived> 72 constexpr explicit operator bool() 73 noexcept(noexcept(ranges::empty(declval<_D2>()))) 74 requires __can_empty<_D2> 75 { 76 return !ranges::empty(__derived()); 77 } 78 79 template<class _D2 = _Derived> 80 constexpr explicit operator bool() const 81 noexcept(noexcept(ranges::empty(declval<const _D2>()))) 82 requires __can_empty<const _D2> 83 { 84 return !ranges::empty(__derived()); 85 } 86 87 template<class _D2 = _Derived> 88 constexpr auto data() 89 noexcept(noexcept(_VSTD::to_address(ranges::begin(__derived())))) 90 requires contiguous_iterator<iterator_t<_D2>> 91 { 92 return _VSTD::to_address(ranges::begin(__derived())); 93 } 94 95 template<class _D2 = _Derived> 96 constexpr auto data() const 97 noexcept(noexcept(_VSTD::to_address(ranges::begin(__derived())))) 98 requires range<const _D2> && contiguous_iterator<iterator_t<const _D2>> 99 { 100 return _VSTD::to_address(ranges::begin(__derived())); 101 } 102 103 template<class _D2 = _Derived> 104 constexpr auto size() 105 noexcept(noexcept(ranges::end(__derived()) - ranges::begin(__derived()))) 106 requires forward_range<_D2> 107 && sized_sentinel_for<sentinel_t<_D2>, iterator_t<_D2>> 108 { 109 return ranges::end(__derived()) - ranges::begin(__derived()); 110 } 111 112 template<class _D2 = _Derived> 113 constexpr auto size() const 114 noexcept(noexcept(ranges::end(__derived()) - ranges::begin(__derived()))) 115 requires forward_range<const _D2> 116 && sized_sentinel_for<sentinel_t<const _D2>, iterator_t<const _D2>> 117 { 118 return ranges::end(__derived()) - ranges::begin(__derived()); 119 } 120 121 template<class _D2 = _Derived> 122 constexpr decltype(auto) front() 123 noexcept(noexcept(*ranges::begin(__derived()))) 124 requires forward_range<_D2> 125 { 126 _LIBCPP_ASSERT(!empty(), 127 "Precondition `!empty()` not satisfied. `.front()` called on an empty view."); 128 return *ranges::begin(__derived()); 129 } 130 131 template<class _D2 = _Derived> 132 constexpr decltype(auto) front() const 133 noexcept(noexcept(*ranges::begin(__derived()))) 134 requires forward_range<const _D2> 135 { 136 _LIBCPP_ASSERT(!empty(), 137 "Precondition `!empty()` not satisfied. `.front()` called on an empty view."); 138 return *ranges::begin(__derived()); 139 } 140 141 template<class _D2 = _Derived> 142 constexpr decltype(auto) back() 143 noexcept(noexcept(*ranges::prev(ranges::end(__derived())))) 144 requires bidirectional_range<_D2> && common_range<_D2> 145 { 146 _LIBCPP_ASSERT(!empty(), 147 "Precondition `!empty()` not satisfied. `.back()` called on an empty view."); 148 return *ranges::prev(ranges::end(__derived())); 149 } 150 151 template<class _D2 = _Derived> 152 constexpr decltype(auto) back() const 153 noexcept(noexcept(*ranges::prev(ranges::end(__derived())))) 154 requires bidirectional_range<const _D2> && common_range<const _D2> 155 { 156 _LIBCPP_ASSERT(!empty(), 157 "Precondition `!empty()` not satisfied. `.back()` called on an empty view."); 158 return *ranges::prev(ranges::end(__derived())); 159 } 160 161 template<random_access_range _RARange = _Derived> 162 constexpr decltype(auto) operator[](range_difference_t<_RARange> __index) 163 noexcept(noexcept(ranges::begin(__derived())[__index])) 164 { 165 return ranges::begin(__derived())[__index]; 166 } 167 168 template<random_access_range _RARange = const _Derived> 169 constexpr decltype(auto) operator[](range_difference_t<_RARange> __index) const 170 noexcept(noexcept(ranges::begin(__derived())[__index])) 171 { 172 return ranges::begin(__derived())[__index]; 173 } 174 }; 175 176 } 177 178 #endif // !defined(_LIBCPP_HAS_NO_RANGES) 179 180 _LIBCPP_END_NAMESPACE_STD 181 182 _LIBCPP_POP_MACROS 183 184 #endif // _LIBCPP___RANGES_VIEW_INTERFACE_H 185