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