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_SIZE_H 11 #define _LIBCPP___RANGES_SIZE_H 12 13 #include <__concepts/arithmetic.h> 14 #include <__concepts/class_or_enum.h> 15 #include <__config> 16 #include <__iterator/concepts.h> 17 #include <__iterator/iterator_traits.h> 18 #include <__ranges/access.h> 19 #include <__type_traits/decay.h> 20 #include <__type_traits/make_signed.h> 21 #include <__type_traits/make_unsigned.h> 22 #include <__type_traits/remove_cvref.h> 23 #include <__utility/auto_cast.h> 24 #include <__utility/declval.h> 25 #include <cstddef> 26 27 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 28 # pragma GCC system_header 29 #endif 30 31 _LIBCPP_BEGIN_NAMESPACE_STD 32 33 #if _LIBCPP_STD_VER >= 20 34 35 namespace ranges { 36 template<class> 37 inline constexpr bool disable_sized_range = false; 38 } // namespace ranges 39 40 // [range.prim.size] 41 42 namespace ranges { 43 namespace __size { 44 void size(auto&) = delete; 45 void size(const auto&) = delete; 46 47 template <class _Tp> 48 concept __size_enabled = !disable_sized_range<remove_cvref_t<_Tp>>; 49 50 template <class _Tp> 51 concept __member_size = 52 __size_enabled<_Tp> && 53 __workaround_52970<_Tp> && 54 requires(_Tp&& __t) { 55 { _LIBCPP_AUTO_CAST(__t.size()) } -> __integer_like; 56 }; 57 58 template <class _Tp> 59 concept __unqualified_size = 60 __size_enabled<_Tp> && 61 !__member_size<_Tp> && 62 __class_or_enum<remove_cvref_t<_Tp>> && 63 requires(_Tp&& __t) { 64 { _LIBCPP_AUTO_CAST(size(__t)) } -> __integer_like; 65 }; 66 67 template <class _Tp> 68 concept __difference = 69 !__member_size<_Tp> && 70 !__unqualified_size<_Tp> && 71 __class_or_enum<remove_cvref_t<_Tp>> && 72 requires(_Tp&& __t) { 73 { ranges::begin(__t) } -> forward_iterator; 74 { ranges::end(__t) } -> sized_sentinel_for<decltype(ranges::begin(std::declval<_Tp>()))>; 75 }; 76 77 struct __fn { 78 79 // `[range.prim.size]`: the array case (for rvalues). 80 template <class _Tp, size_t _Sz> 81 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr size_t operator()(_Tp (&&)[_Sz]) const noexcept { 82 return _Sz; 83 } 84 85 // `[range.prim.size]`: the array case (for lvalues). 86 template <class _Tp, size_t _Sz> 87 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr size_t operator()(_Tp (&)[_Sz]) const noexcept { 88 return _Sz; 89 } 90 91 // `[range.prim.size]`: `auto(t.size())` is a valid expression. 92 template <__member_size _Tp> 93 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr __integer_like auto operator()(_Tp&& __t) const 94 noexcept(noexcept(_LIBCPP_AUTO_CAST(__t.size()))) { 95 return _LIBCPP_AUTO_CAST(__t.size()); 96 } 97 98 // `[range.prim.size]`: `auto(size(t))` is a valid expression. 99 template <__unqualified_size _Tp> 100 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr __integer_like auto operator()(_Tp&& __t) const 101 noexcept(noexcept(_LIBCPP_AUTO_CAST(size(__t)))) { 102 return _LIBCPP_AUTO_CAST(size(__t)); 103 } 104 105 // [range.prim.size]: the `to-unsigned-like` case. 106 template <__difference _Tp> 107 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const 108 noexcept(noexcept(std::__to_unsigned_like(ranges::end(__t) - ranges::begin(__t)))) 109 -> decltype( std::__to_unsigned_like(ranges::end(__t) - ranges::begin(__t))) 110 { return std::__to_unsigned_like(ranges::end(__t) - ranges::begin(__t)); 111 } 112 }; 113 114 } // namespace __size 115 116 inline namespace __cpo { 117 inline constexpr auto size = __size::__fn{}; 118 } // namespace __cpo 119 } // namespace ranges 120 121 // [range.prim.ssize] 122 123 namespace ranges { 124 namespace __ssize { 125 struct __fn { 126 template<class _Tp> 127 requires requires (_Tp&& __t) { ranges::size(__t); } 128 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr integral auto operator()(_Tp&& __t) const 129 noexcept(noexcept(ranges::size(__t))) { 130 using _Signed = make_signed_t<decltype(ranges::size(__t))>; 131 if constexpr (sizeof(ptrdiff_t) > sizeof(_Signed)) 132 return static_cast<ptrdiff_t>(ranges::size(__t)); 133 else 134 return static_cast<_Signed>(ranges::size(__t)); 135 } 136 }; 137 } // namespace __ssize 138 139 inline namespace __cpo { 140 inline constexpr auto ssize = __ssize::__fn{}; 141 } // namespace __cpo 142 } // namespace ranges 143 144 #endif // _LIBCPP_STD_VER >= 20 145 146 _LIBCPP_END_NAMESPACE_STD 147 148 #endif // _LIBCPP___RANGES_SIZE_H 149