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_SIZE_H 10 #define _LIBCPP___RANGES_SIZE_H 11 12 #include <__concepts/class_or_enum.h> 13 #include <__config> 14 #include <__iterator/concepts.h> 15 #include <__iterator/iterator_traits.h> 16 #include <__ranges/access.h> 17 #include <__utility/auto_cast.h> 18 #include <concepts> 19 #include <type_traits> 20 21 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 22 # pragma GCC system_header 23 #endif 24 25 _LIBCPP_BEGIN_NAMESPACE_STD 26 27 #if _LIBCPP_STD_VER > 17 28 29 namespace ranges { 30 template<class> 31 inline constexpr bool disable_sized_range = false; 32 } // namespace ranges 33 34 // [range.prim.size] 35 36 namespace ranges { 37 namespace __size { 38 void size(auto&) = delete; 39 void size(const auto&) = delete; 40 41 template <class _Tp> 42 concept __size_enabled = !disable_sized_range<remove_cvref_t<_Tp>>; 43 44 template <class _Tp> 45 concept __member_size = 46 __size_enabled<_Tp> && 47 __workaround_52970<_Tp> && 48 requires(_Tp&& __t) { 49 { _LIBCPP_AUTO_CAST(__t.size()) } -> __integer_like; 50 }; 51 52 template <class _Tp> 53 concept __unqualified_size = 54 __size_enabled<_Tp> && 55 !__member_size<_Tp> && 56 __class_or_enum<remove_cvref_t<_Tp>> && 57 requires(_Tp&& __t) { 58 { _LIBCPP_AUTO_CAST(size(__t)) } -> __integer_like; 59 }; 60 61 template <class _Tp> 62 concept __difference = 63 !__member_size<_Tp> && 64 !__unqualified_size<_Tp> && 65 __class_or_enum<remove_cvref_t<_Tp>> && 66 requires(_Tp&& __t) { 67 { ranges::begin(__t) } -> forward_iterator; 68 { ranges::end(__t) } -> sized_sentinel_for<decltype(ranges::begin(declval<_Tp>()))>; 69 }; 70 71 struct __fn { 72 73 // `[range.prim.size]`: the array case (for rvalues). 74 template <class _Tp, size_t _Sz> 75 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr size_t operator()(_Tp (&&)[_Sz]) const noexcept { 76 return _Sz; 77 } 78 79 // `[range.prim.size]`: the array case (for lvalues). 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]`: `auto(t.size())` is a valid expression. 86 template <__member_size _Tp> 87 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr __integer_like auto operator()(_Tp&& __t) const 88 noexcept(noexcept(_LIBCPP_AUTO_CAST(__t.size()))) { 89 return _LIBCPP_AUTO_CAST(__t.size()); 90 } 91 92 // `[range.prim.size]`: `auto(size(t))` is a valid expression. 93 template <__unqualified_size _Tp> 94 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr __integer_like auto operator()(_Tp&& __t) const 95 noexcept(noexcept(_LIBCPP_AUTO_CAST(size(__t)))) { 96 return _LIBCPP_AUTO_CAST(size(__t)); 97 } 98 99 // [range.prim.size]: the `to-unsigned-like` case. 100 template <__difference _Tp> 101 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const 102 noexcept(noexcept(std::__to_unsigned_like(ranges::end(__t) - ranges::begin(__t)))) 103 -> decltype( std::__to_unsigned_like(ranges::end(__t) - ranges::begin(__t))) 104 { return std::__to_unsigned_like(ranges::end(__t) - ranges::begin(__t)); 105 } 106 }; 107 108 } // namespace __size 109 110 inline namespace __cpo { 111 inline constexpr auto size = __size::__fn{}; 112 } // namespace __cpo 113 } // namespace ranges 114 115 // [range.prim.ssize] 116 117 namespace ranges { 118 namespace __ssize { 119 struct __fn { 120 template<class _Tp> 121 requires requires (_Tp&& __t) { ranges::size(__t); } 122 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr integral auto operator()(_Tp&& __t) const 123 noexcept(noexcept(ranges::size(__t))) { 124 using _Signed = make_signed_t<decltype(ranges::size(__t))>; 125 if constexpr (sizeof(ptrdiff_t) > sizeof(_Signed)) 126 return static_cast<ptrdiff_t>(ranges::size(__t)); 127 else 128 return static_cast<_Signed>(ranges::size(__t)); 129 } 130 }; 131 } // namespace __ssize 132 133 inline namespace __cpo { 134 inline constexpr auto ssize = __ssize::__fn{}; 135 } // namespace __cpo 136 } // namespace ranges 137 138 #endif // _LIBCPP_STD_VER > 17 139 140 _LIBCPP_END_NAMESPACE_STD 141 142 #endif // _LIBCPP___RANGES_SIZE_H 143