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> requires(_Tp && __t)51concept __member_size = __size_enabled<_Tp> && __workaround_52970<_Tp> && requires(_Tp&& __t) { 52 { _LIBCPP_AUTO_CAST(__t.size()) } -> __integer_like; 53 }; 54 55 template <class _Tp> 56 concept __unqualified_size = 57 __size_enabled<_Tp> && !__member_size<_Tp> && __class_or_enum<remove_cvref_t<_Tp>> && requires(_Tp&& __t) { 58 { _LIBCPP_AUTO_CAST(size(__t)) } -> __integer_like; 59 }; 60 61 template <class _Tp> 62 concept __difference = 63 !__member_size<_Tp> && !__unqualified_size<_Tp> && __class_or_enum<remove_cvref_t<_Tp>> && requires(_Tp&& __t) { 64 { ranges::begin(__t) } -> forward_iterator; 65 { ranges::end(__t) } -> sized_sentinel_for<decltype(ranges::begin(std::declval<_Tp>()))>; 66 }; 67 68 struct __fn { 69 // `[range.prim.size]`: the array case (for rvalues). 70 template <class _Tp, size_t _Sz> operator__fn71 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr size_t operator()(_Tp (&&)[_Sz]) const noexcept { 72 return _Sz; 73 } 74 75 // `[range.prim.size]`: the array case (for lvalues). 76 template <class _Tp, size_t _Sz> operator__fn77 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr size_t operator()(_Tp (&)[_Sz]) const noexcept { 78 return _Sz; 79 } 80 81 // `[range.prim.size]`: `auto(t.size())` is a valid expression. 82 template <__member_size _Tp> operator__fn83 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr __integer_like auto operator()(_Tp&& __t) const 84 noexcept(noexcept(_LIBCPP_AUTO_CAST(__t.size()))) { 85 return _LIBCPP_AUTO_CAST(__t.size()); 86 } 87 88 // `[range.prim.size]`: `auto(size(t))` is a valid expression. 89 template <__unqualified_size _Tp> operator__fn90 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr __integer_like auto operator()(_Tp&& __t) const 91 noexcept(noexcept(_LIBCPP_AUTO_CAST(size(__t)))) { 92 return _LIBCPP_AUTO_CAST(size(__t)); 93 } 94 95 // [range.prim.size]: the `to-unsigned-like` case. 96 template <__difference _Tp> 97 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const 98 noexcept(noexcept(std::__to_unsigned_like(ranges::end(__t) - ranges::begin(__t)))) 99 -> decltype(std::__to_unsigned_like(ranges::end(__t) - ranges::begin(__t))) { 100 return std::__to_unsigned_like(ranges::end(__t) - ranges::begin(__t)); 101 } 102 }; 103 104 } // namespace __size 105 106 inline namespace __cpo { 107 inline constexpr auto size = __size::__fn{}; 108 } // namespace __cpo 109 } // namespace ranges 110 111 // [range.prim.ssize] 112 113 namespace ranges { 114 namespace __ssize { 115 struct __fn { 116 template <class _Tp> requires__fn117 requires requires(_Tp&& __t) { ranges::size(__t); } operator__fn118 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr integral auto operator()(_Tp&& __t) const 119 noexcept(noexcept(ranges::size(__t))) { 120 using _Signed = make_signed_t<decltype(ranges::size(__t))>; 121 if constexpr (sizeof(ptrdiff_t) > sizeof(_Signed)) 122 return static_cast<ptrdiff_t>(ranges::size(__t)); 123 else 124 return static_cast<_Signed>(ranges::size(__t)); 125 } 126 }; 127 } // namespace __ssize 128 129 inline namespace __cpo { 130 inline constexpr auto ssize = __ssize::__fn{}; 131 } // namespace __cpo 132 } // namespace ranges 133 134 #endif // _LIBCPP_STD_VER >= 20 135 136 _LIBCPP_END_NAMESPACE_STD 137 138 #endif // _LIBCPP___RANGES_SIZE_H 139