2 //===----------------------------------------------------------------------===//
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
8 //===----------------------------------------------------------------------===//
9 #ifndef _LIBCPP___RANGES_SIZE_H
10 #define _LIBCPP___RANGES_SIZE_H
12 #include <__concepts/class_or_enum.h>
14 #include <__iterator/concepts.h>
15 #include <__iterator/iterator_traits.h>
16 #include <__ranges/access.h>
17 #include <__utility/auto_cast.h>
19 #include <type_traits>
21 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
22 # pragma GCC system_header
25 _LIBCPP_BEGIN_NAMESPACE_STD
27 #if _LIBCPP_STD_VER > 17
31 inline constexpr bool disable_sized_range = false;
38 void size(auto&) = delete;
39 void size(const auto&) = delete;
42 concept __size_enabled = !disable_sized_range<remove_cvref_t<_Tp>>;
45 concept __member_size =
46 __size_enabled<_Tp> &&
47 __workaround_52970<_Tp> &&
49 { _LIBCPP_AUTO_CAST(__t.size()) } -> __integer_like;
53 concept __unqualified_size =
54 __size_enabled<_Tp> &&
55 !__member_size<_Tp> &&
56 __class_or_enum<remove_cvref_t<_Tp>> &&
58 { _LIBCPP_AUTO_CAST(size(__t)) } -> __integer_like;
62 concept __difference =
63 !__member_size<_Tp> &&
64 !__unqualified_size<_Tp> &&
65 __class_or_enum<remove_cvref_t<_Tp>> &&
67 { ranges::begin(__t) } -> forward_iterator;
68 { ranges::end(__t) } -> sized_sentinel_for<decltype(ranges::begin(declval<_Tp>()))>;
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 {
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 {
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());
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));
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));
108 } // namespace __size
110 inline namespace __cpo {
111 inline constexpr auto size = __size::__fn{};
113 } // namespace ranges
115 // [range.prim.ssize]
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));
128 return static_cast<_Signed>(ranges::size(__t));
131 } // namespace __ssize
133 inline namespace __cpo {
134 inline constexpr auto ssize = __ssize::__fn{};
136 } // namespace ranges
138 #endif // _LIBCPP_STD_VER > 17
140 _LIBCPP_END_NAMESPACE_STD
142 #endif // _LIBCPP___RANGES_SIZE_H