xref: /freebsd-src/contrib/llvm-project/libcxx/include/__ranges/size.h (revision 0fca6ea1d4eea4c934cfff25ac9ee8ad6fe95583)
1fe6060f1SDimitry Andric // -*- C++ -*-
2fe6060f1SDimitry Andric //===----------------------------------------------------------------------===//
3fe6060f1SDimitry Andric //
4fe6060f1SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5fe6060f1SDimitry Andric // See https://llvm.org/LICENSE.txt for license information.
6fe6060f1SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7fe6060f1SDimitry Andric //
8fe6060f1SDimitry Andric //===----------------------------------------------------------------------===//
9bdd1243dSDimitry Andric 
10fe6060f1SDimitry Andric #ifndef _LIBCPP___RANGES_SIZE_H
11fe6060f1SDimitry Andric #define _LIBCPP___RANGES_SIZE_H
12fe6060f1SDimitry Andric 
13bdd1243dSDimitry Andric #include <__concepts/arithmetic.h>
1404eeddc0SDimitry Andric #include <__concepts/class_or_enum.h>
15fe6060f1SDimitry Andric #include <__config>
16fe6060f1SDimitry Andric #include <__iterator/concepts.h>
17fe6060f1SDimitry Andric #include <__iterator/iterator_traits.h>
18fe6060f1SDimitry Andric #include <__ranges/access.h>
19bdd1243dSDimitry Andric #include <__type_traits/decay.h>
20bdd1243dSDimitry Andric #include <__type_traits/make_signed.h>
21bdd1243dSDimitry Andric #include <__type_traits/make_unsigned.h>
22bdd1243dSDimitry Andric #include <__type_traits/remove_cvref.h>
230eae32dcSDimitry Andric #include <__utility/auto_cast.h>
24bdd1243dSDimitry Andric #include <__utility/declval.h>
2561cfbce3SDimitry Andric #include <cstddef>
26fe6060f1SDimitry Andric 
27fe6060f1SDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
28fe6060f1SDimitry Andric #  pragma GCC system_header
29fe6060f1SDimitry Andric #endif
30fe6060f1SDimitry Andric 
31fe6060f1SDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD
32fe6060f1SDimitry Andric 
3306c3fb27SDimitry Andric #if _LIBCPP_STD_VER >= 20
34fe6060f1SDimitry Andric 
35fe6060f1SDimitry Andric namespace ranges {
36fe6060f1SDimitry Andric template <class>
37fe6060f1SDimitry Andric inline constexpr bool disable_sized_range = false;
381fd87a68SDimitry Andric } // namespace ranges
39fe6060f1SDimitry Andric 
40fe6060f1SDimitry Andric // [range.prim.size]
410eae32dcSDimitry Andric 
420eae32dcSDimitry Andric namespace ranges {
43fe6060f1SDimitry Andric namespace __size {
44*0fca6ea1SDimitry Andric void size() = delete;
45fe6060f1SDimitry Andric 
46fe6060f1SDimitry Andric template <class _Tp>
47fe6060f1SDimitry Andric concept __size_enabled = !disable_sized_range<remove_cvref_t<_Tp>>;
48fe6060f1SDimitry Andric 
49fe6060f1SDimitry Andric template <class _Tp>
50*0fca6ea1SDimitry Andric concept __member_size = __size_enabled<_Tp> && requires(_Tp&& __t) {
510eae32dcSDimitry Andric   { _LIBCPP_AUTO_CAST(__t.size()) } -> __integer_like;
52fe6060f1SDimitry Andric };
53fe6060f1SDimitry Andric 
54fe6060f1SDimitry Andric template <class _Tp>
55fe6060f1SDimitry Andric concept __unqualified_size =
56cb14a3feSDimitry Andric     __size_enabled<_Tp> && !__member_size<_Tp> && __class_or_enum<remove_cvref_t<_Tp>> && requires(_Tp&& __t) {
570eae32dcSDimitry Andric       { _LIBCPP_AUTO_CAST(size(__t)) } -> __integer_like;
58fe6060f1SDimitry Andric     };
59fe6060f1SDimitry Andric 
60fe6060f1SDimitry Andric template <class _Tp>
61fe6060f1SDimitry Andric concept __difference =
62cb14a3feSDimitry Andric     !__member_size<_Tp> && !__unqualified_size<_Tp> && __class_or_enum<remove_cvref_t<_Tp>> && requires(_Tp&& __t) {
63fe6060f1SDimitry Andric       { ranges::begin(__t) } -> forward_iterator;
64bdd1243dSDimitry Andric       { ranges::end(__t) } -> sized_sentinel_for<decltype(ranges::begin(std::declval<_Tp>()))>;
65fe6060f1SDimitry Andric     };
66fe6060f1SDimitry Andric 
67fe6060f1SDimitry Andric struct __fn {
6881ad6265SDimitry Andric   // `[range.prim.size]`: the array case (for rvalues).
69fe6060f1SDimitry Andric   template <class _Tp, size_t _Sz>
70fe6060f1SDimitry Andric   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr size_t operator()(_Tp (&&)[_Sz]) const noexcept {
71fe6060f1SDimitry Andric     return _Sz;
72fe6060f1SDimitry Andric   }
73fe6060f1SDimitry Andric 
7481ad6265SDimitry Andric   // `[range.prim.size]`: the array case (for lvalues).
75fe6060f1SDimitry Andric   template <class _Tp, size_t _Sz>
76fe6060f1SDimitry Andric   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr size_t operator()(_Tp (&)[_Sz]) const noexcept {
77fe6060f1SDimitry Andric     return _Sz;
78fe6060f1SDimitry Andric   }
79fe6060f1SDimitry Andric 
8081ad6265SDimitry Andric   // `[range.prim.size]`: `auto(t.size())` is a valid expression.
81fe6060f1SDimitry Andric   template <__member_size _Tp>
82fe6060f1SDimitry Andric   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr __integer_like auto operator()(_Tp&& __t) const
830eae32dcSDimitry Andric       noexcept(noexcept(_LIBCPP_AUTO_CAST(__t.size()))) {
840eae32dcSDimitry Andric     return _LIBCPP_AUTO_CAST(__t.size());
85fe6060f1SDimitry Andric   }
86fe6060f1SDimitry Andric 
8781ad6265SDimitry Andric   // `[range.prim.size]`: `auto(size(t))` is a valid expression.
88fe6060f1SDimitry Andric   template <__unqualified_size _Tp>
89fe6060f1SDimitry Andric   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr __integer_like auto operator()(_Tp&& __t) const
900eae32dcSDimitry Andric       noexcept(noexcept(_LIBCPP_AUTO_CAST(size(__t)))) {
910eae32dcSDimitry Andric     return _LIBCPP_AUTO_CAST(size(__t));
92fe6060f1SDimitry Andric   }
93fe6060f1SDimitry Andric 
9481ad6265SDimitry Andric   // [range.prim.size]: the `to-unsigned-like` case.
95fe6060f1SDimitry Andric   template <__difference _Tp>
9681ad6265SDimitry Andric   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
9781ad6265SDimitry Andric       noexcept(noexcept(std::__to_unsigned_like(ranges::end(__t) - ranges::begin(__t))))
98cb14a3feSDimitry Andric           -> decltype(std::__to_unsigned_like(ranges::end(__t) - ranges::begin(__t))) {
99cb14a3feSDimitry Andric     return std::__to_unsigned_like(ranges::end(__t) - ranges::begin(__t));
100fe6060f1SDimitry Andric   }
101fe6060f1SDimitry Andric };
10281ad6265SDimitry Andric 
1031fd87a68SDimitry Andric } // namespace __size
104fe6060f1SDimitry Andric 
105fe6060f1SDimitry Andric inline namespace __cpo {
106fe6060f1SDimitry Andric inline constexpr auto size = __size::__fn{};
107fe6060f1SDimitry Andric } // namespace __cpo
1080eae32dcSDimitry Andric } // namespace ranges
109fe6060f1SDimitry Andric 
1100eae32dcSDimitry Andric // [range.prim.ssize]
1110eae32dcSDimitry Andric 
1120eae32dcSDimitry Andric namespace ranges {
113fe6060f1SDimitry Andric namespace __ssize {
114fe6060f1SDimitry Andric struct __fn {
115fe6060f1SDimitry Andric   template <class _Tp>
116fe6060f1SDimitry Andric     requires requires(_Tp&& __t) { ranges::size(__t); }
117fe6060f1SDimitry Andric   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr integral auto operator()(_Tp&& __t) const
11881ad6265SDimitry Andric       noexcept(noexcept(ranges::size(__t))) {
119fe6060f1SDimitry Andric     using _Signed = make_signed_t<decltype(ranges::size(__t))>;
120fe6060f1SDimitry Andric     if constexpr (sizeof(ptrdiff_t) > sizeof(_Signed))
121fe6060f1SDimitry Andric       return static_cast<ptrdiff_t>(ranges::size(__t));
122fe6060f1SDimitry Andric     else
123fe6060f1SDimitry Andric       return static_cast<_Signed>(ranges::size(__t));
124fe6060f1SDimitry Andric   }
125fe6060f1SDimitry Andric };
1261fd87a68SDimitry Andric } // namespace __ssize
127fe6060f1SDimitry Andric 
128fe6060f1SDimitry Andric inline namespace __cpo {
129349cc55cSDimitry Andric inline constexpr auto ssize = __ssize::__fn{};
130fe6060f1SDimitry Andric } // namespace __cpo
131fe6060f1SDimitry Andric } // namespace ranges
132fe6060f1SDimitry Andric 
13306c3fb27SDimitry Andric #endif // _LIBCPP_STD_VER >= 20
134fe6060f1SDimitry Andric 
135fe6060f1SDimitry Andric _LIBCPP_END_NAMESPACE_STD
136fe6060f1SDimitry Andric 
137fe6060f1SDimitry Andric #endif // _LIBCPP___RANGES_SIZE_H
138