1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 #ifndef _LIBCPP___ALGORITHM_RANGES_MIN_ELEMENT_H
10 #define _LIBCPP___ALGORITHM_RANGES_MIN_ELEMENT_H
11
12 #include <__config>
13 #include <__functional/identity.h>
14 #include <__functional/invoke.h>
15 #include <__functional/ranges_operations.h>
16 #include <__iterator/concepts.h>
17 #include <__iterator/projected.h>
18 #include <__ranges/access.h>
19 #include <__ranges/concepts.h>
20 #include <__ranges/dangling.h>
21 #include <__utility/forward.h>
22
23 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
24 # pragma GCC system_header
25 #endif
26
27 _LIBCPP_PUSH_MACROS
28 #include <__undef_macros>
29
30 #if _LIBCPP_STD_VER >= 20
31
32 _LIBCPP_BEGIN_NAMESPACE_STD
33
34 namespace ranges {
35
36 // TODO(ranges): `ranges::min_element` can now simply delegate to `std::__min_element`.
37 template <class _Ip, class _Sp, class _Proj, class _Comp>
__min_element_impl(_Ip __first,_Sp __last,_Comp & __comp,_Proj & __proj)38 _LIBCPP_HIDE_FROM_ABI constexpr _Ip __min_element_impl(_Ip __first, _Sp __last, _Comp& __comp, _Proj& __proj) {
39 if (__first == __last)
40 return __first;
41
42 _Ip __i = __first;
43 while (++__i != __last)
44 if (std::invoke(__comp, std::invoke(__proj, *__i), std::invoke(__proj, *__first)))
45 __first = __i;
46 return __first;
47 }
48
49 namespace __min_element {
50 struct __fn {
51 template <forward_iterator _Ip,
52 sentinel_for<_Ip> _Sp,
53 class _Proj = identity,
54 indirect_strict_weak_order<projected<_Ip, _Proj>> _Comp = ranges::less>
55 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Ip
operator__fn56 operator()(_Ip __first, _Sp __last, _Comp __comp = {}, _Proj __proj = {}) const {
57 return ranges::__min_element_impl(__first, __last, __comp, __proj);
58 }
59
60 template <forward_range _Rp,
61 class _Proj = identity,
62 indirect_strict_weak_order<projected<iterator_t<_Rp>, _Proj>> _Comp = ranges::less>
63 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr borrowed_iterator_t<_Rp>
operator__fn64 operator()(_Rp&& __r, _Comp __comp = {}, _Proj __proj = {}) const {
65 return ranges::__min_element_impl(ranges::begin(__r), ranges::end(__r), __comp, __proj);
66 }
67 };
68 } // namespace __min_element
69
70 inline namespace __cpo {
71 inline constexpr auto min_element = __min_element::__fn{};
72 } // namespace __cpo
73 } // namespace ranges
74
75 _LIBCPP_END_NAMESPACE_STD
76
77 #endif // _LIBCPP_STD_VER >= 20
78
79 _LIBCPP_POP_MACROS
80
81 #endif // _LIBCPP___ALGORITHM_RANGES_MIN_ELEMENT_H
82