xref: /llvm-project/libcxx/include/__algorithm/ranges_min_element.h (revision 5aaefa510ef055e8f044ca89e352d4313f3aba49)
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 #  pragma clang include_instead(<algorithm>)
26 #endif
27 
28 #if !defined(_LIBCPP_HAS_NO_CONCEPTS) && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
29 
30 _LIBCPP_BEGIN_NAMESPACE_STD
31 
32 namespace ranges {
33 namespace __min_element {
34 struct __fn {
35   template <class _Ip, class _Sp, class _Proj, class _Comp>
36   _LIBCPP_HIDE_FROM_ABI static constexpr
37   _Ip __go(_Ip __first, _Sp __last, _Comp& __comp, _Proj& __proj) {
38     if (__first == __last)
39       return __first;
40 
41     _Ip __i = __first;
42     while (++__i != __last)
43       if (std::invoke(__comp, std::invoke(__proj, *__i), std::invoke(__proj, *__first)))
44         __first = __i;
45     return __first;
46   }
47 
48   template <forward_iterator _Ip, sentinel_for<_Ip> _Sp, class _Proj = identity,
49             indirect_strict_weak_order<projected<_Ip, _Proj>> _Comp = ranges::less>
50   _LIBCPP_HIDE_FROM_ABI constexpr
51   _Ip operator()(_Ip __first, _Sp __last, _Comp __comp = {}, _Proj __proj = {}) const {
52     return __go(__first, __last, __comp, __proj);
53   }
54 
55   template <forward_range _Rp, class _Proj = identity,
56             indirect_strict_weak_order<projected<iterator_t<_Rp>, _Proj>> _Comp = ranges::less>
57   _LIBCPP_HIDE_FROM_ABI constexpr
58   borrowed_iterator_t<_Rp> operator()(_Rp&& __r, _Comp __comp = {}, _Proj __proj = {}) const {
59     return __go(ranges::begin(__r), ranges::end(__r), __comp, __proj);
60   }
61 };
62 } // namespace __min_element
63 
64 inline namespace __cpo {
65   inline constexpr auto min_element = __min_element::__fn{};
66 } // namespace __cpo
67 } // namespace ranges
68 
69 _LIBCPP_END_NAMESPACE_STD
70 
71 #endif // !defined(_LIBCPP_HAS_NO_CONCEPTS) && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
72 
73 #endif // _LIBCPP___ALGORITHM_RANGES_MIN_ELEMENT_H
74