xref: /freebsd/contrib/llvm-project/libcxx/include/__algorithm/min_element.h (revision 38c63bdc46252d4d8cd313dff4183ec4546d26d9)
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_MIN_ELEMENT_H
10 #define _LIBCPP___ALGORITHM_MIN_ELEMENT_H
11 
12 #include <__algorithm/comp.h>
13 #include <__algorithm/comp_ref_type.h>
14 #include <__config>
15 #include <__functional/identity.h>
16 #include <__functional/invoke.h>
17 #include <__iterator/iterator_traits.h>
18 #include <__type_traits/is_callable.h>
19 #include <__utility/move.h>
20 
21 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
22 #  pragma GCC system_header
23 #endif
24 
25 _LIBCPP_PUSH_MACROS
26 #include <__undef_macros>
27 
28 _LIBCPP_BEGIN_NAMESPACE_STD
29 
30 template <class _Comp, class _Iter, class _Sent, class _Proj>
31 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
32 _Iter __min_element(_Iter __first, _Sent __last, _Comp __comp, _Proj& __proj) {
33   if (__first == __last)
34     return __first;
35 
36   _Iter __i = __first;
37   while (++__i != __last)
38     if (std::__invoke(__comp, std::__invoke(__proj, *__i), std::__invoke(__proj, *__first)))
39       __first = __i;
40 
41   return __first;
42 }
43 
44 template <class _Comp, class _Iter, class _Sent>
45 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
46 _Iter __min_element(_Iter __first, _Sent __last, _Comp __comp) {
47   auto __proj = __identity();
48   return std::__min_element<_Comp>(std::move(__first), std::move(__last), __comp, __proj);
49 }
50 
51 template <class _ForwardIterator, class _Compare>
52 _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _ForwardIterator
53 min_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
54 {
55   static_assert(__has_forward_iterator_category<_ForwardIterator>::value,
56       "std::min_element requires a ForwardIterator");
57   static_assert(__is_callable<_Compare, decltype(*__first), decltype(*__first)>::value,
58               "The comparator has to be callable");
59 
60   return std::__min_element<__comp_ref_type<_Compare> >(std::move(__first), std::move(__last), __comp);
61 }
62 
63 template <class _ForwardIterator>
64 _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _ForwardIterator
65 min_element(_ForwardIterator __first, _ForwardIterator __last)
66 {
67     return _VSTD::min_element(__first, __last, __less<>());
68 }
69 
70 _LIBCPP_END_NAMESPACE_STD
71 
72 _LIBCPP_POP_MACROS
73 
74 #endif // _LIBCPP___ALGORITHM_MIN_ELEMENT_H
75