1 //===----------------------------------------------------------------------===//
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
7 //===----------------------------------------------------------------------===//
9 #ifndef _LIBCPP___CXX03___ALGORITHM_MINMAX_ELEMENT_H
10 #define _LIBCPP___CXX03___ALGORITHM_MINMAX_ELEMENT_H
12 #include <__cxx03/__algorithm/comp.h>
13 #include <__cxx03/__config>
14 #include <__cxx03/__functional/identity.h>
15 #include <__cxx03/__functional/invoke.h>
16 #include <__cxx03/__iterator/iterator_traits.h>
17 #include <__cxx03/__type_traits/is_callable.h>
18 #include <__cxx03/__utility/pair.h>
20 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
21 # pragma GCC system_header
24 _LIBCPP_BEGIN_NAMESPACE_STD
26 template <class _Comp
, class _Proj
>
27 class _MinmaxElementLessFunc
{
32 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR
_MinmaxElementLessFunc(_Comp
& __comp
, _Proj
& __proj
)
33 : __comp_(__comp
), __proj_(__proj
) {}
35 template <class _Iter
>
36 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
bool operator()(_Iter
& __it1
, _Iter
& __it2
) {
37 return std::__invoke(__comp_
, std::__invoke(__proj_
, *__it1
), std::__invoke(__proj_
, *__it2
));
41 template <class _Iter
, class _Sent
, class _Proj
, class _Comp
>
42 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair
<_Iter
, _Iter
>
43 __minmax_element_impl(_Iter __first
, _Sent __last
, _Comp
& __comp
, _Proj
& __proj
) {
44 auto __less
= _MinmaxElementLessFunc
<_Comp
, _Proj
>(__comp
, __proj
);
46 pair
<_Iter
, _Iter
> __result(__first
, __first
);
47 if (__first
== __last
|| ++__first
== __last
)
50 if (__less(__first
, __result
.first
))
51 __result
.first
= __first
;
53 __result
.second
= __first
;
55 while (++__first
!= __last
) {
57 if (++__first
== __last
) {
58 if (__less(__i
, __result
.first
))
60 else if (!__less(__i
, __result
.second
))
61 __result
.second
= __i
;
65 if (__less(__first
, __i
)) {
66 if (__less(__first
, __result
.first
))
67 __result
.first
= __first
;
68 if (!__less(__i
, __result
.second
))
69 __result
.second
= __i
;
71 if (__less(__i
, __result
.first
))
73 if (!__less(__first
, __result
.second
))
74 __result
.second
= __first
;
81 template <class _ForwardIterator
, class _Compare
>
82 _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair
<_ForwardIterator
, _ForwardIterator
>
83 minmax_element(_ForwardIterator __first
, _ForwardIterator __last
, _Compare __comp
) {
85 __has_forward_iterator_category
<_ForwardIterator
>::value
, "std::minmax_element requires a ForwardIterator");
87 __is_callable
<_Compare
, decltype(*__first
), decltype(*__first
)>::value
, "The comparator has to be callable");
88 auto __proj
= __identity();
89 return std::__minmax_element_impl(__first
, __last
, __comp
, __proj
);
92 template <class _ForwardIterator
>
93 _LIBCPP_NODISCARD
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair
<_ForwardIterator
, _ForwardIterator
>
94 minmax_element(_ForwardIterator __first
, _ForwardIterator __last
) {
95 return std::minmax_element(__first
, __last
, __less
<>());
98 _LIBCPP_END_NAMESPACE_STD
100 #endif // _LIBCPP___CXX03___ALGORITHM_MINMAX_ELEMENT_H