xref: /freebsd/contrib/llvm-project/libcxx/include/__algorithm/max_element.h (revision af23369a6deaaeb612ab266eb88b8bb8d560c322)
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_MAX_ELEMENT_H
10 #define _LIBCPP___ALGORITHM_MAX_ELEMENT_H
11 
12 #include <__algorithm/comp.h>
13 #include <__algorithm/comp_ref_type.h>
14 #include <__config>
15 #include <__iterator/iterator_traits.h>
16 
17 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
18 #  pragma GCC system_header
19 #endif
20 
21 _LIBCPP_BEGIN_NAMESPACE_STD
22 
23 template <class _Compare, class _ForwardIterator>
24 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11 _ForwardIterator
25 __max_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
26 {
27     static_assert(__is_cpp17_forward_iterator<_ForwardIterator>::value,
28         "std::max_element requires a ForwardIterator");
29     if (__first != __last)
30     {
31         _ForwardIterator __i = __first;
32         while (++__i != __last)
33             if (__comp(*__first, *__i))
34                 __first = __i;
35     }
36     return __first;
37 }
38 
39 template <class _ForwardIterator, class _Compare>
40 _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11 _ForwardIterator
41 max_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
42 {
43     typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
44     return _VSTD::__max_element<_Comp_ref>(__first, __last, __comp);
45 }
46 
47 
48 template <class _ForwardIterator>
49 _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11 _ForwardIterator
50 max_element(_ForwardIterator __first, _ForwardIterator __last)
51 {
52     return _VSTD::max_element(__first, __last,
53               __less<typename iterator_traits<_ForwardIterator>::value_type>());
54 }
55 
56 _LIBCPP_END_NAMESPACE_STD
57 
58 #endif // _LIBCPP___ALGORITHM_MAX_ELEMENT_H
59