xref: /llvm-project/libcxx/include/__algorithm/adjacent_find.h (revision b905bcc5090cde734e8b7bbceae13bd5a606cc14)
1 // -*- C++ -*-
2 //===----------------------------------------------------------------------===//
3 //
4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5 // See https://llvm.org/LICENSE.txt for license information.
6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #ifndef _LIBCPP___ALGORITHM_ADJACENT_FIND_H
11 #define _LIBCPP___ALGORITHM_ADJACENT_FIND_H
12 
13 #include <__algorithm/comp.h>
14 #include <__config>
15 #include <__functional/identity.h>
16 #include <__type_traits/invoke.h>
17 #include <__utility/move.h>
18 
19 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
20 #  pragma GCC system_header
21 #endif
22 
23 _LIBCPP_PUSH_MACROS
24 #include <__undef_macros>
25 
26 _LIBCPP_BEGIN_NAMESPACE_STD
27 
28 template <class _Iter, class _Sent, class _Pred, class _Proj>
29 [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Iter
30 __adjacent_find(_Iter __first, _Sent __last, _Pred& __pred, _Proj& __proj) {
31   if (__first == __last)
32     return __first;
33 
34   _Iter __i = __first;
35   while (++__i != __last) {
36     if (std::__invoke(__pred, std::__invoke(__proj, *__first), std::__invoke(__proj, *__i)))
37       return __first;
38     __first = __i;
39   }
40   return __i;
41 }
42 
43 template <class _ForwardIterator, class _BinaryPredicate>
44 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
45 adjacent_find(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred) {
46   __identity __proj;
47   return std::__adjacent_find(std::move(__first), std::move(__last), __pred, __proj);
48 }
49 
50 template <class _ForwardIterator>
51 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
52 adjacent_find(_ForwardIterator __first, _ForwardIterator __last) {
53   return std::adjacent_find(std::move(__first), std::move(__last), __equal_to());
54 }
55 
56 _LIBCPP_END_NAMESPACE_STD
57 
58 _LIBCPP_POP_MACROS
59 
60 #endif // _LIBCPP___ALGORITHM_ADJACENT_FIND_H
61