xref: /llvm-project/libcxx/include/__algorithm/unique.h (revision ca7926bd79426fbd8b752d6513c77951db35109f)
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_UNIQUE_H
10 #define _LIBCPP___ALGORITHM_UNIQUE_H
11 
12 #include <__config>
13 #include <__algorithm/comp.h>
14 #include <__algorithm/adjacent_find.h>
15 #include <__iterator/iterator_traits.h>
16 #include <__utility/move.h>
17 
18 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
19 #pragma GCC system_header
20 #endif
21 
22 _LIBCPP_PUSH_MACROS
23 #include <__undef_macros>
24 
25 _LIBCPP_BEGIN_NAMESPACE_STD
26 
27 // unique
28 
29 template <class _ForwardIterator, class _BinaryPredicate>
30 _LIBCPP_NODISCARD_EXT _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
31 unique(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred)
32 {
33     __first = _VSTD::adjacent_find<_ForwardIterator, _BinaryPredicate&>(__first, __last, __pred);
34     if (__first != __last)
35     {
36         // ...  a  a  ?  ...
37         //      f     i
38         _ForwardIterator __i = __first;
39         for (++__i; ++__i != __last;)
40             if (!__pred(*__first, *__i))
41                 *++__first = _VSTD::move(*__i);
42         ++__first;
43     }
44     return __first;
45 }
46 
47 template <class _ForwardIterator>
48 _LIBCPP_NODISCARD_EXT inline
49 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
50 _ForwardIterator
51 unique(_ForwardIterator __first, _ForwardIterator __last)
52 {
53     typedef typename iterator_traits<_ForwardIterator>::value_type __v;
54     return _VSTD::unique(__first, __last, __equal_to<__v>());
55 }
56 
57 _LIBCPP_END_NAMESPACE_STD
58 
59 _LIBCPP_POP_MACROS
60 
61 #endif // _LIBCPP___ALGORITHM_UNIQUE_H
62