xref: /llvm-project/libcxx/include/__algorithm/unique.h (revision 5aaefa510ef055e8f044ca89e352d4313f3aba49)
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 <__algorithm/adjacent_find.h>
13 #include <__algorithm/comp.h>
14 #include <__config>
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 #  pragma clang include_instead(<algorithm>)
21 #endif
22 
23 _LIBCPP_BEGIN_NAMESPACE_STD
24 
25 // unique
26 
27 template <class _ForwardIterator, class _BinaryPredicate>
28 _LIBCPP_NODISCARD_EXT _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
29 unique(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred)
30 {
31     __first = _VSTD::adjacent_find<_ForwardIterator, _BinaryPredicate&>(__first, __last, __pred);
32     if (__first != __last)
33     {
34         // ...  a  a  ?  ...
35         //      f     i
36         _ForwardIterator __i = __first;
37         for (++__i; ++__i != __last;)
38             if (!__pred(*__first, *__i))
39                 *++__first = _VSTD::move(*__i);
40         ++__first;
41     }
42     return __first;
43 }
44 
45 template <class _ForwardIterator>
46 _LIBCPP_NODISCARD_EXT inline
47 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
48 _ForwardIterator
49 unique(_ForwardIterator __first, _ForwardIterator __last)
50 {
51     typedef typename iterator_traits<_ForwardIterator>::value_type __v;
52     return _VSTD::unique(__first, __last, __equal_to<__v>());
53 }
54 
55 _LIBCPP_END_NAMESPACE_STD
56 
57 #endif // _LIBCPP___ALGORITHM_UNIQUE_H
58