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 #include <type_traits>
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 // unique
29 
30 template <class _ForwardIterator, class _BinaryPredicate>
31 _LIBCPP_NODISCARD_EXT _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
32 unique(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred)
33 {
34     __first = _VSTD::adjacent_find<_ForwardIterator, typename add_lvalue_reference<_BinaryPredicate>::type>
35                                  (__first, __last, __pred);
36     if (__first != __last)
37     {
38         // ...  a  a  ?  ...
39         //      f     i
40         _ForwardIterator __i = __first;
41         for (++__i; ++__i != __last;)
42             if (!__pred(*__first, *__i))
43                 *++__first = _VSTD::move(*__i);
44         ++__first;
45     }
46     return __first;
47 }
48 
49 template <class _ForwardIterator>
50 _LIBCPP_NODISCARD_EXT inline
51 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
52 _ForwardIterator
53 unique(_ForwardIterator __first, _ForwardIterator __last)
54 {
55     typedef typename iterator_traits<_ForwardIterator>::value_type __v;
56     return _VSTD::unique(__first, __last, __equal_to<__v>());
57 }
58 
59 _LIBCPP_END_NAMESPACE_STD
60 
61 _LIBCPP_POP_MACROS
62 
63 #endif // _LIBCPP___ALGORITHM_UNIQUE_H
64