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/adjacent_find.h>
14 #include <__iterator/iterator_traits.h>
15 #include <type_traits>
16 
17 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
18 #pragma GCC system_header
19 #endif
20 
21 _LIBCPP_PUSH_MACROS
22 #include <__undef_macros>
23 
24 _LIBCPP_BEGIN_NAMESPACE_STD
25 
26 // unique
27 
28 template <class _ForwardIterator, class _BinaryPredicate>
29 _LIBCPP_NODISCARD_EXT _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
30 unique(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred)
31 {
32     __first = _VSTD::adjacent_find<_ForwardIterator, typename add_lvalue_reference<_BinaryPredicate>::type>
33                                  (__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 // unique_copy
58 
59 template <class _BinaryPredicate, class _InputIterator, class _OutputIterator>
60 _LIBCPP_CONSTEXPR_AFTER_CXX17 _OutputIterator
61 __unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryPredicate __pred,
62               input_iterator_tag, output_iterator_tag)
63 {
64     if (__first != __last)
65     {
66         typename iterator_traits<_InputIterator>::value_type __t(*__first);
67         *__result = __t;
68         ++__result;
69         while (++__first != __last)
70         {
71             if (!__pred(__t, *__first))
72             {
73                 __t = *__first;
74                 *__result = __t;
75                 ++__result;
76             }
77         }
78     }
79     return __result;
80 }
81 
82 template <class _BinaryPredicate, class _ForwardIterator, class _OutputIterator>
83 _LIBCPP_CONSTEXPR_AFTER_CXX17 _OutputIterator
84 __unique_copy(_ForwardIterator __first, _ForwardIterator __last, _OutputIterator __result, _BinaryPredicate __pred,
85               forward_iterator_tag, output_iterator_tag)
86 {
87     if (__first != __last)
88     {
89         _ForwardIterator __i = __first;
90         *__result = *__i;
91         ++__result;
92         while (++__first != __last)
93         {
94             if (!__pred(*__i, *__first))
95             {
96                 *__result = *__first;
97                 ++__result;
98                 __i = __first;
99             }
100         }
101     }
102     return __result;
103 }
104 
105 template <class _BinaryPredicate, class _InputIterator, class _ForwardIterator>
106 _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
107 __unique_copy(_InputIterator __first, _InputIterator __last, _ForwardIterator __result, _BinaryPredicate __pred,
108               input_iterator_tag, forward_iterator_tag)
109 {
110     if (__first != __last)
111     {
112         *__result = *__first;
113         while (++__first != __last)
114             if (!__pred(*__result, *__first))
115                 *++__result = *__first;
116         ++__result;
117     }
118     return __result;
119 }
120 
121 template <class _InputIterator, class _OutputIterator, class _BinaryPredicate>
122 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
123 _OutputIterator
124 unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryPredicate __pred)
125 {
126     return _VSTD::__unique_copy<typename add_lvalue_reference<_BinaryPredicate>::type>
127                               (__first, __last, __result, __pred,
128                                typename iterator_traits<_InputIterator>::iterator_category(),
129                                typename iterator_traits<_OutputIterator>::iterator_category());
130 }
131 
132 template <class _InputIterator, class _OutputIterator>
133 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
134 _OutputIterator
135 unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
136 {
137     typedef typename iterator_traits<_InputIterator>::value_type __v;
138     return _VSTD::unique_copy(__first, __last, __result, __equal_to<__v>());
139 }
140 
141 _LIBCPP_END_NAMESPACE_STD
142 
143 _LIBCPP_POP_MACROS
144 
145 #endif // _LIBCPP___ALGORITHM_UNIQUE_H
146