xref: /freebsd/contrib/llvm-project/libcxx/include/__algorithm/move.h (revision e64bea71c21eb42e97aa615188ba91f6cce0d36d)
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_MOVE_H
10 #define _LIBCPP___ALGORITHM_MOVE_H
11 
12 #include <__algorithm/copy.h>
13 #include <__algorithm/copy_move_common.h>
14 #include <__algorithm/for_each_segment.h>
15 #include <__algorithm/iterator_operations.h>
16 #include <__algorithm/min.h>
17 #include <__config>
18 #include <__fwd/bit_reference.h>
19 #include <__iterator/iterator_traits.h>
20 #include <__iterator/segmented_iterator.h>
21 #include <__type_traits/common_type.h>
22 #include <__type_traits/enable_if.h>
23 #include <__type_traits/is_constructible.h>
24 #include <__utility/move.h>
25 #include <__utility/pair.h>
26 
27 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
28 #  pragma GCC system_header
29 #endif
30 
31 _LIBCPP_PUSH_MACROS
32 #include <__undef_macros>
33 
34 _LIBCPP_BEGIN_NAMESPACE_STD
35 
36 template <class _AlgPolicy, class _InIter, class _Sent, class _OutIter>
37 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
38 __move(_InIter __first, _Sent __last, _OutIter __result);
39 
40 template <class _AlgPolicy>
41 struct __move_impl {
42   template <class _InIter, class _Sent, class _OutIter>
43   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
44   operator()(_InIter __first, _Sent __last, _OutIter __result) const {
45     while (__first != __last) {
46       *__result = _IterOps<_AlgPolicy>::__iter_move(__first);
47       ++__first;
48       ++__result;
49     }
50     return std::make_pair(std::move(__first), std::move(__result));
51   }
52 
53   template <class _InIter, class _OutIter>
54   struct _MoveSegment {
55     using _Traits _LIBCPP_NODEBUG = __segmented_iterator_traits<_InIter>;
56 
57     _OutIter& __result_;
58 
59     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit _MoveSegment(_OutIter& __result)
60         : __result_(__result) {}
61 
62     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
63     operator()(typename _Traits::__local_iterator __lfirst, typename _Traits::__local_iterator __llast) {
64       __result_ = std::__move<_AlgPolicy>(__lfirst, __llast, std::move(__result_)).second;
65     }
66   };
67 
68   template <class _InIter, class _OutIter, __enable_if_t<__is_segmented_iterator<_InIter>::value, int> = 0>
69   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
70   operator()(_InIter __first, _InIter __last, _OutIter __result) const {
71     std::__for_each_segment(__first, __last, _MoveSegment<_InIter, _OutIter>(__result));
72     return std::make_pair(__last, std::move(__result));
73   }
74 
75   template <class _InIter,
76             class _OutIter,
77             __enable_if_t<__has_random_access_iterator_category<_InIter>::value &&
78                               !__is_segmented_iterator<_InIter>::value && __is_segmented_iterator<_OutIter>::value,
79                           int> = 0>
80   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
81   operator()(_InIter __first, _InIter __last, _OutIter __result) const {
82     using _Traits = __segmented_iterator_traits<_OutIter>;
83     using _DiffT  = typename common_type<__iter_diff_t<_InIter>, __iter_diff_t<_OutIter> >::type;
84 
85     if (__first == __last)
86       return std::make_pair(std::move(__first), std::move(__result));
87 
88     auto __local_first      = _Traits::__local(__result);
89     auto __segment_iterator = _Traits::__segment(__result);
90     while (true) {
91       auto __local_last = _Traits::__end(__segment_iterator);
92       auto __size       = std::min<_DiffT>(__local_last - __local_first, __last - __first);
93       auto __iters      = std::__move<_AlgPolicy>(__first, __first + __size, __local_first);
94       __first           = std::move(__iters.first);
95 
96       if (__first == __last)
97         return std::make_pair(std::move(__first), _Traits::__compose(__segment_iterator, std::move(__iters.second)));
98 
99       __local_first = _Traits::__begin(++__segment_iterator);
100     }
101   }
102 
103   template <class _Cp, bool _IsConst>
104   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<__bit_iterator<_Cp, _IsConst>, __bit_iterator<_Cp, false> >
105   operator()(__bit_iterator<_Cp, _IsConst> __first,
106              __bit_iterator<_Cp, _IsConst> __last,
107              __bit_iterator<_Cp, false> __result) {
108     return std::__copy(__first, __last, __result);
109   }
110 
111   // At this point, the iterators have been unwrapped so any `contiguous_iterator` has been unwrapped to a pointer.
112   template <class _In, class _Out, __enable_if_t<__can_lower_move_assignment_to_memmove<_In, _Out>::value, int> = 0>
113   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*>
114   operator()(_In* __first, _In* __last, _Out* __result) const {
115     return std::__copy_trivial_impl(__first, __last, __result);
116   }
117 };
118 
119 template <class _AlgPolicy, class _InIter, class _Sent, class _OutIter>
120 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
121 __move(_InIter __first, _Sent __last, _OutIter __result) {
122   return std::__copy_move_unwrap_iters<__move_impl<_AlgPolicy> >(
123       std::move(__first), std::move(__last), std::move(__result));
124 }
125 
126 template <class _InputIterator, class _OutputIterator>
127 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
128 move(_InputIterator __first, _InputIterator __last, _OutputIterator __result) {
129   static_assert(is_copy_constructible<_InputIterator>::value, "Iterators has to be copy constructible.");
130   static_assert(is_copy_constructible<_OutputIterator>::value, "The output iterator has to be copy constructible.");
131 
132   return std::__move<_ClassicAlgPolicy>(std::move(__first), std::move(__last), std::move(__result)).second;
133 }
134 
135 _LIBCPP_END_NAMESPACE_STD
136 
137 _LIBCPP_POP_MACROS
138 
139 #endif // _LIBCPP___ALGORITHM_MOVE_H
140