xref: /freebsd/contrib/llvm-project/libcxx/include/__algorithm/copy.h (revision f126890ac5386406dadf7c4cfa9566cbb56537c5)
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_COPY_H
10 #define _LIBCPP___ALGORITHM_COPY_H
11 
12 #include <__algorithm/copy_move_common.h>
13 #include <__algorithm/for_each_segment.h>
14 #include <__algorithm/iterator_operations.h>
15 #include <__algorithm/min.h>
16 #include <__config>
17 #include <__iterator/segmented_iterator.h>
18 #include <__type_traits/common_type.h>
19 #include <__utility/move.h>
20 #include <__utility/pair.h>
21 
22 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
23 #  pragma GCC system_header
24 #endif
25 
26 _LIBCPP_PUSH_MACROS
27 #include <__undef_macros>
28 
29 _LIBCPP_BEGIN_NAMESPACE_STD
30 
31 template <class, class _InIter, class _Sent, class _OutIter>
32 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter> __copy(_InIter, _Sent, _OutIter);
33 
34 template <class _AlgPolicy>
35 struct __copy_loop {
36   template <class _InIter, class _Sent, class _OutIter>
37   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
38   operator()(_InIter __first, _Sent __last, _OutIter __result) const {
39     while (__first != __last) {
40       *__result = *__first;
41       ++__first;
42       ++__result;
43     }
44 
45     return std::make_pair(std::move(__first), std::move(__result));
46   }
47 
48   template <class _InIter, class _OutIter>
49   struct _CopySegment {
50     using _Traits = __segmented_iterator_traits<_InIter>;
51 
52     _OutIter& __result_;
53 
54     _LIBCPP_HIDE_FROM_ABI _CopySegment(_OutIter& __result) : __result_(__result) {}
55 
56     _LIBCPP_HIDE_FROM_ABI void
57     operator()(typename _Traits::__local_iterator __lfirst, typename _Traits::__local_iterator __llast) {
58       __result_ = std::__copy<_AlgPolicy>(__lfirst, __llast, std::move(__result_)).second;
59     }
60   };
61 
62   template <class _InIter, class _OutIter, __enable_if_t<__is_segmented_iterator<_InIter>::value, int> = 0>
63   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
64   operator()(_InIter __first, _InIter __last, _OutIter __result) const {
65     std::__for_each_segment(__first, __last, _CopySegment<_InIter, _OutIter>(__result));
66     return std::make_pair(__last, std::move(__result));
67   }
68 
69   template <class _InIter,
70             class _OutIter,
71             __enable_if_t<__has_random_access_iterator_category<_InIter>::value &&
72                               !__is_segmented_iterator<_InIter>::value && __is_segmented_iterator<_OutIter>::value,
73                           int> = 0>
74   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
75   operator()(_InIter __first, _InIter __last, _OutIter __result) const {
76     using _Traits = __segmented_iterator_traits<_OutIter>;
77     using _DiffT  = typename common_type<__iter_diff_t<_InIter>, __iter_diff_t<_OutIter> >::type;
78 
79     if (__first == __last)
80       return std::make_pair(std::move(__first), std::move(__result));
81 
82     auto __local_first      = _Traits::__local(__result);
83     auto __segment_iterator = _Traits::__segment(__result);
84     while (true) {
85       auto __local_last = _Traits::__end(__segment_iterator);
86       auto __size       = std::min<_DiffT>(__local_last - __local_first, __last - __first);
87       auto __iters      = std::__copy<_AlgPolicy>(__first, __first + __size, __local_first);
88       __first           = std::move(__iters.first);
89 
90       if (__first == __last)
91         return std::make_pair(std::move(__first), _Traits::__compose(__segment_iterator, std::move(__iters.second)));
92 
93       __local_first = _Traits::__begin(++__segment_iterator);
94     }
95   }
96 };
97 
98 struct __copy_trivial {
99   // At this point, the iterators have been unwrapped so any `contiguous_iterator` has been unwrapped to a pointer.
100   template <class _In, class _Out, __enable_if_t<__can_lower_copy_assignment_to_memmove<_In, _Out>::value, int> = 0>
101   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*>
102   operator()(_In* __first, _In* __last, _Out* __result) const {
103     return std::__copy_trivial_impl(__first, __last, __result);
104   }
105 };
106 
107 template <class _AlgPolicy, class _InIter, class _Sent, class _OutIter>
108 pair<_InIter, _OutIter> inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
109 __copy(_InIter __first, _Sent __last, _OutIter __result) {
110   return std::__dispatch_copy_or_move<_AlgPolicy, __copy_loop<_AlgPolicy>, __copy_trivial>(
111       std::move(__first), std::move(__last), std::move(__result));
112 }
113 
114 template <class _InputIterator, class _OutputIterator>
115 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
116 copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result) {
117   return std::__copy<_ClassicAlgPolicy>(__first, __last, __result).second;
118 }
119 
120 _LIBCPP_END_NAMESPACE_STD
121 
122 _LIBCPP_POP_MACROS
123 
124 #endif // _LIBCPP___ALGORITHM_COPY_H
125