xref: /llvm-project/libcxx/include/__algorithm/copy.h (revision 09e3a360581dc36d0820d3fb6da9bd7cfed87b5d)
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/iterator_traits.h>
18 #include <__iterator/segmented_iterator.h>
19 #include <__type_traits/common_type.h>
20 #include <__type_traits/enable_if.h>
21 #include <__utility/move.h>
22 #include <__utility/pair.h>
23 
24 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
25 #  pragma GCC system_header
26 #endif
27 
28 _LIBCPP_PUSH_MACROS
29 #include <__undef_macros>
30 
31 _LIBCPP_BEGIN_NAMESPACE_STD
32 
33 template <class, class _InIter, class _Sent, class _OutIter>
34 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter> __copy(_InIter, _Sent, _OutIter);
35 
36 template <class _AlgPolicy>
37 struct __copy_impl {
38   template <class _InIter, class _Sent, class _OutIter>
39   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
40   operator()(_InIter __first, _Sent __last, _OutIter __result) const {
41     while (__first != __last) {
42       *__result = *__first;
43       ++__first;
44       ++__result;
45     }
46 
47     return std::make_pair(std::move(__first), std::move(__result));
48   }
49 
50   template <class _InIter, class _OutIter>
51   struct _CopySegment {
52     using _Traits = __segmented_iterator_traits<_InIter>;
53 
54     _OutIter& __result_;
55 
56     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit _CopySegment(_OutIter& __result)
57         : __result_(__result) {}
58 
59     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
60     operator()(typename _Traits::__local_iterator __lfirst, typename _Traits::__local_iterator __llast) {
61       __result_ = std::__copy<_AlgPolicy>(__lfirst, __llast, std::move(__result_)).second;
62     }
63   };
64 
65   template <class _InIter, class _OutIter, __enable_if_t<__is_segmented_iterator<_InIter>::value, int> = 0>
66   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
67   operator()(_InIter __first, _InIter __last, _OutIter __result) const {
68     std::__for_each_segment(__first, __last, _CopySegment<_InIter, _OutIter>(__result));
69     return std::make_pair(__last, std::move(__result));
70   }
71 
72   template <class _InIter,
73             class _OutIter,
74             __enable_if_t<__has_random_access_iterator_category<_InIter>::value &&
75                               !__is_segmented_iterator<_InIter>::value && __is_segmented_iterator<_OutIter>::value,
76                           int> = 0>
77   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
78   operator()(_InIter __first, _InIter __last, _OutIter __result) const {
79     using _Traits = __segmented_iterator_traits<_OutIter>;
80     using _DiffT  = typename common_type<__iter_diff_t<_InIter>, __iter_diff_t<_OutIter> >::type;
81 
82     if (__first == __last)
83       return std::make_pair(std::move(__first), std::move(__result));
84 
85     auto __local_first      = _Traits::__local(__result);
86     auto __segment_iterator = _Traits::__segment(__result);
87     while (true) {
88       auto __local_last = _Traits::__end(__segment_iterator);
89       auto __size       = std::min<_DiffT>(__local_last - __local_first, __last - __first);
90       auto __iters      = std::__copy<_AlgPolicy>(__first, __first + __size, __local_first);
91       __first           = std::move(__iters.first);
92 
93       if (__first == __last)
94         return std::make_pair(std::move(__first), _Traits::__compose(__segment_iterator, std::move(__iters.second)));
95 
96       __local_first = _Traits::__begin(++__segment_iterator);
97     }
98   }
99 
100   // At this point, the iterators have been unwrapped so any `contiguous_iterator` has been unwrapped to a pointer.
101   template <class _In, class _Out, __enable_if_t<__can_lower_copy_assignment_to_memmove<_In, _Out>::value, int> = 0>
102   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*>
103   operator()(_In* __first, _In* __last, _Out* __result) const {
104     return std::__copy_trivial_impl(__first, __last, __result);
105   }
106 };
107 
108 template <class _AlgPolicy, class _InIter, class _Sent, class _OutIter>
109 pair<_InIter, _OutIter> inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
110 __copy(_InIter __first, _Sent __last, _OutIter __result) {
111   return std::__copy_move_unwrap_iters<__copy_impl<_AlgPolicy> >(
112       std::move(__first), std::move(__last), std::move(__result));
113 }
114 
115 template <class _InputIterator, class _OutputIterator>
116 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
117 copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result) {
118   return std::__copy<_ClassicAlgPolicy>(__first, __last, __result).second;
119 }
120 
121 _LIBCPP_END_NAMESPACE_STD
122 
123 _LIBCPP_POP_MACROS
124 
125 #endif // _LIBCPP___ALGORITHM_COPY_H
126