xref: /freebsd/contrib/llvm-project/libcxx/include/__algorithm/copy.h (revision ecd8cc84dcee7d08be8663f721f0502dc5b65808)
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 _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit _CopySegment(_OutIter& __result)
55          : __result_(__result) {}
56  
57      _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
58      operator()(typename _Traits::__local_iterator __lfirst, typename _Traits::__local_iterator __llast) {
59        __result_ = std::__copy<_AlgPolicy>(__lfirst, __llast, std::move(__result_)).second;
60      }
61    };
62  
63    template <class _InIter, class _OutIter, __enable_if_t<__is_segmented_iterator<_InIter>::value, int> = 0>
64    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
65    operator()(_InIter __first, _InIter __last, _OutIter __result) const {
66      std::__for_each_segment(__first, __last, _CopySegment<_InIter, _OutIter>(__result));
67      return std::make_pair(__last, std::move(__result));
68    }
69  
70    template <class _InIter,
71              class _OutIter,
72              __enable_if_t<__has_random_access_iterator_category<_InIter>::value &&
73                                !__is_segmented_iterator<_InIter>::value && __is_segmented_iterator<_OutIter>::value,
74                            int> = 0>
75    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
76    operator()(_InIter __first, _InIter __last, _OutIter __result) const {
77      using _Traits = __segmented_iterator_traits<_OutIter>;
78      using _DiffT  = typename common_type<__iter_diff_t<_InIter>, __iter_diff_t<_OutIter> >::type;
79  
80      if (__first == __last)
81        return std::make_pair(std::move(__first), std::move(__result));
82  
83      auto __local_first      = _Traits::__local(__result);
84      auto __segment_iterator = _Traits::__segment(__result);
85      while (true) {
86        auto __local_last = _Traits::__end(__segment_iterator);
87        auto __size       = std::min<_DiffT>(__local_last - __local_first, __last - __first);
88        auto __iters      = std::__copy<_AlgPolicy>(__first, __first + __size, __local_first);
89        __first           = std::move(__iters.first);
90  
91        if (__first == __last)
92          return std::make_pair(std::move(__first), _Traits::__compose(__segment_iterator, std::move(__iters.second)));
93  
94        __local_first = _Traits::__begin(++__segment_iterator);
95      }
96    }
97  };
98  
99  struct __copy_trivial {
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::__dispatch_copy_or_move<_AlgPolicy, __copy_loop<_AlgPolicy>, __copy_trivial>(
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