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_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 <__type_traits/is_copy_constructible.h>
20#include <__utility/move.h>
21#include <__utility/pair.h>
22
23#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
24#  pragma GCC system_header
25#endif
26
27_LIBCPP_PUSH_MACROS
28#include <__undef_macros>
29
30_LIBCPP_BEGIN_NAMESPACE_STD
31
32template <class _AlgPolicy, class _InIter, class _Sent, class _OutIter>
33inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
34__move(_InIter __first, _Sent __last, _OutIter __result);
35
36template <class _AlgPolicy>
37struct __move_loop {
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 = _IterOps<_AlgPolicy>::__iter_move(__first);
43      ++__first;
44      ++__result;
45    }
46    return std::make_pair(std::move(__first), std::move(__result));
47  }
48
49  template <class _InIter, class _OutIter>
50  struct _MoveSegment {
51    using _Traits = __segmented_iterator_traits<_InIter>;
52
53    _OutIter& __result_;
54
55    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit _MoveSegment(_OutIter& __result)
56        : __result_(__result) {}
57
58    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
59    operator()(typename _Traits::__local_iterator __lfirst, typename _Traits::__local_iterator __llast) {
60      __result_ = std::__move<_AlgPolicy>(__lfirst, __llast, std::move(__result_)).second;
61    }
62  };
63
64  template <class _InIter, class _OutIter, __enable_if_t<__is_segmented_iterator<_InIter>::value, int> = 0>
65  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
66  operator()(_InIter __first, _InIter __last, _OutIter __result) const {
67    std::__for_each_segment(__first, __last, _MoveSegment<_InIter, _OutIter>(__result));
68    return std::make_pair(__last, std::move(__result));
69  }
70
71  template <class _InIter,
72            class _OutIter,
73            __enable_if_t<__has_random_access_iterator_category<_InIter>::value &&
74                              !__is_segmented_iterator<_InIter>::value && __is_segmented_iterator<_OutIter>::value,
75                          int> = 0>
76  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
77  operator()(_InIter __first, _InIter __last, _OutIter __result) const {
78    using _Traits = __segmented_iterator_traits<_OutIter>;
79    using _DiffT  = typename common_type<__iter_diff_t<_InIter>, __iter_diff_t<_OutIter> >::type;
80
81    if (__first == __last)
82      return std::make_pair(std::move(__first), std::move(__result));
83
84    auto __local_first      = _Traits::__local(__result);
85    auto __segment_iterator = _Traits::__segment(__result);
86    while (true) {
87      auto __local_last = _Traits::__end(__segment_iterator);
88      auto __size       = std::min<_DiffT>(__local_last - __local_first, __last - __first);
89      auto __iters      = std::__move<_AlgPolicy>(__first, __first + __size, __local_first);
90      __first           = std::move(__iters.first);
91
92      if (__first == __last)
93        return std::make_pair(std::move(__first), _Traits::__compose(__segment_iterator, std::move(__iters.second)));
94
95      __local_first = _Traits::__begin(++__segment_iterator);
96    }
97  }
98};
99
100struct __move_trivial {
101  // At this point, the iterators have been unwrapped so any `contiguous_iterator` has been unwrapped to a pointer.
102  template <class _In, class _Out, __enable_if_t<__can_lower_move_assignment_to_memmove<_In, _Out>::value, int> = 0>
103  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*>
104  operator()(_In* __first, _In* __last, _Out* __result) const {
105    return std::__copy_trivial_impl(__first, __last, __result);
106  }
107};
108
109template <class _AlgPolicy, class _InIter, class _Sent, class _OutIter>
110inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
111__move(_InIter __first, _Sent __last, _OutIter __result) {
112  return std::__dispatch_copy_or_move<_AlgPolicy, __move_loop<_AlgPolicy>, __move_trivial>(
113      std::move(__first), std::move(__last), std::move(__result));
114}
115
116template <class _InputIterator, class _OutputIterator>
117inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
118move(_InputIterator __first, _InputIterator __last, _OutputIterator __result) {
119  static_assert(is_copy_constructible<_InputIterator>::value, "Iterators has to be copy constructible.");
120  static_assert(is_copy_constructible<_OutputIterator>::value, "The output iterator has to be copy constructible.");
121
122  return std::__move<_ClassicAlgPolicy>(std::move(__first), std::move(__last), std::move(__result)).second;
123}
124
125_LIBCPP_END_NAMESPACE_STD
126
127_LIBCPP_POP_MACROS
128
129#endif // _LIBCPP___ALGORITHM_MOVE_H
130