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/iterator_operations.h>
13 #include <__algorithm/unwrap_iter.h>
14 #include <__config>
15 #include <__iterator/iterator_traits.h>
16 #include <__iterator/reverse_iterator.h>
17 #include <__utility/move.h>
18 #include <__utility/pair.h>
19 #include <cstring>
20 #include <type_traits>
21 
22 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
23 #  pragma GCC system_header
24 #endif
25 
26 _LIBCPP_BEGIN_NAMESPACE_STD
27 
28 // move
29 
30 template <class _AlgPolicy, class _InIter, class _Sent, class _OutIter>
31 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
32 pair<_InIter, _OutIter> __move_impl(_InIter __first, _Sent __last, _OutIter __result) {
33   while (__first != __last) {
34     *__result = _IterOps<_AlgPolicy>::__iter_move(__first);
35     ++__first;
36     ++__result;
37   }
38   return std::make_pair(std::move(__first), std::move(__result));
39 }
40 
41 template <class _AlgPolicy,
42           class _InType,
43           class _OutType,
44           class = __enable_if_t<is_same<typename remove_const<_InType>::type, _OutType>::value
45                              && is_trivially_move_assignable<_OutType>::value> >
46 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11
47 pair<_InType*, _OutType*> __move_impl(_InType* __first, _InType* __last, _OutType* __result) {
48   if (__libcpp_is_constant_evaluated()
49 // TODO: Remove this once GCC supports __builtin_memmove during constant evaluation
50 #ifndef _LIBCPP_COMPILER_GCC
51    && !is_trivially_copyable<_InType>::value
52 #endif
53      )
54     return std::__move_impl<_AlgPolicy, _InType*, _InType*, _OutType*>(__first, __last, __result);
55   const size_t __n = static_cast<size_t>(__last - __first);
56   ::__builtin_memmove(__result, __first, __n * sizeof(_OutType));
57   return std::make_pair(__first + __n, __result + __n);
58 }
59 
60 template <class>
61 struct __is_trivially_move_assignable_unwrapped_impl : false_type {};
62 
63 template <class _Type>
64 struct __is_trivially_move_assignable_unwrapped_impl<_Type*> : is_trivially_move_assignable<_Type> {};
65 
66 template <class _Iter>
67 struct __is_trivially_move_assignable_unwrapped
68     : __is_trivially_move_assignable_unwrapped_impl<decltype(std::__unwrap_iter<_Iter>(std::declval<_Iter>()))> {};
69 
70 template <class _AlgPolicy,
71           class _InIter,
72           class _OutIter,
73           __enable_if_t<is_same<typename remove_const<typename iterator_traits<_InIter>::value_type>::type,
74                                 typename iterator_traits<_OutIter>::value_type>::value
75                      && __is_cpp17_contiguous_iterator<_InIter>::value
76                      && __is_cpp17_contiguous_iterator<_OutIter>::value
77                      && is_trivially_move_assignable<__iter_value_type<_OutIter> >::value, int> = 0>
78 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
79 pair<reverse_iterator<_InIter>, reverse_iterator<_OutIter> >
80 __move_impl(reverse_iterator<_InIter> __first,
81             reverse_iterator<_InIter> __last,
82             reverse_iterator<_OutIter> __result) {
83   auto __first_base = std::__unwrap_iter(__first.base());
84   auto __last_base = std::__unwrap_iter(__last.base());
85   auto __result_base = std::__unwrap_iter(__result.base());
86   auto __result_first = __result_base - (__first_base - __last_base);
87   std::__move_impl<_AlgPolicy>(__last_base, __first_base, __result_first);
88   return std::make_pair(__last, reverse_iterator<_OutIter>(std::__rewrap_iter(__result.base(), __result_first)));
89 }
90 
91 template <class _AlgPolicy, class _InIter, class _Sent, class _OutIter>
92 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11
93 __enable_if_t<is_copy_constructible<_InIter>::value
94            && is_copy_constructible<_Sent>::value
95            && is_copy_constructible<_OutIter>::value, pair<_InIter, _OutIter> >
96 __move(_InIter __first, _Sent __last, _OutIter __result) {
97   auto __ret = std::__move_impl<_AlgPolicy>(
98       std::__unwrap_iter(__first), std::__unwrap_iter(__last), std::__unwrap_iter(__result));
99   return std::make_pair(std::__rewrap_iter(__first, __ret.first), std::__rewrap_iter(__result, __ret.second));
100 }
101 
102 template <class _AlgPolicy, class _InIter, class _Sent, class _OutIter>
103 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11
104 __enable_if_t<!is_copy_constructible<_InIter>::value
105            || !is_copy_constructible<_Sent>::value
106            || !is_copy_constructible<_OutIter>::value, pair<_InIter, _OutIter> >
107 __move(_InIter __first, _Sent __last, _OutIter __result) {
108   return std::__move_impl<_AlgPolicy>(std::move(__first), std::move(__last), std::move(__result));
109 }
110 
111 template <class _InputIterator, class _OutputIterator>
112 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
113 _OutputIterator move(_InputIterator __first, _InputIterator __last, _OutputIterator __result) {
114   return std::__move<_ClassicAlgPolicy>(__first, __last, __result).second;
115 }
116 
117 _LIBCPP_END_NAMESPACE_STD
118 
119 #endif // _LIBCPP___ALGORITHM_MOVE_H
120