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/unwrap_iter.h>
13 #include <__algorithm/unwrap_range.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 // copy
29 
30 template <class _InIter, class _Sent, class _OutIter>
31 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11
32 pair<_InIter, _OutIter> __copy_impl(_InIter __first, _Sent __last, _OutIter __result) {
33   while (__first != __last) {
34     *__result = *__first;
35     ++__first;
36     ++__result;
37   }
38   return pair<_InIter, _OutIter>(std::move(__first), std::move(__result));
39 }
40 
41 template <class _InValueT,
42           class _OutValueT,
43           class = __enable_if_t<is_same<typename remove_const<_InValueT>::type, _OutValueT>::value
44                              && is_trivially_copy_assignable<_OutValueT>::value> >
45 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11
46 pair<_InValueT*, _OutValueT*> __copy_impl(_InValueT* __first, _InValueT* __last, _OutValueT* __result) {
47   if (__libcpp_is_constant_evaluated()
48 // TODO: Remove this once GCC supports __builtin_memmove during constant evaluation
49 #ifndef _LIBCPP_COMPILER_GCC
50       && !is_trivially_copyable<_InValueT>::value
51 #endif
52      )
53     return std::__copy_impl<_InValueT*, _InValueT*, _OutValueT*>(__first, __last, __result);
54   const size_t __n = static_cast<size_t>(__last - __first);
55   if (__n > 0)
56     ::__builtin_memmove(__result, __first, __n * sizeof(_OutValueT));
57   return std::make_pair(__first + __n, __result + __n);
58 }
59 
60 template <class _InIter, class _OutIter,
61           __enable_if_t<is_same<typename remove_const<__iter_value_type<_InIter> >::type, __iter_value_type<_OutIter> >::value
62                       && __is_cpp17_contiguous_iterator<typename _InIter::iterator_type>::value
63                       && __is_cpp17_contiguous_iterator<typename _OutIter::iterator_type>::value
64                       && is_trivially_copy_assignable<__iter_value_type<_OutIter> >::value
65                       && __is_reverse_iterator<_InIter>::value
66                       && __is_reverse_iterator<_OutIter>::value, int> = 0>
67 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11
68 pair<_InIter, _OutIter>
69 __copy_impl(_InIter __first, _InIter __last, _OutIter __result) {
70   auto __first_base = std::__unwrap_iter(__first.base());
71   auto __last_base = std::__unwrap_iter(__last.base());
72   auto __result_base = std::__unwrap_iter(__result.base());
73   auto __result_first = __result_base - (__first_base - __last_base);
74   std::__copy_impl(__last_base, __first_base, __result_first);
75   return std::make_pair(__last, _OutIter(std::__rewrap_iter(__result.base(), __result_first)));
76 }
77 
78 template <class _InIter, class _Sent, class _OutIter,
79           __enable_if_t<!(is_copy_constructible<_InIter>::value
80                        && is_copy_constructible<_Sent>::value
81                        && is_copy_constructible<_OutIter>::value), int> = 0 >
82 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11
83 pair<_InIter, _OutIter> __copy(_InIter __first, _Sent __last, _OutIter __result) {
84   return std::__copy_impl(std::move(__first), std::move(__last), std::move(__result));
85 }
86 
87 template <class _InIter, class _Sent, class _OutIter,
88           __enable_if_t<is_copy_constructible<_InIter>::value
89                      && is_copy_constructible<_Sent>::value
90                      && is_copy_constructible<_OutIter>::value, int> = 0>
91 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11
92 pair<_InIter, _OutIter> __copy(_InIter __first, _Sent __last, _OutIter __result) {
93   auto __range = std::__unwrap_range(__first, __last);
94   auto __ret   = std::__copy_impl(std::move(__range.first), std::move(__range.second), std::__unwrap_iter(__result));
95   return std::make_pair(
96       std::__rewrap_range<_Sent>(__first, __ret.first), std::__rewrap_iter(__result, __ret.second));
97 }
98 
99 template <class _InputIterator, class _OutputIterator>
100 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
101 _OutputIterator
102 copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result) {
103   return std::__copy(__first, __last, __result).second;
104 }
105 
106 _LIBCPP_END_NAMESPACE_STD
107 
108 #endif // _LIBCPP___ALGORITHM_COPY_H
109