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_BACKWARD_H 10 #define _LIBCPP___ALGORITHM_COPY_BACKWARD_H 11 12 #include <__algorithm/copy.h> 13 #include <__algorithm/iterator_operations.h> 14 #include <__algorithm/ranges_copy.h> 15 #include <__algorithm/unwrap_iter.h> 16 #include <__concepts/same_as.h> 17 #include <__config> 18 #include <__iterator/iterator_traits.h> 19 #include <__iterator/reverse_iterator.h> 20 #include <__ranges/subrange.h> 21 #include <__utility/move.h> 22 #include <__utility/pair.h> 23 #include <cstring> 24 #include <type_traits> 25 26 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 27 # pragma GCC system_header 28 #endif 29 30 _LIBCPP_BEGIN_NAMESPACE_STD 31 32 template <class _AlgPolicy, class _InputIterator, class _OutputIterator, 33 __enable_if_t<is_same<_AlgPolicy, _ClassicAlgPolicy>::value, int> = 0> 34 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11 pair<_InputIterator, _OutputIterator> 35 __copy_backward(_InputIterator __first, _InputIterator __last, _OutputIterator __result) { 36 auto __ret = std::__copy( 37 __unconstrained_reverse_iterator<_InputIterator>(__last), 38 __unconstrained_reverse_iterator<_InputIterator>(__first), 39 __unconstrained_reverse_iterator<_OutputIterator>(__result)); 40 return pair<_InputIterator, _OutputIterator>(__ret.first.base(), __ret.second.base()); 41 } 42 43 #if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES) 44 template <class _AlgPolicy, class _Iter1, class _Sent1, class _Iter2, 45 __enable_if_t<is_same<_AlgPolicy, _RangeAlgPolicy>::value, int> = 0> 46 _LIBCPP_HIDE_FROM_ABI constexpr pair<_Iter1, _Iter2> __copy_backward(_Iter1 __first, _Sent1 __last, _Iter2 __result) { 47 auto __last_iter = _IterOps<_AlgPolicy>::next(__first, std::move(__last)); 48 auto __reverse_range = std::__reverse_range(std::ranges::subrange(std::move(__first), __last_iter)); 49 auto __ret = ranges::copy(std::move(__reverse_range), std::make_reverse_iterator(__result)); 50 return std::make_pair(__last_iter, __ret.out.base()); 51 } 52 #endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES) 53 54 template <class _BidirectionalIterator1, class _BidirectionalIterator2> 55 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 _BidirectionalIterator2 56 copy_backward(_BidirectionalIterator1 __first, _BidirectionalIterator1 __last, _BidirectionalIterator2 __result) { 57 return std::__copy_backward<_ClassicAlgPolicy>(__first, __last, __result).second; 58 } 59 60 _LIBCPP_END_NAMESPACE_STD 61 62 #endif // _LIBCPP___ALGORITHM_COPY_BACKWARD_H 63