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libcxx/include/__algorithm/move_backward.h

//===----------------------------------------------------------------------===// //===----------------------------------------------------------------------===//
// //
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information. // See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// //
//===----------------------------------------------------------------------===// //===----------------------------------------------------------------------===//
#ifndef _LIBCPP___ALGORITHM_MOVE_BACKWARD_H #ifndef _LIBCPP___ALGORITHM_MOVE_BACKWARD_H
#define _LIBCPP___ALGORITHM_MOVE_BACKWARD_H #define _LIBCPP___ALGORITHM_MOVE_BACKWARD_H
#include <__algorithm/copy_move_common.h>
#include <__algorithm/iterator_operations.h> #include <__algorithm/iterator_operations.h>
#include <__algorithm/unwrap_iter.h>
#include <__config> #include <__config>
#include <__utility/move.h> #include <__utility/move.h>
#include <cstring> #include <__utility/pair.h>
#include <type_traits>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header # pragma GCC system_header
#endif #endif
_LIBCPP_BEGIN_NAMESPACE_STD _LIBCPP_BEGIN_NAMESPACE_STD
template <class _AlgPolicy, class _InputIterator, class _OutputIterator> template <class _AlgPolicy>
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX17 struct __move_backward_loop {
_OutputIterator template <class _InIter, class _Sent, class _OutIter>
__move_backward_constexpr(_InputIterator __first, _InputIterator __last, _OutputIterator __result) _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
{ operator()(_InIter __first, _Sent __last, _OutIter __result) const {
while (__first != __last) auto __last_iter = _IterOps<_AlgPolicy>::next(__first, __last);
*--__result = _IterOps<_AlgPolicy>::__iter_move(--__last); auto __original_last_iter = __last_iter;
return __result;
} while (__first != __last_iter) {
*--__result = _IterOps<_AlgPolicy>::__iter_move(--__last_iter);
template <class _AlgPolicy, class _InputIterator, class _OutputIterator> }
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX17
_OutputIterator return std::make_pair(std::move(__original_last_iter), std::move(__result));
__move_backward_impl(_InputIterator __first, _InputIterator __last, _OutputIterator __result) }
{ };
return _VSTD::__move_backward_constexpr<_AlgPolicy>(__first, __last, __result);
} struct __move_backward_trivial {
// At this point, the iterators have been unwrapped so any `contiguous_iterator` has been unwrapped to a pointer.
template <class _In, class _Out, __enable_if_memmovable<_In&&, _Out&> = 0>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*>
operator()(_In* __first, _In* __last, _Out* __result) const {
return std::__copy_backward_trivial_impl(__first, __last, __result);
}
};
template <class _AlgPolicy, class _BidirectionalIterator1, class _Sentinel, class _BidirectionalIterator2>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
pair<_BidirectionalIterator1, _BidirectionalIterator2>
__move_backward(_BidirectionalIterator1 __first, _Sentinel __last, _BidirectionalIterator2 __result) {
static_assert(std::is_copy_constructible<_BidirectionalIterator1>::value &&
std::is_copy_constructible<_BidirectionalIterator1>::value, "Iterators must be copy constructible.");
template <class _AlgPolicy, class _Tp, class _Up> return std::__dispatch_copy_or_move<_AlgPolicy, __move_backward_loop<_AlgPolicy>, __move_backward_trivial>(
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX17 std::move(__first), std::move(__last), std::move(__result));
typename enable_if
<
is_same<__remove_const_t<_Tp>, _Up>::value &&
is_trivially_move_assignable<_Up>::value,
_Up*
>::type
__move_backward_impl(_Tp* __first, _Tp* __last, _Up* __result)
{
const size_t __n = static_cast<size_t>(__last - __first);
if (__n > 0)
{
__result -= __n;
_VSTD::memmove(__result, __first, __n * sizeof(_Up));
}
return __result;
}
template <class _AlgPolicy, class _BidirectionalIterator1, class _BidirectionalIterator2>
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
_BidirectionalIterator2
__move_backward(_BidirectionalIterator1 __first, _BidirectionalIterator1 __last,
_BidirectionalIterator2 __result)
{
if (__libcpp_is_constant_evaluated()) {
return _VSTD::__move_backward_constexpr<_AlgPolicy>(__first, __last, __result);
} else {
return _VSTD::__rewrap_iter(__result,
_VSTD::__move_backward_impl<_AlgPolicy>(_VSTD::__unwrap_iter(__first),
_VSTD::__unwrap_iter(__last),
_VSTD::__unwrap_iter(__result)));
}
} }
template <class _BidirectionalIterator1, class _BidirectionalIterator2> template <class _BidirectionalIterator1, class _BidirectionalIterator2>
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
_BidirectionalIterator2 _BidirectionalIterator2
move_backward(_BidirectionalIterator1 __first, _BidirectionalIterator1 __last, move_backward(_BidirectionalIterator1 __first, _BidirectionalIterator1 __last,
_BidirectionalIterator2 __result) _BidirectionalIterator2 __result)
{ {
return std::__move_backward<_ClassicAlgPolicy>(std::move(__first), std::move(__last), std::move(__result)); return std::__move_backward<_ClassicAlgPolicy>(
std::move(__first), std::move(__last), std::move(__result)).second;
} }
_LIBCPP_END_NAMESPACE_STD _LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___ALGORITHM_MOVE_BACKWARD_H #endif // _LIBCPP___ALGORITHM_MOVE_BACKWARD_H