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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___ALGORITHM_COPY_BACKWARD_H
#define _LIBCPP___ALGORITHM_COPY_BACKWARD_H
#include <__algorithm/unwrap_iter.h>
#include <__config>
#include <__iterator/iterator_traits.h>
#include <cstring>
#include <type_traits>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
template <class _BidirectionalIterator, class _OutputIterator>
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
_OutputIterator
__copy_backward_constexpr(_BidirectionalIterator __first, _BidirectionalIterator __last, _OutputIterator __result)
{
while (__first != __last)
*--__result = *--__last;
return __result;
}
template <class _BidirectionalIterator, class _OutputIterator>
inline _LIBCPP_INLINE_VISIBILITY
_OutputIterator
__copy_backward(_BidirectionalIterator __first, _BidirectionalIterator __last, _OutputIterator __result)
{
return _VSTD::__copy_backward_constexpr(__first, __last, __result);
}
template <class _Tp, class _Up>
inline _LIBCPP_INLINE_VISIBILITY
typename enable_if
<
is_same<typename remove_const<_Tp>::type, _Up>::value &&
is_trivially_copy_assignable<_Up>::value,
_Up*
>::type
__copy_backward(_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 _BidirectionalIterator1, class _BidirectionalIterator2>
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
_BidirectionalIterator2
copy_backward(_BidirectionalIterator1 __first, _BidirectionalIterator1 __last,
_BidirectionalIterator2 __result)
{
if (__libcpp_is_constant_evaluated()) {
return _VSTD::__copy_backward_constexpr(__first, __last, __result);
} else {
return _VSTD::__rewrap_iter(__result,
_VSTD::__copy_backward(_VSTD::__unwrap_iter(__first),
_VSTD::__unwrap_iter(__last),
_VSTD::__unwrap_iter(__result)));
}
}
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___ALGORITHM_COPY_BACKWARD_H
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