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