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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_RANGES_COPY_N_H
#define _LIBCPP___ALGORITHM_RANGES_COPY_N_H
#include <__algorithm/copy.h>
#include <__algorithm/in_out_result.h>
#include <__algorithm/iterator_operations.h>
#include <__algorithm/ranges_copy.h>
#include <__config>
#include <__functional/identity.h>
#include <__iterator/concepts.h>
#include <__iterator/incrementable_traits.h>
#include <__iterator/unreachable_sentinel.h>
#include <__iterator/wrap_iter.h>
#include <__utility/move.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
#if _LIBCPP_STD_VER >= 20
namespace ranges {
template <class _Ip, class _Op>
using copy_n_result = in_out_result<_Ip, _Op>;
namespace __copy_n {
struct __fn {
template <class _InIter, class _DiffType, class _OutIter>
_LIBCPP_HIDE_FROM_ABI constexpr static copy_n_result<_InIter, _OutIter>
__go(_InIter __first, _DiffType __n, _OutIter __result) {
while (__n != 0) {
*__result = *__first;
++__first;
++__result;
--__n;
}
return {std::move(__first), std::move(__result)};
}
template <random_access_iterator _InIter, class _DiffType, random_access_iterator _OutIter>
_LIBCPP_HIDE_FROM_ABI constexpr static copy_n_result<_InIter, _OutIter>
__go(_InIter __first, _DiffType __n, _OutIter __result) {
auto __ret = std::__copy<_RangeAlgPolicy>(__first, __first + __n, __result);
return {__ret.first, __ret.second};
}
template <input_iterator _Ip, weakly_incrementable _Op>
requires indirectly_copyable<_Ip, _Op>
_LIBCPP_HIDE_FROM_ABI constexpr copy_n_result<_Ip, _Op>
operator()(_Ip __first, iter_difference_t<_Ip> __n, _Op __result) const {
return __go(std::move(__first), __n, std::move(__result));
}
};
} // namespace __copy_n
inline namespace __cpo {
inline constexpr auto copy_n = __copy_n::__fn{};
} // namespace __cpo
} // namespace ranges
#endif // _LIBCPP_STD_VER >= 20
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___ALGORITHM_RANGES_COPY_N_H
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