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-rw-r--r--libcxx/include/__algorithm/ranges_copy_n.h76
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diff --git a/libcxx/include/__algorithm/ranges_copy_n.h b/libcxx/include/__algorithm/ranges_copy_n.h
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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/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 > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
+
+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(__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 > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_RANGES_COPY_N_H