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Diffstat (limited to 'libcxx/include/__algorithm/ranges_copy_n.h')
-rw-r--r-- | libcxx/include/__algorithm/ranges_copy_n.h | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/libcxx/include/__algorithm/ranges_copy_n.h b/libcxx/include/__algorithm/ranges_copy_n.h new file mode 100644 index 000000000000..eaa05c954686 --- /dev/null +++ b/libcxx/include/__algorithm/ranges_copy_n.h @@ -0,0 +1,76 @@ +//===----------------------------------------------------------------------===// +// +// 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 |