1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #ifndef _LIBCPP___ALGORITHM_RANGES_COPY_N_H 10 #define _LIBCPP___ALGORITHM_RANGES_COPY_N_H 11 12 #include <__algorithm/copy.h> 13 #include <__algorithm/in_out_result.h> 14 #include <__algorithm/iterator_operations.h> 15 #include <__algorithm/ranges_copy.h> 16 #include <__config> 17 #include <__functional/identity.h> 18 #include <__iterator/concepts.h> 19 #include <__iterator/incrementable_traits.h> 20 #include <__iterator/unreachable_sentinel.h> 21 #include <__iterator/wrap_iter.h> 22 #include <__utility/move.h> 23 24 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 25 # pragma GCC system_header 26 #endif 27 28 _LIBCPP_BEGIN_NAMESPACE_STD 29 30 #if _LIBCPP_STD_VER > 17 31 32 namespace ranges { 33 34 template <class _Ip, class _Op> 35 using copy_n_result = in_out_result<_Ip, _Op>; 36 37 namespace __copy_n { 38 struct __fn { 39 40 template <class _InIter, class _DiffType, class _OutIter> 41 _LIBCPP_HIDE_FROM_ABI constexpr static 42 copy_n_result<_InIter, _OutIter> __go(_InIter __first, _DiffType __n, _OutIter __result) { 43 while (__n != 0) { 44 *__result = *__first; 45 ++__first; 46 ++__result; 47 --__n; 48 } 49 return {std::move(__first), std::move(__result)}; 50 } 51 52 template <random_access_iterator _InIter, class _DiffType, random_access_iterator _OutIter> 53 _LIBCPP_HIDE_FROM_ABI constexpr static 54 copy_n_result<_InIter, _OutIter> __go(_InIter __first, _DiffType __n, _OutIter __result) { 55 auto __ret = std::__copy<_RangeAlgPolicy>(__first, __first + __n, __result); 56 return {__ret.first, __ret.second}; 57 } 58 59 template <input_iterator _Ip, weakly_incrementable _Op> 60 requires indirectly_copyable<_Ip, _Op> 61 _LIBCPP_HIDE_FROM_ABI constexpr 62 copy_n_result<_Ip, _Op> operator()(_Ip __first, iter_difference_t<_Ip> __n, _Op __result) const { 63 return __go(std::move(__first), __n, std::move(__result)); 64 } 65 }; 66 } // namespace __copy_n 67 68 inline namespace __cpo { 69 inline constexpr auto copy_n = __copy_n::__fn{}; 70 } // namespace __cpo 71 } // namespace ranges 72 73 #endif // _LIBCPP_STD_VER > 17 74 75 _LIBCPP_END_NAMESPACE_STD 76 77 #endif // _LIBCPP___ALGORITHM_RANGES_COPY_N_H 78