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_PUSH_MACROS 29 #include <__undef_macros> 30 31 _LIBCPP_BEGIN_NAMESPACE_STD 32 33 #if _LIBCPP_STD_VER >= 20 34 35 namespace ranges { 36 37 template <class _Ip, class _Op> 38 using copy_n_result = in_out_result<_Ip, _Op>; 39 40 namespace __copy_n { 41 struct __fn { 42 template <class _InIter, class _DiffType, class _OutIter> 43 _LIBCPP_HIDE_FROM_ABI constexpr static copy_n_result<_InIter, _OutIter> 44 __go(_InIter __first, _DiffType __n, _OutIter __result) { 45 while (__n != 0) { 46 *__result = *__first; 47 ++__first; 48 ++__result; 49 --__n; 50 } 51 return {std::move(__first), std::move(__result)}; 52 } 53 54 template <random_access_iterator _InIter, class _DiffType, random_access_iterator _OutIter> 55 _LIBCPP_HIDE_FROM_ABI constexpr static copy_n_result<_InIter, _OutIter> 56 __go(_InIter __first, _DiffType __n, _OutIter __result) { 57 auto __ret = std::__copy<_RangeAlgPolicy>(__first, __first + __n, __result); 58 return {__ret.first, __ret.second}; 59 } 60 61 template <input_iterator _Ip, weakly_incrementable _Op> 62 requires indirectly_copyable<_Ip, _Op> 63 _LIBCPP_HIDE_FROM_ABI constexpr copy_n_result<_Ip, _Op> 64 operator()(_Ip __first, iter_difference_t<_Ip> __n, _Op __result) const { 65 return __go(std::move(__first), __n, std::move(__result)); 66 } 67 }; 68 } // namespace __copy_n 69 70 inline namespace __cpo { 71 inline constexpr auto copy_n = __copy_n::__fn{}; 72 } // namespace __cpo 73 } // namespace ranges 74 75 #endif // _LIBCPP_STD_VER >= 20 76 77 _LIBCPP_END_NAMESPACE_STD 78 79 _LIBCPP_POP_MACROS 80 81 #endif // _LIBCPP___ALGORITHM_RANGES_COPY_N_H 82