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