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_COPY_N_H 10 #define _LIBCPP___ALGORITHM_COPY_N_H 11 12 #include <__algorithm/copy.h> 13 #include <__config> 14 #include <__iterator/iterator_traits.h> 15 #include <type_traits> 16 17 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 18 # pragma GCC system_header 19 #endif 20 21 _LIBCPP_BEGIN_NAMESPACE_STD 22 23 template<class _InputIterator, class _Size, class _OutputIterator> 24 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 25 typename enable_if 26 < 27 __is_cpp17_input_iterator<_InputIterator>::value && 28 !__is_cpp17_random_access_iterator<_InputIterator>::value, 29 _OutputIterator 30 >::type 31 copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result) 32 { 33 typedef decltype(_VSTD::__convert_to_integral(__orig_n)) _IntegralSize; 34 _IntegralSize __n = __orig_n; 35 if (__n > 0) 36 { 37 *__result = *__first; 38 ++__result; 39 for (--__n; __n > 0; --__n) 40 { 41 ++__first; 42 *__result = *__first; 43 ++__result; 44 } 45 } 46 return __result; 47 } 48 49 template<class _InputIterator, class _Size, class _OutputIterator> 50 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 51 typename enable_if 52 < 53 __is_cpp17_random_access_iterator<_InputIterator>::value, 54 _OutputIterator 55 >::type 56 copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result) 57 { 58 typedef typename iterator_traits<_InputIterator>::difference_type difference_type; 59 typedef decltype(_VSTD::__convert_to_integral(__orig_n)) _IntegralSize; 60 _IntegralSize __n = __orig_n; 61 return _VSTD::copy(__first, __first + difference_type(__n), __result); 62 } 63 64 _LIBCPP_END_NAMESPACE_STD 65 66 #endif // _LIBCPP___ALGORITHM_COPY_N_H 67