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 <__config> 13 #include <__algorithm/copy.h> 14 #include <__algorithm/unwrap_iter.h> 15 #include <__iterator/iterator_traits.h> 16 #include <cstring> 17 #include <type_traits> 18 19 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 20 #pragma GCC system_header 21 #endif 22 23 _LIBCPP_BEGIN_NAMESPACE_STD 24 25 template<class _InputIterator, class _Size, class _OutputIterator> 26 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 27 typename enable_if 28 < 29 __is_cpp17_input_iterator<_InputIterator>::value && 30 !__is_cpp17_random_access_iterator<_InputIterator>::value, 31 _OutputIterator 32 >::type 33 copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result) 34 { 35 typedef decltype(_VSTD::__convert_to_integral(__orig_n)) _IntegralSize; 36 _IntegralSize __n = __orig_n; 37 if (__n > 0) 38 { 39 *__result = *__first; 40 ++__result; 41 for (--__n; __n > 0; --__n) 42 { 43 ++__first; 44 *__result = *__first; 45 ++__result; 46 } 47 } 48 return __result; 49 } 50 51 template<class _InputIterator, class _Size, class _OutputIterator> 52 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 53 typename enable_if 54 < 55 __is_cpp17_random_access_iterator<_InputIterator>::value, 56 _OutputIterator 57 >::type 58 copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result) 59 { 60 typedef typename iterator_traits<_InputIterator>::difference_type difference_type; 61 typedef decltype(_VSTD::__convert_to_integral(__orig_n)) _IntegralSize; 62 _IntegralSize __n = __orig_n; 63 return _VSTD::copy(__first, __first + difference_type(__n), __result); 64 } 65 66 _LIBCPP_END_NAMESPACE_STD 67 68 #endif // _LIBCPP___ALGORITHM_COPY_N_H 69