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_PUSH_MACROS 24 #include <__undef_macros> 25 26 _LIBCPP_BEGIN_NAMESPACE_STD 27 28 template<class _InputIterator, class _Size, class _OutputIterator> 29 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 30 typename enable_if 31 < 32 __is_cpp17_input_iterator<_InputIterator>::value && 33 !__is_cpp17_random_access_iterator<_InputIterator>::value, 34 _OutputIterator 35 >::type 36 copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result) 37 { 38 typedef decltype(_VSTD::__convert_to_integral(__orig_n)) _IntegralSize; 39 _IntegralSize __n = __orig_n; 40 if (__n > 0) 41 { 42 *__result = *__first; 43 ++__result; 44 for (--__n; __n > 0; --__n) 45 { 46 ++__first; 47 *__result = *__first; 48 ++__result; 49 } 50 } 51 return __result; 52 } 53 54 template<class _InputIterator, class _Size, class _OutputIterator> 55 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 56 typename enable_if 57 < 58 __is_cpp17_random_access_iterator<_InputIterator>::value, 59 _OutputIterator 60 >::type 61 copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result) 62 { 63 typedef decltype(_VSTD::__convert_to_integral(__orig_n)) _IntegralSize; 64 _IntegralSize __n = __orig_n; 65 return _VSTD::copy(__first, __first + __n, __result); 66 } 67 68 _LIBCPP_END_NAMESPACE_STD 69 70 _LIBCPP_POP_MACROS 71 72 #endif // _LIBCPP___ALGORITHM_COPY_N_H 73