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/enable_if.h> 16 #include <__utility/convert_to_integral.h> 17 18 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 19 # pragma GCC system_header 20 #endif 21 22 _LIBCPP_BEGIN_NAMESPACE_STD 23 24 template<class _InputIterator, class _Size, class _OutputIterator, 25 __enable_if_t<__has_input_iterator_category<_InputIterator>::value && 26 !__has_random_access_iterator_category<_InputIterator>::value, int> = 0> 27 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 28 _OutputIterator 29 copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result) 30 { 31 typedef decltype(std::__convert_to_integral(__orig_n)) _IntegralSize; 32 _IntegralSize __n = __orig_n; 33 if (__n > 0) 34 { 35 *__result = *__first; 36 ++__result; 37 for (--__n; __n > 0; --__n) 38 { 39 ++__first; 40 *__result = *__first; 41 ++__result; 42 } 43 } 44 return __result; 45 } 46 47 template<class _InputIterator, class _Size, class _OutputIterator, 48 __enable_if_t<__has_random_access_iterator_category<_InputIterator>::value, int> = 0> 49 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 50 _OutputIterator 51 copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result) 52 { 53 typedef typename iterator_traits<_InputIterator>::difference_type difference_type; 54 typedef decltype(std::__convert_to_integral(__orig_n)) _IntegralSize; 55 _IntegralSize __n = __orig_n; 56 return std::copy(__first, __first + difference_type(__n), __result); 57 } 58 59 _LIBCPP_END_NAMESPACE_STD 60 61 #endif // _LIBCPP___ALGORITHM_COPY_N_H 62