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1// -*- C++ -*-2//===----------------------------------------------------------------------===//3//4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.5// See https://llvm.org/LICENSE.txt for license information.6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception7//8//===----------------------------------------------------------------------===//9 10#ifndef _LIBCPP___ALGORITHM_FOR_EACH_N_H11#define _LIBCPP___ALGORITHM_FOR_EACH_N_H12 13#include <__algorithm/for_each.h>14#include <__algorithm/for_each_n_segment.h>15#include <__config>16#include <__functional/identity.h>17#include <__iterator/iterator_traits.h>18#include <__iterator/segmented_iterator.h>19#include <__type_traits/invoke.h>20#include <__utility/convert_to_integral.h>21#include <__utility/move.h>22 23#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)24# pragma GCC system_header25#endif26 27_LIBCPP_PUSH_MACROS28#include <__undef_macros>29 30_LIBCPP_BEGIN_NAMESPACE_STD31 32template <class _InputIterator, class _Size, class _Func, class _Proj>33_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _InputIterator34__for_each_n(_InputIterator __first, _Size __orig_n, _Func& __f, _Proj& __proj) {35 typedef decltype(std::__convert_to_integral(__orig_n)) _IntegralSize;36 _IntegralSize __n = __orig_n;37 38#ifndef _LIBCPP_CXX03_LANG39 if constexpr (__is_segmented_iterator_v<_InputIterator>) {40 using __local_iterator = typename __segmented_iterator_traits<_InputIterator>::__local_iterator;41 if constexpr (__has_random_access_iterator_category<__local_iterator>::value) {42 return std::__for_each_n_segment(__first, __orig_n, [&](__local_iterator __lfirst, __local_iterator __llast) {43 std::__for_each(__lfirst, __llast, __f, __proj);44 });45 } else {46 return std::__for_each(__first, __first + __n, __f, __proj);47 }48 } else49#endif50 {51 while (__n > 0) {52 std::__invoke(__f, std::__invoke(__proj, *__first));53 ++__first;54 --__n;55 }56 return std::move(__first);57 }58}59 60#if _LIBCPP_STD_VER >= 1761 62template <class _InputIterator, class _Size, class _Func>63inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _InputIterator64for_each_n(_InputIterator __first, _Size __orig_n, _Func __f) {65 __identity __proj;66 return std::__for_each_n(__first, __orig_n, __f, __proj);67}68 69#endif // _LIBCPP_STD_VER >= 1770 71_LIBCPP_END_NAMESPACE_STD72 73_LIBCPP_POP_MACROS74 75#endif // _LIBCPP___ALGORITHM_FOR_EACH_N_H76