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-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP___ALGORITHM_FOR_EACH_N_H
11#define _LIBCPP___ALGORITHM_FOR_EACH_N_H
12
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_header
25#endif
26
27_LIBCPP_PUSH_MACROS
28#include <__undef_macros>
29
30_LIBCPP_BEGIN_NAMESPACE_STD
31
32template <class _InputIterator, class _Size, class _Func, class _Proj>
33_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _InputIterator
34__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_LANG
39 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 } else
49#endif
50 {
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 >= 17
61
62template <class _InputIterator, class _Size, class _Func>
63inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _InputIterator
64for_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 >= 17
70
71_LIBCPP_END_NAMESPACE_STD
72
73_LIBCPP_POP_MACROS
74
75#endif // _LIBCPP___ALGORITHM_FOR_EACH_N_H