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_RANGES_FOR_EACH_H
10#define _LIBCPP___ALGORITHM_RANGES_FOR_EACH_H
11
12#include <__algorithm/for_each.h>
13#include <__algorithm/for_each_n.h>
14#include <__algorithm/in_fun_result.h>
15#include <__concepts/assignable.h>
16#include <__config>
17#include <__functional/identity.h>
18#include <__iterator/concepts.h>
19#include <__iterator/projected.h>
20#include <__ranges/access.h>
21#include <__ranges/concepts.h>
22#include <__ranges/dangling.h>
23#include <__utility/move.h>
24
25#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
26#  pragma GCC system_header
27#endif
28
29_LIBCPP_PUSH_MACROS
30#include <__undef_macros>
31
32#if _LIBCPP_STD_VER >= 20
33
34_LIBCPP_BEGIN_NAMESPACE_STD
35
36namespace ranges {
37
38template <class _Iter, class _Func>
39using for_each_result = in_fun_result<_Iter, _Func>;
40
41struct __for_each {
42private:
43  template <class _Iter, class _Sent, class _Proj, class _Func>
44  _LIBCPP_HIDE_FROM_ABI constexpr static for_each_result<_Iter, _Func>
45  __for_each_impl(_Iter __first, _Sent __last, _Func& __func, _Proj& __proj) {
46    // In the case where we have different iterator and sentinel types, the segmented iterator optimization
47    // in std::for_each will not kick in. Therefore, we prefer std::for_each_n in that case (whenever we can
48    // obtain the `n`).
49    if constexpr (!std::assignable_from<_Iter&, _Sent> && std::sized_sentinel_for<_Sent, _Iter>) {
50      auto __n   = __last - __first;
51      auto __end = std::__for_each_n(std::move(__first), __n, __func, __proj);
52      return {std::move(__end), std::move(__func)};
53    } else {
54      auto __end = std::__for_each(std::move(__first), std::move(__last), __func, __proj);
55      return {std::move(__end), std::move(__func)};
56    }
57  }
58
59public:
60  template <input_iterator _Iter,
61            sentinel_for<_Iter> _Sent,
62            class _Proj = identity,
63            indirectly_unary_invocable<projected<_Iter, _Proj>> _Func>
64  _LIBCPP_HIDE_FROM_ABI constexpr for_each_result<_Iter, _Func>
65  operator()(_Iter __first, _Sent __last, _Func __func, _Proj __proj = {}) const {
66    return __for_each_impl(std::move(__first), std::move(__last), __func, __proj);
67  }
68
69  template <input_range _Range,
70            class _Proj = identity,
71            indirectly_unary_invocable<projected<iterator_t<_Range>, _Proj>> _Func>
72  _LIBCPP_HIDE_FROM_ABI constexpr for_each_result<borrowed_iterator_t<_Range>, _Func>
73  operator()(_Range&& __range, _Func __func, _Proj __proj = {}) const {
74    return __for_each_impl(ranges::begin(__range), ranges::end(__range), __func, __proj);
75  }
76};
77
78inline namespace __cpo {
79inline constexpr auto for_each = __for_each{};
80} // namespace __cpo
81} // namespace ranges
82
83_LIBCPP_END_NAMESPACE_STD
84
85#endif // _LIBCPP_STD_VER >= 20
86
87_LIBCPP_POP_MACROS
88
89#endif // _LIBCPP___ALGORITHM_RANGES_FOR_EACH_H