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_GENERATE_N_H
10#define _LIBCPP___ALGORITHM_RANGES_GENERATE_N_H
11
12#include <__concepts/constructible.h>
13#include <__concepts/invocable.h>
14#include <__config>
15#include <__functional/identity.h>
16#include <__iterator/concepts.h>
17#include <__iterator/incrementable_traits.h>
18#include <__iterator/iterator_traits.h>
19#include <__ranges/access.h>
20#include <__ranges/concepts.h>
21#include <__type_traits/invoke.h>
22#include <__utility/move.h>
23
24#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
25#  pragma GCC system_header
26#endif
27
28_LIBCPP_PUSH_MACROS
29#include <__undef_macros>
30
31#if _LIBCPP_STD_VER >= 20
32
33_LIBCPP_BEGIN_NAMESPACE_STD
34
35namespace ranges {
36struct __generate_n {
37  template <input_or_output_iterator _OutIter, copy_constructible _Func>
38    requires invocable<_Func&> && indirectly_writable<_OutIter, invoke_result_t<_Func&>>
39  _LIBCPP_HIDE_FROM_ABI constexpr _OutIter
40  operator()(_OutIter __first, iter_difference_t<_OutIter> __n, _Func __gen) const {
41    for (; __n > 0; --__n) {
42      *__first = __gen();
43      ++__first;
44    }
45
46    return __first;
47  }
48};
49
50inline namespace __cpo {
51inline constexpr auto generate_n = __generate_n{};
52} // namespace __cpo
53} // namespace ranges
54
55_LIBCPP_END_NAMESPACE_STD
56
57#endif // _LIBCPP_STD_VER >= 20
58
59_LIBCPP_POP_MACROS
60
61#endif // _LIBCPP___ALGORITHM_RANGES_GENERATE_N_H