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_FILL_N_H
10#define _LIBCPP___ALGORITHM_FILL_N_H
11
12#include <__algorithm/min.h>
13#include <__config>
14#include <__fwd/bit_reference.h>
15#include <__memory/pointer_traits.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_PUSH_MACROS
23#include <__undef_macros>
24
25_LIBCPP_BEGIN_NAMESPACE_STD
26
27// fill_n isn't specialized for std::memset, because the compiler already optimizes the loop to a call to std::memset.
28
29template <class _OutputIterator, class _Size, class _Tp>
30inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
31__fill_n(_OutputIterator __first, _Size __n, const _Tp& __value);
32
33template <bool _FillVal, class _Cp>
34_LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void
35__fill_n_bool(__bit_iterator<_Cp, false> __first, typename __size_difference_type_traits<_Cp>::size_type __n) {
36  using _It            = __bit_iterator<_Cp, false>;
37  using __storage_type = typename _It::__storage_type;
38
39  const int __bits_per_word = _It::__bits_per_word;
40  // do first partial word
41  if (__first.__ctz_ != 0) {
42    __storage_type __clz_f = static_cast<__storage_type>(__bits_per_word - __first.__ctz_);
43    __storage_type __dn    = std::min(__clz_f, __n);
44    std::__fill_masked_range(std::__to_address(__first.__seg_), __clz_f - __dn, __first.__ctz_, _FillVal);
45    __n -= __dn;
46    ++__first.__seg_;
47  }
48  // do middle whole words
49  __storage_type __nw = __n / __bits_per_word;
50  std::__fill_n(std::__to_address(__first.__seg_), __nw, _FillVal ? static_cast<__storage_type>(-1) : 0);
51  __n -= __nw * __bits_per_word;
52  // do last partial word
53  if (__n > 0) {
54    __first.__seg_ += __nw;
55    std::__fill_masked_range(std::__to_address(__first.__seg_), __bits_per_word - __n, 0u, _FillVal);
56  }
57}
58
59template <class _Cp, class _Size>
60inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __bit_iterator<_Cp, false>
61__fill_n(__bit_iterator<_Cp, false> __first, _Size __n, const bool& __value) {
62  if (__n > 0) {
63    if (__value)
64      std::__fill_n_bool<true>(__first, __n);
65    else
66      std::__fill_n_bool<false>(__first, __n);
67  }
68  return __first + __n;
69}
70
71template <class _OutputIterator, class _Size, class _Tp>
72inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
73__fill_n(_OutputIterator __first, _Size __n, const _Tp& __value) {
74  for (; __n > 0; ++__first, (void)--__n)
75    *__first = __value;
76  return __first;
77}
78
79template <class _OutputIterator, class _Size, class _Tp>
80inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
81fill_n(_OutputIterator __first, _Size __n, const _Tp& __value) {
82  return std::__fill_n(__first, std::__convert_to_integral(__n), __value);
83}
84
85_LIBCPP_END_NAMESPACE_STD
86
87_LIBCPP_POP_MACROS
88
89#endif // _LIBCPP___ALGORITHM_FILL_N_H