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 <__iterator/iterator_traits.h> 16 #include <__memory/pointer_traits.h> 17 #include <__utility/convert_to_integral.h> 18 19 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 20 # pragma GCC system_header 21 #endif 22 23 _LIBCPP_PUSH_MACROS 24 #include <__undef_macros> 25 26 _LIBCPP_BEGIN_NAMESPACE_STD 27 28 // fill_n isn't specialized for std::memset, because the compiler already optimizes the loop to a call to std::memset. 29 30 template <class _OutputIterator, class _Size, class _Tp> 31 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator 32 __fill_n(_OutputIterator __first, _Size __n, const _Tp& __value); 33 34 template <bool _FillVal, class _Cp> 35 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void 36 __fill_n_bool(__bit_iterator<_Cp, false> __first, typename _Cp::size_type __n) { 37 using _It = __bit_iterator<_Cp, false>; 38 using __storage_type = typename _It::__storage_type; 39 40 const int __bits_per_word = _It::__bits_per_word; 41 // do first partial word 42 if (__first.__ctz_ != 0) { 43 __storage_type __clz_f = static_cast<__storage_type>(__bits_per_word - __first.__ctz_); 44 __storage_type __dn = std::min(__clz_f, __n); 45 __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn)); 46 if (_FillVal) 47 *__first.__seg_ |= __m; 48 else 49 *__first.__seg_ &= ~__m; 50 __n -= __dn; 51 ++__first.__seg_; 52 } 53 // do middle whole words 54 __storage_type __nw = __n / __bits_per_word; 55 std::__fill_n(std::__to_address(__first.__seg_), __nw, _FillVal ? static_cast<__storage_type>(-1) : 0); 56 __n -= __nw * __bits_per_word; 57 // do last partial word 58 if (__n > 0) { 59 __first.__seg_ += __nw; 60 __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n); 61 if (_FillVal) 62 *__first.__seg_ |= __m; 63 else 64 *__first.__seg_ &= ~__m; 65 } 66 } 67 68 template <class _Cp, class _Size> 69 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __bit_iterator<_Cp, false> 70 __fill_n(__bit_iterator<_Cp, false> __first, _Size __n, const bool& __value) { 71 if (__n > 0) { 72 if (__value) 73 std::__fill_n_bool<true>(__first, __n); 74 else 75 std::__fill_n_bool<false>(__first, __n); 76 } 77 return __first + __n; 78 } 79 80 template <class _OutputIterator, class _Size, class _Tp> 81 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator 82 __fill_n(_OutputIterator __first, _Size __n, const _Tp& __value) { 83 for (; __n > 0; ++__first, (void)--__n) 84 *__first = __value; 85 return __first; 86 } 87 88 template <class _OutputIterator, class _Size, class _Tp> 89 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator 90 fill_n(_OutputIterator __first, _Size __n, const _Tp& __value) { 91 return std::__fill_n(__first, std::__convert_to_integral(__n), __value); 92 } 93 94 _LIBCPP_END_NAMESPACE_STD 95 96 _LIBCPP_POP_MACROS 97 98 #endif // _LIBCPP___ALGORITHM_FILL_N_H 99