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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-exception7//8//===----------------------------------------------------------------------===//9 10#ifndef _LIBCPP___CXX03___ALGORITHM_FIND_H11#define _LIBCPP___CXX03___ALGORITHM_FIND_H12 13#include <__cxx03/__algorithm/find_segment_if.h>14#include <__cxx03/__algorithm/min.h>15#include <__cxx03/__algorithm/unwrap_iter.h>16#include <__cxx03/__bit/countr.h>17#include <__cxx03/__bit/invert_if.h>18#include <__cxx03/__config>19#include <__cxx03/__functional/identity.h>20#include <__cxx03/__fwd/bit_reference.h>21#include <__cxx03/__iterator/segmented_iterator.h>22#include <__cxx03/__string/constexpr_c_functions.h>23#include <__cxx03/__type_traits/is_integral.h>24#include <__cxx03/__type_traits/is_same.h>25#include <__cxx03/__type_traits/is_signed.h>26#include <__cxx03/__utility/move.h>27#include <__cxx03/limits>28 29#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS30# include <__cxx03/cwchar>31#endif32 33#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)34# pragma GCC system_header35#endif36 37_LIBCPP_PUSH_MACROS38#include <__cxx03/__undef_macros>39 40_LIBCPP_BEGIN_NAMESPACE_STD41 42// generic implementation43template <class _Iter, class _Sent, class _Tp, class _Proj>44_LIBCPP_HIDE_FROM_ABI _Iter __find(_Iter __first, _Sent __last, const _Tp& __value, _Proj& __proj) {45 for (; __first != __last; ++__first)46 if (std::__invoke(__proj, *__first) == __value)47 break;48 return __first;49}50 51// trivially equality comparable implementations52template <class _Tp,53 class _Up,54 class _Proj,55 __enable_if_t<__is_identity<_Proj>::value && __libcpp_is_trivially_equality_comparable<_Tp, _Up>::value &&56 sizeof(_Tp) == 1,57 int> = 0>58_LIBCPP_HIDE_FROM_ABI _Tp* __find(_Tp* __first, _Tp* __last, const _Up& __value, _Proj&) {59 if (auto __ret = std::__constexpr_memchr(__first, __value, __last - __first))60 return __ret;61 return __last;62}63 64#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS65template <class _Tp,66 class _Up,67 class _Proj,68 __enable_if_t<__is_identity<_Proj>::value && __libcpp_is_trivially_equality_comparable<_Tp, _Up>::value &&69 sizeof(_Tp) == sizeof(wchar_t) && _LIBCPP_ALIGNOF(_Tp) >= _LIBCPP_ALIGNOF(wchar_t),70 int> = 0>71_LIBCPP_HIDE_FROM_ABI _Tp* __find(_Tp* __first, _Tp* __last, const _Up& __value, _Proj&) {72 if (auto __ret = std::__constexpr_wmemchr(__first, __value, __last - __first))73 return __ret;74 return __last;75}76#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS77 78// TODO: This should also be possible to get right with different signedness79// cast integral types to allow vectorization80template <class _Tp,81 class _Up,82 class _Proj,83 __enable_if_t<__is_identity<_Proj>::value && !__libcpp_is_trivially_equality_comparable<_Tp, _Up>::value &&84 is_integral<_Tp>::value && is_integral<_Up>::value &&85 is_signed<_Tp>::value == is_signed<_Up>::value,86 int> = 0>87_LIBCPP_HIDE_FROM_ABI _Tp* __find(_Tp* __first, _Tp* __last, const _Up& __value, _Proj& __proj) {88 if (__value < numeric_limits<_Tp>::min() || __value > numeric_limits<_Tp>::max())89 return __last;90 return std::__find(__first, __last, _Tp(__value), __proj);91}92 93// __bit_iterator implementation94template <bool _ToFind, class _Cp, bool _IsConst>95_LIBCPP_HIDE_FROM_ABI __bit_iterator<_Cp, _IsConst>96__find_bool(__bit_iterator<_Cp, _IsConst> __first, typename _Cp::size_type __n) {97 using _It = __bit_iterator<_Cp, _IsConst>;98 using __storage_type = typename _It::__storage_type;99 100 const int __bits_per_word = _It::__bits_per_word;101 // do first partial word102 if (__first.__ctz_ != 0) {103 __storage_type __clz_f = static_cast<__storage_type>(__bits_per_word - __first.__ctz_);104 __storage_type __dn = std::min(__clz_f, __n);105 __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));106 __storage_type __b = std::__invert_if<!_ToFind>(*__first.__seg_) & __m;107 if (__b)108 return _It(__first.__seg_, static_cast<unsigned>(std::__countr_zero(__b)));109 if (__n == __dn)110 return __first + __n;111 __n -= __dn;112 ++__first.__seg_;113 }114 // do middle whole words115 for (; __n >= __bits_per_word; ++__first.__seg_, __n -= __bits_per_word) {116 __storage_type __b = std::__invert_if<!_ToFind>(*__first.__seg_);117 if (__b)118 return _It(__first.__seg_, static_cast<unsigned>(std::__countr_zero(__b)));119 }120 // do last partial word121 if (__n > 0) {122 __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);123 __storage_type __b = std::__invert_if<!_ToFind>(*__first.__seg_) & __m;124 if (__b)125 return _It(__first.__seg_, static_cast<unsigned>(std::__countr_zero(__b)));126 }127 return _It(__first.__seg_, static_cast<unsigned>(__n));128}129 130template <class _Cp, bool _IsConst, class _Tp, class _Proj, __enable_if_t<__is_identity<_Proj>::value, int> = 0>131inline _LIBCPP_HIDE_FROM_ABI __bit_iterator<_Cp, _IsConst>132__find(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last, const _Tp& __value, _Proj&) {133 if (static_cast<bool>(__value))134 return std::__find_bool<true>(__first, static_cast<typename _Cp::size_type>(__last - __first));135 return std::__find_bool<false>(__first, static_cast<typename _Cp::size_type>(__last - __first));136}137 138// segmented iterator implementation139 140template <class>141struct __find_segment;142 143template <class _SegmentedIterator,144 class _Tp,145 class _Proj,146 __enable_if_t<__is_segmented_iterator<_SegmentedIterator>::value, int> = 0>147_LIBCPP_HIDE_FROM_ABI _SegmentedIterator148__find(_SegmentedIterator __first, _SegmentedIterator __last, const _Tp& __value, _Proj& __proj) {149 return std::__find_segment_if(std::move(__first), std::move(__last), __find_segment<_Tp>(__value), __proj);150}151 152template <class _Tp>153struct __find_segment {154 const _Tp& __value_;155 156 _LIBCPP_HIDE_FROM_ABI __find_segment(const _Tp& __value) : __value_(__value) {}157 158 template <class _InputIterator, class _Proj>159 _LIBCPP_HIDE_FROM_ABI _InputIterator operator()(_InputIterator __first, _InputIterator __last, _Proj& __proj) const {160 return std::__find(__first, __last, __value_, __proj);161 }162};163 164// public API165template <class _InputIterator, class _Tp>166_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _InputIterator167find(_InputIterator __first, _InputIterator __last, const _Tp& __value) {168 __identity __proj;169 return std::__rewrap_iter(170 __first, std::__find(std::__unwrap_iter(__first), std::__unwrap_iter(__last), __value, __proj));171}172 173_LIBCPP_END_NAMESPACE_STD174 175_LIBCPP_POP_MACROS176 177#endif // _LIBCPP___CXX03___ALGORITHM_FIND_H178