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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-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP___CXX03___ALGORITHM_FIND_H
11#define _LIBCPP___CXX03___ALGORITHM_FIND_H
12
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_CHARACTERS
30# include <__cxx03/cwchar>
31#endif
32
33#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
34# pragma GCC system_header
35#endif
36
37_LIBCPP_PUSH_MACROS
38#include <__cxx03/__undef_macros>
39
40_LIBCPP_BEGIN_NAMESPACE_STD
41
42// generic implementation
43template <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 implementations
52template <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_CHARACTERS
65template <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_CHARACTERS
77
78// TODO: This should also be possible to get right with different signedness
79// cast integral types to allow vectorization
80template <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 implementation
94template <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 word
102 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::__libcpp_ctz(__b)));
109 if (__n == __dn)
110 return __first + __n;
111 __n -= __dn;
112 ++__first.__seg_;
113 }
114 // do middle whole words
115 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::__libcpp_ctz(__b)));
119 }
120 // do last partial word
121 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::__libcpp_ctz(__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 implementation
139
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 _SegmentedIterator
148__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 API
165template <class _InputIterator, class _Tp>
166_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _InputIterator
167find(_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_STD
174
175_LIBCPP_POP_MACROS
176
177#endif // _LIBCPP___CXX03___ALGORITHM_FIND_H
178

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source code of libcxx/include/__cxx03/__algorithm/find.h