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___ALGORITHM_FIND_H
11#define _LIBCPP___ALGORITHM_FIND_H
12
13#include <__algorithm/find_segment_if.h>
14#include <__algorithm/min.h>
15#include <__algorithm/unwrap_iter.h>
16#include <__bit/countr.h>
17#include <__bit/invert_if.h>
18#include <__config>
19#include <__functional/identity.h>
20#include <__fwd/bit_reference.h>
21#include <__iterator/segmented_iterator.h>
22#include <__string/constexpr_c_functions.h>
23#include <__type_traits/enable_if.h>
24#include <__type_traits/invoke.h>
25#include <__type_traits/is_equality_comparable.h>
26#include <__type_traits/is_integral.h>
27#include <__type_traits/is_signed.h>
28#include <__utility/move.h>
29#include <limits>
30
31#if _LIBCPP_HAS_WIDE_CHARACTERS
32# include <cwchar>
33#endif
34
35#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
36# pragma GCC system_header
37#endif
38
39_LIBCPP_PUSH_MACROS
40#include <__undef_macros>
41
42_LIBCPP_BEGIN_NAMESPACE_STD
43
44// generic implementation
45template <class _Iter, class _Sent, class _Tp, class _Proj>
46_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Iter
47__find(_Iter __first, _Sent __last, const _Tp& __value, _Proj& __proj) {
48 for (; __first != __last; ++__first)
49 if (std::__invoke(__proj, *__first) == __value)
50 break;
51 return __first;
52}
53
54// trivially equality comparable implementations
55template <class _Tp,
56 class _Up,
57 class _Proj,
58 __enable_if_t<__is_identity<_Proj>::value && __libcpp_is_trivially_equality_comparable<_Tp, _Up>::value &&
59 sizeof(_Tp) == 1,
60 int> = 0>
61_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Tp* __find(_Tp* __first, _Tp* __last, const _Up& __value, _Proj&) {
62 if (auto __ret = std::__constexpr_memchr(__first, __value, __last - __first))
63 return __ret;
64 return __last;
65}
66
67#if _LIBCPP_HAS_WIDE_CHARACTERS
68template <class _Tp,
69 class _Up,
70 class _Proj,
71 __enable_if_t<__is_identity<_Proj>::value && __libcpp_is_trivially_equality_comparable<_Tp, _Up>::value &&
72 sizeof(_Tp) == sizeof(wchar_t) && _LIBCPP_ALIGNOF(_Tp) >= _LIBCPP_ALIGNOF(wchar_t),
73 int> = 0>
74_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Tp* __find(_Tp* __first, _Tp* __last, const _Up& __value, _Proj&) {
75 if (auto __ret = std::__constexpr_wmemchr(__first, __value, __last - __first))
76 return __ret;
77 return __last;
78}
79#endif // _LIBCPP_HAS_WIDE_CHARACTERS
80
81// TODO: This should also be possible to get right with different signedness
82// cast integral types to allow vectorization
83template <class _Tp,
84 class _Up,
85 class _Proj,
86 __enable_if_t<__is_identity<_Proj>::value && !__libcpp_is_trivially_equality_comparable<_Tp, _Up>::value &&
87 is_integral<_Tp>::value && is_integral<_Up>::value &&
88 is_signed<_Tp>::value == is_signed<_Up>::value,
89 int> = 0>
90_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Tp*
91__find(_Tp* __first, _Tp* __last, const _Up& __value, _Proj& __proj) {
92 if (__value < numeric_limits<_Tp>::min() || __value > numeric_limits<_Tp>::max())
93 return __last;
94 return std::__find(__first, __last, _Tp(__value), __proj);
95}
96
97// __bit_iterator implementation
98template <bool _ToFind, class _Cp, bool _IsConst>
99_LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI __bit_iterator<_Cp, _IsConst>
100__find_bool(__bit_iterator<_Cp, _IsConst> __first, typename __size_difference_type_traits<_Cp>::size_type __n) {
101 using _It = __bit_iterator<_Cp, _IsConst>;
102 using __storage_type = typename _It::__storage_type;
103
104 const int __bits_per_word = _It::__bits_per_word;
105 // do first partial word
106 if (__first.__ctz_ != 0) {
107 __storage_type __clz_f = static_cast<__storage_type>(__bits_per_word - __first.__ctz_);
108 __storage_type __dn = std::min(__clz_f, __n);
109 __storage_type __m = std::__middle_mask<__storage_type>(__clz_f - __dn, __first.__ctz_);
110 __storage_type __b = std::__invert_if<!_ToFind>(*__first.__seg_) & __m;
111 if (__b)
112 return _It(__first.__seg_, static_cast<unsigned>(std::__countr_zero(__b)));
113 if (__n == __dn)
114 return __first + __n;
115 __n -= __dn;
116 ++__first.__seg_;
117 }
118 // do middle whole words
119 for (; __n >= __bits_per_word; ++__first.__seg_, __n -= __bits_per_word) {
120 __storage_type __b = std::__invert_if<!_ToFind>(*__first.__seg_);
121 if (__b)
122 return _It(__first.__seg_, static_cast<unsigned>(std::__countr_zero(__b)));
123 }
124 // do last partial word
125 if (__n > 0) {
126 __storage_type __m = std::__trailing_mask<__storage_type>(__bits_per_word - __n);
127 __storage_type __b = std::__invert_if<!_ToFind>(*__first.__seg_) & __m;
128 if (__b)
129 return _It(__first.__seg_, static_cast<unsigned>(std::__countr_zero(__b)));
130 }
131 return _It(__first.__seg_, static_cast<unsigned>(__n));
132}
133
134template <class _Cp, bool _IsConst, class _Tp, class _Proj, __enable_if_t<__is_identity<_Proj>::value, int> = 0>
135inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __bit_iterator<_Cp, _IsConst>
136__find(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last, const _Tp& __value, _Proj&) {
137 if (static_cast<bool>(__value))
138 return std::__find_bool<true>(
139 __first, static_cast<typename __size_difference_type_traits<_Cp>::size_type>(__last - __first));
140 return std::__find_bool<false>(
141 __first, static_cast<typename __size_difference_type_traits<_Cp>::size_type>(__last - __first));
142}
143
144// segmented iterator implementation
145
146template <class>
147struct __find_segment;
148
149template <class _SegmentedIterator,
150 class _Tp,
151 class _Proj,
152 __enable_if_t<__is_segmented_iterator<_SegmentedIterator>::value, int> = 0>
153_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _SegmentedIterator
154__find(_SegmentedIterator __first, _SegmentedIterator __last, const _Tp& __value, _Proj& __proj) {
155 return std::__find_segment_if(std::move(__first), std::move(__last), __find_segment<_Tp>(__value), __proj);
156}
157
158template <class _Tp>
159struct __find_segment {
160 const _Tp& __value_;
161
162 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR __find_segment(const _Tp& __value) : __value_(__value) {}
163
164 template <class _InputIterator, class _Proj>
165 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _InputIterator
166 operator()(_InputIterator __first, _InputIterator __last, _Proj& __proj) const {
167 return std::__find(__first, __last, __value_, __proj);
168 }
169};
170
171// public API
172template <class _InputIterator, class _Tp>
173[[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _InputIterator
174find(_InputIterator __first, _InputIterator __last, const _Tp& __value) {
175 __identity __proj;
176 return std::__rewrap_iter(
177 __first, std::__find(std::__unwrap_iter(__first), std::__unwrap_iter(__last), __value, __proj));
178}
179
180_LIBCPP_END_NAMESPACE_STD
181
182_LIBCPP_POP_MACROS
183
184#endif // _LIBCPP___ALGORITHM_FIND_H
185