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