xref: /llvm-project/libcxx/include/__algorithm/equal.h (revision b905bcc5090cde734e8b7bbceae13bd5a606cc14)
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_EQUAL_H
11 #define _LIBCPP___ALGORITHM_EQUAL_H
12 
13 #include <__algorithm/comp.h>
14 #include <__algorithm/unwrap_iter.h>
15 #include <__config>
16 #include <__functional/identity.h>
17 #include <__iterator/distance.h>
18 #include <__iterator/iterator_traits.h>
19 #include <__string/constexpr_c_functions.h>
20 #include <__type_traits/desugars_to.h>
21 #include <__type_traits/enable_if.h>
22 #include <__type_traits/invoke.h>
23 #include <__type_traits/is_equality_comparable.h>
24 #include <__type_traits/is_volatile.h>
25 #include <__utility/move.h>
26 
27 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
28 #  pragma GCC system_header
29 #endif
30 
31 _LIBCPP_PUSH_MACROS
32 #include <__undef_macros>
33 
34 _LIBCPP_BEGIN_NAMESPACE_STD
35 
36 template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
37 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool __equal_iter_impl(
38     _InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _BinaryPredicate& __pred) {
39   for (; __first1 != __last1; ++__first1, (void)++__first2)
40     if (!__pred(*__first1, *__first2))
41       return false;
42   return true;
43 }
44 
45 template <class _Tp,
46           class _Up,
47           class _BinaryPredicate,
48           __enable_if_t<__desugars_to_v<__equal_tag, _BinaryPredicate, _Tp, _Up> && !is_volatile<_Tp>::value &&
49                             !is_volatile<_Up>::value && __libcpp_is_trivially_equality_comparable<_Tp, _Up>::value,
50                         int> = 0>
51 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
52 __equal_iter_impl(_Tp* __first1, _Tp* __last1, _Up* __first2, _BinaryPredicate&) {
53   return std::__constexpr_memcmp_equal(__first1, __first2, __element_count(__last1 - __first1));
54 }
55 
56 template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
57 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
58 equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _BinaryPredicate __pred) {
59   return std::__equal_iter_impl(
60       std::__unwrap_iter(__first1), std::__unwrap_iter(__last1), std::__unwrap_iter(__first2), __pred);
61 }
62 
63 template <class _InputIterator1, class _InputIterator2>
64 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
65 equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2) {
66   return std::equal(__first1, __last1, __first2, __equal_to());
67 }
68 
69 #if _LIBCPP_STD_VER >= 14
70 
71 template <class _Iter1, class _Sent1, class _Iter2, class _Sent2, class _Pred, class _Proj1, class _Proj2>
72 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool __equal_impl(
73     _Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2, _Pred& __comp, _Proj1& __proj1, _Proj2& __proj2) {
74   while (__first1 != __last1 && __first2 != __last2) {
75     if (!std::__invoke(__comp, std::__invoke(__proj1, *__first1), std::__invoke(__proj2, *__first2)))
76       return false;
77     ++__first1;
78     ++__first2;
79   }
80   return __first1 == __last1 && __first2 == __last2;
81 }
82 
83 template <class _Tp,
84           class _Up,
85           class _Pred,
86           class _Proj1,
87           class _Proj2,
88           __enable_if_t<__desugars_to_v<__equal_tag, _Pred, _Tp, _Up> && __is_identity<_Proj1>::value &&
89                             __is_identity<_Proj2>::value && !is_volatile<_Tp>::value && !is_volatile<_Up>::value &&
90                             __libcpp_is_trivially_equality_comparable<_Tp, _Up>::value,
91                         int> = 0>
92 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
93 __equal_impl(_Tp* __first1, _Tp* __last1, _Up* __first2, _Up*, _Pred&, _Proj1&, _Proj2&) {
94   return std::__constexpr_memcmp_equal(__first1, __first2, __element_count(__last1 - __first1));
95 }
96 
97 template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
98 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
99 equal(_InputIterator1 __first1,
100       _InputIterator1 __last1,
101       _InputIterator2 __first2,
102       _InputIterator2 __last2,
103       _BinaryPredicate __pred) {
104   if constexpr (__has_random_access_iterator_category<_InputIterator1>::value &&
105                 __has_random_access_iterator_category<_InputIterator2>::value) {
106     if (std::distance(__first1, __last1) != std::distance(__first2, __last2))
107       return false;
108   }
109   __identity __proj;
110   return std::__equal_impl(
111       std::__unwrap_iter(__first1),
112       std::__unwrap_iter(__last1),
113       std::__unwrap_iter(__first2),
114       std::__unwrap_iter(__last2),
115       __pred,
116       __proj,
117       __proj);
118 }
119 
120 template <class _InputIterator1, class _InputIterator2>
121 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
122 equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2) {
123   return std::equal(__first1, __last1, __first2, __last2, __equal_to());
124 }
125 
126 #endif // _LIBCPP_STD_VER >= 14
127 
128 _LIBCPP_END_NAMESPACE_STD
129 
130 _LIBCPP_POP_MACROS
131 
132 #endif // _LIBCPP___ALGORITHM_EQUAL_H
133