xref: /llvm-project/libcxx/include/__algorithm/equal.h (revision a2fe4105812531f944f174f2ecfe0c67b8cffaed)
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 <__functional/invoke.h>
18 #include <__iterator/distance.h>
19 #include <__iterator/iterator_traits.h>
20 #include <__string/constexpr_c_functions.h>
21 #include <__type_traits/enable_if.h>
22 #include <__type_traits/integral_constant.h>
23 #include <__type_traits/is_constant_evaluated.h>
24 #include <__type_traits/is_equality_comparable.h>
25 #include <__type_traits/is_volatile.h>
26 #include <__type_traits/operation_traits.h>
27 #include <__utility/move.h>
28 
29 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
30 #  pragma GCC system_header
31 #endif
32 
33 _LIBCPP_PUSH_MACROS
34 #include <__undef_macros>
35 
36 _LIBCPP_BEGIN_NAMESPACE_STD
37 
38 template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
39 _LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool __equal_iter_impl(
40     _InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _BinaryPredicate& __pred) {
41   for (; __first1 != __last1; ++__first1, (void)++__first2)
42     if (!__pred(*__first1, *__first2))
43       return false;
44   return true;
45 }
46 
47 template <class _Tp,
48           class _Up,
49           class _BinaryPredicate,
50           __enable_if_t<__desugars_to<__equal_tag, _BinaryPredicate, _Tp, _Up>::value && !is_volatile<_Tp>::value &&
51                             !is_volatile<_Up>::value && __libcpp_is_trivially_equality_comparable<_Tp, _Up>::value,
52                         int> = 0>
53 _LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
54 __equal_iter_impl(_Tp* __first1, _Tp* __last1, _Up* __first2, _BinaryPredicate&) {
55   return std::__constexpr_memcmp_equal(__first1, __first2, __element_count(__last1 - __first1));
56 }
57 
58 template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
59 _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
60 equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _BinaryPredicate __pred) {
61   return std::__equal_iter_impl(
62       std::__unwrap_iter(__first1), std::__unwrap_iter(__last1), std::__unwrap_iter(__first2), __pred);
63 }
64 
65 template <class _InputIterator1, class _InputIterator2>
66 _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
67 equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2) {
68   return std::equal(__first1, __last1, __first2, __equal_to());
69 }
70 
71 #if _LIBCPP_STD_VER >= 14
72 
73 template <class _Iter1, class _Sent1, class _Iter2, class _Sent2, class _Pred, class _Proj1, class _Proj2>
74 _LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool __equal_impl(
75     _Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2, _Pred& __comp, _Proj1& __proj1, _Proj2& __proj2) {
76   while (__first1 != __last1 && __first2 != __last2) {
77     if (!std::__invoke(__comp, std::__invoke(__proj1, *__first1), std::__invoke(__proj2, *__first2)))
78       return false;
79     ++__first1;
80     ++__first2;
81   }
82   return __first1 == __last1 && __first2 == __last2;
83 }
84 
85 template <class _Tp,
86           class _Up,
87           class _Pred,
88           class _Proj1,
89           class _Proj2,
90           __enable_if_t<__desugars_to<__equal_tag, _Pred, _Tp, _Up>::value && __is_identity<_Proj1>::value &&
91                             __is_identity<_Proj2>::value && !is_volatile<_Tp>::value && !is_volatile<_Up>::value &&
92                             __libcpp_is_trivially_equality_comparable<_Tp, _Up>::value,
93                         int> = 0>
94 _LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
95 __equal_impl(_Tp* __first1, _Tp* __last1, _Up* __first2, _Up*, _Pred&, _Proj1&, _Proj2&) {
96   return std::__constexpr_memcmp_equal(__first1, __first2, __element_count(__last1 - __first1));
97 }
98 
99 template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
100 _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
101 equal(_InputIterator1 __first1,
102       _InputIterator1 __last1,
103       _InputIterator2 __first2,
104       _InputIterator2 __last2,
105       _BinaryPredicate __pred) {
106   if constexpr (__has_random_access_iterator_category<_InputIterator1>::value &&
107                 __has_random_access_iterator_category<_InputIterator2>::value) {
108     if (std::distance(__first1, __last1) != std::distance(__first2, __last2))
109       return false;
110   }
111   __identity __proj;
112   return std::__equal_impl(
113       std::__unwrap_iter(__first1),
114       std::__unwrap_iter(__last1),
115       std::__unwrap_iter(__first2),
116       std::__unwrap_iter(__last2),
117       __pred,
118       __proj,
119       __proj);
120 }
121 
122 template <class _InputIterator1, class _InputIterator2>
123 _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
124 equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2) {
125   return std::equal(__first1, __last1, __first2, __last2, __equal_to());
126 }
127 
128 #endif // _LIBCPP_STD_VER >= 14
129 
130 _LIBCPP_END_NAMESPACE_STD
131 
132 _LIBCPP_POP_MACROS
133 
134 #endif // _LIBCPP___ALGORITHM_EQUAL_H
135