xref: /freebsd/contrib/llvm-project/libcxx/include/__algorithm/set_intersection.h (revision 3f0efe05432b1633991114ca4ca330102a561959)
1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #ifndef _LIBCPP___ALGORITHM_SET_INTERSECTION_H
10 #define _LIBCPP___ALGORITHM_SET_INTERSECTION_H
11 
12 #include <__algorithm/comp.h>
13 #include <__algorithm/comp_ref_type.h>
14 #include <__algorithm/iterator_operations.h>
15 #include <__config>
16 #include <__iterator/iterator_traits.h>
17 #include <__iterator/next.h>
18 #include <__utility/move.h>
19 
20 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
21 #  pragma GCC system_header
22 #endif
23 
24 _LIBCPP_PUSH_MACROS
25 #include <__undef_macros>
26 
27 _LIBCPP_BEGIN_NAMESPACE_STD
28 
29 template <class _InIter1, class _InIter2, class _OutIter>
30 struct __set_intersection_result {
31   _InIter1 __in1_;
32   _InIter2 __in2_;
33   _OutIter __out_;
34 
35   // need a constructor as C++03 aggregate init is hard
36   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
37   __set_intersection_result(_InIter1&& __in_iter1, _InIter2&& __in_iter2, _OutIter&& __out_iter)
38       : __in1_(std::move(__in_iter1)), __in2_(std::move(__in_iter2)), __out_(std::move(__out_iter)) {}
39 };
40 
41 template <class _AlgPolicy, class _Compare, class _InIter1, class _Sent1, class _InIter2, class _Sent2, class _OutIter>
42 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __set_intersection_result<_InIter1, _InIter2, _OutIter>
43 __set_intersection(
44     _InIter1 __first1, _Sent1 __last1, _InIter2 __first2, _Sent2 __last2, _OutIter __result, _Compare&& __comp) {
45   while (__first1 != __last1 && __first2 != __last2) {
46     if (__comp(*__first1, *__first2))
47       ++__first1;
48     else {
49       if (!__comp(*__first2, *__first1)) {
50         *__result = *__first1;
51         ++__result;
52         ++__first1;
53       }
54       ++__first2;
55     }
56   }
57 
58   return __set_intersection_result<_InIter1, _InIter2, _OutIter>(
59       _IterOps<_AlgPolicy>::next(std::move(__first1), std::move(__last1)),
60       _IterOps<_AlgPolicy>::next(std::move(__first2), std::move(__last2)),
61       std::move(__result));
62 }
63 
64 template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
65 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator set_intersection(
66     _InputIterator1 __first1,
67     _InputIterator1 __last1,
68     _InputIterator2 __first2,
69     _InputIterator2 __last2,
70     _OutputIterator __result,
71     _Compare __comp) {
72   return std::__set_intersection<_ClassicAlgPolicy, __comp_ref_type<_Compare> >(
73              std::move(__first1),
74              std::move(__last1),
75              std::move(__first2),
76              std::move(__last2),
77              std::move(__result),
78              __comp)
79       .__out_;
80 }
81 
82 template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
83 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator set_intersection(
84     _InputIterator1 __first1,
85     _InputIterator1 __last1,
86     _InputIterator2 __first2,
87     _InputIterator2 __last2,
88     _OutputIterator __result) {
89   return std::__set_intersection<_ClassicAlgPolicy>(
90              std::move(__first1),
91              std::move(__last1),
92              std::move(__first2),
93              std::move(__last2),
94              std::move(__result),
95              __less<>())
96       .__out_;
97 }
98 
99 _LIBCPP_END_NAMESPACE_STD
100 
101 _LIBCPP_POP_MACROS
102 
103 #endif // _LIBCPP___ALGORITHM_SET_INTERSECTION_H
104