xref: /llvm-project/libcxx/include/__algorithm/set_intersection.h (revision 295b951ebcfea8d1fedf8abf4ffd449a83a551fd)
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 <__utility/move.h>
18 
19 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
20 #  pragma GCC system_header
21 #endif
22 
23 _LIBCPP_BEGIN_NAMESPACE_STD
24 
25 template <class _InIter1, class _InIter2, class _OutIter>
26 struct __set_intersection_result {
27   _InIter1 in1;
28   _InIter2 in2;
29   _OutIter out;
30 
31   // need a constructor as C++03 aggregate init is hard
32   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
33   __set_intersection_result(_InIter1&& __in_iter1, _InIter2&& __in_iter2, _OutIter&& __out_iter)
34       : in1(std::move(__in_iter1)), in2(std::move(__in_iter2)), out(std::move(__out_iter)) {}
35 };
36 
37 template <class _AlgPolicy, class _Compare, class _InIter1, class _Sent1, class _InIter2, class _Sent2, class _OutIter>
38 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 __set_intersection_result<_InIter1, _InIter2, _OutIter>
39 __set_intersection(
40     _InIter1 __first1, _Sent1 __last1, _InIter2 __first2, _Sent2 __last2, _OutIter __result, _Compare&& __comp) {
41   while (__first1 != __last1 && __first2 != __last2) {
42     if (__comp(*__first1, *__first2))
43       ++__first1;
44     else {
45       if (!__comp(*__first2, *__first1)) {
46         *__result = *__first1;
47         ++__result;
48         ++__first1;
49       }
50       ++__first2;
51     }
52   }
53 
54   return __set_intersection_result<_InIter1, _InIter2, _OutIter>(
55       _IterOps<_AlgPolicy>::next(std::move(__first1), std::move(__last1)),
56       _IterOps<_AlgPolicy>::next(std::move(__first2), std::move(__last2)),
57       std::move(__result));
58 }
59 
60 template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
61 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 _OutputIterator set_intersection(
62     _InputIterator1 __first1,
63     _InputIterator1 __last1,
64     _InputIterator2 __first2,
65     _InputIterator2 __last2,
66     _OutputIterator __result,
67     _Compare __comp) {
68   typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
69   return std::__set_intersection<_ClassicAlgPolicy, _Comp_ref>(
70              std::move(__first1),
71              std::move(__last1),
72              std::move(__first2),
73              std::move(__last2),
74              std::move(__result),
75              __comp)
76       .out;
77 }
78 
79 template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
80 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 _OutputIterator set_intersection(
81     _InputIterator1 __first1,
82     _InputIterator1 __last1,
83     _InputIterator2 __first2,
84     _InputIterator2 __last2,
85     _OutputIterator __result) {
86   return std::__set_intersection<_ClassicAlgPolicy>(
87              std::move(__first1),
88              std::move(__last1),
89              std::move(__first2),
90              std::move(__last2),
91              std::move(__result),
92              __less<typename iterator_traits<_InputIterator1>::value_type,
93                     typename iterator_traits<_InputIterator2>::value_type>())
94       .out;
95 }
96 
97 _LIBCPP_END_NAMESPACE_STD
98 
99 #endif // _LIBCPP___ALGORITHM_SET_INTERSECTION_H
100