xref: /freebsd-src/contrib/llvm-project/libcxx/include/__algorithm/equal_range.h (revision 0fca6ea1d4eea4c934cfff25ac9ee8ad6fe95583)
1fe6060f1SDimitry Andric //===----------------------------------------------------------------------===//
2fe6060f1SDimitry Andric //
3fe6060f1SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4fe6060f1SDimitry Andric // See https://llvm.org/LICENSE.txt for license information.
5fe6060f1SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6fe6060f1SDimitry Andric //
7fe6060f1SDimitry Andric //===----------------------------------------------------------------------===//
8fe6060f1SDimitry Andric 
9fe6060f1SDimitry Andric #ifndef _LIBCPP___ALGORITHM_EQUAL_RANGE_H
10fe6060f1SDimitry Andric #define _LIBCPP___ALGORITHM_EQUAL_RANGE_H
11fe6060f1SDimitry Andric 
12fe6060f1SDimitry Andric #include <__algorithm/comp.h>
13fe6060f1SDimitry Andric #include <__algorithm/comp_ref_type.h>
14fe6060f1SDimitry Andric #include <__algorithm/half_positive.h>
1581ad6265SDimitry Andric #include <__algorithm/iterator_operations.h>
16fe6060f1SDimitry Andric #include <__algorithm/lower_bound.h>
17fe6060f1SDimitry Andric #include <__algorithm/upper_bound.h>
1804eeddc0SDimitry Andric #include <__config>
1981ad6265SDimitry Andric #include <__functional/identity.h>
20fcaf7f86SDimitry Andric #include <__functional/invoke.h>
2181ad6265SDimitry Andric #include <__iterator/advance.h>
2281ad6265SDimitry Andric #include <__iterator/distance.h>
2381ad6265SDimitry Andric #include <__iterator/iterator_traits.h>
24972a253aSDimitry Andric #include <__iterator/next.h>
25fcaf7f86SDimitry Andric #include <__type_traits/is_callable.h>
26*0fca6ea1SDimitry Andric #include <__type_traits/is_constructible.h>
27fcaf7f86SDimitry Andric #include <__utility/move.h>
2881ad6265SDimitry Andric #include <__utility/pair.h>
29fe6060f1SDimitry Andric 
30fe6060f1SDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
31fe6060f1SDimitry Andric #  pragma GCC system_header
32fe6060f1SDimitry Andric #endif
33fe6060f1SDimitry Andric 
34b3edf446SDimitry Andric _LIBCPP_PUSH_MACROS
35b3edf446SDimitry Andric #include <__undef_macros>
36b3edf446SDimitry Andric 
37fe6060f1SDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD
38fe6060f1SDimitry Andric 
39fcaf7f86SDimitry Andric template <class _AlgPolicy, class _Compare, class _Iter, class _Sent, class _Tp, class _Proj>
40bdd1243dSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_Iter, _Iter>
41fcaf7f86SDimitry Andric __equal_range(_Iter __first, _Sent __last, const _Tp& __value, _Compare&& __comp, _Proj&& __proj) {
42fcaf7f86SDimitry Andric   auto __len  = _IterOps<_AlgPolicy>::distance(__first, __last);
43fcaf7f86SDimitry Andric   _Iter __end = _IterOps<_AlgPolicy>::next(__first, __last);
44fcaf7f86SDimitry Andric   while (__len != 0) {
45fcaf7f86SDimitry Andric     auto __half_len = std::__half_positive(__len);
46fcaf7f86SDimitry Andric     _Iter __mid     = _IterOps<_AlgPolicy>::next(__first, __half_len);
47fcaf7f86SDimitry Andric     if (std::__invoke(__comp, std::__invoke(__proj, *__mid), __value)) {
48fcaf7f86SDimitry Andric       __first = ++__mid;
49fcaf7f86SDimitry Andric       __len -= __half_len + 1;
50fcaf7f86SDimitry Andric     } else if (std::__invoke(__comp, __value, std::__invoke(__proj, *__mid))) {
51fcaf7f86SDimitry Andric       __end = __mid;
52fcaf7f86SDimitry Andric       __len = __half_len;
53fcaf7f86SDimitry Andric     } else {
54fcaf7f86SDimitry Andric       _Iter __mp1 = __mid;
55cb14a3feSDimitry Andric       return pair<_Iter, _Iter>(std::__lower_bound<_AlgPolicy>(__first, __mid, __value, __comp, __proj),
56fcaf7f86SDimitry Andric                                 std::__upper_bound<_AlgPolicy>(++__mp1, __end, __value, __comp, __proj));
57fe6060f1SDimitry Andric     }
58fe6060f1SDimitry Andric   }
59fcaf7f86SDimitry Andric   return pair<_Iter, _Iter>(__first, __first);
60fe6060f1SDimitry Andric }
61fe6060f1SDimitry Andric 
62fe6060f1SDimitry Andric template <class _ForwardIterator, class _Tp, class _Compare>
63*0fca6ea1SDimitry Andric _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_ForwardIterator, _ForwardIterator>
64fcaf7f86SDimitry Andric equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value, _Compare __comp) {
65cb14a3feSDimitry Andric   static_assert(__is_callable<_Compare, decltype(*__first), const _Tp&>::value, "The comparator has to be callable");
66cb14a3feSDimitry Andric   static_assert(is_copy_constructible<_ForwardIterator>::value, "Iterator has to be copy constructible");
67fcaf7f86SDimitry Andric   return std::__equal_range<_ClassicAlgPolicy>(
68bdd1243dSDimitry Andric       std::move(__first),
69bdd1243dSDimitry Andric       std::move(__last),
70bdd1243dSDimitry Andric       __value,
71bdd1243dSDimitry Andric       static_cast<__comp_ref_type<_Compare> >(__comp),
72bdd1243dSDimitry Andric       std::__identity());
73fe6060f1SDimitry Andric }
74fe6060f1SDimitry Andric 
75fe6060f1SDimitry Andric template <class _ForwardIterator, class _Tp>
76*0fca6ea1SDimitry Andric _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_ForwardIterator, _ForwardIterator>
77fcaf7f86SDimitry Andric equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value) {
7806c3fb27SDimitry Andric   return std::equal_range(std::move(__first), std::move(__last), __value, __less<>());
79fe6060f1SDimitry Andric }
80fe6060f1SDimitry Andric 
81fe6060f1SDimitry Andric _LIBCPP_END_NAMESPACE_STD
82fe6060f1SDimitry Andric 
83b3edf446SDimitry Andric _LIBCPP_POP_MACROS
84b3edf446SDimitry Andric 
85fe6060f1SDimitry Andric #endif // _LIBCPP___ALGORITHM_EQUAL_RANGE_H
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