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_EQUAL_RANGE_H
10#define _LIBCPP___ALGORITHM_EQUAL_RANGE_H
11
12#include <__algorithm/comp.h>
13#include <__algorithm/comp_ref_type.h>
14#include <__algorithm/half_positive.h>
15#include <__algorithm/iterator_operations.h>
16#include <__algorithm/lower_bound.h>
17#include <__algorithm/upper_bound.h>
18#include <__config>
19#include <__functional/identity.h>
20#include <__type_traits/invoke.h>
21#include <__type_traits/is_callable.h>
22#include <__type_traits/is_constructible.h>
23#include <__utility/move.h>
24#include <__utility/pair.h>
25
26#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
27#  pragma GCC system_header
28#endif
29
30_LIBCPP_PUSH_MACROS
31#include <__undef_macros>
32
33_LIBCPP_BEGIN_NAMESPACE_STD
34
35template <class _AlgPolicy, class _Compare, class _Iter, class _Sent, class _Tp, class _Proj>
36_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_Iter, _Iter>
37__equal_range(_Iter __first, _Sent __last, const _Tp& __value, _Compare&& __comp, _Proj&& __proj) {
38  auto __len  = _IterOps<_AlgPolicy>::distance(__first, __last);
39  _Iter __end = _IterOps<_AlgPolicy>::next(__first, __last);
40  while (__len != 0) {
41    auto __half_len = std::__half_positive(__len);
42    _Iter __mid     = _IterOps<_AlgPolicy>::next(__first, __half_len);
43    if (std::__invoke(__comp, std::__invoke(__proj, *__mid), __value)) {
44      __first = ++__mid;
45      __len -= __half_len + 1;
46    } else if (std::__invoke(__comp, __value, std::__invoke(__proj, *__mid))) {
47      __end = __mid;
48      __len = __half_len;
49    } else {
50      _Iter __mp1 = __mid;
51      return pair<_Iter, _Iter>(std::__lower_bound<_AlgPolicy>(__first, __mid, __value, __comp, __proj),
52                                std::__upper_bound<_AlgPolicy>(++__mp1, __end, __value, __comp, __proj));
53    }
54  }
55  return pair<_Iter, _Iter>(__first, __first);
56}
57
58template <class _ForwardIterator, class _Tp, class _Compare>
59[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_ForwardIterator, _ForwardIterator>
60equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value, _Compare __comp) {
61  static_assert(__is_callable<_Compare&, decltype(*__first), const _Tp&>::value, "The comparator has to be callable");
62  static_assert(is_copy_constructible<_ForwardIterator>::value, "Iterator has to be copy constructible");
63  return std::__equal_range<_ClassicAlgPolicy>(
64      std::move(__first),
65      std::move(__last),
66      __value,
67      static_cast<__comp_ref_type<_Compare> >(__comp),
68      std::__identity());
69}
70
71template <class _ForwardIterator, class _Tp>
72[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_ForwardIterator, _ForwardIterator>
73equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value) {
74  return std::equal_range(std::move(__first), std::move(__last), __value, __less<>());
75}
76
77_LIBCPP_END_NAMESPACE_STD
78
79_LIBCPP_POP_MACROS
80
81#endif // _LIBCPP___ALGORITHM_EQUAL_RANGE_H