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_RANGES_MERGE_H
10#define _LIBCPP___ALGORITHM_RANGES_MERGE_H
11
12#include <__algorithm/in_in_out_result.h>
13#include <__algorithm/ranges_copy.h>
14#include <__config>
15#include <__functional/identity.h>
16#include <__functional/invoke.h>
17#include <__functional/ranges_operations.h>
18#include <__iterator/concepts.h>
19#include <__iterator/mergeable.h>
20#include <__ranges/access.h>
21#include <__ranges/concepts.h>
22#include <__ranges/dangling.h>
23#include <__type_traits/remove_cvref.h>
24#include <__utility/move.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#if _LIBCPP_STD_VER >= 20
34
35_LIBCPP_BEGIN_NAMESPACE_STD
36
37namespace ranges {
38
39template <class _InIter1, class _InIter2, class _OutIter>
40using merge_result = in_in_out_result<_InIter1, _InIter2, _OutIter>;
41
42namespace __merge {
43
44template < class _InIter1,
45 class _Sent1,
46 class _InIter2,
47 class _Sent2,
48 class _OutIter,
49 class _Comp,
50 class _Proj1,
51 class _Proj2>
52_LIBCPP_HIDE_FROM_ABI constexpr merge_result<__remove_cvref_t<_InIter1>,
53 __remove_cvref_t<_InIter2>,
54 __remove_cvref_t<_OutIter>>
55__merge_impl(_InIter1&& __first1,
56 _Sent1&& __last1,
57 _InIter2&& __first2,
58 _Sent2&& __last2,
59 _OutIter&& __result,
60 _Comp&& __comp,
61 _Proj1&& __proj1,
62 _Proj2&& __proj2) {
63 for (; __first1 != __last1 && __first2 != __last2; ++__result) {
64 if (std::invoke(__comp, std::invoke(__proj2, *__first2), std::invoke(__proj1, *__first1))) {
65 *__result = *__first2;
66 ++__first2;
67 } else {
68 *__result = *__first1;
69 ++__first1;
70 }
71 }
72 auto __ret1 = ranges::copy(std::move(__first1), std::move(__last1), std::move(__result));
73 auto __ret2 = ranges::copy(std::move(__first2), std::move(__last2), std::move(__ret1.out));
74 return {std::move(__ret1.in), std::move(__ret2.in), std::move(__ret2.out)};
75}
76
77struct __fn {
78 template <input_iterator _InIter1,
79 sentinel_for<_InIter1> _Sent1,
80 input_iterator _InIter2,
81 sentinel_for<_InIter2> _Sent2,
82 weakly_incrementable _OutIter,
83 class _Comp = less,
84 class _Proj1 = identity,
85 class _Proj2 = identity>
86 requires mergeable<_InIter1, _InIter2, _OutIter, _Comp, _Proj1, _Proj2>
87 _LIBCPP_HIDE_FROM_ABI constexpr merge_result<_InIter1, _InIter2, _OutIter> operator()(
88 _InIter1 __first1,
89 _Sent1 __last1,
90 _InIter2 __first2,
91 _Sent2 __last2,
92 _OutIter __result,
93 _Comp __comp = {},
94 _Proj1 __proj1 = {},
95 _Proj2 __proj2 = {}) const {
96 return __merge::__merge_impl(__first1, __last1, __first2, __last2, __result, __comp, __proj1, __proj2);
97 }
98
99 template <input_range _Range1,
100 input_range _Range2,
101 weakly_incrementable _OutIter,
102 class _Comp = less,
103 class _Proj1 = identity,
104 class _Proj2 = identity>
105 requires mergeable<iterator_t<_Range1>, iterator_t<_Range2>, _OutIter, _Comp, _Proj1, _Proj2>
106 _LIBCPP_HIDE_FROM_ABI constexpr merge_result<borrowed_iterator_t<_Range1>, borrowed_iterator_t<_Range2>, _OutIter>
107 operator()(_Range1&& __range1,
108 _Range2&& __range2,
109 _OutIter __result,
110 _Comp __comp = {},
111 _Proj1 __proj1 = {},
112 _Proj2 __proj2 = {}) const {
113 return __merge::__merge_impl(
114 ranges::begin(__range1),
115 ranges::end(__range1),
116 ranges::begin(__range2),
117 ranges::end(__range2),
118 __result,
119 __comp,
120 __proj1,
121 __proj2);
122 }
123};
124
125} // namespace __merge
126
127inline namespace __cpo {
128inline constexpr auto merge = __merge::__fn{};
129} // namespace __cpo
130} // namespace ranges
131
132_LIBCPP_END_NAMESPACE_STD
133
134#endif // _LIBCPP_STD_VER >= 20
135
136_LIBCPP_POP_MACROS
137
138#endif // _LIBCPP___ALGORITHM_RANGES_MERGE_H
139