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
42struct __merge {
43 template <input_iterator _InIter1,
44 sentinel_for<_InIter1> _Sent1,
45 input_iterator _InIter2,
46 sentinel_for<_InIter2> _Sent2,
47 weakly_incrementable _OutIter,
48 class _Comp = less,
49 class _Proj1 = identity,
50 class _Proj2 = identity>
51 requires mergeable<_InIter1, _InIter2, _OutIter, _Comp, _Proj1, _Proj2>
52 _LIBCPP_HIDE_FROM_ABI constexpr merge_result<_InIter1, _InIter2, _OutIter> operator()(
53 _InIter1 __first1,
54 _Sent1 __last1,
55 _InIter2 __first2,
56 _Sent2 __last2,
57 _OutIter __result,
58 _Comp __comp = {},
59 _Proj1 __proj1 = {},
60 _Proj2 __proj2 = {}) const {
61 return __merge::__merge_impl(__first1, __last1, __first2, __last2, __result, __comp, __proj1, __proj2);
62 }
63
64 template <input_range _Range1,
65 input_range _Range2,
66 weakly_incrementable _OutIter,
67 class _Comp = less,
68 class _Proj1 = identity,
69 class _Proj2 = identity>
70 requires mergeable<iterator_t<_Range1>, iterator_t<_Range2>, _OutIter, _Comp, _Proj1, _Proj2>
71 _LIBCPP_HIDE_FROM_ABI constexpr merge_result<borrowed_iterator_t<_Range1>, borrowed_iterator_t<_Range2>, _OutIter>
72 operator()(_Range1&& __range1,
73 _Range2&& __range2,
74 _OutIter __result,
75 _Comp __comp = {},
76 _Proj1 __proj1 = {},
77 _Proj2 __proj2 = {}) const {
78 return __merge::__merge_impl(
79 ranges::begin(__range1),
80 ranges::end(__range1),
81 ranges::begin(__range2),
82 ranges::end(__range2),
83 __result,
84 __comp,
85 __proj1,
86 __proj2);
87 }
88
89 template < class _InIter1,
90 class _Sent1,
91 class _InIter2,
92 class _Sent2,
93 class _OutIter,
94 class _Comp,
95 class _Proj1,
96 class _Proj2>
97 _LIBCPP_HIDE_FROM_ABI static constexpr merge_result<__remove_cvref_t<_InIter1>,
98 __remove_cvref_t<_InIter2>,
99 __remove_cvref_t<_OutIter>>
100 __merge_impl(_InIter1&& __first1,
101 _Sent1&& __last1,
102 _InIter2&& __first2,
103 _Sent2&& __last2,
104 _OutIter&& __result,
105 _Comp&& __comp,
106 _Proj1&& __proj1,
107 _Proj2&& __proj2) {
108 for (; __first1 != __last1 && __first2 != __last2; ++__result) {
109 if (std::invoke(__comp, std::invoke(__proj2, *__first2), std::invoke(__proj1, *__first1))) {
110 *__result = *__first2;
111 ++__first2;
112 } else {
113 *__result = *__first1;
114 ++__first1;
115 }
116 }
117 auto __ret1 = ranges::copy(std::move(__first1), std::move(__last1), std::move(__result));
118 auto __ret2 = ranges::copy(std::move(__first2), std::move(__last2), std::move(__ret1.out));
119 return {std::move(__ret1.in), std::move(__ret2.in), std::move(__ret2.out)};
120 }
121};
122
123inline namespace __cpo {
124inline constexpr auto merge = __merge{};
125} // namespace __cpo
126} // namespace ranges
127
128_LIBCPP_END_NAMESPACE_STD
129
130#endif // _LIBCPP_STD_VER >= 20
131
132_LIBCPP_POP_MACROS
133
134#endif // _LIBCPP___ALGORITHM_RANGES_MERGE_H
135