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 <__utility/move.h>
24 #include <type_traits>
25
26 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
27 # pragma GCC system_header
28 #endif
29
30 #if _LIBCPP_STD_VER > 17
31
32 _LIBCPP_BEGIN_NAMESPACE_STD
33
34 namespace ranges {
35
36 template <class _InIter1, class _InIter2, class _OutIter>
37 using merge_result = in_in_out_result<_InIter1, _InIter2, _OutIter>;
38
39 namespace __merge {
40
41 template <
42 class _InIter1,
43 class _Sent1,
44 class _InIter2,
45 class _Sent2,
46 class _OutIter,
47 class _Comp,
48 class _Proj1,
49 class _Proj2>
50 _LIBCPP_HIDE_FROM_ABI constexpr merge_result<__remove_cvref_t<_InIter1>, __remove_cvref_t<_InIter2>, __remove_cvref_t<_OutIter>>
__merge_impl(_InIter1 && __first1,_Sent1 && __last1,_InIter2 && __first2,_Sent2 && __last2,_OutIter && __result,_Comp && __comp,_Proj1 && __proj1,_Proj2 && __proj2)51 __merge_impl(
52 _InIter1&& __first1,
53 _Sent1&& __last1,
54 _InIter2&& __first2,
55 _Sent2&& __last2,
56 _OutIter&& __result,
57 _Comp&& __comp,
58 _Proj1&& __proj1,
59 _Proj2&& __proj2) {
60 for (; __first1 != __last1 && __first2 != __last2; ++__result) {
61 if (std::invoke(__comp, std::invoke(__proj2, *__first2), std::invoke(__proj1, *__first1))) {
62 *__result = *__first2;
63 ++__first2;
64 } else {
65 *__result = *__first1;
66 ++__first1;
67 }
68 }
69 auto __ret1 = ranges::copy(std::move(__first1), std::move(__last1), std::move(__result));
70 auto __ret2 = ranges::copy(std::move(__first2), std::move(__last2), std::move(__ret1.out));
71 return {std::move(__ret1.in), std::move(__ret2.in), std::move(__ret2.out)};
72 }
73
74 struct __fn {
75 template <
76 input_iterator _InIter1,
77 sentinel_for<_InIter1> _Sent1,
78 input_iterator _InIter2,
79 sentinel_for<_InIter2> _Sent2,
80 weakly_incrementable _OutIter,
81 class _Comp = less,
82 class _Proj1 = identity,
83 class _Proj2 = identity>
84 requires mergeable<_InIter1, _InIter2, _OutIter, _Comp, _Proj1, _Proj2>
operator__fn85 _LIBCPP_HIDE_FROM_ABI constexpr merge_result<_InIter1, _InIter2, _OutIter> operator()(
86 _InIter1 __first1,
87 _Sent1 __last1,
88 _InIter2 __first2,
89 _Sent2 __last2,
90 _OutIter __result,
91 _Comp __comp = {},
92 _Proj1 __proj1 = {},
93 _Proj2 __proj2 = {}) const {
94 return __merge::__merge_impl(__first1, __last1, __first2, __last2, __result, __comp, __proj1, __proj2);
95 }
96
97 template <
98 input_range _Range1,
99 input_range _Range2,
100 weakly_incrementable _OutIter,
101 class _Comp = less,
102 class _Proj1 = identity,
103 class _Proj2 = identity>
104 requires mergeable<
105 iterator_t<_Range1>,
106 iterator_t<_Range2>,
107 _OutIter,
108 _Comp,
109 _Proj1,
110 _Proj2>
111 _LIBCPP_HIDE_FROM_ABI constexpr merge_result<borrowed_iterator_t<_Range1>, borrowed_iterator_t<_Range2>, _OutIter>
operator__fn112 operator()(
113 _Range1&& __range1,
114 _Range2&& __range2,
115 _OutIter __result,
116 _Comp __comp = {},
117 _Proj1 __proj1 = {},
118 _Proj2 __proj2 = {}) const {
119 return __merge::__merge_impl(
120 ranges::begin(__range1),
121 ranges::end(__range1),
122 ranges::begin(__range2),
123 ranges::end(__range2),
124 __result,
125 __comp,
126 __proj1,
127 __proj2);
128 }
129 };
130
131 } // namespace __merge
132
133 inline namespace __cpo {
134 inline constexpr auto merge = __merge::__fn{};
135 } // namespace __cpo
136 } // namespace ranges
137
138 _LIBCPP_END_NAMESPACE_STD
139
140 #endif // _LIBCPP_STD_VER > 17
141
142 #endif // _LIBCPP___ALGORITHM_RANGES_MERGE_H
143