1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
|
/*
* Copyright 2018 Google
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_IMMUTABLE_MAP_ENTRY_H_
#define FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_IMMUTABLE_MAP_ENTRY_H_
#include <functional>
#include <utility>
namespace firebase {
namespace firestore {
namespace immutable {
/**
* Compares two keys out of a map entry.
*
* @tparam K The type of the first value in the pair.
* @tparam V The type of the second value in the pair.
* @tparam C The comparator for use for values of type K
*/
template <typename K, typename V, typename C = std::less<K>>
struct KeyComparator {
using pair_type = std::pair<K, V>;
explicit KeyComparator(const C& comparator = C())
: key_comparator_(comparator) {
}
bool operator()(const K& lhs, const pair_type& rhs) const noexcept {
return key_comparator_(lhs, rhs.first);
}
bool operator()(const pair_type& lhs, const K& rhs) const noexcept {
return key_comparator_(lhs.first, rhs);
}
bool operator()(const pair_type& lhs, const pair_type& rhs) const noexcept {
return key_comparator_(lhs.first, rhs.first);
}
const C& comparator() const {
return key_comparator_;
}
private:
C key_comparator_;
};
} // namespace immutable
} // namespace firestore
} // namespace firebase
#endif // FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_IMMUTABLE_MAP_ENTRY_H_
|
