1 | // Copyright 2016 the V8 project authors. All rights reserved. |
2 | // Use of this source code is governed by a BSD-style license that can be |
3 | // found in the LICENSE file. |
4 | |
5 | #ifndef V8_BASE_HASHMAP_ENTRY_H_ |
6 | #define V8_BASE_HASHMAP_ENTRY_H_ |
7 | |
8 | #include <cstdint> |
9 | |
10 | namespace v8 { |
11 | namespace base { |
12 | |
13 | // HashMap entries are (key, value, hash) triplets, with a boolean indicating if |
14 | // they are an empty entry. Some clients may not need to use the value slot |
15 | // (e.g. implementers of sets, where the key is the value). |
16 | template <typename Key, typename Value> |
17 | struct TemplateHashMapEntry { |
18 | Key key; |
19 | Value value; |
20 | uint32_t hash; // The full hash value for key |
21 | |
22 | TemplateHashMapEntry(Key key, Value value, uint32_t hash) |
23 | : key(key), value(value), hash(hash), exists_(true) {} |
24 | |
25 | bool exists() const { return exists_; } |
26 | |
27 | void clear() { exists_ = false; } |
28 | |
29 | private: |
30 | bool exists_; |
31 | }; |
32 | |
33 | // Specialization for pointer-valued keys |
34 | template <typename Key, typename Value> |
35 | struct TemplateHashMapEntry<Key*, Value> { |
36 | Key* key; |
37 | Value value; |
38 | uint32_t hash; // The full hash value for key |
39 | |
40 | TemplateHashMapEntry(Key* key, Value value, uint32_t hash) |
41 | : key(key), value(value), hash(hash) {} |
42 | |
43 | bool exists() const { return key != nullptr; } |
44 | |
45 | void clear() { key = nullptr; } |
46 | }; |
47 | |
48 | // TODO(leszeks): There could be a specialisation for void values (e.g. for |
49 | // sets), which omits the value field |
50 | |
51 | } // namespace base |
52 | } // namespace v8 |
53 | |
54 | #endif // V8_BASE_HASHMAP_ENTRY_H_ |
55 | |