1 /*
2  * Copyright (C) 2014 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef ART_LIBARTBASE_BASE_HASH_MAP_H_
18 #define ART_LIBARTBASE_BASE_HASH_MAP_H_
19 
20 #include <utility>
21 
22 #include "hash_set.h"
23 
24 namespace art {
25 
26 template <typename Fn>
27 class HashMapWrapper {
28  public:
29   // Hash function.
30   template <class Key, class Value>
operator()31   size_t operator()(const std::pair<Key, Value>& pair) const {
32     return fn_(pair.first);
33   }
34   template <class Key>
operator()35   size_t operator()(const Key& key) const {
36     return fn_(key);
37   }
38   template <class Key, class Value>
operator()39   bool operator()(const std::pair<Key, Value>& a, const std::pair<Key, Value>& b) const {
40     return fn_(a.first, b.first);
41   }
42   template <class Key, class Value, class Element>
operator()43   bool operator()(const std::pair<Key, Value>& a, const Element& element) const {
44     return fn_(a.first, element);
45   }
46 
47  private:
48   Fn fn_;
49 };
50 
51 template <typename Key, typename Value>
52 class DefaultMapEmptyFn {
53  public:
MakeEmpty(std::pair<Key,Value> & item)54   void MakeEmpty(std::pair<Key, Value>& item) const {
55     item = std::pair<Key, Value>();
56   }
IsEmpty(const std::pair<Key,Value> & item)57   bool IsEmpty(const std::pair<Key, Value>& item) const {
58     return item.first == Key();
59   }
60 };
61 
62 template <class Key,
63           class Value,
64           class EmptyFn = DefaultMapEmptyFn<Key, Value>,
65           class HashFn = DefaultHashFn<Key>,
66           class Pred = DefaultPred<Key>,
67           class Alloc = std::allocator<std::pair<Key, Value>>>
68 class HashMap : public HashSet<std::pair<Key, Value>,
69                                EmptyFn,
70                                HashMapWrapper<HashFn>,
71                                HashMapWrapper<Pred>,
72                                Alloc> {
73  private:
74   using Base = HashSet<std::pair<Key, Value>,
75                        EmptyFn,
76                        HashMapWrapper<HashFn>,
77                        HashMapWrapper<Pred>,
78                        Alloc>;
79 
80  public:
HashMap()81   HashMap() : Base() { }
HashMap(const Alloc & alloc)82   explicit HashMap(const Alloc& alloc)
83       : Base(alloc) { }
84 };
85 
86 }  // namespace art
87 
88 #endif  // ART_LIBARTBASE_BASE_HASH_MAP_H_
89