1 /*
2  * Copyright (C) 2016 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 LIBMEMUNREACHABLE_LEAK_H_
18 #define LIBMEMUNREACHABLE_LEAK_H_
19 
20 #include <functional>
21 #include <vector>
22 
23 #include "memunreachable/memunreachable.h"
24 
25 // Custom std::hash specialization so that Leak::Backtrace can be used
26 // as a key in std::unordered_map.
27 namespace std {
28 
29 template<>
30 struct hash<Leak::Backtrace> {
31   std::size_t operator()(const Leak::Backtrace& key) const {
32     std::size_t seed = 0;
33 
34     hash_combine(seed, key.num_frames);
35     for (size_t i = 0; i < key.num_frames; i++) {
36       hash_combine(seed, key.frames[i]);
37     }
38 
39     return seed;
40   }
41 
42  private:
43   template<typename T>
44   inline void hash_combine(std::size_t& seed, const T& v) const {
45     std::hash<T> hasher;
46     seed ^= hasher(v) + 0x9e3779b9 + (seed << 6) + (seed >> 2);
47   }
48 };
49 
50 }  // namespace std
51 
52 static bool operator==(const Leak::Backtrace& lhs, const Leak::Backtrace& rhs) {
53   return (lhs.num_frames == rhs.num_frames) &&
54       memcmp(lhs.frames, rhs.frames, lhs.num_frames * sizeof(lhs.frames[0])) == 0;
55 }
56 
57 #endif
58