1//===-- sanitizer_common.h --------------------------------------*- C++ -*-===//
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// This file implements a simple hash function.
10//===----------------------------------------------------------------------===//
11
12#ifndef SANITIZER_HASH_H
13#define SANITIZER_HASH_H
14
15#include "sanitizer_internal_defs.h"
16
17namespace __sanitizer {
18class MurMur2HashBuilder {
19 static const u32 m = 0x5bd1e995;
20 static const u32 seed = 0x9747b28c;
21 static const u32 r = 24;
22 u32 h;
23
24 public:
25 explicit MurMur2HashBuilder(u32 init = 0) { h = seed ^ init; }
26 void add(u32 k) {
27 k *= m;
28 k ^= k >> r;
29 k *= m;
30 h *= m;
31 h ^= k;
32 }
33 u32 get() {
34 u32 x = h;
35 x ^= x >> 13;
36 x *= m;
37 x ^= x >> 15;
38 return x;
39 }
40};
41
42class MurMur2Hash64Builder {
43 static const u64 m = 0xc6a4a7935bd1e995ull;
44 static const u64 seed = 0x9747b28c9747b28cull;
45 static const u64 r = 47;
46 u64 h;
47
48 public:
49 explicit MurMur2Hash64Builder(u64 init = 0) { h = seed ^ (init * m); }
50 void add(u64 k) {
51 k *= m;
52 k ^= k >> r;
53 k *= m;
54 h ^= k;
55 h *= m;
56 }
57 u64 get() {
58 u64 x = h;
59 x ^= x >> r;
60 x *= m;
61 x ^= x >> r;
62 return x;
63 }
64};
65} // namespace __sanitizer
66
67#endif // SANITIZER_HASH_H
68