1 /** @file
2
3 @section license License
4
5 Licensed to the Apache Software Foundation (ASF) under one
6 or more contributor license agreements. See the NOTICE file
7 distributed with this work for additional information
8 regarding copyright ownership. The ASF licenses this file
9 to you under the Apache License, Version 2.0 (the
10 "License"); you may not use this file except in compliance
11 with the License. You may obtain a copy of the License at
12
13 http://www.apache.org/licenses/LICENSE-2.0
14
15 Unless required by applicable law or agreed to in writing, software
16 distributed under the License is distributed on an "AS IS" BASIS,
17 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
18 See the License for the specific language governing permissions and
19 limitations under the License.
20 */
21
22 /*
23 http://www.isthe.com/chongo/tech/comp/fnv/
24
25 Currently implemented FNV-1a 32bit and FNV-1a 64bit
26 */
27
28 #pragma once
29
30 #include "tscore/Hash.h"
31 #include <cstdint>
32
33 struct ATSHash32FNV1a : ATSHash32 {
34 ATSHash32FNV1a();
35
36 template <typename Transform> void update(const void *data, size_t len, Transform xfrm);
37 void
updateATSHash32FNV1a38 update(const void *data, size_t len) override
39 {
40 update(data, len, ATSHash::nullxfrm());
41 }
42
43 void final() override;
44 uint32_t get() const override;
45 void clear() override;
46
47 private:
48 uint32_t hval;
49 };
50
51 template <typename Transform>
52 void
update(const void * data,size_t len,Transform xfrm)53 ATSHash32FNV1a::update(const void *data, size_t len, Transform xfrm)
54 {
55 uint8_t *bp = (uint8_t *)data;
56 uint8_t *be = bp + len;
57
58 for (; bp < be; ++bp) {
59 hval ^= (uint32_t)xfrm(*bp);
60 hval += (hval << 1) + (hval << 4) + (hval << 7) + (hval << 8) + (hval << 24);
61 }
62 }
63
64 struct ATSHash64FNV1a : ATSHash64 {
65 ATSHash64FNV1a();
66
67 template <typename Transform> void update(const void *data, size_t len, Transform xfrm);
68 void
updateATSHash64FNV1a69 update(const void *data, size_t len) override
70 {
71 update(data, len, ATSHash::nullxfrm());
72 }
73
74 void final() override;
75 uint64_t get() const override;
76 void clear() override;
77
78 private:
79 uint64_t hval;
80 };
81
82 template <typename Transform>
83 void
update(const void * data,size_t len,Transform xfrm)84 ATSHash64FNV1a::update(const void *data, size_t len, Transform xfrm)
85 {
86 uint8_t *bp = (uint8_t *)data;
87 uint8_t *be = bp + len;
88
89 for (; bp < be; ++bp) {
90 hval ^= (uint64_t)xfrm(*bp);
91 hval += (hval << 1) + (hval << 4) + (hval << 5) + (hval << 7) + (hval << 8) + (hval << 40);
92 }
93 }
94