1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
|
/*
* Copyright (c) 2017-2019 Cisco and/or its affiliates.
* Copyright 2017 Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <hicn/transport/portability/portability.h>
#include <cstddef>
#include <cstdint>
#include <cstring>
#include <string>
#include <tuple>
#include <type_traits>
#include <utility>
namespace utils {
namespace hash {
/*
* Fowler / Noll / Vo (FNV) Hash
* http://www.isthe.com/chongo/tech/comp/fnv/
*/
const uint32_t FNV_32_HASH_START = 2166136261UL;
const uint64_t FNV_64_HASH_START = 14695981039346656037ULL;
TRANSPORT_ALWAYS_INLINE uint32_t fnv32(const char *s,
uint32_t hash = FNV_32_HASH_START) {
for (; *s; ++s) {
hash +=
(hash << 1) + (hash << 4) + (hash << 7) + (hash << 8) + (hash << 24);
hash ^= *s;
}
return hash;
}
TRANSPORT_ALWAYS_INLINE uint32_t fnv32_buf(const void *buf, size_t n,
uint32_t hash = FNV_32_HASH_START) {
// forcing signed char, since other platforms can use unsigned
const signed char *char_buf = reinterpret_cast<const signed char *>(buf);
for (size_t i = 0; i < n; ++i) {
hash +=
(hash << 1) + (hash << 4) + (hash << 7) + (hash << 8) + (hash << 24);
hash ^= char_buf[i];
}
return hash;
}
TRANSPORT_ALWAYS_INLINE uint32_t fnv32(const std::string &str,
uint32_t hash = FNV_32_HASH_START) {
return fnv32_buf(str.data(), str.size(), hash);
}
TRANSPORT_ALWAYS_INLINE uint64_t fnv64(const char *s,
uint64_t hash = FNV_64_HASH_START) {
for (; *s; ++s) {
hash += (hash << 1) + (hash << 4) + (hash << 5) + (hash << 7) +
(hash << 8) + (hash << 40);
hash ^= *s;
}
return hash;
}
TRANSPORT_ALWAYS_INLINE uint64_t fnv64_buf(const void *buf, size_t n,
uint64_t hash = FNV_64_HASH_START) {
// forcing signed char, since other platforms can use unsigned
const signed char *char_buf = reinterpret_cast<const signed char *>(buf);
for (size_t i = 0; i < n; ++i) {
hash += (hash << 1) + (hash << 4) + (hash << 5) + (hash << 7) +
(hash << 8) + (hash << 40);
hash ^= char_buf[i];
}
return hash;
}
TRANSPORT_ALWAYS_INLINE uint64_t fnv64(const std::string &str,
uint64_t hash = FNV_64_HASH_START) {
return fnv64_buf(str.data(), str.size(), hash);
}
} // namespace hash
} // namespace utils
|
