cubefs
42 строки · 1.2 Кб
1// Copyright 2015 The Prometheus Authors
2// Licensed under the Apache License, Version 2.0 (the "License");
3// you may not use this file except in compliance with the License.
4// You may obtain a copy of the License at
5//
6// http://www.apache.org/licenses/LICENSE-2.0
7//
8// Unless required by applicable law or agreed to in writing, software
9// distributed under the License is distributed on an "AS IS" BASIS,
10// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11// See the License for the specific language governing permissions and
12// limitations under the License.
13
14package model
15
16// Inline and byte-free variant of hash/fnv's fnv64a.
17
18const (
19offset64 = 14695981039346656037
20prime64 = 1099511628211
21)
22
23// hashNew initializes a new fnv64a hash value.
24func hashNew() uint64 {
25return offset64
26}
27
28// hashAdd adds a string to a fnv64a hash value, returning the updated hash.
29func hashAdd(h uint64, s string) uint64 {
30for i := 0; i < len(s); i++ {
31h ^= uint64(s[i])
32h *= prime64
33}
34return h
35}
36
37// hashAddByte adds a byte to a fnv64a hash value, returning the updated hash.
38func hashAddByte(h uint64, b byte) uint64 {
39h ^= uint64(b)
40h *= prime64
41return h
42}
43