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Version: 2.5.x

基本介绍

常用经典哈希函数Go语言实现,提供 uint32uint64 类型的哈希函数。

使用方式

import "github.com/gogf/gf/v2/encoding/ghash"

接口文档

https://pkg.go.dev/github.com/gogf/gf/v2/encoding/ghash

基准测试

goos: darwin
goarch: amd64
pkg: github.com/gogf/gf/v2/encoding/ghash
cpu: Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
Benchmark_BKDR
Benchmark_BKDR-12 39315165 26.88 ns/op
Benchmark_BKDR64
Benchmark_BKDR64-12 62891215 22.61 ns/op
Benchmark_SDBM
Benchmark_SDBM-12 49689925 25.40 ns/op
Benchmark_SDBM64
Benchmark_SDBM64-12 48860472 24.38 ns/op
Benchmark_RS
Benchmark_RS-12 39463418 25.52 ns/op
Benchmark_RS64
Benchmark_RS64-12 53318370 19.45 ns/op
Benchmark_JS
Benchmark_JS-12 53751033 23.20 ns/op
Benchmark_JS64
Benchmark_JS64-12 62440287 19.25 ns/op
Benchmark_PJW
Benchmark_PJW-12 42439626 27.85 ns/op
Benchmark_PJW64
Benchmark_PJW64-12 37491696 33.28 ns/op
Benchmark_ELF
Benchmark_ELF-12 38034584 31.74 ns/op
Benchmark_ELF64
Benchmark_ELF64-12 44047201 27.58 ns/op
Benchmark_DJB
Benchmark_DJB-12 46994352 22.60 ns/op
Benchmark_DJB64
Benchmark_DJB64-12 61980186 19.19 ns/op
Benchmark_AP
Benchmark_AP-12 29544234 40.58 ns/op
Benchmark_AP64
Benchmark_AP64-12 28123783 42.48 ns/op

重复测试

测试结果与测试内容有关联性和随机性,我这里通过 uint64 数值的范围遍历来进行简单的重复性测试,本身不够严谨,因此仅供趣味性参考。

package main

import (
"encoding/binary"
"fmt"
"math"

"github.com/gogf/gf/v2/encoding/ghash"
)

func main() {
var (
m = make(map[uint64]struct{})
b = make([]byte, 8)
ok bool
hash uint64
)
for i := uint64(0); i < math.MaxUint64; i++ {
binary.LittleEndian.PutUint64(b, i)
hash = ghash.PJW64(b)
if _, ok = m[hash]; ok {
fmt.Println("repeated found:", i)
break
}
m[hash] = struct{}{}
}
}

测试结果如下:

哈希函数重复位置备注
AP648388640
BKDR6433536
DJB648448
ELF644096
JS64734
PJW642
RS64-32G Memory OOM
SDBM64-32G Memory OOM