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基本介绍
常用经典哈希函数Go语言实现，提供uint32及uint64类型的哈希函数。
使用方式：
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import "github.com/gogf/gf/v2/encoding/ghash" |
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基准测试
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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 |
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39315165 |
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26. |
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88 ns/op Benchmark_BKDR64 Benchmark_BKDR64-12 |
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62891215 22. |
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61 ns/op Benchmark_SDBM Benchmark_SDBM-12 |
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49689925 |
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25. |
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40 ns/op Benchmark_SDBM64 Benchmark_SDBM64-12 |
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48860472 |
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24. |
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38 ns/op Benchmark_ |
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RS
Benchmark_RS-12 |
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39463418 |
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25. |
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52 ns/op Benchmark_ |
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RS64 Benchmark_ |
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RS64-12 |
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53318370 |
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19. |
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45 ns/op Benchmark_ |
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JS
Benchmark_JS-12 |
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53751033 |
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23. |
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20 ns/op Benchmark_JS64 Benchmark_JS64-12 |
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62440287 |
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19.25 ns/op Benchmark_PJW Benchmark_PJW-12 |
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42439626 |
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27. |
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85 ns/op Benchmark_PJW64 Benchmark_PJW64-12 |
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37491696 |
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33. |
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28 ns/op Benchmark_ |
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ELF Benchmark_ |
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ELF-12 |
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38034584 |
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31. |
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74 ns/op Benchmark_ |
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ELF64 Benchmark_ |
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ELF64-12 |
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44047201 |
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27. |
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58 ns/op Benchmark_ |
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DJB Benchmark_ |
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DJB-12 |
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46994352 |
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22. |
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60 ns/op Benchmark_ |
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DJB64 Benchmark_ |
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DJB64-12 |
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61980186 |
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19. |
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19 ns/op Benchmark_ |
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AP Benchmark_ |
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AP-12 |
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29544234 |
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40. |
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58 ns/op Benchmark_ |
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AP64 Benchmark_ |
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AP64-12 |
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28123783 |
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42. |
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48 ns/op |
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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。
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|---|---|---|
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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 |
|---|---|---|
AP64 | 8388640 | |
BKDR64 | 33536 | |
DJB64 | 8448 | |
ELF64 | 4096 | |
JS64 | 734 | |
PJW64 | 2 | |
RS64 | - | 32G Memory OOM |
SDBM64 | - | 32G Memory OOM |
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