golang实现base62编码

package main

import (
"fmt"
"math"
)

var base = []string {"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z","A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z","1","2","3","4","5","6","7","8","9","0"}

func base62encode(num int) string {
baseStr := ""
for {
if num <= 0 {
break
}

i := num % 62
baseStr += base[i]
num = (num - i) / 62
}
return baseStr
}

func base62decode(base62 string) int {
rs := 0
len := len(base62)
f := flip(base)
for  i := 0; i < len; i++ {
rs += f[string(base62[i])] * int(math.Pow(62, float64(i)))
}
return rs
}

func flip(s []string) map[string]int {
f := make(map[string]int)
for index, value := range s {
f[value] = index
}
return f
}

func main() {
m := base62encode(12645354)
fmt.Println(m)
fmt.Println(base62decode(m))
}