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base62.go
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/
base62.go
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package main
import (
"bytes"
"math"
)
const alphabet = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
func Base62Encode(number int64) string {
if number == 0 {
return string(alphabet[0])
}
chars := make([]byte, 0)
length := int64(len(alphabet))
for number > 0 {
result := number / length
remainder := number % length
chars = append(chars, alphabet[remainder])
number = result
}
for i, j := 0, len(chars)-1; i < j; i, j = i+1, j-1 {
chars[i], chars[j] = chars[j], chars[i]
}
return string(chars)
}
func Base62Decode(token string) int64 {
number := int64(0)
idx := 0.0
chars := []byte(alphabet)
charsLength := float64(len(chars))
tokenLength := float64(len(token))
for _, c := range []byte(token) {
power := tokenLength - (idx + 1)
index := bytes.IndexByte(chars, c)
number += int64(index) * int64(math.Pow(charsLength, power))
idx++
}
return number
}