Last active
February 14, 2019 21:51
-
-
Save dwin/a8c422137b6e9393835ad4fe97045b8a to your computer and use it in GitHub Desktop.
Generate Random String in Go
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
// | |
// Do Use This the generated string is not very random at all | |
// | |
package main | |
import ( | |
"fmt" | |
"math/rand" | |
"time" | |
) | |
func main() { | |
src := rand.NewSource(time.Now().UTC().UnixNano()) | |
fmt.Println(RandStringBytesMaskImprSrc(src,10)) | |
} | |
const ( | |
chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ" | |
letterIdxBits = 6 // 6 bits to represent a letter index | |
letterIdxMask = 1<<letterIdxBits - 1 // All 1-bits, as many as letterIdxBits | |
letterIdxMax = 63 / letterIdxBits // # of letter indices fitting in 63 bits | |
) | |
func RandStringBytesMaskImprSrc(src rand.Source, n int) string { | |
b := make([]byte, n) | |
// A src.Int63() generates 63 random bits, enough for letterIdxMax characters! | |
for i, cache, remain := n-1, src.Int63(), letterIdxMax; i >= 0; { | |
if remain == 0 { | |
cache, remain = src.Int63(), letterIdxMax | |
} | |
if idx := int(cache & letterIdxMask); idx < len(chars) { | |
b[i] = chars[idx] | |
i-- | |
} | |
cache >>= letterIdxBits | |
remain-- | |
} | |
return string(b) | |
} |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
complete-guide-start-making-money-talku/","image":"https://dm46l3i5mnhr0.cloudfront.net/talku/point_banner_earn_100_+dollar@2x.png"}],"topVersion":"","taskConfig":