iot_server/internal/pkg/utils/uuid.go

48 lines
1.1 KiB
Go

package utils
import (
"fmt"
"hash/crc32"
rand2 "math/rand"
"time"
"github.com/google/uuid"
)
func GenUUID() string {
uuidHash := crc32.ChecksumIEEE([]byte(uuid.New().String()))
return fmt.Sprint(uuidHash)
}
func RandomNum() string {
return fmt.Sprintf("%08v", rand2.New(rand2.NewSource(time.Now().UnixNano())).Int31n(100000000))
}
const letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
const (
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 GenerateDeviceSecret(n int) string {
b := make([]byte, n)
// A rand.Int63() generates 63 random bits, enough for letterIdxMax letters!
for i, cache, remain := n-1, rand2.Int63(), letterIdxMax; i >= 0; {
if remain == 0 {
cache, remain = rand2.Int63(), letterIdxMax
}
if idx := int(cache & letterIdxMask); idx < len(letterBytes) {
b[i] = letterBytes[idx]
i--
}
cache >>= letterIdxBits
remain--
}
return string(b)
}
func GenerateSaltKey() string {
return uuid.New().String()
}