/
guid.go
57 lines (50 loc) · 943 Bytes
/
guid.go
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package nd
import (
"crypto/rand"
"encoding/hex"
"errors"
"strings"
)
var Guidv4 func() []byte
func init() {
ResetGuidv4()
}
func ResetGuidv4() {
Guidv4 = func() []byte {
t := make([]byte, 16)
rand.Read(t)
t[6] = t[6]&0xF | 64
return t
}
}
func LockGuid() string {
id := Guidv4String()
ForceGuid(id)
return id
}
func Guidv4String() string {
t := Guidv4()
tmp := make([]byte, 36)
hex.Encode(tmp[:8], t[:4])
tmp[8] = '-'
hex.Encode(tmp[9:], t[4:6])
tmp[13] = '-'
hex.Encode(tmp[14:], t[6:8])
tmp[18] = '-'
hex.Encode(tmp[19:], t[8:10])
tmp[23] = '-'
hex.Encode(tmp[24:], t[10:])
return string(tmp)
}
func ForceGuid(guid string) error {
if len(guid) < 28 {
return errors.New("Length of the GUID should be at least 28 hexadecimal characters")
}
guid = strings.Replace(guid, "-", "", -1)
g, err := hex.DecodeString(guid)
if err != nil {
return err
}
Guidv4 = func() []byte { return g }
return nil
}