func NewFileName(fileName string) string {
l := len(fileName)
i := strings.LastIndex(fileName, ".")
newFileName := make([]byte, (l - i + 32))
copy(newFileName[:32], id.UUID32())
copy(newFileName[32:], fileName[i:])
return string(newFileName)
}
func TestNewName(t *testing.T) {
fileName := "111.jpgx"
l := len(fileName)
i := strings.LastIndex(fileName, ".")
newFileName := make([]byte, (l - i + 32 + 1))
id := id.UUID32()
fmt.Println("id:", id)
copy(newFileName[:32], id)
copy(newFileName[33:], fileName[i:])
fmt.Println(string(newFileName))
}