杂-ip转int，int转ip

IP和int之间相互转换

func toInt(ip string) int64 {
    i := 3
    sum := int64(0)
    for j, v := range strings.Split(ip, ".") {
        intV, _ := strconv.ParseInt(v, 10, 64)
        sum = sum + intV*int64(math.Pow(float64(256), float64(i-j)))
    }
    fmt.Println(sum)
    return sum
}

func toIp(num int64) string {
    s := make([]string, 4)
    i := 3
    for i >= 0 {
        s[i] = strconv.FormatInt(num % 256,10)
        num /= 256
        i--
    }
    return strings.Join(s, ".")
}