How to Convert IPv4 Addresses to/from Long in Scala

Question

I was looking for a basic utility with 2 functions to convert IPv4 Addresses to/from Long in Scala, such as "10.10.10.10" to its Long representation of 168430090 and back. A basic utility such as this exists in many languages (such as python), but appears to require re-writing the same code for everyone for the JVM.

What is the recommended approach on unifying IPv4ToLong and LongToIPv4 functions?

Answer 1

import java.net.InetAddress
def IPv4ToLong(dottedIP: String): Long = {
  val addrArray: Array[String] = dottedIP.split("\\.")
  var num: Long = 0
  var i: Int = 0
  while (i < addrArray.length) {
    val power: Int = 3 - i
    num = num + ((addrArray(i).toInt % 256) * Math.pow(256, power)).toLong
    i += 1
  }
  num
}

def LongToIPv4 (ip : Long) : String = {
  val bytes: Array[Byte] = new Array[Byte](4)
  bytes(0) = ((ip & 0xff000000) >> 24).toByte
  bytes(1) = ((ip & 0x00ff0000) >> 16).toByte
  bytes(2) = ((ip & 0x0000ff00) >> 8).toByte
  bytes(3) = (ip & 0x000000ff).toByte
  InetAddress.getByAddress(bytes).getHostAddress()
}

scala> IPv4ToLong("10.10.10.10")
res0: Long = 168430090

scala> LongToIPv4(168430090L)
res1: String = 10.10.10.10