Canonicalize CIDR: Difference between revisions

<lang ecmascript>import "os" for Process

import "/fmt" for Fmt, Conv

var args = Process.arguments

var cidr = (args.count > 0) ? args[0] : Fiber.abort("Please pass the CIDR to be canonicalized.")

// dotted-decimal / bits in network part

var split = cidr.split("/")

var dotted = split[0]

var size = Num.fromString(split[1])

// get IP as binary string

var binary = dotted.split(".").map { |n| Fmt.swrite("$08b", Num.fromString(n)) }.join()

// replace the host part with all zeros

binary = binary[0...size] + "0" * (32 - size)

// convert back to dotted-decimal

var chunks = Str.chunks(binary, 8)

var canon = chunks.map { |c| Conv.atoi(c, 2) }.join(".")

// and output

System.print(canon + "/" + split[1])</lang>

$ wren canonicalize_cidr.wren 87.70.141.1/22

87.70.140.0/22