Merge pull request #598 from vectos/feature-cidr-addresses

cidr: Add addresses method

shared/src/main/scala/com/comcast/ip4s/Cidr.scala

@@ -114,6 +114,16 @@ sealed class Cidr[+A <: IpAddress] protected (val address: A, val prefixBits: In
     a => a >= start && a <= end
   }
 
+  /** Returns an iterator over all addresses in the range described by this CIDR.
+    * @return
+    */
+  def addresses: Iterator[IpAddress] = {
+    val start: IpAddress = prefix
+    val end: IpAddress = last
+
+    Iterator.iterate(start)(_.next).takeWhile(_ <= end)
+  }
+
   override def toString: String = s"$address/$prefixBits"
   override def hashCode: Int = MurmurHash3.productHash(this, productPrefix.hashCode)
   override def equals(other: Any): Boolean =

test-kit/shared/src/test/scala/com/comcast/ip4s/CidrTest.scala

@@ -41,4 +41,11 @@ class CidrTest extends BaseTestSuite {
       assertEquals(cidr.isDefined, (prefixBits <= max && prefixBits >= 0))
     }
   }
+
+  test("addresses should return iterator") {
+    val cidr = Cidr(ipv4"10.0.0.0", 8)
+    val addresses = cidr.addresses
+
+    assertEquals(addresses.size, 16777216)
+  }
 }