Added a None constructor for Cidr.

Return Cidr.None when we are passed an invalid IPv4Address.

diff --git a/src/Cidr.hs b/src/Cidr.hs
index efd3ae0413b43095ae2dab5abc046f6885806354..4bb3d48ef788656c79abf8f971a46f07f1a3a48d 100644 (file)
--- a/src/Cidr.hs
+++ b/src/Cidr.hs
@@ -11,8 +11,8 @@ import ListUtils
 import Octet
 
 
-data Cidr = Cidr { ipv4address :: IPv4Address,
-                   maskbits :: Maskbits }
+data Cidr = None | Cidr { ipv4address :: IPv4Address,
+                          maskbits :: Maskbits }
             deriving (Eq, Show)
 
 -- Will return True if the passed String is in CIDR notation, False
@@ -34,9 +34,11 @@ octets_from_string s = map read (take 4 (splitWith (`elem` "./") s))
 
 
 cidr_from_string :: String -> Cidr
-cidr_from_string s = Cidr addr mbits
+cidr_from_string s
+    | addr == IPv4Address.None = Cidr.None
+    | otherwise = Cidr addr mbits
                where
-                 addr = IPv4Address (oct1) (oct2) (oct3) (oct4)
+                 addr = ipv4address_from_octets (oct1) (oct2) (oct3) (oct4)
                  oct1 = octet_from_int (octs !! 0)
                  oct2 = octet_from_int (octs !! 1)
                  oct3 = octet_from_int (octs !! 2)