X-Git-Url: https://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2FCidr.hs;h=266b7c57f8a8e8318124a2518900de75a4d166ca;hb=b22b30048819a3a53517e44370a97a2e37ba3f10;hp=12d9689df71a7cbe955f4be1edb74c934263ef65;hpb=1b7390b71484de63c8ded01371a1dd2adf93909e;p=hath.git

diff --git a/src/Cidr.hs b/src/Cidr.hs
index 12d9689..266b7c5 100644
--- a/src/Cidr.hs
+++ b/src/Cidr.hs
@@ -1,7 +1,7 @@
 module Cidr
 ( Cidr(..),
   cidr_from_string,
-  contains
+  combine_all
 ) where
 
 import IPv4Address
@@ -91,3 +91,21 @@ contains (Cidr addr1 mbits1) (Cidr addr2 mbits2)
     where
       addr1masked = apply_mask addr1 mbits1
       addr2masked = apply_mask addr2 mbits1
+
+
+contains_proper :: Cidr -> Cidr -> Bool
+contains_proper cidr1 cidr2 =
+    (cidr1 `contains` cidr2) && (not (cidr1 == cidr2))
+
+
+-- A CIDR range is redundant (with respect to the given list) if
+-- another CIDR range in that list properly contains it.
+redundant :: [Cidr] -> Cidr -> Bool
+redundant cidrlist cidr = any ((flip contains_proper) cidr) cidrlist
+
+
+-- We want to get rid of all the Cidrs that are properly contained
+-- in some other Cidr.
+combine_all :: [Cidr] -> [Cidr]
+combine_all cidrs =
+    filter (not . (redundant cidrs)) cidrs