From: Michael Orlitzky <michael@orlitzky.com>
Date: Sat, 8 May 2010 16:45:46 +0000 (-0400)
Subject: Implemented the combine_all function for Cidrs containing one another.
X-Git-Tag: 0.0.1~68
X-Git-Url: https://gitweb.michael.orlitzky.com/?a=commitdiff_plain;h=b22b30048819a3a53517e44370a97a2e37ba3f10;p=hath.git

Implemented the combine_all function for Cidrs containing one another.
Removed the 'contains' export from the Cidr module.
Added a 'contains_proper' convenience function.
---

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