lib/ipaddress/prefix.rb in ipaddress-0.7.5 vs lib/ipaddress/prefix.rb in ipaddress-0.8.0

@@ -16,11 +16,11 @@
   # both the subclasses.
   #
   # IPAddress::Prefix shouldn't be accesses directly, unless
   # for particular needs.
   #
-  class Prefix
+  class Prefix 
 
     include Comparable
 
     attr_reader :prefix
 
@@ -243,9 +243,22 @@
     #   prefix.to_u128
     #     #=> 340282366920938463444927863358058659840
     #
     def to_u128
       bits.to_i(2)
+    end
+
+    #
+    # Returns the length of the host portion
+    # of a netmask. 
+    #
+    #   prefix = Prefix128.new 96
+    #
+    #   prefix.host_prefix
+    #     #=> 32
+    #
+    def host_prefix
+      128 - @prefix
     end
 
   end # class Prefix123 < Prefix
 
 end # module IPAddress