Added IPv6#network method, thanks to Leif Gensert (closes #12)

CHANGELOG.rdoc

@@ -1,3 +1,8 @@
+== ipaddress 0.8.0
+
+NEW::     IPv6#network
+
+
 == ipaddress 0.7.5
 
 CHANGED:: IPAddress::IPv4#each_host to improve speed

README.rdoc

@@ -924,8 +924,8 @@ Feel free to join us and tell us what you think!
 Thanks to Luca Russo (vargolo) and Simone Carletti 
 (weppos) for all the support and technical review. Thanks to Marco Beri, 
 Bryan T. Richardson, Nicolas Fevrier, jdpace, Daniele Alessandri, jrdioko, 
-Ghislain Charrier, Pawel Krzesniak, Mark Sullivan, Erik Ahlström and 
-Steve Rawlinson for their support, feedback and bug reports.
+Ghislain Charrier, Pawel Krzesniak, Mark Sullivan, Leif Gensert, 
+Erik Ahlström and Steve Rawlinson for their support, feedback and bug reports.
 
 == Copyright
 

lib/ipaddress/ipv6.rb

@@ -430,6 +430,19 @@ def literal
       @address.gsub(":","-") + ".ipv6-literal.net"
     end
 
+    #
+    # Returns a new IPv6 object with the network number 
+    # for the given IP.
+    #
+    #   ip = IPAddress "2001:db8:1:1:1:1:1:1/32" 
+    #
+    #   ip.network.to_string
+    #     #=> "2001:db8::/32"
+    #
+    def network
+      self.class.parse_u128(network_u128, @prefix)
+    end
+
     #
     # Extract 16 bits groups from a string
     #

test/ipaddress/ipv6_test.rb

@@ -32,6 +32,11 @@ def setup
 
     @invalid_ipv6 = [":1:2:3:4:5:6:7",
                      ":1:2:3:4:5:6:7"]
+
+    @networks = {
+      "2001:db8:1:1:1:1:1:1/32" => "2001:db8::/32",
+      "2001:db8:1:1:1:1:1::/32" => "2001:db8::/32",
+      "2001:db8::1/64" => "2001:db8::/64"}
 
     @ip = @klass.new "2001:db8::8:800:200c:417a/64"
     @network = @klass.new "2001:db8:8:800::/64"
@@ -186,6 +191,14 @@ def test_method_loopback?
     assert_equal true, @klass.new("::1").loopback?
     assert_equal false, @ip.loopback?        
   end
+
+  def test_method_network
+    @networks.each do |addr,net|
+      ip = @klass.new addr
+      assert_instance_of @klass, ip.network
+      assert_equal net, ip.network.to_string
+    end
+  end
 
   def test_classmethod_expand
     compressed = "2001:db8:0:cd30::"