+ Adds a specification for the new ldap extensible filter

I am not sure about this, since I haven't been able to find
documentation about what this does. This should work, though.

Cleanup of comments and exceptions, adds specification for
Filter.ex and a parser method.

lib/net/ber/ber_parser.rb

@@ -102,7 +102,7 @@ module Net
           n.ber_identifier = id
           n
         else
-          raise BerError.new( "unsupported object type: id=#{id}" )
+          raise BerError, "unsupported object type: id=0x#{id.to_s(16)}"
         end
 
         obj

lib/net/ldap.rb

@@ -283,6 +283,8 @@ module Net
           0 => :string,             # password
           1 => :string,             # Kerberos v4
           2 => :string,             # Kerberos v5
+          3 => :string,             # SearchFilter-extensible
+          4 => :string,             # SearchFilter-extensible
           7 => :string,             # serverSaslCreds
         },
         :constructed => {
@@ -294,6 +296,7 @@ module Net
           5 => :array,              # SearchFilter-GE
           6 => :array,              # SearchFilter-LE
           7 => :array,              # serverSaslCreds
+          9 => :array,              # SearchFilter-extensible
         }
       }
     })

lib/net/ldap/filter.rb

@@ -247,11 +247,32 @@ class Net::LDAP::Filter
         eq(ber.first.to_s, str)
       when 0xa5 # context-specific constructed 5, "greaterOrEqual"
         ge(ber.first.to_s, ber.last.to_s)
-      when 0xa6 # context-specific constructed 5, "lessOrEqual"
+      when 0xa6 # context-specific constructed 6, "lessOrEqual"
         le(ber.first.to_s, ber.last.to_s)
       when 0x87 # context-specific primitive 7, "present"
         # call to_s to get rid of the BER-identifiedness of the incoming string.
         present?(ber.to_s)
+      when 0xa9 # context-specific constructed 9, "extensible comparison"
+        raise Net::LDAP::LdapError, "Invalid extensible search filter, should be at least two elements" if ber.size<2
+        
+        # Reassembles the extensible filter parts 
+        # (["sn", "2.4.6.8.10", "Barbara Jones", '1'])
+        type = value = dn = rule = nil
+        ber.each do |element|
+          case element.ber_identifier
+            when 0x81 then rule=element
+            when 0x82 then type=element
+            when 0x83 then value=element
+            when 0x84 then dn='dn'
+          end
+        end
+
+        attribute = ''
+        attribute << type if type
+        attribute << ":#{dn}" if dn
+        attribute << ":#{rule}" if rule
+        
+        ex(attribute, value)
       else
         raise Net::LDAP::LdapError, "Invalid BER tag-value (#{ber.ber_identifier}) in search filter."
       end