diff --git a/lib/public_suffix.rb b/lib/public_suffix.rb
index 7b79dd3b..5dd11640 100644
--- a/lib/public_suffix.rb
+++ b/lib/public_suffix.rb
@@ -7,7 +7,7 @@
 require_relative "public_suffix/domain"
 require_relative "public_suffix/version"
 require_relative "public_suffix/errors"
-require_relative "public_suffix/rule"
+require_relative "public_suffix/rules"
 require_relative "public_suffix/list"
 
 # PublicSuffix is a Ruby domain name parser based on the Public Suffix List.
@@ -64,19 +64,16 @@ module PublicSuffix
   #   If domain is not a valid domain.
   # @raise [PublicSuffix::DomainNotAllowed]
   #   If a rule for +domain+ is found, but the rule doesn't allow +domain+.
-  def self.parse(name, list: List.default, default_rule: list.default_rule, ignore_private: false)
+  def self.parse(name, list: List.default, ignore_private: false)
     what = normalize(name)
     raise what if what.is_a?(DomainInvalid)
 
-    rule = list.find(what, default: default_rule, ignore_private: ignore_private)
+    rule = list.find(what, ignore_private: ignore_private)
 
     # rubocop:disable Style/IfUnlessModifier
     if rule.nil?
       raise DomainInvalid, "`#{what}` is not a valid domain"
     end
-    if rule.decompose(what).last.nil?
-      raise DomainNotAllowed, "`#{what}` is not allowed according to Registry policy"
-    end
     # rubocop:enable Style/IfUnlessModifier
 
     decompose(what, rule)
@@ -119,13 +116,8 @@ def self.parse(name, list: List.default, default_rule: list.default_rule, ignore
   # @param  [String, #to_s] name The domain name or fully qualified domain name to validate.
   # @param  [Boolean] ignore_private
   # @return [Boolean]
-  def self.valid?(name, list: List.default, default_rule: list.default_rule, ignore_private: false)
-    what = normalize(name)
-    return false if what.is_a?(DomainInvalid)
-
-    rule = list.find(what, default: default_rule, ignore_private: ignore_private)
-
-    !rule.nil? && !rule.decompose(what).last.nil?
+  def self.valid?(name, list: List.default, ignore_private: false)
+    !normalize(name).is_a?(DomainInvalid)
   end
 
   # Attempt to parse the name and returns the domain, if valid.
@@ -146,13 +138,13 @@ def self.domain(name, **options)
   # private
 
   def self.decompose(name, rule)
-    left, right = rule.decompose(name)
+    rule_len = rule.split(DOT).length
+    parts = name.split(DOT)
 
-    parts = left.split(DOT)
     # If we have 0 parts left, there is just a tld and no domain or subdomain
     # If we have 1 part  left, there is just a tld, domain and not subdomain
     # If we have 2 parts left, the last part is the domain, the other parts (combined) are the subdomain
-    tld = right
+    tld = rule.empty?  ? nil : parts.pop(rule_len).join(DOT)
     sld = parts.empty? ? nil : parts.pop
     trd = parts.empty? ? nil : parts.join(DOT)
 
diff --git a/lib/public_suffix/domain.rb b/lib/public_suffix/domain.rb
index 4c4edd44..88e3107f 100644
--- a/lib/public_suffix/domain.rb
+++ b/lib/public_suffix/domain.rb
@@ -133,7 +133,7 @@ def name
     #
     # @return [String]
     def domain
-      [@sld, @tld].join(DOT) if domain?
+      [@sld, @tld].compact.join(DOT) if domain?
     end
 
     # Returns a subdomain-like representation of this object
@@ -165,7 +165,7 @@ def domain
     #
     # @return [String]
     def subdomain
-      [@trd, @sld, @tld].join(DOT) if subdomain?
+      [@trd, @sld, @tld].compact.join(DOT) if subdomain?
     end
 
     # Checks whether <tt>self</tt> looks like a domain.
@@ -196,7 +196,7 @@ def subdomain
     #
     # @return [Boolean]
     def domain?
-      !(@tld.nil? || @sld.nil?)
+      !@sld.nil?
     end
 
     # Checks whether <tt>self</tt> looks like a subdomain.
@@ -227,7 +227,7 @@ def domain?
     #
     # @return [Boolean]
     def subdomain?
-      !(@tld.nil? || @sld.nil? || @trd.nil?)
+      !(@sld.nil? || @trd.nil?)
     end
 
   end
diff --git a/lib/public_suffix/list.rb b/lib/public_suffix/list.rb
index 04e53a98..3bd69522 100644
--- a/lib/public_suffix/list.rb
+++ b/lib/public_suffix/list.rb
@@ -69,6 +69,7 @@ def self.default=(value)
     def self.parse(input, private_domains: true)
       comment_token = "//".freeze
       private_token = "===BEGIN PRIVATE DOMAINS===".freeze
+      space_re = /\p{Space}/
       section = nil # 1 == ICANN, 2 == PRIVATE
 
       new do |list|
@@ -90,7 +91,8 @@ def self.parse(input, private_domains: true)
             next
 
           else
-            list.add(Rule.factory(line, private: section == 2))
+            rule = line.split(space_re).first
+            list.add(rule, private: section == 2)
 
           end
         end
@@ -103,41 +105,23 @@ def self.parse(input, private_domains: true)
     # @yield [self] Yields on self.
     # @yieldparam [PublicSuffix::List] self The newly created instance.
     def initialize
-      @rules = {}
+      @rules = Rules.new
+      add('*', private: false)
       yield(self) if block_given?
     end
 
-
-    # Checks whether two lists are equal.
-    #
-    # List <tt>one</tt> is equal to <tt>two</tt>, if <tt>two</tt> is an instance of
-    # {PublicSuffix::List} and each +PublicSuffix::Rule::*+
-    # in list <tt>one</tt> is available in list <tt>two</tt>, in the same order.
-    #
-    # @param  other [PublicSuffix::List] the List to compare
-    # @return [Boolean]
-    def ==(other)
-      return false unless other.is_a?(List)
-      equal?(other) || @rules == other.rules
-    end
-    alias eql? ==
-
-    # Iterates each rule in the list.
-    def each(&block)
-      Enumerator.new do |y|
-        @rules.each do |key, node|
-          y << entry_to_rule(node, key)
-        end
-      end.each(&block)
-    end
-
-
     # Adds the given object to the list and optionally refreshes the rule index.
     #
     # @param  rule [PublicSuffix::Rule::*] the rule to add to the list
     # @return [self]
-    def add(rule)
-      @rules[rule.value] = rule_to_entry(rule)
+    def add(rule, private: false)
+      exception = false
+      if rule[0] == BANG
+        exception = true
+        rule = rule[1..-1]
+      end
+      lbls = rule.split(DOT).reverse
+      @rules.add(lbls, exception, private)
       self
     end
     alias << add
@@ -160,7 +144,7 @@ def empty?
     #
     # @return [self]
     def clear
-      @rules.clear
+      @rules = Rules.new
       self
     end
 
@@ -169,77 +153,19 @@ def clear
     # @param  name [#to_s] the hostname
     # @param  default [PublicSuffix::Rule::*] the default rule to return in case no rule matches
     # @return [PublicSuffix::Rule::*]
-    def find(name, default: default_rule, **options)
-      rule = select(name, **options).inject do |l, r|
-        return r if r.class == Rule::Exception
-        l.length > r.length ? l : r
-      end
-      rule || default
+    def find(name, ignore_private: false)
+      lbls = name.split(DOT).reverse
+      r = @rules.get_regdom(lbls, !ignore_private)
+      r.reverse[1..-1].join(DOT)
     end
 
-    # Selects all the rules matching given hostame.
-    #
-    # If `ignore_private` is set to true, the algorithm will skip the rules that are flagged as
-    # private domain. Note that the rules will still be part of the loop.
-    # If you frequently need to access lists ignoring the private domains,
-    # you should create a list that doesn't include these domains setting the
-    # `private_domains: false` option when calling {.parse}.
-    #
-    # Note that this method is currently private, as you should not rely on it. Instead,
-    # the public interface is {#find}. The current internal algorithm allows to return all
-    # matching rules, but different data structures may not be able to do it, and instead would
-    # return only the match. For this reason, you should rely on {#find}.
-    #
-    # @param  name [#to_s] the hostname
-    # @param  ignore_private [Boolean]
-    # @return [Array<PublicSuffix::Rule::*>]
-    def select(name, ignore_private: false)
-      name = name.to_s
-
-      parts = name.split(DOT).reverse!
-      index = 0
-      query = parts[index]
-      rules = []
-
-      loop do
-        match = @rules[query]
-        if !match.nil? && (ignore_private == false || match.private == false)
-          rules << entry_to_rule(match, query)
-        end
-
-        index += 1
-        break if index >= parts.size
-        query = parts[index] + DOT + query
-      end
-
-      rules
-    end
-    private :select
-
     # Gets the default rule.
     #
     # @see PublicSuffix::Rule.default_rule
     #
     # @return [PublicSuffix::Rule::*]
     def default_rule
-      PublicSuffix::Rule.default
-    end
-
-
-    protected
-
-    attr_reader :rules
-
-
-    private
-
-    def entry_to_rule(entry, value)
-      entry.type.new(value: value, length: entry.length, private: entry.private)
-    end
-
-    def rule_to_entry(rule)
-      Rule::Entry.new(rule.class, rule.length, rule.private)
+      '*'
     end
-
   end
 end
diff --git a/lib/public_suffix/rules.rb b/lib/public_suffix/rules.rb
new file mode 100644
index 00000000..b8ae417a
--- /dev/null
+++ b/lib/public_suffix/rules.rb
@@ -0,0 +1,75 @@
+# = Public Suffix
+#
+# Domain name parser based on the Public Suffix List.
+#
+# Copyright (c) 2009-2017 Simone Carletti <weppos@weppos.net>
+
+module PublicSuffix
+
+  # A Rule is a special object which holds a single definition
+  # of the Public Suffix List.
+  #
+  # There are 3 types of rules, each one represented by a specific
+  # subclass within the +PublicSuffix::Rule+ namespace.
+  #
+  # To create a new Rule, use the {PublicSuffix::Rule#factory} method.
+  #
+  #   PublicSuffix::Rule.factory("ar")
+  #   # => #<PublicSuffix::Rule::Normal>
+  #
+  class Rules
+    def initialize
+      @children = {}
+      @terminus = false
+      @priv = false
+      @exception = false
+    end
+
+    def empty?
+      @children.empty? && !@terminus
+    end
+
+    def size
+      sz = @terminus ? 1 : 0
+      @children.each{|k,v|sz += v.size}
+      sz
+    end
+
+    def add(x, excpt, priv)
+      lbl = x.shift
+      if lbl.nil?
+        raise 'Duplicate rule' if @terminus
+        @terminus = true
+        @priv = priv
+        @exception = excpt
+        return
+      end
+      @children[lbl] ||= Rules.new
+      @children[lbl].add(x, excpt, priv)
+    end
+
+    def get_regdom(lbls, priv = true, matched_lbls = [])
+      # Avoid modifying our input by copying it first
+      lbls = lbls.dup
+      lbl = lbls.shift
+      if lbl.nil?
+        if @terminus && (!@priv || priv)
+          if @exception
+            return matched_lbls
+          end
+          raise DomainNotAllowed, "#{matched_lbls.reverse.join(".")} is not allowed according to Registry policy"
+        end
+        return nil
+      end
+      r = @children[lbl].get_regdom(lbls, priv, matched_lbls + [lbl]) if @children.key?(lbl)
+      return r if !r.nil?
+      r = @children['*'].get_regdom(lbls, priv, matched_lbls + [lbl]) if @children.key?('*')
+      return r if !r.nil?
+      if @terminus && (!@priv || priv)
+        return matched_lbls if @exception
+        return matched_lbls + [lbl]
+      end
+      nil
+    end
+  end
+end