Change @scanner.match to respond nil/@scanner in order to impro…

…ve processing speed.

lib/rexml/parsers/baseparser.rb

@@ -274,8 +274,7 @@ def pull_event
             return [ :elementdecl, @source.match( ELEMENTDECL_PATTERN, true )[1] ]
 
           when ENTITY_START
-            match = @source.match( ENTITYDECL, true ).compact
-            match[0] = :entitydecl
+            match = [:entitydecl, *@source.match( ENTITYDECL, true ).captures.compact]
             ref = false
             if match[1] == '%'
               ref = true

lib/rexml/source.rb

@@ -70,11 +70,10 @@ def read
 
     def match(pattern, cons=false)
       if cons
-        @scanner.scan(pattern)
+        @scanner.scan(pattern).nil? ? nil : @scanner
       else
-        @scanner.check(pattern)
+        @scanner.check(pattern).nil? ? nil : @scanner
       end
-      @scanner.matched? ? [@scanner.matched, *@scanner.captures] : nil
     end
 
     # @return true if the Source is exhausted
@@ -158,24 +157,24 @@ def read
 
     def match( pattern, cons=false )
       if cons
-        @scanner.scan(pattern)
+        md = @scanner.scan(pattern)
       else
-        @scanner.check(pattern)
+        md = @scanner.check(pattern)
       end
-      while !@scanner.matched? and @source
+      while md.nil? and @source
         begin
           @scanner << readline
           if cons
-            @scanner.scan(pattern)
+            md = @scanner.scan(pattern)
           else
-            @scanner.check(pattern)
+            md = @scanner.check(pattern)
           end
         rescue
           @source = nil
         end
       end
 
-      @scanner.matched? ? [@scanner.matched, *@scanner.captures] : nil
+      md.nil? ? nil : @scanner
     end
 
     def empty?

test/test_document.rb

@@ -173,6 +173,18 @@ def test_empty_value
             REXML::Document.new(xml)
           end
         end
+
+        def test_empty_entity
+          xml = <<EOF
+<!DOCTYPE root [
+  <!ENTITY>
+]>
+EOF
+
+          assert_raise(REXML::ParseException) do
+            REXML::Document.new(xml)
+          end
+        end
       end
     end