$xml = open("foo").read

NAMECHAR = '[\-\w\d\.:]'
NAME = "([\\w:]#{NAMECHAR}*)"
REFERENCE = /&(?!#{NAME};)/
NUMERICENTITY = /&#0*((?:\d+)|(?:x[a-fA-F0-9]+));/

def unnormalize( string, doctype=nil, filter=nil, illegal=nil )
  rv = string.clone
  rv.gsub!( /\r\n?/, "\n" )
  matches = rv.scan( REFERENCE )
  return rv if matches.size == 0
  rv.gsub!( NUMERICENTITY ) {|m|
    m=$1
    m = "0#{m}" if m[0] == ?x
    [Integer(m)].pack('U*')
  }
  matches.collect!{|x|x[0]}.compact!
  if matches.size > 0
    if doctype
      matches.each do |entity_reference|
        unless filter and filter.include?(entity_reference)
          entity_value = doctype.entity( entity_reference )
          p entity_reference
          re = /&#{entity_reference};/
          rv.gsub!( re, entity_value ) if entity_value
        end
      end
    else
      matches.each do |entity_reference|
        unless filter and filter.include?(entity_reference)
          entity_value = DocType::DEFAULT_ENTITIES[ entity_reference ]
          re = /&#{entity_reference};/
          rv.gsub!( re, entity_value.value ) if entity_value
        end
      end
    end
    rv.gsub!( /&/, '&' )
  end
  rv
end

def bench
    t = Time.now
    100.times {
        unnormalize($xml)
    }
    p Time.now - t
end

bench
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