class REXML::Parsers::BaseParser

def unnormalize( string, entities=nil, filter=nil )
  if string.include?("\r")
    rv = string.gsub( Private::CARRIAGE_RETURN_NEWLINE_PATTERN, "\n" )
  else
    rv = string.dup
  end
  matches = rv.scan( REFERENCE_RE )
  return rv if matches.size == 0
  rv.gsub!( Private::CHARACTER_REFERENCES ) {
    m=$1
    if m.start_with?("x")
      code_point = Integer(m[1..-1], 16)
    else
      code_point = Integer(m, 10)
    end
    [code_point].pack('U*')
  }
  matches.collect!{|x|x[0]}.compact!
  if filter
    matches.reject! do |entity_reference|
      filter.include?(entity_reference)
    end
  end
  if matches.size > 0
    matches.tally.each do |entity_reference, n|
      entity_expansion_count_before = @entity_expansion_count
      entity_value = entity( entity_reference, entities )
      if entity_value
        if n > 1
          entity_expansion_count_delta =
            @entity_expansion_count - entity_expansion_count_before
          record_entity_expansion(entity_expansion_count_delta * (n - 1))
        end
        re = Private::DEFAULT_ENTITIES_PATTERNS[entity_reference] || /&#{entity_reference};/
        rv.gsub!( re, entity_value )
        if rv.bytesize > @entity_expansion_text_limit
          raise "entity expansion has grown too large"
        end
      else
        er = DEFAULT_ENTITIES[entity_reference]
        rv.gsub!( er[0], er[2] ) if er
      end
    end
    rv.gsub!( Private::DEFAULT_ENTITIES_PATTERNS['amp'], '&' )
  end
  rv
end