#!/usr/bin/ruby
require 'rexml/document'
require 'rexml/streamlistener'

class String

  def entitize
    gsub(/[&'"<>]/) {|c|
      case c
      when '&' then '&amp;'
      when '"' then '&quot;'
      when "'" then '&apos;'
      when '<' then '&lt;'
      when '>' then '&gt;'
      else c
      end
    }
  end

end

class MDStream 
  include REXML::StreamListener

  def initialize
    @mode = nil
  end

  PATS = [
    #/^([A-Za-z]+:)?pointOfContact$/,
    /^(gmd:)?contactInfo$/,
    /^(gmd:)?referenceSystemInfo$/,
    /^(gmd:)?metadataConstraints$/,
    /^(gmd:)?contentInfo$/,
    /^(gmd:)?qualityInfo$/
  ]

  def tag_start n, a
    for pat in PATS
      if pat === n
        @mode = pat
      end
    end
    return if @mode
    r = [ "<#{n}" ]
    for k, v in a
      r.push [ k, '="', v.entitize, '"' ].join
    end
    r.push '>'
    print r.join(' ')
  end

  def text t
    return if @mode
    print t.entitize
  end

  def tag_end n
    unless @mode
      print "</#{n}>"
    end
    @mode = nil if @mode and @mode === n
  end

end

list = MDStream.new
for file in ARGV
  source = File.new(file)
  REXML::Document.parse_stream(source, list)
end