module Erubis::PreprocessingHelper

def _decode(arg)
  arg = arg.to_s
  arg.gsub!(/%3C%25(?:=|%3D)(.*?)%25%3E/) { "<%=#{CGI.unescape($1)}%>" }
  arg.gsub!(/&lt;%=(.*?)%&gt;/) { "<%=#{CGI.unescapeHTML($1)}%>" }
  return arg
end