# File lib/zip/zip.rb, line 1682
      def initial_parse(binstr)
        if ! binstr
          # If nil, start with empty.
          return false
        elsif binstr[0,2] != self.class.const_get(:HEADER_ID)
          $stderr.puts "Warning: weired extra feild header ID. skip parsing"
          return false
        end
        [binstr[2,2].unpack("v")[0], binstr[4..-1]]
      end