# File lib/pdf/reader/parser.rb, line 101
    def hex_string
      str = ""

      loop do
        token = @buffer.token
        break if token == ">"
        str << token
      end

      # add a missing digit if required, as required by the spec
      str << "0" unless str.size % 2 == 0
      str.scan(/../).map {|i| i.hex.chr}.join
    end