differences= (PDF::Reader::Encoding)

    # File lib/pdf/reader/encoding.rb, line 86
        def differences=(diff)
          raise ArgumentError, "diff must be an array" unless diff.kind_of?(Array)

          @differences = {}
          byte = 0
          diff.each do |val|
            if val.kind_of?(Numeric)
              byte = val.to_i
            else
              @differences[byte] = val
              byte += 1
            end
          end
          @differences
        end