# 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