# File lib/CharDistributionAnalysis.rb, line 116
        def get_order(aStr)
            # for euc-TW encoding, we are interested 
            #   first  byte range: 0xc4 -- 0xfe
            #   second byte range: 0xa1 -- 0xfe
            # no validation needed here. State machine has done that
            if aStr[0] >= 0xC4
                return 94 * (aStr[0] - 0xC4) + aStr[1] - 0xA1
            else
                return -1
            end
        end