# File lib/CharDistributionAnalysis.rb, line 204
        def get_order(aStr)
            # for sjis encoding, we are interested 
            #   first  byte range: 0x81 -- 0x9f , 0xe0 -- 0xfe
            #   second byte range: 0x40 -- 0x7e,  0x81 -- oxfe
            # no validation needed here. State machine has done that
            if (aStr[0] >= 0x81) && (aStr[0] <= 0x9F)
                order = 188 * (aStr[0] - 0x81)
            elsif (aStr[0] >= 0xE0) and (aStr[0] <= 0xEF)
                order = 188 * (aStr[0] - 0xE0 + 31)
            else
                return -1;
            end
            order = order + aStr[1] - 0x40
            if aStr[1] > 0x7F
                order =- 1
            end
            return order
        end