Contents

module NumberPlate
  module SG
    module Checksum
      CHECK_SUM = { 0 => "A", 1 => "Z", 2 => "Y", 3 => "X", 4 => "U", 5 => "T", 6 => "S", 7 => "R", 8 => "P", 9 => "M", 10 => "L", 11 => "K", 12 => "J", 13 => "H", 14 => "G", 15 => "E", 16 => "D", 17 => "C", 18 => "B" }
      MULTIPLIER = [9, 4, 5, 4, 3, 2]

      def checksum
        get_checksum_from_numbers(numbers)
      end

      def numbers
        numbers = []
        @letters.split(//).each do |alphebat|
          numbers << (alphebat.ord - 64)
        end

        if numbers.length == 3
          numbers = numbers[1,2]
        elsif numbers.length == 1
          numbers = [1] + numbers
        end

        numerals = ("000" + @numerals)[-4,4]
        numbers + numerals.split(//).map(&:to_i)
      end

      def get_checksum_from_numbers(numbers)
        checksum_array = []
        numbers.zip(MULTIPLIER) { |x, y| checksum_array << (x * y) }
        checksum_key = checksum_array.reduce(:+) % 19
        CHECK_SUM[checksum_key]
      end

    end
  end
end

Version data entries

2 entries across 2 versions & 1 rubygems

Version	Path
number_plate_sg-0.2.0	lib/number_plate/sg/checksum.rb
number_plate_sg-0.1.0	lib/number_plate/sg/checksum.rb