Contents

# http://www.bgc.se/upload/Gemensamt/Trycksaker/Manualer/BG6070.pdf section 5.2

module BankTools
  module SE
    class Bankgiro
      class InvalidOCR < StandardError; end
      class OverlongOCR < InvalidOCR; end
      class BadChecksum < InvalidOCR; end
      class MustBeNumeric < InvalidOCR; end

      class OCR
        MIN_LENGTH = 2
        MAX_LENGTH = 25

        def self.number_to_ocr(number, opts = {})
          number = number.to_s
          add_length_digit = opts.fetch(:length_digit, false)
          pad = opts.fetch(:pad, "").to_s

          raise MustBeNumeric unless number.match(/\A\d+\z/)
          # Padding isn't something BGC specifies, but we needed it to support a legacy scheme.
          number += pad
          # Adding 2: 1 length digit, 1 check digit.
          number += ((number.length + 2) % 10).to_s if add_length_digit

          number_with_ocr = number + Utils.luhn_checksum(number).to_s

          length = number_with_ocr.length
          if length > MAX_LENGTH
            raise OverlongOCR, "Bankgiro OCR must be #{MIN_LENGTH} - #{MAX_LENGTH} characters (this one would be #{length} characters)"
          end

          number_with_ocr
        end

        def self.number_from_ocr(number, opts = {})
          number = number.to_s
          strip_length_digit = opts.fetch(:length_digit, false)
          strip_padding = opts.fetch(:pad, "").to_s

          raise MustBeNumeric unless number.match(/\A\d+\z/)
          raise BadChecksum unless Utils.valid_luhn?(number)

          digits_to_chop  = 1  # Checksum.
          digits_to_chop += 1 if strip_length_digit
          digits_to_chop += strip_padding.length

          number[0...-digits_to_chop]
        end
      end
    end
  end
end

Version data entries

2 entries across 2 versions & 1 rubygems

Version	Path
banktools-se-0.11.0	lib/banktools-se/bankgiro/ocr.rb
banktools-se-0.10.0	lib/banktools-se/bankgiro/ocr.rb