28 lines
846 B
Ruby
28 lines
846 B
Ruby
# Copyright (C) 2012-2022 Zammad Foundation, https://zammad-foundation.org/
|
|
|
|
module Ticket::Number::Base
|
|
extend self
|
|
|
|
private
|
|
|
|
# The algorithm to calculate the checksum is derived from the one
|
|
# Deutsche Bundesbahn (german railway company) uses for calculation
|
|
# of the check digit of their vehikel numbering.
|
|
# The checksum is calculated by alternately multiplying the digits
|
|
# with 1 and 2 and adding the resulsts from left to right of the
|
|
# vehikel number. The modulus to 10 of this sum is substracted from
|
|
# 10. See: http://www.pruefziffernberechnung.de/F/Fahrzeugnummer.shtml
|
|
# (german)
|
|
def checksum(number)
|
|
chksum = 0
|
|
mult = 1
|
|
|
|
number.to_s.chars.map(&:to_i).each do |digit|
|
|
chksum += digit * mult
|
|
mult = (mult % 3) + 1
|
|
end
|
|
|
|
chksum = 10 - (chksum % 10)
|
|
chksum.to_s[0]
|
|
end
|
|
end
|