28 lines
845 B
Ruby
28 lines
845 B
Ruby
# Copyright (C) 2012-2021 Zammad Foundation, http://zammad-foundation.org/
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module Ticket::Number::Base
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extend self
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private
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# The algorithm to calculate the checksum is derived from the one
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# Deutsche Bundesbahn (german railway company) uses for calculation
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# of the check digit of their vehikel numbering.
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# The checksum is calculated by alternately multiplying the digits
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# with 1 and 2 and adding the resulsts from left to right of the
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# vehikel number. The modulus to 10 of this sum is substracted from
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# 10. See: http://www.pruefziffernberechnung.de/F/Fahrzeugnummer.shtml
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# (german)
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def checksum(number)
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chksum = 0
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mult = 1
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number.to_s.chars.map(&:to_i).each do |digit|
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chksum += digit * mult
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mult = (mult % 3) + 1
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end
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chksum = 10 - (chksum % 10)
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chksum.to_s[0]
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end
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end
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