Module: TrackingNumber::ChecksumValidations

Defined in:
lib/tracking_number/checksum_validations.rb

Class Method Summary collapse

Class Method Details

.validates_mod10?(sequence, check_digit, extras = {}) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/tracking_number/checksum_validations.rb', line 35

def validates_mod10?(sequence, check_digit, extras = {})
  total = 0
  sequence.chars.each_with_index do |c, i|
    x = if c[/[0-9]/] # numeric
      c.to_i
    else
      (c[0].ord - 3) % 10
    end

    if extras[:odds_multiplier] && i.odd?
      x *= extras[:odds_multiplier].to_i
    elsif extras[:evens_multiplier] && i.even?
      x *= extras[:evens_multiplier].to_i
    end

    total += x
  end

  check = (total % 10)
  check = (10 - check) unless (check.zero?)

  return (check.to_i == check_digit.to_i)
end

.validates_mod7?(sequence, check_digit, extras = {}) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/tracking_number/checksum_validations.rb', line 59

def validates_mod7?(sequence, check_digit, extras = {})
  # standard mod 7 check
  return true if sequence.to_i % 7 == check_digit.to_i
end

.validates_mod_37_36?(sequence, check_digit, extras = {}) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/tracking_number/checksum_validations.rb', line 64

def validates_mod_37_36?(sequence, check_digit, extras = {})
  # From https://esolutions.dpd.com/dokumente/DPD_Parcel_Label_Specification_2.4.1_EN.pdf

  mod = 36
  weights = {A: 10, B: 11, C: 12, D: 13, E: 14, F: 15, G: 16, H: 17, I: 18, J: 19, K: 20, L: 21, M: 22, N: 23, O: 24, P: 25, Q: 26, R: 27, S: 28, T: 29, U: 30, V: 31, W: 32, X: 33, Y: 34, Z: 35}
  cd = mod
  sequence.chars.to_a.each do |char, i|
    val = (char =~ /[A-Za-z]/  ? weights[char.to_sym] : char.to_i)

    cd = val + cd
    cd = cd - mod if cd > mod
    cd = cd * 2
    cd = cd - (mod + 1) if cd > mod
  end

  cd = (mod + 1) - cd
  cd = 0 if cd == mod
  computed = if cd >= 10
               weights.find { |a, val| val == cd }[0].to_s
             else
               cd.to_s
             end

  computed == check_digit
end

.validates_s10?(sequence, check_digit, extras = {}) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/tracking_number/checksum_validations.rb', line 4

def validates_s10?(sequence, check_digit, extras = {})
  weighting = [8,6,4,2,3,5,9,7]

  total = 0
  sequence.chars.to_a.zip(weighting).each do |(a,b)|
    total += a.to_i * b.to_i
  end

  remainder = total % 11
  check = case remainder
  when 1
    0
  when 0
    5
  else
    11 - remainder
  end

  return check.to_i == check_digit.to_i
end

.validates_sum_product_with_weightings_and_modulo?(sequence, check_digit, extras = {}) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/tracking_number/checksum_validations.rb', line 25

def validates_sum_product_with_weightings_and_modulo?(sequence, check_digit, extras = {})
  weighting = extras[:weightings] || []

  total = 0
  sequence.chars.to_a.zip(weighting).each do |(a,b)|
    total += a.to_i * b
  end
  return (total % extras[:modulo1] % extras[:modulo2]) == check_digit.to_i
end