Class: Relaton::Isbn::Isbn

Inherits:
Object
  • Object
show all
Defined in:
lib/relaton/isbn/isbn.rb

Instance Method Summary collapse

Constructor Details

#initialize(isbn) ⇒ Isbn

Create ISBN object.

Parameters:

  • isbn (String) —

    ISBN 13 number



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# File 'lib/relaton/isbn/isbn.rb', line 9

def initialize(isbn)
  @isbn = isbn&.delete("-")&.sub(/^ISBN[\s:]/i, "")
end

Instance Method Details

#calc_check_digit10 ⇒ Object 



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# File 'lib/relaton/isbn/isbn.rb', line 33

def calc_check_digit10
  sum = 0
  @isbn[..-2].chars.each_with_index do |c, i|
    sum += c.to_i * (10 - i)
  end
  chk = (11 - sum % 11) % 11
  chk == 10 ? "X" : chk.to_s
end

#calc_check_digit13 ⇒ Object 



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# File 'lib/relaton/isbn/isbn.rb', line 42

def calc_check_digit13
  sum = 0
  @isbn[..-2].chars.each_with_index do |c, i|
    sum += c.to_i * (i.even? ? 1 : 3)
  end
  ((10 - sum % 10) % 10).to_s
end

#check10? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/relaton/isbn/isbn.rb', line 25

def check10?
  @isbn[9] == calc_check_digit10
end

#check13? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/relaton/isbn/isbn.rb', line 29

def check13?
  @isbn[12] == calc_check_digit13
end

#check? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/relaton/isbn/isbn.rb', line 17

def check?
  case @isbn
  when /^\d{9}[\dX]$/i then check10?
  when /^\d{13}$/ then check13?
  else false
  end
end

#convert_to13 ⇒ Object 



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# File 'lib/relaton/isbn/isbn.rb', line 50

def convert_to13
  return unless check?

  return @isbn if @isbn.size == 13

  @isbn = "978#{@isbn}"
  @isbn[12] = calc_check_digit13
  @isbn
end

#parse ⇒ Object 



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# File 'lib/relaton/isbn/isbn.rb', line 13

def parse
  convert_to13
end