Module: Ibandit::CheckDigit

Defined in:
lib/ibandit/check_digit.rb

Constant Summary collapse

ITALIAN_ODD_MAPPING = 
{
  "A" => 1,  "B" => 0,  "C" => 5,  "D" => 7,  "E" => 9,  "F" => 13,
  "G" => 15, "H" => 17, "I" => 19, "J" => 21, "K" => 2,  "L" => 4,
  "M" => 18, "N" => 20, "O" => 11, "P" => 3,  "Q" => 6,  "R" => 8,
  "S" => 12, "T" => 14, "U" => 16, "V" => 10, "W" => 22, "X" => 25,
  "Y" => 24, "Z" => 23, "0" => 1,  "1" => 0,  "2" => 5,  "3" => 7,
  "4" => 9,  "5" => 13, "6" => 15, "7" => 17, "8" => 19, "9" => 21
}.freeze

Class Method Summary collapse

Class Method Details

.iban(country_code, bban) ⇒ Object 



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# File 'lib/ibandit/check_digit.rb', line 14

def self.iban(country_code, bban)
  chars = bban + country_code + "00"
  digits = chars.bytes.map do |byte|
    case byte
    when 48..57 then byte.chr           # 0..9
    when 65..90 then (byte - 55).to_s   # A..Z
    else
      raise InvalidCharacterError,
            "Unexpected non-alphanumeric character '#{byte.chr}'"
    end
  end
  remainder = digits.join.to_i % 97
  sprintf("%<check_digit>02d", check_digit: 98 - remainder)
end

.italian(string) ⇒ Object 



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# File 'lib/ibandit/check_digit.rb', line 29

def self.italian(string)
  scaled_values = string.chars.map.with_index do |char, index|
    if index.even?
      if ITALIAN_ODD_MAPPING.include?(char)
        ITALIAN_ODD_MAPPING[char]
      else
        raise InvalidCharacterError,
              "Unexpected character '#{char}'"
      end
    else
      case char.ord
      when 48..57 then char.to_i         # 0..9
      when 65..90 then char.ord - 65     # A..Z
      else
        raise InvalidCharacterError,
              "Unexpected character '#{char}'"
      end
    end
  end

  ((scaled_values.sum % 26) + 65).chr
end