Class: Barcode1DTools::EAN13

Inherits:
Barcode1D show all
Defined in:
lib/barcode1dtools/ean13.rb

Overview

The value encoded is an integer, and a checksum digit will be added. You can add the option :checksum_included => true when initializing to specify that you have already included a checksum.

# Note that this number is a UPC-A, with the number system of 08, # manufacturer’s code of “28999”, product code of “00682”, and a # checksum of “3” (not included) num = ‘082899900682’ bc = Barcode1DTools::EAN13.new(num) pattern = bc.bars rle_pattern = bc.rle width = bc.width check_digit = Barcode1DTools::EAN13.generate_check_digit_for(num)

The object created is immutable.

There are two formats for the returned pattern (wn format is not available):

bars - 1s and 0s specifying black lines and white spaces.  Actual
       characters can be changed from "1" and 0" with options
       :line_character and :space_character.  Each character
       in the string renders to a single unit width.

rle -  Run-length-encoded version of the pattern.  The first
       number is always a black line, with subsequent digits
       alternating between spaces and lines.  The digits specify
       the width of each line or space.

The “width” method will tell you the total end-to-end width, in units, of the entire barcode.

Unlike some of the other barcodes, e.g. Code 3 of 9, there is no “wnstr” for EAN & UPC style barcodes because the bars and spaces are variable width from 1 to 3 units.

Note that JAN codes (Japanese) are simply EAN-13’s, and they always start with “49”. The table below shows “49” to be “Japan”.

Also note that many books use a “bookland” code, perhaps along with a UPC Supplemental. The bookland code is really an EAN-13 with the initial 3 digits of “978”. The next 9 digits are the first 9 digits of the ISBN, and of course we still include the final check digit. An ISBN is 10 digits, however, the final digit is also a check digit, so it is not necessary.

MISCELLANEOUS INFORMATION

An EAN-13 with an initial “number system” digit of “0” is a UPC-A. The BarcodeTools::UPC_A module actually just uses this EAN13 module.

A EAN-13 barcode has 4 elements:

  1. A two-digit “number system” designation

  2. A 5-digit manufacturer’s code

  3. A 5-digit product code

  4. A single digit checksum

There is some flexibility in EAN-13 on the digit layout. Sometimes, the first three digits indicate numbering system, i.e. some number systems are further split up. An example is “74”, which is used for Central America with “740” for Guatemala, “741” for El Salvador, etc.

Here is the complete table from www.barcodeisland.com:

00-13: USA & Canada 590: Poland 780: Chile 20-29: In-Store Functions 594: Romania 784: Paraguay 30-37: France 599: Hungary 785: Peru 40-44: Germany 600 & 601: South Africa 786: Ecuador 45: Japan (also 49) 609: Mauritius 789: Brazil 46: Russian Federation 611: Morocco 80 - 83: Italy 471: Taiwan 613: Algeria 84: Spain 474: Estonia 619: Tunisia 850: Cuba 475: Latvia 622: Egypt 858: Slovakia 477: Lithuania 625: Jordan 859: Czech Republic 479: Sri Lanka 626: Iran 860: Yugloslavia 480: Philippines 64: Finland 869: Turkey 482: Ukraine 690-692: China 87: Netherlands 484: Moldova 70: Norway 880: South Korea 485: Armenia 729: Israel 885: Thailand 486: Georgia 73: Sweden 888: Singapore 487: Kazakhstan 740: Guatemala 890: India 489: Hong Kong 741: El Salvador 893: Vietnam 49: Japan (JAN-13) 742: Honduras 899: Indonesia 50: United Kingdom 743: Nicaragua 90 & 91: Austria 520: Greece 744: Costa Rica 93: Australia 528: Lebanon 746: Dominican Republic 94: New Zealand 529: Cyprus 750: Mexico 955: Malaysia 531: Macedonia 759: Venezuela 977: ISSN 535: Malta 76: Switzerland 978: ISBN 539: Ireland 770: Colombia 979: ISMN 54: Belgium & Luxembourg 773: Uruguay 980: Refund receipts 560: Portugal 775: Peru 981 & 982: CCC 569: Iceland 777: Bolivia 99: Coupons 57: Denmark 779: Argentina

ISSN - International Standard Serial Number for Periodicals ISBN - International Standard Book Numbering ISMN - International Standard Music Number CCC - Common Currency Coupons

RENDERING

When rendered, the initial digit of the number system is shown to the left and above the rest of the digits. The other two sets of six digits each are shown at the bottom of the code, aligned with the bottom of the code, and with the middle guard pattern bars extending down between them. The lower digits may be aligned flush with the bottom of the barcode, or the center of the text may be aligned with the bottom of the barcode.

Direct Known Subclasses

UPC_A

Constant Summary collapse

LEFT_PATTERNS =

left side, odd/even

{
  '0' => { 'o' => '0001101', 'e' => '0100111'},
  '1' => { 'o' => '0011001', 'e' => '0110011'},
  '2' => { 'o' => '0010011', 'e' => '0011011'},
  '3' => { 'o' => '0111101', 'e' => '0100001'},
  '4' => { 'o' => '0100011', 'e' => '0011101'},
  '5' => { 'o' => '0110001', 'e' => '0111001'},
  '6' => { 'o' => '0101111', 'e' => '0000101'},
  '7' => { 'o' => '0111011', 'e' => '0010001'},
  '8' => { 'o' => '0110111', 'e' => '0001001'},
  '9' => { 'o' => '0001011', 'e' => '0010111'},
}
LEFT_PATTERNS_RLE =

All left patterns start with a space and end with a bar

{
  '0' => { 'o' => '3211', 'e' => '1123'},
  '1' => { 'o' => '2221', 'e' => '1222'},
  '2' => { 'o' => '2122', 'e' => '2212'},
  '3' => { 'o' => '1411', 'e' => '1141'},
  '4' => { 'o' => '1132', 'e' => '2311'},
  '5' => { 'o' => '1231', 'e' => '1321'},
  '6' => { 'o' => '1114', 'e' => '4111'},
  '7' => { 'o' => '1312', 'e' => '2131'},
  '8' => { 'o' => '1213', 'e' => '3121'},
  '9' => { 'o' => '3112', 'e' => '2113'},
}
LEFT_PARITY_PATTERNS = 
{
  '0' => 'oooooo',
  '1' => 'ooeoee',
  '2' => 'ooeeoe',
  '3' => 'ooeeeo',
  '4' => 'oeooee',
  '5' => 'oeeooe',
  '6' => 'oeeeoo',
  '7' => 'oeoeoe',
  '8' => 'oeoeeo',
  '9' => 'oeeoeo',
}
RIGHT_PATTERNS =

right side

{
  '0' => '1110010',
  '1' => '1100110',
  '2' => '1101100',
  '3' => '1000010',
  '4' => '1011100',
  '5' => '1001110',
  '6' => '1010000',
  '7' => '1000100',
  '8' => '1001000',
  '9' => '1110100',
}
RIGHT_PATTERNS_RLE =

All right patterns start with a bar and end with a space

{
  '0' => '3211',
  '1' => '2221',
  '2' => '2122',
  '3' => '1411',
  '4' => '1132',
  '5' => '1231',
  '6' => '1114',
  '7' => '1312',
  '8' => '1213',
  '9' => '3112',
}
SIDE_GUARD_PATTERN =

AAAAHHHHHHHHH side + middle + side is 666, the number of the beast

'101'
MIDDLE_GUARD_PATTERN = 
'01010'
SIDE_GUARD_PATTERN_RLE =

Starts with bar

'111'
MIDDLE_GUARD_PATTERN_RLE =

Starts with space

'11111'
DEFAULT_OPTIONS = 
{
  :line_character => '1',
  :space_character => '0'
}

Instance Attribute Summary collapse

Attributes inherited from Barcode1D

#check_digit, #encoded_string, #options, #value

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Barcode1D

bar_pair, bars_to_rle, rle_to_bars, rle_to_wn, wn_pair, wn_to_rle

Constructor Details

#initialize(value, options = {}) ⇒ EAN13

Options are :line_character, :space_character, and :checksum_included.

Raises:



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# File 'lib/barcode1dtools/ean13.rb', line 334

def initialize(value, options = {})

  @options = DEFAULT_OPTIONS.merge(options)

  # Can we encode this value?
  raise UnencodableCharactersError unless self.class.can_encode?(value, @options)

  if @options[:checksum_included]
    @encoded_string = value.to_s
    raise ChecksumError unless self.class.validate_check_digit_for(@encoded_string)
    md = @encoded_string.match(/^(\d+?)(\d)$/)
    @value, @check_digit = md[1], md[2].to_i
  else
    # need to add a checksum
    @value = value.to_s
    @check_digit = self.class.generate_check_digit_for(@value)
    @encoded_string = "#{@value}#{@check_digit}"
  end

  md = @value.match(/^(\d{2})(\d{5})(\d{5})/)
  @number_system, @manufacturers_code, @product_code = md[1], md[2], md[3]
end

Instance Attribute Details

#manufacturers_code ⇒ Object (readonly)

Returns the value of attribute manufacturers_code.



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# File 'lib/barcode1dtools/ean13.rb', line 211

def manufacturers_code
  @manufacturers_code
end

#number_system ⇒ Object (readonly)

Specific for EAN



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# File 'lib/barcode1dtools/ean13.rb', line 210

def number_system
  @number_system
end

#product_code ⇒ Object (readonly)

Returns the value of attribute product_code.



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# File 'lib/barcode1dtools/ean13.rb', line 212

def product_code
  @product_code
end

Class Method Details

.can_encode?(value, options = nil) ⇒ Boolean

returns true or false - must be 12-13 digits

Returns:

  • (Boolean) 


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# File 'lib/barcode1dtools/ean13.rb', line 216

def can_encode?(value, options = nil)
  if !options
    value.to_s =~ /^[0-9]{12,13}$/
  elsif (options[:checksum_included])
    value.to_s =~ /^[0-9]{13}$/
  else
    value.to_s =~ /^[0-9]{12}$/
  end
end

.decode(str) ⇒ Object

Decode a string representing an rle or bar pattern EAN-13. Note that the string might be backward or forward. This will return an EAN13 object.

Raises:



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# File 'lib/barcode1dtools/ean13.rb', line 246

def decode(str)
  if str.length == 95
    # bar pattern
    str = bars_to_rle(str)
  elsif str.length == 59
    # rle
  else
    raise UnencodableCharactersError, "Pattern must be 95 unit bar pattern or 59 character rle."
  end

  # Check the guard patterns
  unless str[0..2] == SIDE_GUARD_PATTERN_RLE && str[56..58] == SIDE_GUARD_PATTERN_RLE && str[27..31] == MIDDLE_GUARD_PATTERN_RLE
    raise UnencodableCharactersError, "Missing or incorrect guard patterns"
  end

  # Now I have an rle pattern, simply need to decode
  # according to the LEFT_PATTERNS_RLE, keeping track
  # of the parity for each position.

  # Set up the decoder
  left_parity_sequence = ''
  left_digits = ''
  right_parity_sequence = ''
  right_digits = ''
  left_initial_offset = SIDE_GUARD_PATTERN_RLE.length
  right_initial_offset = SIDE_GUARD_PATTERN_RLE.length + (4*6) + MIDDLE_GUARD_PATTERN_RLE.length

  # Decode the left side
  (0..5).each do |left_offset|
    found = false
    digit_rle = str[(left_initial_offset + left_offset*4),4]
    ['o','e'].each do |parity|
      ('0'..'9').each do |digit|
        if LEFT_PATTERNS_RLE[digit][parity] == digit_rle
          left_parity_sequence += parity
          left_digits += digit
          found = true
          break
        end
      end
    end
    raise UndecodableCharactersError, "Invalid sequence: #{digit_rle}" unless found
  end

  # Decode the right side
  (0..5).each do |right_offset|
    found = false
    digit_rle = str[(right_initial_offset + right_offset*4),4]
    ['o','e'].each do |parity|
      ('0'..'9').each do |digit|
        if LEFT_PATTERNS_RLE[digit][parity] == digit_rle
          right_parity_sequence += parity
          right_digits += digit
          found = true
          break
        end
      end
    end
    raise UndecodableCharactersError, "Invalid sequence: #{digit_rle}" unless found
  end

  # If left parity sequence is 'eeeeee', the string is reversed
  if left_parity_sequence == 'eeeeee'
    left_digits, right_digits, left_parity_sequence = right_digits.reverse, left_digits.reverse, right_parity_sequence.reverse.tr('eo','oe')
  end

  # Now, find the parity digit
  parity_digit = nil
  ('0'..'9').each do |x|
    if LEFT_PARITY_PATTERNS[x] == left_parity_sequence
      parity_digit = x
      break
    end
  end

  raise UndecodableCharactersError, "Weird parity: #{left_parity_sequence}" unless parity_digit

  # Debugging
  #puts "Left digits: #{left_digits} Left parity: #{left_parity_sequence}"
  #puts "Right digits: #{right_digits} Right parity: #{right_parity_sequence}"
  #puts "Parity: #{parity_digit}"

  EAN13.new(parity_digit + left_digits + right_digits, :checksum_included => true)
end

.generate_check_digit_for(value) ⇒ Object

Generates check digit given a string to encode. It assumes there is no check digit on the “value”.

Raises:



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# File 'lib/barcode1dtools/ean13.rb', line 228

def generate_check_digit_for(value)
  raise UnencodableCharactersError unless self.can_encode?(value, :checksum_included => false)
  mult = 3
  value = value.split('').inject(0) { |a,c| mult = 4 - mult ; a + c.to_i * mult }
  (10 - (value % 10)) % 10
end

.validate_check_digit_for(value) ⇒ Object

validates the check digit given a string - assumes check digit is last digit of string.

Raises:



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# File 'lib/barcode1dtools/ean13.rb', line 237

def validate_check_digit_for(value)
  raise UnencodableCharactersError unless self.can_encode?(value, :checksum_included => true)
  md = value.match(/^(\d{12})(\d)$/)
  self.generate_check_digit_for(md[1]) == md[2].to_i
end

Instance Method Details

#bars ⇒ Object

returns 1s and 0s (for “black” and “white”)



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# File 'lib/barcode1dtools/ean13.rb', line 373

def bars
  @bars ||= self.class.rle_to_bars(self.rle, @options)
end

#rle ⇒ Object

returns a run-length-encoded string representation



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# File 'lib/barcode1dtools/ean13.rb', line 363

def rle
  if @rle
    @rle
  else
    md = @encoded_string.match(/^(\d)(\d{6})(\d{6})/)
    @rle = gen_rle(md[1], md[2], md[3])
  end
end

#width ⇒ Object

returns the total unit width of the bar code



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# File 'lib/barcode1dtools/ean13.rb', line 378

def width
  @width ||= rle.split('').inject(0) { |a,c| a + c.to_i }
end

#wn ⇒ Object

not usable with EAN codes

Raises:



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# File 'lib/barcode1dtools/ean13.rb', line 358

def wn
  raise NotImplementedError
end