Class: Barcode1DTools::UPC_A

Inherits:
EAN13 show all
Defined in:
lib/barcode1dtools/upc_a.rb

Overview

Barcode1DTools::UPC_A - Create pattern for UPC-A barcodes. The value encoded is an 11-digit 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.

Example

# 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 = '82899900682'
bc = Barcode1DTools::UPC_A.new(num)
pattern = bc.bars
rle_pattern = bc.rle
width = bc.width
check_digit = Barcode1DTools::UPC_A.generate_check_digit_for(num)

Other Information

A UPC-A barcode is an EAN-13 with an initial digit of “0” (that is the left digit of the number system designator). Like the EAN-13, the code is broken into a single-digit number system, 5 digit manufacturer code, 5 digit product code, and single digit checksum.

The number system is:

0, 1, 6, 7, 8 - standard UPC codes
2    - a product weight- generally calculated at the store.
3    - pharmaceuticals
4    - used for loyalty cards at stores
5    - coupons
9    - coupons
978  - for books, with a 10-digit ISBN coming after 978

For code 2, the manufacturer code becomes an item number, and the product number is used for either the weight or the price, with the first digit determining which.

For 5 and 9, the manufacturer code is the same as a standard UPC. The first three digits of the product code are used as a “family code” set by the manufacturer, and the last two digits are a “coupon code” which determines the amount of the discount based on a table released by the GS1 US (formerly the UCC). Code 5 coupons may be doubled or tripled, but code 9 may not.

Formats

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.

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 “w/n” format for EAN & UPC style barcodes because the bars and spaces are variable width from 1 to 4 units.

Rendering

The UPC-A is typically rendered at 1-1.5 inch across, and half an inch high. The number system digit and checksum digit are shown on the left and right sides of the code. The other two sets of five digits are rendered at the bottom of the barcode. The alignment can be either bottom of the text flush with bottom of barcode, or middle of text aligned with bottom of barcode. The two sets of five digits are separated by the two middle guard bars which always extend to the bottom. There should be at least 9 spaces of quiet area on either side of the code.

Constant Summary

Constants inherited from EAN13

EAN13::DEFAULT_OPTIONS, EAN13::LEFT_PARITY_PATTERNS, EAN13::LEFT_PATTERNS, EAN13::LEFT_PATTERNS_RLE, EAN13::MIDDLE_GUARD_PATTERN, EAN13::MIDDLE_GUARD_PATTERN_RLE, EAN13::RIGHT_PATTERNS, EAN13::RIGHT_PATTERNS_RLE, EAN13::SIDE_GUARD_PATTERN, EAN13::SIDE_GUARD_PATTERN_RLE

Instance Attribute Summary

Attributes inherited from EAN13

#manufacturers_code, #number_system, #product_code

Attributes inherited from Barcode1D

#check_digit, #encoded_string, #options, #value

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from EAN13

#bars, #width, #wn

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 = {}) ⇒ UPC_A

Create a new UPC_A object with a given value. Options are :line_character, :space_character, and :checksum_included.

Raises:



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# File 'lib/barcode1dtools/upc_a.rb', line 132

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

Class Method Details

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

Returns true or false - must be 11-13 digits. This also handles the case where the leading 0 is added.

Returns:

  • (Boolean) 


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# File 'lib/barcode1dtools/upc_a.rb', line 94

def can_encode?(value, options = nil)
  if !options
    value.to_s =~ /^0?[0-9]{11,12}$/
  elsif (options[:checksum_included])
    value.to_s =~ /^0?[0-9]{12}$/
  else
    value.to_s =~ /^0?[0-9]{11}$/
  end
end

.decode(value) ⇒ Object

Decode a bar pattern or rle pattern and return a UPC_A object.



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# File 'lib/barcode1dtools/upc_a.rb', line 119

def decode(value)
  ean = super(value)
  if ean.value[0,1] == '0'
    new(ean.value[1,11])
  else
    raise UnencodableCharactersError
  end
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”.



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# File 'lib/barcode1dtools/upc_a.rb', line 106

def generate_check_digit_for(value)
  super('0' + value)
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/upc_a.rb', line 112

def validate_check_digit_for(value)
  raise UnencodableCharactersError unless self.can_encode?(value, :checksum_included => true)
  md = value.match(/^(0?\d{11})(\d)$/)
  self.generate_check_digit_for(md[1]) == md[2].to_i
end

Instance Method Details

#rle ⇒ Object

Returns a run-length-encoded string representation.



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# File 'lib/barcode1dtools/upc_a.rb', line 156

def rle
  if @rle
    @rle
  else
    md = @encoded_string.match(/^(\d{6})(\d{6})/)
    @rle = gen_rle('0', md[1], md[2])
  end
end

#to_upc_e ⇒ Object

Returns a UPC_E object with the same value as the current UPC_A object, if possible.



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# File 'lib/barcode1dtools/upc_a.rb', line 167

def to_upc_e
  UPC_E.new(UPC_E.upca_value_to_upce_value(@value), options.merge(:checksum_included => false))
end

#upc_e_encodable? ⇒ Boolean

Returns true if the current value may be encoded as UPC-E.

Returns:

  • (Boolean) 


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# File 'lib/barcode1dtools/upc_a.rb', line 172

def upc_e_encodable?
  begin
    UPC_E.new(UPC_E.upca_value_to_upce_value(@value), options.merge(:checksum_included => false))
    return true
  rescue UnencodableCharactersError
    return false
  end
end