Class: Barcode1DTools::UPC_Supplemental_5

Inherits:
Barcode1D
  • Object
show all
Defined in:
lib/barcode1dtools/upc_supplemental_5.rb

Constant Summary collapse

LEFT_PATTERNS = 
UPC_A::LEFT_PATTERNS
LEFT_PATTERNS_RLE = 
UPC_A::LEFT_PATTERNS_RLE
PARITY_PATTERNS =

parity patterns, essentially binary counting where “e” is “1” and “o” is “0”

{
  '0' => 'eeooo',
  '1' => 'eoeoo',
  '2' => 'eooeo',
  '3' => 'eoooe',
  '4' => 'oeeoo',
  '5' => 'ooeeo',
  '6' => 'oooee',
  '7' => 'oeoeo',
  '8' => 'oeooe',
  '9' => 'ooeoe'
}
LEFT_GUARD_PATTERN = 
'1011'
MIDDLE_GUARD_PATTERN = 
'01'
LEFT_GUARD_PATTERN_RLE = 
'112'
MIDDLE_GUARD_PATTERN_RLE = 
'11'
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 = {}) ⇒ UPC_Supplemental_5

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

Raises:



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# File 'lib/barcode1dtools/upc_supplemental_5.rb', line 191

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 = sprintf('%05d%1d',@value.to_i,@check_digit)
  end

  md = @value.match(/^(\d)(\d{4})/)
  @currency_code, @price = md[1], md[2]
end

Instance Attribute Details

#currency_code ⇒ Object (readonly)

Returns the value of attribute currency_code.



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# File 'lib/barcode1dtools/upc_supplemental_5.rb', line 96

def currency_code
  @currency_code
end

#price ⇒ Object (readonly)

Returns the value of attribute price.



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# File 'lib/barcode1dtools/upc_supplemental_5.rb', line 97

def price
  @price
end

Class Method Details

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

Returns true or false - must be 5 or 6 digits. This also handles the case where the leading 0 is added.

Returns:

  • (Boolean) 


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# File 'lib/barcode1dtools/upc_supplemental_5.rb', line 102

def can_encode?(value, options = nil)
  if !options
    value.to_s =~ /^\d{5,6}$/
  elsif (options[:checksum_included])
    value.to_s =~ /^\d{6}$/
  else
    value.to_s =~ /^\d{5}$/
  end
end

.decode(str) ⇒ Object

Raises:



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# File 'lib/barcode1dtools/upc_supplemental_5.rb', line 127

def decode(str)
  if str.length == 47
    # bar pattern
    str = bars_to_rle(str)
  elsif str.length == 31 && str =~ /^[1-9]+$/
    # rle
  else
    raise UnencodableCharactersError, "Pattern must be 47 unit bar pattern or 31 character rle."
  end

  # This string is "aaabbbb(ccdddd)" where "aaa" is the left
  # guard pattern, "bbbb" is the first digit, "cc" is the
  # intra-digit guard pattern, and "dddd" is the second
  # digit.  (ccdddd) occurs 4 times.

  # See if the string is reversed
  if str[28..30] == LEFT_GUARD_PATTERN_RLE.reverse && [7,13,19,25].all? { |x| str[29-x,2] == MIDDLE_GUARD_PATTERN_RLE.reverse }
    str.reverse!
  end

  # Check the guard patterns
  unless (str[0..2] == LEFT_GUARD_PATTERN_RLE && [7,13,19,25].all? { |x| str[x,2] == MIDDLE_GUARD_PATTERN_RLE.reverse })
    raise UnencodableCharactersError, "Missing or incorrect guard patterns"
  end

  parity_sequence = ''
  digits = ''
  left_initial_offset = LEFT_GUARD_PATTERN_RLE.length

  # Decode
  (0..4).each do |left_offset|
    found = false
    digit_rle = str[(left_initial_offset + left_offset*6),4]
    ['o','e'].each do |parity|
      ('0'..'9').each do |digit|
        if LEFT_PATTERNS_RLE[digit][parity] == digit_rle
          parity_sequence += parity
          digits += digit
          found = true
          break
        end
      end
    end
    raise UndecodableCharactersError, "Invalid sequence: #{digit_rle}" unless found
  end

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

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

  UPC_Supplemental_5.new(digits + parity_digit, :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”.



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# File 'lib/barcode1dtools/upc_supplemental_5.rb', line 114

def generate_check_digit_for(value)
  mult = 9  # alternates 3 and 9
  sprintf('%05d',value.to_i).reverse.chars.inject(0) { |a,c| mult = 12 - mult; a + c.to_i * mult } % 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/upc_supplemental_5.rb', line 121

def validate_check_digit_for(value)
  raise UnencodableCharactersError unless self.can_encode?(value, :checksum_included => true)
  md = value.match(/^(\d{5})(\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/upc_supplemental_5.rb', line 230

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/upc_supplemental_5.rb', line 220

def rle
  if @rle
    @rle
  else
    md = @encoded_string.match(/(\d{5})(\d)$/)
    @rle = gen_rle(md[1], md[2])
  end
end

#width ⇒ Object

returns the total unit width of the bar code



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# File 'lib/barcode1dtools/upc_supplemental_5.rb', line 235

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

#wn ⇒ Object

not usable with EAN-style codes

Raises:



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# File 'lib/barcode1dtools/upc_supplemental_5.rb', line 215

def wn
  raise NotImplementedError
end