Class: Barcode1DTools::Coop2of5
- Defined in:
- lib/barcode1dtools/coop2of5.rb
Overview
Barcode1DTools::Coop2of5 - Create and decode bar patterns for COOP 2 of 5. The value encoded is a number with digits 0-9. Internally, the value is treated as a string to preserve leading zeroes.
Use :checksum_included => true if you have already added a checksum and wish to have it validated, or :skip_checksum => true if you don’t wish to add one or have it validated.
Note: COOP 2 of 5 is low-density and limited. It should not be used in any new applications.
Example
val = "3423"
bc = Barcode1DTools::Coop2of5.new(val)
pattern = bc.
rle_pattern = bc.rle
width = bc.width
The object created is immutable.
Barcode1DTools::Coop2of5 creates the patterns that you need to display COOP 2 of 5 barcodes. It can also decode a simple w/n string.
Coop2of5 characters consist of 3 bars and 2 spaces, with a narrow space between them. 2 of the bars/spaces in each symbol are wide.
Formats
There are three formats for the returned pattern:
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.
wn - The native format for this barcode type. The string consists of a series of “w” and “n” characters. The first item is always a black line, with subsequent characters alternating between spaces and lines. A “wide” item is twice the width of a “narrow” item.
The “width” method will tell you the total end-to-end width, in units, of the entire barcode.
Rendering
The standard w/n ratio seems to be 2:1. There seem to be no real standards for display.
Constant Summary collapse
- CHAR_SEQUENCE =
Character sequence - 0-based offset in this string is character number.
"0123456789"
- PATTERNS =
Patterns for making bar codes. Note that the position weights are 7, 4, 2, 1 and the last bit is parity. Each letter is an alternating bar then space, and there is a narrow space between each character.
{ '0'=> {'val'=>0 ,'wn'=>'wwnnn'}, '1'=> {'val'=>1 ,'wn'=>'nnnww'}, '2'=> {'val'=>2 ,'wn'=>'nnwnw'}, '3'=> {'val'=>3 ,'wn'=>'nnwwn'}, '4'=> {'val'=>4 ,'wn'=>'nwnnw'}, '5'=> {'val'=>5 ,'wn'=>'nwnwn'}, '6'=> {'val'=>6 ,'wn'=>'nwwnn'}, '7'=> {'val'=>7 ,'wn'=>'wnnnw'}, '8'=> {'val'=>8 ,'wn'=>'wnnwn'}, '9'=> {'val'=>9 ,'wn'=>'wnwnn'} }
- GUARD_PATTERN_LEFT_WN =
Left guard pattern
'wnw'
- GUARD_PATTERN_RIGHT_WN =
Right guard pattern
'nww'
- DEFAULT_OPTIONS =
{ :line_character => '1', :space_character => '0', :w_character => 'w', :n_character => 'n', :wn_ratio => '2' }
Instance Attribute Summary
Attributes inherited from Barcode1D
#check_digit, #encoded_string, #options, #value
Class Method Summary collapse
-
.can_encode?(value) ⇒ Boolean
Coop2of5 can encode digits.
-
.decode(str, options = {}) ⇒ Object
Decode a string in rle or w/n format.
-
.generate_check_digit_for(value) ⇒ Object
Generates a check digit for a given value.
-
.validate_check_digit_for(value) ⇒ Object
Validates a check digit given a string of digits.
Instance Method Summary collapse
-
#bars ⇒ Object
Returns 1s and 0s (for “black” and “white”).
-
#initialize(value, options = {}) ⇒ Coop2of5
constructor
Create a new Coop2of5 object with a given value.
-
#rle ⇒ Object
Returns a run-length-encoded string representation.
-
#width ⇒ Object
Returns the total unit width of the bar code.
-
#wn ⇒ Object
Returns a string of “w” or “n” (“wide” and “narrow”).
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 = {}) ⇒ Coop2of5
Create a new Coop2of5 object with a given value. Options are :line_character, :space_character, :w_character, :n_character, :checksum_included, and :skip_checksum.
179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 |
# File 'lib/barcode1dtools/coop2of5.rb', line 179 def initialize(value, = {}) @options = DEFAULT_OPTIONS.merge() # Can we encode this value? raise UnencodableCharactersError unless self.class.can_encode?(value) @value = value.to_s if @options[:skip_checksum] @encoded_string = value.to_s @value = value.to_s @check_digit = nil elsif @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 @value = value.to_s @check_digit = self.class.generate_check_digit_for(@value) @encoded_string = "#{@value}#{@check_digit}" end end |
Class Method Details
.can_encode?(value) ⇒ Boolean
Coop2of5 can encode digits. This will return true given a string of digits.
103 104 105 |
# File 'lib/barcode1dtools/coop2of5.rb', line 103 def can_encode?(value) value.to_s =~ /\A[0-9]+\z/ end |
.decode(str, options = {}) ⇒ Object
Decode a string in rle or w/n format. This will return a Coop2of5 object.
127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 |
# File 'lib/barcode1dtools/coop2of5.rb', line 127 def decode(str, = {}) if str =~ /[^1-3]/ && str =~ /[^wn]/ raise UnencodableCharactersError, "Pattern must be rle or wn" end # ensure a wn string if str =~ /[1-3]/ str = str.tr('123','nww') end if str.reverse =~ /\A#{GUARD_PATTERN_LEFT_WN}n.*?#{GUARD_PATTERN_RIGHT_WN}\z/ str.reverse! end unless str =~ /\A#{GUARD_PATTERN_LEFT_WN}n(.*?)#{GUARD_PATTERN_RIGHT_WN}\z/ raise UnencodableCharactersError, "Start/stop pattern is not detected." end wn_pattern = $1 # Each pattern is 3 bars and 2 spaces, with a space between. unless wn_pattern.size % 6 == 0 raise UnencodableCharactersError, "Wrong number of bars." end decoded_string = '' wn_pattern.scan(/(.{5})n/).each do |chunk| chunk = chunk.first found = false PATTERNS.each do |char,hsh| if chunk == hsh['wn'] decoded_string += char found = true break; end end raise UndecodableCharactersError, "Invalid sequence: #{chunk}" unless found end Coop2of5.new(decoded_string, ) end |
.generate_check_digit_for(value) ⇒ Object
Generates a check digit for a given value. This uses a Luhn algorithm.
109 110 111 112 113 114 |
# File 'lib/barcode1dtools/coop2of5.rb', line 109 def generate_check_digit_for(value) raise UnencodableCharactersError unless self.can_encode?(value) mult = 3 value = value.reverse.split('').inject(0) { |a,c| mult = 4 - mult ; a + c.to_i * mult } (10 - (value % 10)) % 10 end |
.validate_check_digit_for(value) ⇒ Object
Validates a check digit given a string of digits. It is assumed that the last digit is the check digit. Returns “true” if the check digit is correct.
119 120 121 122 123 |
# File 'lib/barcode1dtools/coop2of5.rb', line 119 def validate_check_digit_for(value) raise UnencodableCharactersError unless self.can_encode?(value) md = value.match(/^(\d+?)(\d)$/) 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”)
215 216 217 |
# File 'lib/barcode1dtools/coop2of5.rb', line 215 def @bars ||= self.class.(self.rle, @options) end |
#rle ⇒ Object
Returns a run-length-encoded string representation
210 211 212 |
# File 'lib/barcode1dtools/coop2of5.rb', line 210 def rle @rle ||= self.class.wn_to_rle(self.wn, @options) end |
#width ⇒ Object
Returns the total unit width of the bar code
220 221 222 |
# File 'lib/barcode1dtools/coop2of5.rb', line 220 def width @width ||= rle.split('').inject(0) { |a,c| a + c.to_i } end |
#wn ⇒ Object
Returns a string of “w” or “n” (“wide” and “narrow”)
205 206 207 |
# File 'lib/barcode1dtools/coop2of5.rb', line 205 def wn @wn ||= wn_str.tr('wn', @options[:w_character].to_s + @options[:n_character].to_s) end |