Class: Barcode1DTools::MSI
- Defined in:
- lib/barcode1dtools/msi.rb
Overview
Barcode1DTools::MSI - Create and decode bar patterns for MSI. The value encoded is a string which may contain the digits 0-9.
There are four possible check digit calculations, and you may use the option :check_digit => ‘x’ to choose which one to use. “x” may be one of “mod 10”, “mod 11”, “mod 1010”, or “mod 1110”. The default is “mod 10”. For a mod 11 check digit, you may use :check_style => ‘ibm’ or ‘ncr’.
MSI is a terrible symbology in modern terms and should not be used in any new applications.
val = “2898289238” bc = Barcode1DTools::MSI.new(val) pattern = bc.bars rle_pattern = bc.rle width = bc.width
The object created is immutable.
Barcode1DTools::MSI creates the patterns that you need to display MSI barcodes. It can also decode a simple w/n string.
MSI characters consist of 4 bars and 4 spaces. The representation is simply binary where a binary “0” is represented as a narrow bar followed by a wide space and a binary “1” is a wide bar followed by a narrow space. The bits are ordered descending, so 9 is 1001 binary, “wn nw nw wn” in w/n format.
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 author is aware of no 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
{ '0'=> {'val'=>0 ,'wn'=>'nwnwnwnw'}, '1'=> {'val'=>1 ,'wn'=>'nwnwnwwn'}, '2'=> {'val'=>2 ,'wn'=>'nwnwwnnw'}, '3'=> {'val'=>3 ,'wn'=>'nwnwwnwn'}, '4'=> {'val'=>4 ,'wn'=>'nwwnnwnw'}, '5'=> {'val'=>5 ,'wn'=>'nwwnnwwn'}, '6'=> {'val'=>6 ,'wn'=>'nwwnwnnw'}, '7'=> {'val'=>7 ,'wn'=>'nwwnwnwn'}, '8'=> {'val'=>8 ,'wn'=>'wnnwnwnw'}, '9'=> {'val'=>9 ,'wn'=>'wnnwnwwn'} }
- GUARD_PATTERN_LEFT_WN =
'wn'
- GUARD_PATTERN_RIGHT_WN =
'nwn'
- DEFAULT_OPTIONS =
{ :line_character => '1', :space_character => '0', :w_character => 'w', :n_character => 'n', :wn_ratio => '2', :check_digit => 'mod 10', :check_style => 'ibm' }
Instance Attribute Summary
Attributes inherited from Barcode1D
#check_digit, #encoded_string, #options, #value
Class Method Summary collapse
-
.can_encode?(value) ⇒ Boolean
MSI can encode digits.
-
.decode(str, options = {}) ⇒ Object
Decode a string in rle format.
- .generate_check_digit_for(value, options = {}) ⇒ Object
- .generate_mod10_check_digit_for(value) ⇒ Object
- .generate_mod11_check_digit_for(value, style) ⇒ Object
- .split_payload_and_check_digits(value, options = {}) ⇒ Object
- .validate_check_digit_for(value, options = {}) ⇒ Object
Instance Method Summary collapse
-
#bars ⇒ Object
returns 1s and 0s (for “black” and “white”).
-
#initialize(value, options = {}) ⇒ MSI
constructor
Options are :line_character, :space_character, :w_character, :n_character, :checksum_included, and :skip_checksum.
-
#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 = {}) ⇒ MSI
Options are :line_character, :space_character, :w_character, :n_character, :checksum_included, and :skip_checksum.
211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 |
# File 'lib/barcode1dtools/msi.rb', line 211 def initialize(value, = {}) @options = DEFAULT_OPTIONS.merge() # Can we encode this value? raise UnencodableCharactersError unless self.class.can_encode?(value) if @options[:skip_checksum] @encoded_string = value.to_s @value = value.to_s @check_digit = nil elsif @options[:checksum_included] raise ChecksumError unless self.class.validate_check_digit_for(value, ) @encoded_string = value.to_s @value, @check_digit = self.class.split_payload_and_check_digits(value, ) 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
MSI can encode digits
102 103 104 |
# File 'lib/barcode1dtools/msi.rb', line 102 def can_encode?(value) value.to_s =~ /\A\d+\z/ end |
.decode(str, options = {}) ⇒ Object
Decode a string in rle format. This will return a MSI object.
161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 |
# File 'lib/barcode1dtools/msi.rb', line 161 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}.*?#{GUARD_PATTERN_RIGHT_WN}\z/ str.reverse! end unless str =~ /\A#{GUARD_PATTERN_LEFT_WN}(.*?)#{GUARD_PATTERN_RIGHT_WN}\z/ raise UnencodableCharactersError, "Start/stop pattern is not detected." end wn_pattern = $1 # Each pattern is 4 bars and 4 spaces, with a space between. unless wn_pattern.size % 8 == 0 raise UnencodableCharactersError, "Wrong number of bars." end decoded_string = '' wn_pattern.scan(/.{8}/).each do |chunk| 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 MSI.new(decoded_string, ) end |
.generate_check_digit_for(value, options = {}) ⇒ Object
106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 |
# File 'lib/barcode1dtools/msi.rb', line 106 def generate_check_digit_for(value, = {}) if [:check_digit] == 'mod 10' generate_mod10_check_digit_for(value).to_s elsif [:check_digit] == 'mod 11' generate_mod11_check_digit_for(value, [:check_style]).to_s elsif [:check_digit] == 'mod 1010' mod10 = generate_mod10_check_digit_for(value) mod10_2 = generate_mod10_check_digit_for(value + mod10.to_s) "#{mod10}#{mod10_2}" elsif [:check_digit] == 'mod 1110' mod11 = generate_mod11_check_digit_for(value, [:check_style]) mod10_2 = generate_mod10_check_digit_for(value + mod11.to_s) "#{mod11}#{mod10_2}" end end |
.generate_mod10_check_digit_for(value) ⇒ Object
136 137 138 139 140 141 142 143 144 145 146 147 148 149 |
# File 'lib/barcode1dtools/msi.rb', line 136 def generate_mod10_check_digit_for(value) value = value.to_s valarr = value.scan(/\d\d?/) if value.size.odd? odd = valarr.collect { |c| c[0,1] } even = valarr.collect { |c| c[1,1] } else odd = valarr.collect { |c| c[1,1] } even = valarr.collect { |c| c[0,1] } end odd = (odd.join.to_i * 2).to_s.split('').inject(0) { |a,c| a + c.to_i } even = even.inject(0) { |a,c| a + c.to_i } (10 - ((odd + even) % 10)) % 10 end |
.generate_mod11_check_digit_for(value, style) ⇒ Object
151 152 153 154 155 156 157 |
# File 'lib/barcode1dtools/msi.rb', line 151 def generate_mod11_check_digit_for(value, style) max = (style == 'ncr' ? 9 : 7) value = value.to_s weight = 1 sum = value.split('').reverse.inject(0) { |a,c| weight = (weight == max ? 2 : weight + 1); a + weight * c.to_i } (11 - (sum % 11)) % 11 end |
.split_payload_and_check_digits(value, options = {}) ⇒ Object
127 128 129 130 131 132 133 134 |
# File 'lib/barcode1dtools/msi.rb', line 127 def split_payload_and_check_digits(value, = {}) if [:check_digit] == 'mod 1010' || [:check_digit] == 'mod 1110' md = value.to_s.match(/\A(.*?)(..)\z/) else md = value.to_s.match(/\A(.*?)(.)\z/) end [md[1], md[2]] end |
.validate_check_digit_for(value, options = {}) ⇒ Object
122 123 124 125 |
# File 'lib/barcode1dtools/msi.rb', line 122 def validate_check_digit_for(value, = {}) payload, check_digits = split_payload_and_check_digits(value, ) self.generate_check_digit_for(payload, ) == check_digits end |
Instance Method Details
#bars ⇒ Object
returns 1s and 0s (for “black” and “white”)
244 245 246 |
# File 'lib/barcode1dtools/msi.rb', line 244 def @bars ||= self.class.(self.rle, @options) end |
#rle ⇒ Object
returns a run-length-encoded string representation
239 240 241 |
# File 'lib/barcode1dtools/msi.rb', line 239 def rle @rle ||= self.class.wn_to_rle(self.wn, @options) end |
#width ⇒ Object
returns the total unit width of the bar code
249 250 251 |
# File 'lib/barcode1dtools/msi.rb', line 249 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”)
234 235 236 |
# File 'lib/barcode1dtools/msi.rb', line 234 def wn @wn ||= wn_str.tr('wn', @options[:w_character].to_s + @options[:n_character].to_s) end |