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| 1 | +import BarcodeReader from './barcode_reader'; |
| 2 | +import ArrayHelper from '../common/array_helper'; |
| 3 | + |
| 4 | +function Code93Reader() { |
| 5 | + BarcodeReader.call(this); |
| 6 | +} |
| 7 | + |
| 8 | +const ALPHABETH_STRING = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ-. $/+%abcd*"; |
| 9 | + |
| 10 | +var properties = { |
| 11 | + ALPHABETH_STRING: {value: ALPHABETH_STRING}, |
| 12 | + ALPHABET: {value: ALPHABETH_STRING.split('').map(char => char.charCodeAt(0))}, |
| 13 | + CHARACTER_ENCODINGS: {value: [ |
| 14 | + 0x114, 0x148, 0x144, 0x142, 0x128, 0x124, 0x122, 0x150, 0x112, 0x10A, |
| 15 | + 0x1A8, 0x1A4, 0x1A2, 0x194, 0x192, 0x18A, 0x168, 0x164, 0x162, 0x134, |
| 16 | + 0x11A, 0x158, 0x14C, 0x146, 0x12C, 0x116, 0x1B4, 0x1B2, 0x1AC, 0x1A6, |
| 17 | + 0x196, 0x19A, 0x16C, 0x166, 0x136, 0x13A, 0x12E, 0x1D4, 0x1D2, 0x1CA, |
| 18 | + 0x16E, 0x176, 0x1AE, 0x126, 0x1DA, 0x1D6, 0x132, 0x15E |
| 19 | + ]}, |
| 20 | + ASTERISK: {value: 0x15E}, |
| 21 | + FORMAT: {value: "code_93", writeable: false} |
| 22 | +}; |
| 23 | + |
| 24 | +Code93Reader.prototype = Object.create(BarcodeReader.prototype, properties); |
| 25 | +Code93Reader.prototype.constructor = Code93Reader; |
| 26 | + |
| 27 | +Code93Reader.prototype._decode = function() { |
| 28 | + var self = this, |
| 29 | + counters = [0, 0, 0, 0, 0, 0], |
| 30 | + result = [], |
| 31 | + start = self._findStart(), |
| 32 | + decodedChar, |
| 33 | + lastStart, |
| 34 | + pattern, |
| 35 | + nextStart; |
| 36 | + |
| 37 | + if (!start) { |
| 38 | + return null; |
| 39 | + } |
| 40 | + nextStart = self._nextSet(self._row, start.end); |
| 41 | + |
| 42 | + do { |
| 43 | + counters = self._toCounters(nextStart, counters); |
| 44 | + pattern = self._toPattern(counters); |
| 45 | + if (pattern < 0) { |
| 46 | + return null; |
| 47 | + } |
| 48 | + decodedChar = self._patternToChar(pattern); |
| 49 | + if (decodedChar < 0){ |
| 50 | + return null; |
| 51 | + } |
| 52 | + result.push(decodedChar); |
| 53 | + lastStart = nextStart; |
| 54 | + nextStart += ArrayHelper.sum(counters); |
| 55 | + nextStart = self._nextSet(self._row, nextStart); |
| 56 | + } while (decodedChar !== '*'); |
| 57 | + result.pop(); |
| 58 | + |
| 59 | + if (!result.length) { |
| 60 | + return null; |
| 61 | + } |
| 62 | + |
| 63 | + if (!self._verifyEnd(lastStart, nextStart, counters)) { |
| 64 | + return null; |
| 65 | + } |
| 66 | + |
| 67 | + if (!self._verifyChecksums(result)) { |
| 68 | + return null; |
| 69 | + } |
| 70 | + |
| 71 | + result = result.slice(0, result.length - 2); |
| 72 | + if ((result = self._decodeExtended(result)) === null) { |
| 73 | + return null; |
| 74 | + }; |
| 75 | + |
| 76 | + return { |
| 77 | + code: result.join(""), |
| 78 | + start: start.start, |
| 79 | + end: nextStart, |
| 80 | + startInfo: start, |
| 81 | + decodedCodes: result |
| 82 | + }; |
| 83 | +}; |
| 84 | + |
| 85 | +Code93Reader.prototype._verifyEnd = function(lastStart, nextStart) { |
| 86 | + if (lastStart === nextStart || !this._row[nextStart]) { |
| 87 | + return false; |
| 88 | + } |
| 89 | + return true; |
| 90 | +}; |
| 91 | + |
| 92 | +Code93Reader.prototype._patternToChar = function(pattern) { |
| 93 | + var i, |
| 94 | + self = this; |
| 95 | + |
| 96 | + for (i = 0; i < self.CHARACTER_ENCODINGS.length; i++) { |
| 97 | + if (self.CHARACTER_ENCODINGS[i] === pattern) { |
| 98 | + return String.fromCharCode(self.ALPHABET[i]); |
| 99 | + } |
| 100 | + } |
| 101 | + return -1; |
| 102 | +}; |
| 103 | + |
| 104 | +Code93Reader.prototype._toPattern = function(counters) { |
| 105 | + const numCounters = counters.length; |
| 106 | + let pattern = 0; |
| 107 | + let sum = 0; |
| 108 | + for (let i = 0; i < numCounters; i++) { |
| 109 | + sum += counters[i]; |
| 110 | + } |
| 111 | + |
| 112 | + for (let i = 0; i < numCounters; i++) { |
| 113 | + let normalized = Math.round(counters[i] * 9 / sum); |
| 114 | + if (normalized < 1 || normalized > 4) { |
| 115 | + return -1; |
| 116 | + } |
| 117 | + if ((i & 1) === 0) { |
| 118 | + for (let j = 0; j < normalized; j++) { |
| 119 | + pattern = (pattern << 1) | 1; |
| 120 | + } |
| 121 | + } else { |
| 122 | + pattern <<= normalized; |
| 123 | + } |
| 124 | + } |
| 125 | + |
| 126 | + return pattern; |
| 127 | +}; |
| 128 | + |
| 129 | +Code93Reader.prototype._findStart = function() { |
| 130 | + var self = this, |
| 131 | + offset = self._nextSet(self._row), |
| 132 | + patternStart = offset, |
| 133 | + counter = [0, 0, 0, 0, 0, 0], |
| 134 | + counterPos = 0, |
| 135 | + isWhite = false, |
| 136 | + i, |
| 137 | + j, |
| 138 | + whiteSpaceMustStart; |
| 139 | + |
| 140 | + for ( i = offset; i < self._row.length; i++) { |
| 141 | + if (self._row[i] ^ isWhite) { |
| 142 | + counter[counterPos]++; |
| 143 | + } else { |
| 144 | + if (counterPos === counter.length - 1) { |
| 145 | + // find start pattern |
| 146 | + if (self._toPattern(counter) === self.ASTERISK) { |
| 147 | + whiteSpaceMustStart = Math.floor(Math.max(0, patternStart - ((i - patternStart) / 4))); |
| 148 | + if (self._matchRange(whiteSpaceMustStart, patternStart, 0)) { |
| 149 | + return { |
| 150 | + start: patternStart, |
| 151 | + end: i |
| 152 | + }; |
| 153 | + } |
| 154 | + } |
| 155 | + |
| 156 | + patternStart += counter[0] + counter[1]; |
| 157 | + for ( j = 0; j < 4; j++) { |
| 158 | + counter[j] = counter[j + 2]; |
| 159 | + } |
| 160 | + counter[4] = 0; |
| 161 | + counter[5] = 0; |
| 162 | + counterPos--; |
| 163 | + } else { |
| 164 | + counterPos++; |
| 165 | + } |
| 166 | + counter[counterPos] = 1; |
| 167 | + isWhite = !isWhite; |
| 168 | + } |
| 169 | + } |
| 170 | + return null; |
| 171 | +}; |
| 172 | + |
| 173 | +Code93Reader.prototype._decodeExtended = function(charArray) { |
| 174 | + const length = charArray.length; |
| 175 | + const result = []; |
| 176 | + for (let i = 0; i < length; i++) { |
| 177 | + const char = charArray[i]; |
| 178 | + if (char >= 'a' && char <= 'd') { |
| 179 | + if (i > (length - 2)) { |
| 180 | + return null; |
| 181 | + } |
| 182 | + const nextChar = charArray[++i]; |
| 183 | + const nextCharCode = nextChar.charCodeAt(0); |
| 184 | + let decodedChar; |
| 185 | + switch (char) { |
| 186 | + case 'a': |
| 187 | + if (nextChar >= 'A' && nextChar <= 'Z') { |
| 188 | + decodedChar = String.fromCharCode(nextCharCode - 64); |
| 189 | + } else { |
| 190 | + return null; |
| 191 | + } |
| 192 | + break; |
| 193 | + case 'b': |
| 194 | + if (nextChar >= 'A' && nextChar <= 'E') { |
| 195 | + decodedChar = String.fromCharCode(nextCharCode - 38); |
| 196 | + } else if (nextChar >= 'F' && nextChar <= 'J') { |
| 197 | + decodedChar = String.fromCharCode(nextCharCode - 11); |
| 198 | + } else if (nextChar >= 'K' && nextChar <= 'O') { |
| 199 | + decodedChar = String.fromCharCode(nextCharCode + 16); |
| 200 | + } else if (nextChar >= 'P' && nextChar <= 'S') { |
| 201 | + decodedChar = String.fromCharCode(nextCharCode + 43); |
| 202 | + } else if (nextChar >= 'T' && nextChar <= 'Z') { |
| 203 | + decodedChar = String.fromCharCode(127); |
| 204 | + } else { |
| 205 | + return null; |
| 206 | + } |
| 207 | + break; |
| 208 | + case 'c': |
| 209 | + if (nextChar >= 'A' && nextChar <= 'O') { |
| 210 | + decodedChar = String.fromCharCode(nextCharCode - 32); |
| 211 | + } else if (nextChar === 'Z') { |
| 212 | + decodedChar = ':'; |
| 213 | + } else { |
| 214 | + return null; |
| 215 | + } |
| 216 | + break; |
| 217 | + case 'd': |
| 218 | + if (nextChar >= 'A' && nextChar <= 'Z') { |
| 219 | + decodedChar = String.fromCharCode(nextCharCode + 32); |
| 220 | + } else { |
| 221 | + return null; |
| 222 | + } |
| 223 | + break; |
| 224 | + } |
| 225 | + result.push(decodedChar); |
| 226 | + } else { |
| 227 | + result.push(char); |
| 228 | + } |
| 229 | + } |
| 230 | + return result; |
| 231 | +}; |
| 232 | + |
| 233 | +Code93Reader.prototype._verifyChecksums = function(charArray) { |
| 234 | + return this._matchCheckChar(charArray, charArray.length - 2, 20) |
| 235 | + && this._matchCheckChar(charArray, charArray.length - 1, 15); |
| 236 | +}; |
| 237 | + |
| 238 | +Code93Reader.prototype._matchCheckChar = function(charArray, index, maxWeight) { |
| 239 | + const arrayToCheck = charArray.slice(0, index); |
| 240 | + const length = arrayToCheck.length; |
| 241 | + const weightedSums = arrayToCheck.reduce((sum, char, i) => { |
| 242 | + const weight = (((i * -1) + (length - 1)) % maxWeight) + 1; |
| 243 | + const value = this.ALPHABET.indexOf(char.charCodeAt(0)); |
| 244 | + return sum + (weight * value); |
| 245 | + }, 0); |
| 246 | + |
| 247 | + const checkChar = this.ALPHABET[(weightedSums % 47)]; |
| 248 | + return checkChar === charArray[index].charCodeAt(0); |
| 249 | +}; |
| 250 | + |
| 251 | +export default Code93Reader; |
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