Merge pull request #196 from serratus/feature/194
Added basic support for 2of5 barcodes Closes #194pull/197/head
Christoph Oberhofer
8 years ago
committed by
GitHub
@ -0,0 +1,257 @@
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import BarcodeReader from './barcode_reader';
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function TwoOfFiveReader(opts) {
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BarcodeReader.call(this, opts);
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this.barSpaceRatio = [1, 1];
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}
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var N = 1,
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W = 3,
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properties = {
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START_PATTERN: {value: [W, N, W, N, N, N]},
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STOP_PATTERN: {value: [W, N, N, N, W]},
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CODE_PATTERN: {value: [
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[N, N, W, W, N],
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[W, N, N, N, W],
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[N, W, N, N, W],
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[W, W, N, N, N],
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[N, N, W, N, W],
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[W, N, W, N, N],
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[N, W, W, N, N],
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[N, N, N, W, W],
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[W, N, N, W, N],
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[N, W, N, W, N]
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]},
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SINGLE_CODE_ERROR: {value: 0.78, writable: true},
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AVG_CODE_ERROR: {value: 0.30, writable: true},
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FORMAT: {value: "2of5"}
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};
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const startPatternLength = properties.START_PATTERN.value.reduce((sum, val) => sum + val, 0);
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TwoOfFiveReader.prototype = Object.create(BarcodeReader.prototype, properties);
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TwoOfFiveReader.prototype.constructor = TwoOfFiveReader;
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TwoOfFiveReader.prototype._findPattern = function(pattern, offset, isWhite, tryHarder) {
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var counter = [],
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self = this,
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i,
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counterPos = 0,
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bestMatch = {
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error: Number.MAX_VALUE,
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code: -1,
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start: 0,
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end: 0
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},
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error,
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j,
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sum,
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epsilon = self.AVG_CODE_ERROR;
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isWhite = isWhite || false;
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tryHarder = tryHarder || false;
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if (!offset) {
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offset = self._nextSet(self._row);
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}
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for ( i = 0; i < pattern.length; i++) {
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counter[i] = 0;
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}
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for ( i = offset; i < self._row.length; i++) {
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if (self._row[i] ^ isWhite) {
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counter[counterPos]++;
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} else {
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if (counterPos === counter.length - 1) {
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sum = 0;
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for ( j = 0; j < counter.length; j++) {
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sum += counter[j];
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}
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error = self._matchPattern(counter, pattern);
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if (error < epsilon) {
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bestMatch.error = error;
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bestMatch.start = i - sum;
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bestMatch.end = i;
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return bestMatch;
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}
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if (tryHarder) {
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for (j = 0; j < counter.length - 2; j++) {
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counter[j] = counter[j + 2];
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}
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counter[counter.length - 2] = 0;
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counter[counter.length - 1] = 0;
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counterPos--;
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} else {
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return null;
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}
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} else {
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counterPos++;
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}
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counter[counterPos] = 1;
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isWhite = !isWhite;
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}
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}
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return null;
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};
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TwoOfFiveReader.prototype._findStart = function() {
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var self = this,
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leadingWhitespaceStart,
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offset = self._nextSet(self._row),
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startInfo,
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narrowBarWidth = 1;
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while (!startInfo) {
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startInfo = self._findPattern(self.START_PATTERN, offset, false, true);
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if (!startInfo) {
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return null;
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}
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narrowBarWidth = Math.floor((startInfo.end - startInfo.start) / startPatternLength);
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leadingWhitespaceStart = startInfo.start - narrowBarWidth * 5;
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if (leadingWhitespaceStart >= 0) {
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if (self._matchRange(leadingWhitespaceStart, startInfo.start, 0)) {
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return startInfo;
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}
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}
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offset = startInfo.end;
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startInfo = null;
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}
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};
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TwoOfFiveReader.prototype._verifyTrailingWhitespace = function(endInfo) {
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var self = this,
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trailingWhitespaceEnd;
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trailingWhitespaceEnd = endInfo.end + ((endInfo.end - endInfo.start) / 2);
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if (trailingWhitespaceEnd < self._row.length) {
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if (self._matchRange(endInfo.end, trailingWhitespaceEnd, 0)) {
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return endInfo;
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}
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}
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return null;
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};
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TwoOfFiveReader.prototype._findEnd = function() {
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var self = this,
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endInfo,
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tmp,
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offset;
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self._row.reverse();
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offset = self._nextSet(self._row);
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endInfo = self._findPattern(self.STOP_PATTERN, offset, false, true);
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self._row.reverse();
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if (endInfo === null) {
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return null;
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}
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// reverse numbers
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tmp = endInfo.start;
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endInfo.start = self._row.length - endInfo.end;
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endInfo.end = self._row.length - tmp;
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return endInfo !== null ? self._verifyTrailingWhitespace(endInfo) : null;
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};
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TwoOfFiveReader.prototype._decodeCode = function(counter) {
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var j,
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self = this,
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sum = 0,
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normalized,
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error,
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epsilon = self.AVG_CODE_ERROR,
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code,
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bestMatch = {
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error: Number.MAX_VALUE,
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code: -1,
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start: 0,
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end: 0
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};
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for ( j = 0; j < counter.length; j++) {
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sum += counter[j];
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}
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for (code = 0; code < self.CODE_PATTERN.length; code++) {
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error = self._matchPattern(counter, self.CODE_PATTERN[code]);
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if (error < bestMatch.error) {
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bestMatch.code = code;
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bestMatch.error = error;
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}
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}
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if (bestMatch.error < epsilon) {
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return bestMatch;
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}
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};
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TwoOfFiveReader.prototype._decodePayload = function(counters, result, decodedCodes) {
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var i,
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self = this,
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pos = 0,
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counterLength = counters.length,
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counter = [0, 0, 0, 0, 0],
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code;
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while (pos < counterLength) {
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for (i = 0; i < 5; i++) {
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counter[i] = counters[pos] * this.barSpaceRatio[0];
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pos += 2;
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}
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code = self._decodeCode(counter);
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if (!code) {
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return null;
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}
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result.push(code.code + "");
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decodedCodes.push(code);
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}
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return code;
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};
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TwoOfFiveReader.prototype._verifyCounterLength = function(counters) {
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return (counters.length % 10 === 0);
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};
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TwoOfFiveReader.prototype._decode = function() {
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var startInfo,
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endInfo,
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self = this,
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code,
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result = [],
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decodedCodes = [],
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counters;
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startInfo = self._findStart();
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if (!startInfo) {
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return null;
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}
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decodedCodes.push(startInfo);
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endInfo = self._findEnd();
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if (!endInfo) {
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return null;
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}
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counters = self._fillCounters(startInfo.end, endInfo.start, false);
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if (!self._verifyCounterLength(counters)) {
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return null;
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}
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code = self._decodePayload(counters, result, decodedCodes);
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if (!code) {
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return null;
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}
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if (result.length < 5) {
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return null;
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}
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decodedCodes.push(endInfo);
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return {
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code: result.join(""),
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start: startInfo.start,
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end: endInfo.end,
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startInfo: startInfo,
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decodedCodes: decodedCodes
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};
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};
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export default TwoOfFiveReader;
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After Width: | Height: | Size: 174 KiB |
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After Width: | Height: | Size: 178 KiB |
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After Width: | Height: | Size: 171 KiB |
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After Width: | Height: | Size: 162 KiB |
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After Width: | Height: | Size: 164 KiB |
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After Width: | Height: | Size: 145 KiB |
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After Width: | Height: | Size: 122 KiB |
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After Width: | Height: | Size: 168 KiB |
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After Width: | Height: | Size: 156 KiB |
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After Width: | Height: | Size: 183 KiB |
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After Width: | Height: | Size: 173 KiB |
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After Width: | Height: | Size: 169 KiB |
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After Width: | Height: | Size: 147 KiB |
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After Width: | Height: | Size: 187 KiB |