/*
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* Copyright 2008 ZXing authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/*namespace com.google.zxing.oned {*/
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import BarcodeFormat from '../BarcodeFormat';
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import DecodeHintType from '../DecodeHintType';
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import FormatException from '../FormatException';
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import NotFoundException from '../NotFoundException';
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import Result from '../Result';
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import ResultPoint from '../ResultPoint';
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import StringBuilder from '../util/StringBuilder';
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import System from '../util/System';
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import OneDReader from './OneDReader';
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/**
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* <p>Decodes ITF barcodes.</p>
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*
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* @author Tjieco
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*/
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export default class ITFReader extends OneDReader {
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constructor() {
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// private static W = 3; // Pixel width of a 3x wide line
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// private static w = 2; // Pixel width of a 2x wide line
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// private static N = 1; // Pixed width of a narrow line
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super(...arguments);
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// Stores the actual narrow line width of the image being decoded.
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this.narrowLineWidth = -1;
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}
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// See ITFWriter.PATTERNS
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/*
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/!**
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* Patterns of Wide / Narrow lines to indicate each digit
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*!/
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*/
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decodeRow(rowNumber, row, hints) {
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// Find out where the Middle section (payload) starts & ends
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let startRange = this.decodeStart(row);
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let endRange = this.decodeEnd(row);
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let result = new StringBuilder();
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ITFReader.decodeMiddle(row, startRange[1], endRange[0], result);
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let resultString = result.toString();
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let allowedLengths = null;
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if (hints != null) {
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allowedLengths = hints.get(DecodeHintType.ALLOWED_LENGTHS);
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}
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if (allowedLengths == null) {
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allowedLengths = ITFReader.DEFAULT_ALLOWED_LENGTHS;
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}
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// To avoid false positives with 2D barcodes (and other patterns), make
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// an assumption that the decoded string must be a 'standard' length if it's short
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let length = resultString.length;
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let lengthOK = false;
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let maxAllowedLength = 0;
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for (let value of allowedLengths) {
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if (length === value) {
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lengthOK = true;
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break;
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}
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if (value > maxAllowedLength) {
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maxAllowedLength = value;
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}
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}
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if (!lengthOK && length > maxAllowedLength) {
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lengthOK = true;
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}
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if (!lengthOK) {
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throw new FormatException();
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}
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const points = [new ResultPoint(startRange[1], rowNumber), new ResultPoint(endRange[0], rowNumber)];
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let resultReturn = new Result(resultString, null, // no natural byte representation for these barcodes
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0, points, BarcodeFormat.ITF, new Date().getTime());
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return resultReturn;
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}
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/*
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/!**
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* @param row row of black/white values to search
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* @param payloadStart offset of start pattern
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* @param resultString {@link StringBuilder} to append decoded chars to
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* @throws NotFoundException if decoding could not complete successfully
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*!/*/
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static decodeMiddle(row, payloadStart, payloadEnd, resultString) {
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// Digits are interleaved in pairs - 5 black lines for one digit, and the
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// 5
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// interleaved white lines for the second digit.
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// Therefore, need to scan 10 lines and then
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// split these into two arrays
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let counterDigitPair = new Int32Array(10); // 10
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let counterBlack = new Int32Array(5); // 5
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let counterWhite = new Int32Array(5); // 5
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counterDigitPair.fill(0);
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counterBlack.fill(0);
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counterWhite.fill(0);
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while (payloadStart < payloadEnd) {
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// Get 10 runs of black/white.
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OneDReader.recordPattern(row, payloadStart, counterDigitPair);
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// Split them into each array
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for (let k = 0; k < 5; k++) {
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let twoK = 2 * k;
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counterBlack[k] = counterDigitPair[twoK];
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counterWhite[k] = counterDigitPair[twoK + 1];
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}
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let bestMatch = ITFReader.decodeDigit(counterBlack);
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resultString.append(bestMatch.toString());
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bestMatch = this.decodeDigit(counterWhite);
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resultString.append(bestMatch.toString());
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counterDigitPair.forEach(function (counterDigit) {
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payloadStart += counterDigit;
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});
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}
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}
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/*/!**
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* Identify where the start of the middle / payload section starts.
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*
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* @param row row of black/white values to search
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* @return Array, containing index of start of 'start block' and end of
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* 'start block'
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*!/*/
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decodeStart(row) {
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let endStart = ITFReader.skipWhiteSpace(row);
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let startPattern = ITFReader.findGuardPattern(row, endStart, ITFReader.START_PATTERN);
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// Determine the width of a narrow line in pixels. We can do this by
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// getting the width of the start pattern and dividing by 4 because its
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// made up of 4 narrow lines.
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this.narrowLineWidth = (startPattern[1] - startPattern[0]) / 4;
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this.validateQuietZone(row, startPattern[0]);
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return startPattern;
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}
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/*/!**
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* The start & end patterns must be pre/post fixed by a quiet zone. This
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* zone must be at least 10 times the width of a narrow line. Scan back until
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* we either get to the start of the barcode or match the necessary number of
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* quiet zone pixels.
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*
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* Note: Its assumed the row is reversed when using this method to find
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* quiet zone after the end pattern.
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*
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* ref: http://www.barcode-1.net/i25code.html
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*
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* @param row bit array representing the scanned barcode.
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* @param startPattern index into row of the start or end pattern.
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* @throws NotFoundException if the quiet zone cannot be found
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*!/*/
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validateQuietZone(row, startPattern) {
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let quietCount = this.narrowLineWidth * 10; // expect to find this many pixels of quiet zone
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// if there are not so many pixel at all let's try as many as possible
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quietCount = quietCount < startPattern ? quietCount : startPattern;
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for (let i = startPattern - 1; quietCount > 0 && i >= 0; i--) {
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if (row.get(i)) {
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break;
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}
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quietCount--;
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}
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if (quietCount !== 0) {
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// Unable to find the necessary number of quiet zone pixels.
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throw new NotFoundException();
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}
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}
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/*
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/!**
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* Skip all whitespace until we get to the first black line.
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*
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* @param row row of black/white values to search
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* @return index of the first black line.
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* @throws NotFoundException Throws exception if no black lines are found in the row
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*!/*/
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static skipWhiteSpace(row) {
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const width = row.getSize();
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const endStart = row.getNextSet(0);
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if (endStart === width) {
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throw new NotFoundException();
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}
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return endStart;
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}
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/*/!**
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* Identify where the end of the middle / payload section ends.
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*
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* @param row row of black/white values to search
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* @return Array, containing index of start of 'end block' and end of 'end
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* block'
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*!/*/
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decodeEnd(row) {
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// For convenience, reverse the row and then
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// search from 'the start' for the end block
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row.reverse();
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try {
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let endStart = ITFReader.skipWhiteSpace(row);
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let endPattern;
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try {
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endPattern = ITFReader.findGuardPattern(row, endStart, ITFReader.END_PATTERN_REVERSED[0]);
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}
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catch (error) {
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if (error instanceof NotFoundException) {
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endPattern = ITFReader.findGuardPattern(row, endStart, ITFReader.END_PATTERN_REVERSED[1]);
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}
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}
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// The start & end patterns must be pre/post fixed by a quiet zone. This
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// zone must be at least 10 times the width of a narrow line.
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// ref: http://www.barcode-1.net/i25code.html
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this.validateQuietZone(row, endPattern[0]);
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// Now recalculate the indices of where the 'endblock' starts & stops to
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// accommodate
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// the reversed nature of the search
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let temp = endPattern[0];
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endPattern[0] = row.getSize() - endPattern[1];
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endPattern[1] = row.getSize() - temp;
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return endPattern;
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}
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finally {
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// Put the row back the right way.
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row.reverse();
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}
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}
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/*
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/!**
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* @param row row of black/white values to search
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* @param rowOffset position to start search
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* @param pattern pattern of counts of number of black and white pixels that are
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* being searched for as a pattern
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* @return start/end horizontal offset of guard pattern, as an array of two
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* ints
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* @throws NotFoundException if pattern is not found
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*!/*/
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static findGuardPattern(row, rowOffset, pattern) {
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let patternLength = pattern.length;
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let counters = new Int32Array(patternLength);
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let width = row.getSize();
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let isWhite = false;
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let counterPosition = 0;
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let patternStart = rowOffset;
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counters.fill(0);
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for (let x = rowOffset; x < width; x++) {
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if (row.get(x) !== isWhite) {
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counters[counterPosition]++;
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}
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else {
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if (counterPosition === patternLength - 1) {
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if (OneDReader.patternMatchVariance(counters, pattern, ITFReader.MAX_INDIVIDUAL_VARIANCE) < ITFReader.MAX_AVG_VARIANCE) {
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return [patternStart, x];
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}
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patternStart += counters[0] + counters[1];
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System.arraycopy(counters, 2, counters, 0, counterPosition - 1);
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counters[counterPosition - 1] = 0;
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counters[counterPosition] = 0;
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counterPosition--;
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}
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else {
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counterPosition++;
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}
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counters[counterPosition] = 1;
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isWhite = !isWhite;
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}
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}
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throw new NotFoundException();
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}
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/*/!**
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* Attempts to decode a sequence of ITF black/white lines into single
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* digit.
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*
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* @param counters the counts of runs of observed black/white/black/... values
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* @return The decoded digit
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* @throws NotFoundException if digit cannot be decoded
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*!/*/
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static decodeDigit(counters) {
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let bestVariance = ITFReader.MAX_AVG_VARIANCE; // worst variance we'll accept
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let bestMatch = -1;
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let max = ITFReader.PATTERNS.length;
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for (let i = 0; i < max; i++) {
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let pattern = ITFReader.PATTERNS[i];
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let variance = OneDReader.patternMatchVariance(counters, pattern, ITFReader.MAX_INDIVIDUAL_VARIANCE);
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if (variance < bestVariance) {
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bestVariance = variance;
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bestMatch = i;
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}
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else if (variance === bestVariance) {
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// if we find a second 'best match' with the same variance, we can not reliably report to have a suitable match
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bestMatch = -1;
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}
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}
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if (bestMatch >= 0) {
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return bestMatch % 10;
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}
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else {
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throw new NotFoundException();
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}
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}
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}
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ITFReader.PATTERNS = [
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Int32Array.from([1, 1, 2, 2, 1]),
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Int32Array.from([2, 1, 1, 1, 2]),
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Int32Array.from([1, 2, 1, 1, 2]),
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Int32Array.from([2, 2, 1, 1, 1]),
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Int32Array.from([1, 1, 2, 1, 2]),
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Int32Array.from([2, 1, 2, 1, 1]),
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Int32Array.from([1, 2, 2, 1, 1]),
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Int32Array.from([1, 1, 1, 2, 2]),
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Int32Array.from([2, 1, 1, 2, 1]),
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Int32Array.from([1, 2, 1, 2, 1]),
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Int32Array.from([1, 1, 3, 3, 1]),
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Int32Array.from([3, 1, 1, 1, 3]),
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Int32Array.from([1, 3, 1, 1, 3]),
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Int32Array.from([3, 3, 1, 1, 1]),
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Int32Array.from([1, 1, 3, 1, 3]),
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Int32Array.from([3, 1, 3, 1, 1]),
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Int32Array.from([1, 3, 3, 1, 1]),
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Int32Array.from([1, 1, 1, 3, 3]),
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Int32Array.from([3, 1, 1, 3, 1]),
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Int32Array.from([1, 3, 1, 3, 1]) // 9
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];
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ITFReader.MAX_AVG_VARIANCE = 0.38;
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ITFReader.MAX_INDIVIDUAL_VARIANCE = 0.5;
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/* /!** Valid ITF lengths. Anything longer than the largest value is also allowed. *!/*/
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ITFReader.DEFAULT_ALLOWED_LENGTHS = [6, 8, 10, 12, 14];
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/*/!**
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* Start/end guard pattern.
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*
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* Note: The end pattern is reversed because the row is reversed before
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* searching for the END_PATTERN
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*!/*/
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ITFReader.START_PATTERN = Int32Array.from([1, 1, 1, 1]);
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ITFReader.END_PATTERN_REVERSED = [
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Int32Array.from([1, 1, 2]),
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Int32Array.from([1, 1, 3]) // 3x
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];
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