@zxing/library
Version:
TypeScript port of ZXing multi-format 1D/2D barcode image processing library.
58 lines (57 loc) • 2.23 kB
JavaScript
/*
* Copyright 2008 ZXing authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import BarcodeFormat from '../BarcodeFormat';
import UPCEANReader from './UPCEANReader';
/**
* <p>Implements decoding of the EAN-8 format.</p>
*
* @author Sean Owen
*/
export default class EAN8Reader extends UPCEANReader {
constructor() {
super();
this.decodeMiddleCounters = Int32Array.from([0, 0, 0, 0]);
}
decodeMiddle(row, startRange, resultString) {
const counters = this.decodeMiddleCounters;
counters[0] = 0;
counters[1] = 0;
counters[2] = 0;
counters[3] = 0;
let end = row.getSize();
let rowOffset = startRange[1];
for (let x = 0; x < 4 && rowOffset < end; x++) {
let bestMatch = UPCEANReader.decodeDigit(row, counters, rowOffset, UPCEANReader.L_PATTERNS);
resultString += String.fromCharCode(('0'.charCodeAt(0) + bestMatch));
for (let counter of counters) {
rowOffset += counter;
}
}
let middleRange = UPCEANReader.findGuardPattern(row, rowOffset, true, UPCEANReader.MIDDLE_PATTERN, new Int32Array(UPCEANReader.MIDDLE_PATTERN.length).fill(0));
rowOffset = middleRange[1];
for (let x = 0; x < 4 && rowOffset < end; x++) {
let bestMatch = UPCEANReader.decodeDigit(row, counters, rowOffset, UPCEANReader.L_PATTERNS);
resultString += String.fromCharCode(('0'.charCodeAt(0) + bestMatch));
for (let counter of counters) {
rowOffset += counter;
}
}
return { rowOffset, resultString };
}
getBarcodeFormat() {
return BarcodeFormat.EAN_8;
}
}