@zxing/library
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TypeScript port of ZXing multi-format 1D/2D barcode image processing library.
152 lines (151 loc) • 6.79 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 DecodeHintType from '../DecodeHintType';
import Result from '../Result';
import ResultMetadataType from '../ResultMetadataType';
import ResultPoint from '../ResultPoint';
import UPCEANExtensionSupport from './UPCEANExtensionSupport';
import AbstractUPCEANReader from './AbstractUPCEANReader';
import NotFoundException from '../NotFoundException';
import FormatException from '../FormatException';
import ChecksumException from '../ChecksumException';
/**
* <p>Encapsulates functionality and implementation that is common to UPC and EAN families
* of one-dimensional barcodes.</p>
*
* @author dswitkin@google.com (Daniel Switkin)
* @author Sean Owen
* @author alasdair@google.com (Alasdair Mackintosh)
*/
export default class UPCEANReader extends AbstractUPCEANReader {
constructor() {
super();
this.decodeRowStringBuffer = '';
UPCEANReader.L_AND_G_PATTERNS = UPCEANReader.L_PATTERNS.map(arr => Int32Array.from(arr));
for (let i = 10; i < 20; i++) {
let widths = UPCEANReader.L_PATTERNS[i - 10];
let reversedWidths = new Int32Array(widths.length);
for (let j = 0; j < widths.length; j++) {
reversedWidths[j] = widths[widths.length - j - 1];
}
UPCEANReader.L_AND_G_PATTERNS[i] = reversedWidths;
}
}
decodeRow(rowNumber, row, hints) {
let startGuardRange = UPCEANReader.findStartGuardPattern(row);
let resultPointCallback = hints == null ? null : hints.get(DecodeHintType.NEED_RESULT_POINT_CALLBACK);
if (resultPointCallback != null) {
const resultPoint = new ResultPoint((startGuardRange[0] + startGuardRange[1]) / 2.0, rowNumber);
resultPointCallback.foundPossibleResultPoint(resultPoint);
}
let budello = this.decodeMiddle(row, startGuardRange, this.decodeRowStringBuffer);
let endStart = budello.rowOffset;
let result = budello.resultString;
if (resultPointCallback != null) {
const resultPoint = new ResultPoint(endStart, rowNumber);
resultPointCallback.foundPossibleResultPoint(resultPoint);
}
let endRange = UPCEANReader.decodeEnd(row, endStart);
if (resultPointCallback != null) {
const resultPoint = new ResultPoint((endRange[0] + endRange[1]) / 2.0, rowNumber);
resultPointCallback.foundPossibleResultPoint(resultPoint);
}
// Make sure there is a quiet zone at least as big as the end pattern after the barcode. The
// spec might want more whitespace, but in practice this is the maximum we can count on.
let end = endRange[1];
let quietEnd = end + (end - endRange[0]);
if (quietEnd >= row.getSize() || !row.isRange(end, quietEnd, false)) {
throw new NotFoundException();
}
let resultString = result.toString();
// UPC/EAN should never be less than 8 chars anyway
if (resultString.length < 8) {
throw new FormatException();
}
if (!UPCEANReader.checkChecksum(resultString)) {
throw new ChecksumException();
}
let left = (startGuardRange[1] + startGuardRange[0]) / 2.0;
let right = (endRange[1] + endRange[0]) / 2.0;
let format = this.getBarcodeFormat();
let resultPoint = [new ResultPoint(left, rowNumber), new ResultPoint(right, rowNumber)];
let decodeResult = new Result(resultString, null, 0, resultPoint, format, new Date().getTime());
let extensionLength = 0;
try {
let extensionResult = UPCEANExtensionSupport.decodeRow(rowNumber, row, endRange[1]);
decodeResult.putMetadata(ResultMetadataType.UPC_EAN_EXTENSION, extensionResult.getText());
decodeResult.putAllMetadata(extensionResult.getResultMetadata());
decodeResult.addResultPoints(extensionResult.getResultPoints());
extensionLength = extensionResult.getText().length;
}
catch (err) {
}
let allowedExtensions = hints == null ? null : hints.get(DecodeHintType.ALLOWED_EAN_EXTENSIONS);
if (allowedExtensions != null) {
let valid = false;
for (let length in allowedExtensions) {
if (extensionLength.toString() === length) { // check me
valid = true;
break;
}
}
if (!valid) {
throw new NotFoundException();
}
}
if (format === BarcodeFormat.EAN_13 || format === BarcodeFormat.UPC_A) {
// let countryID = eanManSupport.lookupContryIdentifier(resultString); todo
// if (countryID != null) {
// decodeResult.putMetadata(ResultMetadataType.POSSIBLE_COUNTRY, countryID);
// }
}
return decodeResult;
}
static checkChecksum(s) {
return UPCEANReader.checkStandardUPCEANChecksum(s);
}
static checkStandardUPCEANChecksum(s) {
let length = s.length;
if (length === 0)
return false;
let check = parseInt(s.charAt(length - 1), 10);
return UPCEANReader.getStandardUPCEANChecksum(s.substring(0, length - 1)) === check;
}
static getStandardUPCEANChecksum(s) {
let length = s.length;
let sum = 0;
for (let i = length - 1; i >= 0; i -= 2) {
let digit = s.charAt(i).charCodeAt(0) - '0'.charCodeAt(0);
if (digit < 0 || digit > 9) {
throw new FormatException();
}
sum += digit;
}
sum *= 3;
for (let i = length - 2; i >= 0; i -= 2) {
let digit = s.charAt(i).charCodeAt(0) - '0'.charCodeAt(0);
if (digit < 0 || digit > 9) {
throw new FormatException();
}
sum += digit;
}
return (1000 - sum) % 10;
}
static decodeEnd(row, endStart) {
return UPCEANReader.findGuardPattern(row, endStart, false, UPCEANReader.START_END_PATTERN, new Int32Array(UPCEANReader.START_END_PATTERN.length).fill(0));
}
}