@zxing/library
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TypeScript port of ZXing multi-format 1D/2D barcode image processing library.
181 lines (180 loc) • 6.68 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 UPCEANReader from './UPCEANReader';
import StringBuilder from '../util/StringBuilder';
import NotFoundException from '../NotFoundException';
import BarcodeFormat from '../BarcodeFormat';
// package com.google.zxing.oned;
// import com.google.zxing.BarcodeFormat;
// import com.google.zxing.FormatException;
// import com.google.zxing.NotFoundException;
// import com.google.zxing.common.BitArray;
/**
* <p>Implements decoding of the UPC-E format.</p>
* <p><a href="http://www.barcodeisland.com/upce.phtml">This</a> is a great reference for
* UPC-E information.</p>
*
* @author Sean Owen
*
* @source https://github.com/zxing/zxing/blob/3c96923276dd5785d58eb970b6ba3f80d36a9505/core/src/main/java/com/google/zxing/oned/UPCEReader.java
*
* @experimental
*/
export default /* final */ class UPCEReader extends UPCEANReader {
constructor() {
super();
this.decodeMiddleCounters = new Int32Array(4);
}
/**
* @throws NotFoundException
*/
// @Override
decodeMiddle(row, startRange, result) {
const counters = this.decodeMiddleCounters.map(x => x);
counters[0] = 0;
counters[1] = 0;
counters[2] = 0;
counters[3] = 0;
const end = row.getSize();
let rowOffset = startRange[1];
let lgPatternFound = 0;
for (let x = 0; x < 6 && rowOffset < end; x++) {
const bestMatch = UPCEReader.decodeDigit(row, counters, rowOffset, UPCEReader.L_AND_G_PATTERNS);
result += String.fromCharCode(('0'.charCodeAt(0) + bestMatch % 10));
for (let counter of counters) {
rowOffset += counter;
}
if (bestMatch >= 10) {
lgPatternFound |= 1 << (5 - x);
}
}
UPCEReader.determineNumSysAndCheckDigit(new StringBuilder(result), lgPatternFound);
return rowOffset;
}
/**
* @throws NotFoundException
*/
// @Override
decodeEnd(row, endStart) {
return UPCEReader.findGuardPatternWithoutCounters(row, endStart, true, UPCEReader.MIDDLE_END_PATTERN);
}
/**
* @throws FormatException
*/
// @Override
checkChecksum(s) {
return UPCEANReader.checkChecksum(UPCEReader.convertUPCEtoUPCA(s));
}
/**
* @throws NotFoundException
*/
static determineNumSysAndCheckDigit(resultString, lgPatternFound) {
for (let numSys = 0; numSys <= 1; numSys++) {
for (let d = 0; d < 10; d++) {
if (lgPatternFound === this.NUMSYS_AND_CHECK_DIGIT_PATTERNS[numSys][d]) {
resultString.insert(0, /*(char)*/ ('0' + numSys));
resultString.append(/*(char)*/ ('0' + d));
return;
}
}
}
throw NotFoundException.getNotFoundInstance();
}
// @Override
getBarcodeFormat() {
return BarcodeFormat.UPC_E;
}
/**
* Expands a UPC-E value back into its full, equivalent UPC-A code value.
*
* @param upce UPC-E code as string of digits
* @return equivalent UPC-A code as string of digits
*/
static convertUPCEtoUPCA(upce) {
// the following line is equivalent to upce.getChars(1, 7, upceChars, 0);
const upceChars = upce.slice(1, 7).split('').map(x => x.charCodeAt(0));
const result = new StringBuilder( /*12*/);
result.append(upce.charAt(0));
let lastChar = upceChars[5];
switch (lastChar) {
case 0:
case 1:
case 2:
result.appendChars(upceChars, 0, 2);
result.append(lastChar);
result.append('0000');
result.appendChars(upceChars, 2, 3);
break;
case 3:
result.appendChars(upceChars, 0, 3);
result.append('00000');
result.appendChars(upceChars, 3, 2);
break;
case 4:
result.appendChars(upceChars, 0, 4);
result.append('00000');
result.append(upceChars[4]);
break;
default:
result.appendChars(upceChars, 0, 5);
result.append('0000');
result.append(lastChar);
break;
}
// Only append check digit in conversion if supplied
if (upce.length >= 8) {
result.append(upce.charAt(7));
}
return result.toString();
}
}
/**
* The pattern that marks the middle, and end, of a UPC-E pattern.
* There is no "second half" to a UPC-E barcode.
*/
UPCEReader.MIDDLE_END_PATTERN = Int32Array.from([1, 1, 1, 1, 1, 1]);
// For an UPC-E barcode, the final digit is represented by the parities used
// to encode the middle six digits, according to the table below.
//
// Parity of next 6 digits
// Digit 0 1 2 3 4 5
// 0 Even Even Even Odd Odd Odd
// 1 Even Even Odd Even Odd Odd
// 2 Even Even Odd Odd Even Odd
// 3 Even Even Odd Odd Odd Even
// 4 Even Odd Even Even Odd Odd
// 5 Even Odd Odd Even Even Odd
// 6 Even Odd Odd Odd Even Even
// 7 Even Odd Even Odd Even Odd
// 8 Even Odd Even Odd Odd Even
// 9 Even Odd Odd Even Odd Even
//
// The encoding is represented by the following array, which is a bit pattern
// using Odd = 0 and Even = 1. For example, 5 is represented by:
//
// Odd Even Even Odd Odd Even
// in binary:
// 0 1 1 0 0 1 == 0x19
//
/**
* See {@link #L_AND_G_PATTERNS}; these values similarly represent patterns of
* even-odd parity encodings of digits that imply both the number system (0 or 1)
* used, and the check digit.
*/
UPCEReader.NUMSYS_AND_CHECK_DIGIT_PATTERNS = [
Int32Array.from([0x38, 0x34, 0x32, 0x31, 0x2C, 0x26, 0x23, 0x2A, 0x29, 0x25]),
Int32Array.from([0x07, 0x0B, 0x0D, 0x0E, 0x13, 0x19, 0x1C, 0x15, 0x16, 0x1]),
];