@zxing/library
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TypeScript port of ZXing multi-format 1D/2D barcode image processing library.
275 lines (274 loc) • 11 kB
JavaScript
/*
* Copyright 2010 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.
*/
/*namespace com.google.zxing.oned {*/
import BarcodeFormat from '../BarcodeFormat';
import ChecksumException from '../ChecksumException';
import FormatException from '../FormatException';
import NotFoundException from '../NotFoundException';
import OneDReader from './OneDReader';
import Result from '../Result';
//import com.google.zxing.ResultMetadataType;
import ResultPoint from '../ResultPoint';
/**
* <p>Decodes Code 93 barcodes.</p>
*
* @author Sean Owen
* @see Code39Reader
*/
export default class Code93Reader extends OneDReader {
//public Code93Reader() {
// decodeRowResult = new StringBuilder(20);
// counters = new int[6];
//}
constructor() {
super();
this.decodeRowResult = '';
this.counters = new Int32Array(6);
}
decodeRow(rowNumber, row, hints) {
let start = this.findAsteriskPattern(row);
// Read off white space
let nextStart = row.getNextSet(start[1]);
let end = row.getSize();
let theCounters = this.counters;
theCounters.fill(0);
this.decodeRowResult = '';
let decodedChar;
let lastStart;
do {
Code93Reader.recordPattern(row, nextStart, theCounters);
let pattern = this.toPattern(theCounters);
if (pattern < 0) {
throw new NotFoundException();
}
decodedChar = this.patternToChar(pattern);
this.decodeRowResult += decodedChar;
lastStart = nextStart;
for (let counter of theCounters) {
nextStart += counter;
}
// Read off white space
nextStart = row.getNextSet(nextStart);
} while (decodedChar !== '*');
this.decodeRowResult = this.decodeRowResult.substring(0, this.decodeRowResult.length - 1); // remove asterisk
let lastPatternSize = 0;
for (let counter of theCounters) {
lastPatternSize += counter;
}
// Should be at least one more black module
if (nextStart === end || !row.get(nextStart)) {
throw new NotFoundException();
}
if (this.decodeRowResult.length < 2) {
// false positive -- need at least 2 checksum digits
throw new NotFoundException();
}
this.checkChecksums(this.decodeRowResult);
// Remove checksum digits
this.decodeRowResult = this.decodeRowResult.substring(0, this.decodeRowResult.length - 2);
let resultString = this.decodeExtended(this.decodeRowResult);
let left = (start[1] + start[0]) / 2.0;
let right = lastStart + lastPatternSize / 2.0;
return new Result(resultString, null, 0, [new ResultPoint(left, rowNumber), new ResultPoint(right, rowNumber)], BarcodeFormat.CODE_93, new Date().getTime());
}
findAsteriskPattern(row) {
let width = row.getSize();
let rowOffset = row.getNextSet(0);
this.counters.fill(0);
let theCounters = this.counters;
let patternStart = rowOffset;
let isWhite = false;
let patternLength = theCounters.length;
let counterPosition = 0;
for (let i = rowOffset; i < width; i++) {
if (row.get(i) !== isWhite) {
theCounters[counterPosition]++;
}
else {
if (counterPosition === patternLength - 1) {
if (this.toPattern(theCounters) === Code93Reader.ASTERISK_ENCODING) {
return new Int32Array([patternStart, i]);
}
patternStart += theCounters[0] + theCounters[1];
theCounters.copyWithin(0, 2, 2 + counterPosition - 1);
theCounters[counterPosition - 1] = 0;
theCounters[counterPosition] = 0;
counterPosition--;
}
else {
counterPosition++;
}
theCounters[counterPosition] = 1;
isWhite = !isWhite;
}
}
throw new NotFoundException;
}
toPattern(counters) {
let sum = 0;
for (const counter of counters) {
sum += counter;
}
let pattern = 0;
let max = counters.length;
for (let i = 0; i < max; i++) {
let scaled = Math.round(counters[i] * 9.0 / sum);
if (scaled < 1 || scaled > 4) {
return -1;
}
if ((i & 0x01) === 0) {
for (let j = 0; j < scaled; j++) {
pattern = (pattern << 1) | 0x01;
}
}
else {
pattern <<= scaled;
}
}
return pattern;
}
patternToChar(pattern) {
for (let i = 0; i < Code93Reader.CHARACTER_ENCODINGS.length; i++) {
if (Code93Reader.CHARACTER_ENCODINGS[i] === pattern) {
return Code93Reader.ALPHABET_STRING.charAt(i);
}
}
throw new NotFoundException();
}
decodeExtended(encoded) {
let length = encoded.length;
let decoded = '';
for (let i = 0; i < length; i++) {
let c = encoded.charAt(i);
if (c >= 'a' && c <= 'd') {
if (i >= length - 1) {
throw new FormatException();
}
let next = encoded.charAt(i + 1);
let decodedChar = '\0';
switch (c) {
case 'd':
// +A to +Z map to a to z
if (next >= 'A' && next <= 'Z') {
decodedChar = String.fromCharCode(next.charCodeAt(0) + 32);
}
else {
throw new FormatException();
}
break;
case 'a':
// $A to $Z map to control codes SH to SB
if (next >= 'A' && next <= 'Z') {
decodedChar = String.fromCharCode(next.charCodeAt(0) - 64);
}
else {
throw new FormatException();
}
break;
case 'b':
if (next >= 'A' && next <= 'E') {
// %A to %E map to control codes ESC to USep
decodedChar = String.fromCharCode(next.charCodeAt(0) - 38);
}
else if (next >= 'F' && next <= 'J') {
// %F to %J map to ; < = > ?
decodedChar = String.fromCharCode(next.charCodeAt(0) - 11);
}
else if (next >= 'K' && next <= 'O') {
// %K to %O map to [ \ ] ^ _
decodedChar = String.fromCharCode(next.charCodeAt(0) + 16);
}
else if (next >= 'P' && next <= 'T') {
// %P to %T map to { | } ~ DEL
decodedChar = String.fromCharCode(next.charCodeAt(0) + 43);
}
else if (next === 'U') {
// %U map to NUL
decodedChar = '\0';
}
else if (next === 'V') {
// %V map to @
decodedChar = '@';
}
else if (next === 'W') {
// %W map to `
decodedChar = '`';
}
else if (next >= 'X' && next <= 'Z') {
// %X to %Z all map to DEL (127)
decodedChar = String.fromCharCode(127);
}
else {
throw new FormatException();
}
break;
case 'c':
// /A to /O map to ! to , and /Z maps to :
if (next >= 'A' && next <= 'O') {
decodedChar = String.fromCharCode(next.charCodeAt(0) - 32);
}
else if (next === 'Z') {
decodedChar = ':';
}
else {
throw new FormatException();
}
break;
}
decoded += decodedChar;
// bump up i again since we read two characters
i++;
}
else {
decoded += c;
}
}
return decoded;
}
checkChecksums(result) {
let length = result.length;
this.checkOneChecksum(result, length - 2, 20);
this.checkOneChecksum(result, length - 1, 15);
}
checkOneChecksum(result, checkPosition, weightMax) {
let weight = 1;
let total = 0;
for (let i = checkPosition - 1; i >= 0; i--) {
total += weight * Code93Reader.ALPHABET_STRING.indexOf(result.charAt(i));
if (++weight > weightMax) {
weight = 1;
}
}
if (result.charAt(checkPosition) !== Code93Reader.ALPHABET_STRING[total % 47]) {
throw new ChecksumException;
}
}
}
// Note that 'abcd' are dummy characters in place of control characters.
Code93Reader.ALPHABET_STRING = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ-. $/+%abcd*";
/**
* These represent the encodings of characters, as patterns of wide and narrow bars.
* The 9 least-significant bits of each int correspond to the pattern of wide and narrow.
*/
Code93Reader.CHARACTER_ENCODINGS = [
0x114, 0x148, 0x144, 0x142, 0x128, 0x124, 0x122, 0x150, 0x112, 0x10A,
0x1A8, 0x1A4, 0x1A2, 0x194, 0x192, 0x18A, 0x168, 0x164, 0x162, 0x134,
0x11A, 0x158, 0x14C, 0x146, 0x12C, 0x116, 0x1B4, 0x1B2, 0x1AC, 0x1A6,
0x196, 0x19A, 0x16C, 0x166, 0x136, 0x13A,
0x12E, 0x1D4, 0x1D2, 0x1CA, 0x16E, 0x176, 0x1AE,
0x126, 0x1DA, 0x1D6, 0x132, 0x15E,
];
Code93Reader.ASTERISK_ENCODING = Code93Reader.CHARACTER_ENCODINGS[47];