src/core/datamatrix/decoder/DecodedBitStreamParser.ts
import DecoderResult from '../../common/DecoderResult';
import BitSource from '../../common/BitSource';
import StringBuilder from '../../util/StringBuilder';
import StringEncoding from '../../util/StringEncoding';
import StringUtils from '../../common/StringUtils';
import FormatException from '../../FormatException';
import IllegalStateException from '../../IllegalStateException';
/*
* 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.
*/
enum Mode {
PAD_ENCODE, // Not really a mode
ASCII_ENCODE,
C40_ENCODE,
TEXT_ENCODE,
ANSIX12_ENCODE,
EDIFACT_ENCODE,
BASE256_ENCODE
}
/**
* <p>Data Matrix Codes can encode text as bits in one of several modes, and can use multiple modes
* in one Data Matrix Code. This class decodes the bits back into text.</p>
*
* <p>See ISO 16022:2006, 5.2.1 - 5.2.9.2</p>
*
* @author bbrown@google.com (Brian Brown)
* @author Sean Owen
*/
export default class DecodedBitStreamParser {
/**
* See ISO 16022:2006, Annex C Table C.1
* The C40 Basic Character Set (*'s used for placeholders for the shift values)
*/
private static C40_BASIC_SET_CHARS: string[] = [
'*', '*', '*', ' ', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N',
'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'
];
private static C40_SHIFT2_SET_CHARS: string[] = [
'!', '"', '#', '$', '%', '&', '\'', '(', ')', '*', '+', ',', '-', '.',
'/', ':', ';', '<', '=', '>', '?', '@', '[', '\\', ']', '^', '_'
];
/**
* See ISO 16022:2006, Annex C Table C.2
* The Text Basic Character Set (*'s used for placeholders for the shift values)
*/
private static TEXT_BASIC_SET_CHARS: string[] = [
'*', '*', '*', ' ', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'
];
// Shift 2 for Text is the same encoding as C40
private static TEXT_SHIFT2_SET_CHARS = DecodedBitStreamParser.C40_SHIFT2_SET_CHARS;
private static TEXT_SHIFT3_SET_CHARS: string[] = [
'`', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N',
'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '{', '|', '}', '~', String.fromCharCode(127)
];
static decode(bytes: Uint8Array): DecoderResult {
const bits = new BitSource(bytes);
const result = new StringBuilder();
const resultTrailer = new StringBuilder();
const byteSegments = new Array<Uint8Array>();
let mode = Mode.ASCII_ENCODE;
do {
if (mode === Mode.ASCII_ENCODE) {
mode = this.decodeAsciiSegment(bits, result, resultTrailer);
} else {
switch (mode) {
case Mode.C40_ENCODE:
this.decodeC40Segment(bits, result);
break;
case Mode.TEXT_ENCODE:
this.decodeTextSegment(bits, result);
break;
case Mode.ANSIX12_ENCODE:
this.decodeAnsiX12Segment(bits, result);
break;
case Mode.EDIFACT_ENCODE:
this.decodeEdifactSegment(bits, result);
break;
case Mode.BASE256_ENCODE:
this.decodeBase256Segment(bits, result, byteSegments);
break;
default:
throw new FormatException();
}
mode = Mode.ASCII_ENCODE;
}
} while (mode !== Mode.PAD_ENCODE && bits.available() > 0);
if (resultTrailer.length() > 0) {
result.append(resultTrailer.toString());
}
return new DecoderResult(bytes, result.toString(), byteSegments.length === 0 ? null : byteSegments, null);
}
/**
* See ISO 16022:2006, 5.2.3 and Annex C, Table C.2
*/
private static decodeAsciiSegment(bits: BitSource,
result: StringBuilder,
resultTrailer: StringBuilder): Mode {
let upperShift = false;
do {
let oneByte = bits.readBits(8);
if (oneByte === 0) {
throw new FormatException();
} else if (oneByte <= 128) { // ASCII data (ASCII value + 1)
if (upperShift) {
oneByte += 128;
// upperShift = false;
}
result.append(String.fromCharCode(oneByte - 1));
return Mode.ASCII_ENCODE;
} else if (oneByte === 129) { // Pad
return Mode.PAD_ENCODE;
} else if (oneByte <= 229) { // 2-digit data 00-99 (Numeric Value + 130)
const value = oneByte - 130;
if (value < 10) { // pad with '0' for single digit values
result.append('0');
}
result.append('' + value);
} else {
switch (oneByte) {
case 230: // Latch to C40 encodation
return Mode.C40_ENCODE;
case 231: // Latch to Base 256 encodation
return Mode.BASE256_ENCODE;
case 232: // FNC1
result.append(String.fromCharCode(29)); // translate as ASCII 29
break;
case 233: // Structured Append
case 234: // Reader Programming
// Ignore these symbols for now
// throw ReaderException.getInstance();
break;
case 235: // Upper Shift (shift to Extended ASCII)
upperShift = true;
break;
case 236: // 05 Macro
result.append('[)>\u001E05\u001D');
resultTrailer.insert(0, '\u001E\u0004');
break;
case 237: // 06 Macro
result.append('[)>\u001E06\u001D');
resultTrailer.insert(0, '\u001E\u0004');
break;
case 238: // Latch to ANSI X12 encodation
return Mode.ANSIX12_ENCODE;
case 239: // Latch to Text encodation
return Mode.TEXT_ENCODE;
case 240: // Latch to EDIFACT encodation
return Mode.EDIFACT_ENCODE;
case 241: // ECI Character
// TODO(bbrown): I think we need to support ECI
// throw ReaderException.getInstance();
// Ignore this symbol for now
break;
default:
// Not to be used in ASCII encodation
// but work around encoders that end with 254, latch back to ASCII
if (oneByte !== 254 || bits.available() !== 0) {
throw new FormatException();
}
break;
}
}
} while (bits.available() > 0);
return Mode.ASCII_ENCODE;
}
/**
* See ISO 16022:2006, 5.2.5 and Annex C, Table C.1
*/
private static decodeC40Segment(bits: BitSource, result: StringBuilder): void {
// Three C40 values are encoded in a 16-bit value as
// (1600 * C1) + (40 * C2) + C3 + 1
// TODO(bbrown): The Upper Shift with C40 doesn't work in the 4 value scenario all the time
let upperShift = false;
const cValues: number[] = [];
let shift = 0;
do {
// If there is only one byte left then it will be encoded as ASCII
if (bits.available() === 8) {
return;
}
const firstByte = bits.readBits(8);
if (firstByte === 254) { // Unlatch codeword
return;
}
this.parseTwoBytes(firstByte, bits.readBits(8), cValues);
for (let i = 0; i < 3; i++) {
const cValue = cValues[i];
switch (shift) {
case 0:
if (cValue < 3) {
shift = cValue + 1;
} else if (cValue < this.C40_BASIC_SET_CHARS.length) {
const c40char = this.C40_BASIC_SET_CHARS[cValue];
if (upperShift) {
result.append(String.fromCharCode(c40char.charCodeAt(0) + 128));
upperShift = false;
} else {
result.append(c40char);
}
} else {
throw new FormatException();
}
break;
case 1:
if (upperShift) {
result.append(String.fromCharCode(cValue + 128));
upperShift = false;
} else {
result.append(String.fromCharCode(cValue));
}
shift = 0;
break;
case 2:
if (cValue < this.C40_SHIFT2_SET_CHARS.length) {
const c40char = this.C40_SHIFT2_SET_CHARS[cValue];
if (upperShift) {
result.append(String.fromCharCode(c40char.charCodeAt(0) + 128));
upperShift = false;
} else {
result.append(c40char);
}
} else {
switch (cValue) {
case 27: // FNC1
result.append(String.fromCharCode(29)); // translate as ASCII 29
break;
case 30: // Upper Shift
upperShift = true;
break;
default:
throw new FormatException();
}
}
shift = 0;
break;
case 3:
if (upperShift) {
result.append(String.fromCharCode(cValue + 224));
upperShift = false;
} else {
result.append(String.fromCharCode(cValue + 96));
}
shift = 0;
break;
default:
throw new FormatException();
}
}
} while (bits.available() > 0);
}
/**
* See ISO 16022:2006, 5.2.6 and Annex C, Table C.2
*/
private static decodeTextSegment(bits: BitSource, result: StringBuilder): void {
// Three Text values are encoded in a 16-bit value as
// (1600 * C1) + (40 * C2) + C3 + 1
// TODO(bbrown): The Upper Shift with Text doesn't work in the 4 value scenario all the time
let upperShift = false;
let cValues: number[] = [];
let shift = 0;
do {
// If there is only one byte left then it will be encoded as ASCII
if (bits.available() === 8) {
return;
}
const firstByte = bits.readBits(8);
if (firstByte === 254) { // Unlatch codeword
return;
}
this.parseTwoBytes(firstByte, bits.readBits(8), cValues);
for (let i = 0; i < 3; i++) {
const cValue = cValues[i];
switch (shift) {
case 0:
if (cValue < 3) {
shift = cValue + 1;
} else if (cValue < this.TEXT_BASIC_SET_CHARS.length) {
const textChar = this.TEXT_BASIC_SET_CHARS[cValue];
if (upperShift) {
result.append(String.fromCharCode(textChar.charCodeAt(0) + 128));
upperShift = false;
} else {
result.append(textChar);
}
} else {
throw new FormatException();
}
break;
case 1:
if (upperShift) {
result.append(String.fromCharCode(cValue + 128));
upperShift = false;
} else {
result.append(String.fromCharCode(cValue));
}
shift = 0;
break;
case 2:
// Shift 2 for Text is the same encoding as C40
if (cValue < this.TEXT_SHIFT2_SET_CHARS.length) {
const textChar = this.TEXT_SHIFT2_SET_CHARS[cValue];
if (upperShift) {
result.append(String.fromCharCode(textChar.charCodeAt(0) + 128));
upperShift = false;
} else {
result.append(textChar);
}
} else {
switch (cValue) {
case 27: // FNC1
result.append(String.fromCharCode(29)); // translate as ASCII 29
break;
case 30: // Upper Shift
upperShift = true;
break;
default:
throw new FormatException();
}
}
shift = 0;
break;
case 3:
if (cValue < this.TEXT_SHIFT3_SET_CHARS.length) {
const textChar = this.TEXT_SHIFT3_SET_CHARS[cValue];
if (upperShift) {
result.append(String.fromCharCode(textChar.charCodeAt(0) + 128));
upperShift = false;
} else {
result.append(textChar);
}
shift = 0;
} else {
throw new FormatException();
}
break;
default:
throw new FormatException();
}
}
} while (bits.available() > 0);
}
/**
* See ISO 16022:2006, 5.2.7
*/
private static decodeAnsiX12Segment(bits: BitSource,
result: StringBuilder): void {
// Three ANSI X12 values are encoded in a 16-bit value as
// (1600 * C1) + (40 * C2) + C3 + 1
const cValues: number[] = [];
do {
// If there is only one byte left then it will be encoded as ASCII
if (bits.available() === 8) {
return;
}
const firstByte = bits.readBits(8);
if (firstByte === 254) { // Unlatch codeword
return;
}
this.parseTwoBytes(firstByte, bits.readBits(8), cValues);
for (let i = 0; i < 3; i++) {
const cValue = cValues[i];
switch (cValue) {
case 0: // X12 segment terminator <CR>
result.append('\r');
break;
case 1: // X12 segment separator *
result.append('*');
break;
case 2: // X12 sub-element separator >
result.append('>');
break;
case 3: // space
result.append(' ');
break;
default:
if (cValue < 14) { // 0 - 9
result.append(String.fromCharCode(cValue + 44));
} else if (cValue < 40) { // A - Z
result.append(String.fromCharCode(cValue + 51));
} else {
throw new FormatException();
}
break;
}
}
} while (bits.available() > 0);
}
private static parseTwoBytes(firstByte: number, secondByte: number, result: number[]): void {
let fullBitValue = (firstByte << 8) + secondByte - 1;
let temp = Math.floor(fullBitValue / 1600);
result[0] = temp;
fullBitValue -= temp * 1600;
temp = Math.floor(fullBitValue / 40);
result[1] = temp;
result[2] = fullBitValue - temp * 40;
}
/**
* See ISO 16022:2006, 5.2.8 and Annex C Table C.3
*/
private static decodeEdifactSegment(bits: BitSource, result: StringBuilder): void {
do {
// If there is only two or less bytes left then it will be encoded as ASCII
if (bits.available() <= 16) {
return;
}
for (let i = 0; i < 4; i++) {
let edifactValue = bits.readBits(6);
// Check for the unlatch character
if (edifactValue === 0x1F) { // 011111
// Read rest of byte, which should be 0, and stop
const bitsLeft = 8 - bits.getBitOffset();
if (bitsLeft !== 8) {
bits.readBits(bitsLeft);
}
return;
}
if ((edifactValue & 0x20) === 0) { // no 1 in the leading (6th) bit
edifactValue |= 0x40; // Add a leading 01 to the 6 bit binary value
}
result.append(String.fromCharCode(edifactValue));
}
} while (bits.available() > 0);
}
/**
* See ISO 16022:2006, 5.2.9 and Annex B, B.2
*/
private static decodeBase256Segment(bits: BitSource,
result: StringBuilder,
byteSegments: Uint8Array[]): void {
// Figure out how long the Base 256 Segment is.
let codewordPosition = 1 + bits.getByteOffset(); // position is 1-indexed
const d1 = this.unrandomize255State(bits.readBits(8), codewordPosition++);
let count: number;
if (d1 === 0) { // Read the remainder of the symbol
count = bits.available() / 8 | 0;
} else if (d1 < 250) {
count = d1;
} else {
count = 250 * (d1 - 249) + this.unrandomize255State(bits.readBits(8), codewordPosition++);
}
// We're seeing NegativeArraySizeException errors from users.
if (count < 0) {
throw new FormatException();
}
const bytes = new Uint8Array(count);
for (let i = 0; i < count; i++) {
// Have seen this particular error in the wild, such as at
// http://www.bcgen.com/demo/IDAutomationStreamingDataMatrix.aspx?MODE=3&D=Fred&PFMT=3&PT=F&X=0.3&O=0&LM=0.2
if (bits.available() < 8) {
throw new FormatException();
}
bytes[i] = this.unrandomize255State(bits.readBits(8), codewordPosition++);
}
byteSegments.push(bytes);
try {
result.append(StringEncoding.decode(bytes, StringUtils.ISO88591));
} catch (uee) {
throw new IllegalStateException('Platform does not support required encoding: ' + uee.message);
}
}
/**
* See ISO 16022:2006, Annex B, B.2
*/
private static unrandomize255State(randomizedBase256Codeword: number,
base256CodewordPosition: number): number {
const pseudoRandomNumber = ((149 * base256CodewordPosition) % 255) + 1;
const tempVariable = randomizedBase256Codeword - pseudoRandomNumber;
return tempVariable >= 0 ? tempVariable : tempVariable + 256;
}
}