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1c4f85ee24
git-svn-id: https://zxing.googlecode.com/svn/trunk@820 59b500cc-1b3d-0410-9834-0bbf25fbcc57
450 lines
18 KiB
C#
450 lines
18 KiB
C#
/*
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* Copyright 2008 ZXing authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Text;
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using com.google.zxing.common;
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namespace com.google.zxing.datamatrix.decoder
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{
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/**
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* <p>Encapsulates a block of data within a Data Matrix Code. Data Matrix Codes may split their data into
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* multiple blocks, each of which is a unit of data and error-correction codewords. Each
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* is represented by an instance of this class.</p>
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*
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* @author bbrown@google.com (Brian Brown)
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*/
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public sealed class DecodedBitStreamParser
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{
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/**
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* See ISO 16022:2006, Annex C Table C.1
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* The C40 Basic Character Set (*'s used for placeholders for the shift values)
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*/
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private static char[] C40_BASIC_SET_CHARS = {
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'*', '*', '*', ' ', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
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'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N',
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'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'
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};
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private static char[] C40_SHIFT2_SET_CHARS = {
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'!', '"', '#', '$', '%', '&', '\'', '(', ')', '*', '+', ',', '-', '.',
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'/', ':', ';', '<', '=', '>', '?', '@', '[', '\\', ']', '^', '_'
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};
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/**
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* See ISO 16022:2006, Annex C Table C.2
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* The Text Basic Character Set (*'s used for placeholders for the shift values)
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*/
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private static char[] TEXT_BASIC_SET_CHARS = {
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'*', '*', '*', ' ', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
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'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
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'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'
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};
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private static char[] TEXT_SHIFT3_SET_CHARS = {
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'\'', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N',
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'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '{', '|', '}', '~', (char) 127
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};
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private const int PAD_ENCODE = 0; // Not really an encoding
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private const int ASCII_ENCODE = 1;
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private const int C40_ENCODE = 2;
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private const int TEXT_ENCODE = 3;
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private const int ANSIX12_ENCODE = 4;
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private const int EDIFACT_ENCODE = 5;
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private const int BASE256_ENCODE = 6;
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private DecodedBitStreamParser() {
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}
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public static DecoderResult decode(sbyte[] bytes) {
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BitSource bits = new BitSource(bytes);
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StringBuilder result = new StringBuilder();
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StringBuilder resultTrailer = new StringBuilder(0);
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System.Collections.ArrayList byteSegments = new System.Collections.ArrayList(1);
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int mode = ASCII_ENCODE;
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do {
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if (mode == ASCII_ENCODE) {
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mode = decodeAsciiSegment(bits, result, resultTrailer);
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} else {
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switch (mode) {
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case C40_ENCODE:
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decodeC40Segment(bits, result);
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break;
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case TEXT_ENCODE:
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decodeTextSegment(bits, result);
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break;
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case ANSIX12_ENCODE:
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decodeAnsiX12Segment(bits, result);
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break;
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case EDIFACT_ENCODE:
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decodeEdifactSegment(bits, result);
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break;
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case BASE256_ENCODE:
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decodeBase256Segment(bits, result, byteSegments);
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break;
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default:
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throw new ReaderException();
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}
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mode = ASCII_ENCODE;
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}
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} while (mode != PAD_ENCODE && bits.available() > 0);
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if (resultTrailer.Length > 0) {
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result.Append(resultTrailer);
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}
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return new DecoderResult(bytes, result.ToString(), int.Equals(byteSegments.Count,0) ? null : byteSegments);
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}
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/**
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* See ISO 16022:2006, 5.2.3 and Annex C, Table C.2
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*/
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private static int decodeAsciiSegment(BitSource bits, StringBuilder result, StringBuilder resultTrailer)
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{
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bool upperShift = false;
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do {
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int oneByte = bits.readBits(8);
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if (oneByte == 0) {
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throw new ReaderException();
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} else if (oneByte <= 128) { // ASCII data (ASCII value + 1)
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oneByte = upperShift ? (oneByte + 128) : oneByte;
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upperShift = false;
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result.Append((char) (oneByte - 1));
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return ASCII_ENCODE;
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} else if (oneByte == 129) { // Pad
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return PAD_ENCODE;
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} else if (oneByte <= 229) { // 2-digit data 00-99 (Numeric Value + 130)
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int value = oneByte - 130;
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if (value < 10) { // padd with '0' for single digit values
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result.Append('0');
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}
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result.Append(value);
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} else if (oneByte == 230) { // Latch to C40 encodation
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return C40_ENCODE;
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} else if (oneByte == 231) { // Latch to Base 256 encodation
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return BASE256_ENCODE;
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} else if (oneByte == 232) { // FNC1
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throw new ReaderException();
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} else if (oneByte == 233) { // Structured Append
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throw new ReaderException();
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} else if (oneByte == 234) { // Reader Programming
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throw new ReaderException();
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} else if (oneByte == 235) { // Upper Shift (shift to Extended ASCII)
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upperShift = true;
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} else if (oneByte == 236) { // 05 Macro
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result.Append("[)>\u001E05\u001D");
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resultTrailer.Insert(0, "\u001E\u0004");
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} else if (oneByte == 237) { // 06 Macro
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result.Append("[)>\u001E06\u001D");
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resultTrailer.Insert(0, "\u001E\u0004");
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} else if (oneByte == 238) { // Latch to ANSI X12 encodation
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return ANSIX12_ENCODE;
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} else if (oneByte == 239) { // Latch to Text encodation
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return TEXT_ENCODE;
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} else if (oneByte == 240) { // Latch to EDIFACT encodation
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return EDIFACT_ENCODE;
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} else if (oneByte == 241) { // ECI Character
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// TODO(bbrown): I think we need to support ECI
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throw new ReaderException();
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} else if (oneByte >= 242) { // Not to be used in ASCII encodation
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throw new ReaderException();
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}
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} while (bits.available() > 0);
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return ASCII_ENCODE;
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}
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/**
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* See ISO 16022:2006, 5.2.5 and Annex C, Table C.1
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*/
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private static void decodeC40Segment(BitSource bits, StringBuilder result) {
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// Three C40 values are encoded in a 16-bit value as
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// (1600 * C1) + (40 * C2) + C3 + 1
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// TODO(bbrown): The Upper Shift with C40 doesn't work in the 4 value scenario all the time
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bool upperShift = false;
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int[] cValues = new int[3];
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do {
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// If there is only one byte left then it will be encoded as ASCII
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if (bits.available() == 8) {
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return;
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}
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int firstByte = bits.readBits(8);
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if (firstByte == 254) { // Unlatch codeword
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return;
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}
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parseTwoBytes(firstByte, bits.readBits(8), cValues);
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int shift = 0;
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for (int i = 0; i < 3; i++) {
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int cValue = cValues[i];
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switch (shift) {
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case 0:
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if (cValue < 3) {
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shift = cValue + 1;
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} else {
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if (upperShift) {
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result.Append((char) (C40_BASIC_SET_CHARS[cValue] + 128));
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upperShift = false;
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} else {
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result.Append(C40_BASIC_SET_CHARS[cValue]);
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}
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}
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break;
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case 1:
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if (upperShift) {
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result.Append((char) (cValue + 128));
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upperShift = false;
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} else {
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result.Append(cValue);
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}
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shift = 0;
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break;
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case 2:
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if (cValue < 27) {
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if (upperShift) {
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result.Append((char) (C40_SHIFT2_SET_CHARS[cValue] + 128));
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upperShift = false;
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} else {
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result.Append(C40_SHIFT2_SET_CHARS[cValue]);
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}
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} else if (cValue == 27) { // FNC1
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throw new ReaderException();
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} else if (cValue == 30) { // Upper Shift
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upperShift = true;
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} else {
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throw new ReaderException();
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}
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shift = 0;
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break;
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case 3:
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if (upperShift) {
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result.Append((char) (cValue + 224));
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upperShift = false;
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} else {
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result.Append((char) (cValue + 96));
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}
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shift = 0;
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break;
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default:
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throw new ReaderException();
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}
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}
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} while (bits.available() > 0);
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}
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/**
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* See ISO 16022:2006, 5.2.6 and Annex C, Table C.2
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*/
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private static void decodeTextSegment(BitSource bits, StringBuilder result) {
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// Three Text values are encoded in a 16-bit value as
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// (1600 * C1) + (40 * C2) + C3 + 1
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// TODO(bbrown): The Upper Shift with Text doesn't work in the 4 value scenario all the time
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bool upperShift = false;
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int[] cValues = new int[3];
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do {
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// If there is only one byte left then it will be encoded as ASCII
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if (bits.available() == 8) {
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return;
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}
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int firstByte = bits.readBits(8);
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if (firstByte == 254) { // Unlatch codeword
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return;
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}
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parseTwoBytes(firstByte, bits.readBits(8), cValues);
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int shift = 0;
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for (int i = 0; i < 3; i++) {
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int cValue = cValues[i];
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switch (shift) {
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case 0:
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if (cValue < 3) {
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shift = cValue + 1;
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} else {
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if (upperShift) {
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result.Append((char) (TEXT_BASIC_SET_CHARS[cValue] + 128));
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upperShift = false;
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} else {
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result.Append(TEXT_BASIC_SET_CHARS[cValue]);
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}
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}
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break;
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case 1:
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if (upperShift) {
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result.Append((char) (cValue + 128));
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upperShift = false;
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} else {
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result.Append(cValue);
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}
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shift = 0;
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break;
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case 2:
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// Shift 2 for Text is the same encoding as C40
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if (cValue < 27) {
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if (upperShift) {
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result.Append((char) (C40_SHIFT2_SET_CHARS[cValue] + 128));
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upperShift = false;
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} else {
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result.Append(C40_SHIFT2_SET_CHARS[cValue]);
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}
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} else if (cValue == 27) { // FNC1
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throw new ReaderException();
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} else if (cValue == 30) { // Upper Shift
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upperShift = true;
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} else {
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throw new ReaderException();
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}
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shift = 0;
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break;
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case 3:
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if (upperShift) {
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result.Append((char) (TEXT_SHIFT3_SET_CHARS[cValue] + 128));
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upperShift = false;
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} else {
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result.Append(TEXT_SHIFT3_SET_CHARS[cValue]);
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}
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shift = 0;
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break;
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default:
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throw new ReaderException();
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}
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}
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} while (bits.available() > 0);
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}
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/**
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* See ISO 16022:2006, 5.2.7
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*/
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private static void decodeAnsiX12Segment(BitSource bits, StringBuilder result) {
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// Three ANSI X12 values are encoded in a 16-bit value as
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// (1600 * C1) + (40 * C2) + C3 + 1
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int[] cValues = new int[3];
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do {
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// If there is only one byte left then it will be encoded as ASCII
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if (bits.available() == 8) {
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return;
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}
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int firstByte = bits.readBits(8);
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if (firstByte == 254) { // Unlatch codeword
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return;
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}
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parseTwoBytes(firstByte, bits.readBits(8), cValues);
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for (int i = 0; i < 3; i++) {
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int cValue = cValues[i];
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if (cValue == 0) { // X12 segment terminator <CR>
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result.Append('\r');
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} else if (cValue == 1) { // X12 segment separator *
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result.Append('*');
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} else if (cValue == 2) { // X12 sub-element separator >
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result.Append('>');
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} else if (cValue == 3) { // space
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result.Append(' ');
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} else if (cValue < 14) { // 0 - 9
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result.Append((char) (cValue + 44));
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} else if (cValue < 40) { // A - Z
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result.Append((char) (cValue + 51));
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} else {
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throw new ReaderException();
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}
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}
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} while (bits.available() > 0);
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}
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private static void parseTwoBytes(int firstByte, int secondByte, int[] result) {
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int fullBitValue = (firstByte << 8) + secondByte - 1;
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int temp = fullBitValue / 1600;
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result[0] = temp;
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fullBitValue -= temp * 1600;
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temp = fullBitValue / 40;
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result[1] = temp;
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result[2] = fullBitValue - temp * 40;
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}
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/**
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* See ISO 16022:2006, 5.2.8 and Annex C Table C.3
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*/
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private static void decodeEdifactSegment(BitSource bits, StringBuilder result) {
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bool unlatch = false;
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do {
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// If there is only two or less bytes left then it will be encoded as ASCII
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if (bits.available() <= 16) {
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return;
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}
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for (int i = 0; i < 4; i++) {
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int edifactValue = bits.readBits(6);
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// Check for the unlatch character
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if (edifactValue == 0x2B67) { // 011111
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unlatch = true;
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// If we encounter the unlatch code then continue reading because the Codeword triple
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// is padded with 0's
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}
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if (!unlatch) {
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if ((edifactValue & 32) == 0) { // no 1 in the leading (6th) bit
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edifactValue |= 64; // Add a leading 01 to the 6 bit binary value
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}
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result.Append(edifactValue);
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}
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}
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} while (!unlatch && bits.available() > 0);
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}
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/**
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* See ISO 16022:2006, 5.2.9 and Annex B, B.2
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*/
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private static void decodeBase256Segment(BitSource bits, StringBuilder result, System.Collections.ArrayList byteSegments) {
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// Figure out how long the Base 256 Segment is.
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int d1 = bits.readBits(8);
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int count;
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if (d1 == 0) { // Read the remainder of the symbol
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count = bits.available() / 8;
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} else if (d1 < 250) {
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count = d1;
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} else {
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count = 250 * (d1 - 249) + bits.readBits(8);
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}
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byte[] bytes = new byte[count];
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for (int i = 0; i < count; i++) {
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bytes[i] = unrandomize255State(bits.readBits(8), i);
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}
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byteSegments.Add(bytes);
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try {
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result.Append(System.Text.Encoding.GetEncoding("iso-8859-1").GetString(bytes));
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} catch (Exception uee) {
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throw new Exception("Platform does not support required encoding: " + uee);
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}
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}
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/**
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* See ISO 16022:2006, Annex B, B.2
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*/
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private static byte unrandomize255State(int randomizedBase256Codeword,
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int base256CodewordPosition) {
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int pseudoRandomNumber = ((149 * base256CodewordPosition) % 255) + 1;
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int tempVariable = randomizedBase256Codeword - pseudoRandomNumber;
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return (byte) (tempVariable >= 0 ? tempVariable : (tempVariable + 256));
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}
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}
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}
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