2 * Copyright 2007 ZXing authors
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4 * Licensed under the Apache License, Version 2.0 (the "License");
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5 * you may not use this file except in compliance with the License.
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6 * You may obtain a copy of the License at
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8 * http://www.apache.org/licenses/LICENSE-2.0
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10 * Unless required by applicable law or agreed to in writing, software
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11 * distributed under the License is distributed on an "AS IS" BASIS,
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12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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13 * See the License for the specific language governing permissions and
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14 * limitations under the License.
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17 package com.google.zxing.datamatrix.decoder;
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19 import com.google.zxing.ReaderException;
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20 import com.google.zxing.common.BitMatrix;
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23 * @author bbrown@google.com (Brian Brown)
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25 final class BitMatrixParser {
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27 private final BitMatrix mappingBitMatrix;
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28 private final BitMatrix readMappingMatrix;
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29 private final Version version;
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32 * @param bitMatrix {@link BitMatrix} to parse
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33 * @throws ReaderException if dimension is < 10 or > 144 or not 0 mod 2
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35 BitMatrixParser(BitMatrix bitMatrix) throws ReaderException {
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36 int dimension = bitMatrix.getDimension();
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37 if (dimension < 10 || dimension > 144 || (dimension & 0x01) != 0) {
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38 throw ReaderException.getInstance();
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41 version = readVersion(bitMatrix);
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42 this.mappingBitMatrix = extractDataRegion(bitMatrix);
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43 // TODO(bbrown): Make this work for rectangular symbols
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44 this.readMappingMatrix = new BitMatrix(this.mappingBitMatrix.getDimension());
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48 * <p>Creates the version object based on the dimension of the original bit matrix from
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49 * the datamatrix code.</p>
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51 * <p>See ISO 16022:2006 Table 7 - ECC 200 symbol attributes</p>
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53 * @param bitMatrix Original {@link BitMatrix} including alignment patterns
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54 * @return {@link Version} encapsulating the Data Matrix Code's "version"
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55 * @throws ReaderException if the dimensions of the mapping matrix are not valid
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56 * Data Matrix dimensions.
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58 Version readVersion(BitMatrix bitMatrix) throws ReaderException {
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60 if (version != null) {
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64 // TODO(bbrown): make this work for rectangular dimensions as well.
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65 int numRows = bitMatrix.getDimension();
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66 int numColumns = numRows;
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68 return Version.getVersionForDimensions(numRows, numColumns);
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72 * <p>Reads the bits in the {@link BitMatrix} representing the mapping matrix (No alignment patterns)
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73 * in the correct order in order to reconstitute the codewords bytes contained within the
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74 * Data Matrix Code.</p>
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76 * @return bytes encoded within the Data Matrix Code
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77 * @throws ReaderException if the exact number of bytes expected is not read
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79 byte[] readCodewords() throws ReaderException {
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81 byte[] result = new byte[version.getTotalCodewords()];
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82 int resultOffset = 0;
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86 // TODO(bbrown): Data Matrix can be rectangular, assuming square for now
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87 int numRows = mappingBitMatrix.getDimension();
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88 int numColumns = numRows;
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90 boolean corner1Read = false;
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91 boolean corner2Read = false;
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92 boolean corner3Read = false;
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93 boolean corner4Read = false;
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95 // Read all of the codewords
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97 // Check the four corner cases
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98 if ((row == numRows) && (column == 0) && !corner1Read) {
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99 result[resultOffset++] = (byte) readCorner1(numRows, numColumns);
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102 corner1Read = true;
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103 } else if ((row == numRows-2) && (column == 0) && ((numColumns & 0x03) != 0) && !corner2Read) {
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104 result[resultOffset++] = (byte) readCorner2(numRows, numColumns);
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107 corner2Read = true;
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108 } else if ((row == numRows+4) && (column == 2) && ((numColumns & 0x07) == 0) && !corner3Read) {
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109 result[resultOffset++] = (byte) readCorner3(numRows, numColumns);
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112 corner3Read = true;
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113 } else if ((row == numRows-2) && (column == 0) && ((numColumns & 0x07) == 4) && !corner4Read) {
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114 result[resultOffset++] = (byte) readCorner4(numRows, numColumns);
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117 corner4Read = true;
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119 // Sweep upward diagonally to the right
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121 if ((row < numRows) && (column >= 0) && !readMappingMatrix.get(row, column)) {
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122 result[resultOffset++] = (byte) readUtah(row, column, numRows, numColumns);
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126 } while ((row >= 0) && (column < numColumns));
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130 // Sweep downward diagonally to the left
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132 if ((row >= 0) && (column < numColumns) && !readMappingMatrix.get(row, column)) {
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133 result[resultOffset++] = (byte) readUtah(row, column, numRows, numColumns);
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137 } while ((row < numRows) && (column >= 0));
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141 } while ((row < numRows) || (column < numColumns));
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143 if (resultOffset != version.getTotalCodewords()) {
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144 throw ReaderException.getInstance();
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150 * <p>Reads a bit of the mapping matrix accounting for boundary wrapping.</p>
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152 * @param row Row to read in the mapping matrix
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153 * @param column Column to read in the mapping matrix
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154 * @param numRows Number of rows in the mapping matrix
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155 * @param numColumns Number of columns in the mapping matrix
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156 * @return value of the given bit in the mapping matrix
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158 boolean readModule(int row, int column, int numRows, int numColumns) {
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159 // Adjust the row and column indices based on boundary wrapping
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162 column += 4 - ((numRows + 4) & 0x07);
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165 column += numColumns;
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166 row += 4 - ((numColumns + 4) & 0x07);
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168 readMappingMatrix.set(row, column);
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169 return mappingBitMatrix.get(row, column);
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173 * <p>Reads the 8 bits of the standard utah shaped pattern.</p>
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175 * <p>See ISO 16022:2006, 5.8.1 Figure 6</p>
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177 * @param row Current row in the mapping matrix, anchored at the 8th bit (LSB) of the pattern
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178 * @param column Current column in the mapping matrix, anchored at the 8th bit (LSB) of the pattern
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179 * @param numRows Number of rows in the mapping matrix
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180 * @param numColumns Number of columns in the mapping matrix
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181 * @return byte from the utah shape
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183 int readUtah(int row, int column, int numRows, int numColumns) {
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184 int currentByte = 0;
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185 if (readModule(row - 2, column - 2, numRows, numColumns)) {
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189 if (readModule(row - 2, column - 1, numRows, numColumns)) {
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193 if (readModule(row - 1, column - 2, numRows, numColumns)) {
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197 if (readModule(row - 1, column - 1, numRows, numColumns)) {
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201 if (readModule(row - 1, column, numRows, numColumns)) {
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205 if (readModule(row, column - 2, numRows, numColumns)) {
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209 if (readModule(row, column - 1, numRows, numColumns)) {
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213 if (readModule(row, column, numRows, numColumns)) {
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216 return currentByte;
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220 * <p>Reads the 8 bits of the special corner condition 1.</p>
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222 * <p>See ISO 16022:2006, Figure F.3</p>
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224 * @param numRows Number of rows in the mapping matrix
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225 * @param numColumns Number of columns in the mapping matrix
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226 * @return byte from the Corner condition 1
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228 int readCorner1(int numRows, int numColumns) {
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229 int currentByte = 0;
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230 if (readModule(numRows - 1, 0, numRows, numColumns)) {
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234 if (readModule(numRows - 1, 1, numRows, numColumns)) {
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238 if (readModule(numRows - 1, 2, numRows, numColumns)) {
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242 if (readModule(0, numColumns - 2, numRows, numColumns)) {
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246 if (readModule(0, numColumns - 1, numRows, numColumns)) {
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250 if (readModule(1, numColumns - 1, numRows, numColumns)) {
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254 if (readModule(2, numColumns - 1, numRows, numColumns)) {
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258 if (readModule(3, numColumns - 1, numRows, numColumns)) {
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261 return currentByte;
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265 * <p>Reads the 8 bits of the special corner condition 2.</p>
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267 * <p>See ISO 16022:2006, Figure F.4</p>
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269 * @param numRows Number of rows in the mapping matrix
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270 * @param numColumns Number of columns in the mapping matrix
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271 * @return byte from the Corner condition 2
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273 int readCorner2(int numRows, int numColumns) {
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274 int currentByte = 0;
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275 if (readModule(numRows - 3, 0, numRows, numColumns)) {
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279 if (readModule(numRows - 2, 0, numRows, numColumns)) {
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283 if (readModule(numRows - 1, 0, numRows, numColumns)) {
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287 if (readModule(0, numColumns - 4, numRows, numColumns)) {
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291 if (readModule(0, numColumns - 3, numRows, numColumns)) {
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295 if (readModule(0, numColumns - 2, numRows, numColumns)) {
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299 if (readModule(0, numColumns - 1, numRows, numColumns)) {
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303 if (readModule(1, numColumns - 1, numRows, numColumns)) {
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306 return currentByte;
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310 * <p>Reads the 8 bits of the special corner condition 3.</p>
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312 * <p>See ISO 16022:2006, Figure F.5</p>
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314 * @param numRows Number of rows in the mapping matrix
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315 * @param numColumns Number of columns in the mapping matrix
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316 * @return byte from the Corner condition 3
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318 int readCorner3(int numRows, int numColumns) {
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319 int currentByte = 0;
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320 if (readModule(numRows - 1, 0, numRows, numColumns)) {
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324 if (readModule(numRows - 1, numColumns - 1, numRows, numColumns)) {
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328 if (readModule(0, numColumns - 3, numRows, numColumns)) {
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332 if (readModule(0, numColumns - 2, numRows, numColumns)) {
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336 if (readModule(0, numColumns - 1, numRows, numColumns)) {
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340 if (readModule(1, numColumns - 3, numRows, numColumns)) {
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344 if (readModule(1, numColumns - 2, numRows, numColumns)) {
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348 if (readModule(1, numColumns - 1, numRows, numColumns)) {
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351 return currentByte;
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355 * <p>Reads the 8 bits of the special corner condition 4.</p>
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357 * <p>See ISO 16022:2006, Figure F.6</p>
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359 * @param numRows Number of rows in the mapping matrix
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360 * @param numColumns Number of columns in the mapping matrix
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361 * @return byte from the Corner condition 4
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363 int readCorner4(int numRows, int numColumns) {
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364 int currentByte = 0;
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365 if (readModule(numRows - 3, 0, numRows, numColumns)) {
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369 if (readModule(numRows - 2, 0, numRows, numColumns)) {
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373 if (readModule(numRows - 1, 0, numRows, numColumns)) {
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377 if (readModule(0, numColumns - 2, numRows, numColumns)) {
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381 if (readModule(0, numColumns - 1, numRows, numColumns)) {
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385 if (readModule(1, numColumns - 1, numRows, numColumns)) {
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389 if (readModule(2, numColumns - 1, numRows, numColumns)) {
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393 if (readModule(3, numColumns - 1, numRows, numColumns)) {
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396 return currentByte;
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400 * <p>Extracts the data region from a {@link BitMatrix} that contains
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401 * alignment patterns.</p>
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403 * @param bitMatrix Original {@link BitMatrix} with alignment patterns
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404 * @return BitMatrix that has the alignment patterns removed
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406 BitMatrix extractDataRegion(BitMatrix bitMatrix) {
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407 int symbolSizeRows = version.getSymbolSizeRows();
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408 int symbolSizeColumns = version.getSymbolSizeColumns();
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410 // TODO(bbrown): Make this work with rectangular codes
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411 if (bitMatrix.getDimension() != symbolSizeRows) {
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412 throw new IllegalArgumentException("Dimension of bitMarix must match the version size");
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415 int dataRegionSizeRows = version.getDataRegionSizeRows();
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416 int dataRegionSizeColumns = version.getDataRegionSizeColumns();
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418 int numDataRegionsRow = symbolSizeRows / dataRegionSizeRows;
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419 int numDataRegionsColumn = symbolSizeColumns / dataRegionSizeColumns;
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421 int sizeDataRegionRow = numDataRegionsRow * dataRegionSizeRows;
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422 //int sizeDataRegionColumn = numDataRegionsColumn * dataRegionSizeColumns;
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424 // TODO(bbrown): Make this work with rectangular codes
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425 BitMatrix bitMatrixWithoutAlignment = new BitMatrix(sizeDataRegionRow);
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426 for (int dataRegionRow = 0; dataRegionRow < numDataRegionsRow; ++dataRegionRow) {
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427 int dataRegionRowOffset = dataRegionRow * dataRegionSizeRows;
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428 for (int dataRegionColumn = 0; dataRegionColumn < numDataRegionsColumn; ++dataRegionColumn) {
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429 int dataRegionColumnOffset = dataRegionColumn * dataRegionSizeColumns;
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430 for (int i = 0; i < dataRegionSizeRows; ++i) {
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431 int readRowOffset = dataRegionRow * (dataRegionSizeRows + 2) + 1 + i;
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432 int writeRowOffset = dataRegionRowOffset + i;
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433 for (int j = 0; j < dataRegionSizeColumns; ++j) {
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434 int readColumnOffset = dataRegionColumn * (dataRegionSizeColumns + 2) + 1 + j;
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435 if (bitMatrix.get(readRowOffset, readColumnOffset)) {
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436 int writeColumnOffset = dataRegionColumnOffset + j;
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437 bitMatrixWithoutAlignment.set(writeRowOffset, writeColumnOffset);
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443 return bitMatrixWithoutAlignment;
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