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Core barcode encoding/decoding library
/*
* Copyright 2007 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.
*/
package com.google.zxing.datamatrix.decoder;
import com.google.zxing.FormatException;
import com.google.zxing.common.BitMatrix;
/**
* @author [email protected] (Brian Brown)
*/
final class BitMatrixParser {
private final BitMatrix mappingBitMatrix;
private final BitMatrix readMappingMatrix;
private final Version version;
/**
* @param bitMatrix {@link BitMatrix} to parse
* @throws FormatException if dimension is < 8 or > 144 or not 0 mod 2
*/
BitMatrixParser(BitMatrix bitMatrix) throws FormatException {
int dimension = bitMatrix.getHeight();
if (dimension < 8 || dimension > 144 || (dimension & 0x01) != 0) {
throw FormatException.getFormatInstance();
}
version = readVersion(bitMatrix);
this.mappingBitMatrix = extractDataRegion(bitMatrix);
this.readMappingMatrix = new BitMatrix(this.mappingBitMatrix.getWidth(), this.mappingBitMatrix.getHeight());
}
Version getVersion() {
return version;
}
/**
* Creates the version object based on the dimension of the original bit matrix from
* the datamatrix code.
*
* See ISO 16022:2006 Table 7 - ECC 200 symbol attributes
*
* @param bitMatrix Original {@link BitMatrix} including alignment patterns
* @return {@link Version} encapsulating the Data Matrix Code's "version"
* @throws FormatException if the dimensions of the mapping matrix are not valid
* Data Matrix dimensions.
*/
private static Version readVersion(BitMatrix bitMatrix) throws FormatException {
int numRows = bitMatrix.getHeight();
int numColumns = bitMatrix.getWidth();
return Version.getVersionForDimensions(numRows, numColumns);
}
/**
* Reads the bits in the {@link BitMatrix} representing the mapping matrix (No alignment patterns)
* in the correct order in order to reconstitute the codewords bytes contained within the
* Data Matrix Code.
*
* @return bytes encoded within the Data Matrix Code
* @throws FormatException if the exact number of bytes expected is not read
*/
byte[] readCodewords() throws FormatException {
byte[] result = new byte[version.getTotalCodewords()];
int resultOffset = 0;
int row = 4;
int column = 0;
int numRows = mappingBitMatrix.getHeight();
int numColumns = mappingBitMatrix.getWidth();
boolean corner1Read = false;
boolean corner2Read = false;
boolean corner3Read = false;
boolean corner4Read = false;
// Read all of the codewords
do {
// Check the four corner cases
if ((row == numRows) && (column == 0) && !corner1Read) {
result[resultOffset++] = (byte) readCorner1(numRows, numColumns);
row -= 2;
column += 2;
corner1Read = true;
} else if ((row == numRows - 2) && (column == 0) && ((numColumns & 0x03) != 0) && !corner2Read) {
result[resultOffset++] = (byte) readCorner2(numRows, numColumns);
row -= 2;
column += 2;
corner2Read = true;
} else if ((row == numRows + 4) && (column == 2) && ((numColumns & 0x07) == 0) && !corner3Read) {
result[resultOffset++] = (byte) readCorner3(numRows, numColumns);
row -= 2;
column += 2;
corner3Read = true;
} else if ((row == numRows - 2) && (column == 0) && ((numColumns & 0x07) == 4) && !corner4Read) {
result[resultOffset++] = (byte) readCorner4(numRows, numColumns);
row -= 2;
column += 2;
corner4Read = true;
} else {
// Sweep upward diagonally to the right
do {
if ((row < numRows) && (column >= 0) && !readMappingMatrix.get(column, row)) {
result[resultOffset++] = (byte) readUtah(row, column, numRows, numColumns);
}
row -= 2;
column += 2;
} while ((row >= 0) && (column < numColumns));
row += 1;
column += 3;
// Sweep downward diagonally to the left
do {
if ((row >= 0) && (column < numColumns) && !readMappingMatrix.get(column, row)) {
result[resultOffset++] = (byte) readUtah(row, column, numRows, numColumns);
}
row += 2;
column -= 2;
} while ((row < numRows) && (column >= 0));
row += 3;
column += 1;
}
} while ((row < numRows) || (column < numColumns));
if (resultOffset != version.getTotalCodewords()) {
throw FormatException.getFormatInstance();
}
return result;
}
/**
* Reads a bit of the mapping matrix accounting for boundary wrapping.
*
* @param row Row to read in the mapping matrix
* @param column Column to read in the mapping matrix
* @param numRows Number of rows in the mapping matrix
* @param numColumns Number of columns in the mapping matrix
* @return value of the given bit in the mapping matrix
*/
private boolean readModule(int row, int column, int numRows, int numColumns) {
// Adjust the row and column indices based on boundary wrapping
if (row < 0) {
row += numRows;
column += 4 - ((numRows + 4) & 0x07);
}
if (column < 0) {
column += numColumns;
row += 4 - ((numColumns + 4) & 0x07);
}
readMappingMatrix.set(column, row);
return mappingBitMatrix.get(column, row);
}
/**
* Reads the 8 bits of the standard Utah-shaped pattern.
*
* See ISO 16022:2006, 5.8.1 Figure 6
*
* @param row Current row in the mapping matrix, anchored at the 8th bit (LSB) of the pattern
* @param column Current column in the mapping matrix, anchored at the 8th bit (LSB) of the pattern
* @param numRows Number of rows in the mapping matrix
* @param numColumns Number of columns in the mapping matrix
* @return byte from the utah shape
*/
private int readUtah(int row, int column, int numRows, int numColumns) {
int currentByte = 0;
if (readModule(row - 2, column - 2, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(row - 2, column - 1, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(row - 1, column - 2, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(row - 1, column - 1, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(row - 1, column, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(row, column - 2, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(row, column - 1, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(row, column, numRows, numColumns)) {
currentByte |= 1;
}
return currentByte;
}
/**
* Reads the 8 bits of the special corner condition 1.
*
* See ISO 16022:2006, Figure F.3
*
* @param numRows Number of rows in the mapping matrix
* @param numColumns Number of columns in the mapping matrix
* @return byte from the Corner condition 1
*/
private int readCorner1(int numRows, int numColumns) {
int currentByte = 0;
if (readModule(numRows - 1, 0, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(numRows - 1, 1, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(numRows - 1, 2, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(0, numColumns - 2, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(0, numColumns - 1, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(1, numColumns - 1, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(2, numColumns - 1, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(3, numColumns - 1, numRows, numColumns)) {
currentByte |= 1;
}
return currentByte;
}
/**
* Reads the 8 bits of the special corner condition 2.
*
* See ISO 16022:2006, Figure F.4
*
* @param numRows Number of rows in the mapping matrix
* @param numColumns Number of columns in the mapping matrix
* @return byte from the Corner condition 2
*/
private int readCorner2(int numRows, int numColumns) {
int currentByte = 0;
if (readModule(numRows - 3, 0, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(numRows - 2, 0, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(numRows - 1, 0, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(0, numColumns - 4, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(0, numColumns - 3, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(0, numColumns - 2, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(0, numColumns - 1, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(1, numColumns - 1, numRows, numColumns)) {
currentByte |= 1;
}
return currentByte;
}
/**
* Reads the 8 bits of the special corner condition 3.
*
* See ISO 16022:2006, Figure F.5
*
* @param numRows Number of rows in the mapping matrix
* @param numColumns Number of columns in the mapping matrix
* @return byte from the Corner condition 3
*/
private int readCorner3(int numRows, int numColumns) {
int currentByte = 0;
if (readModule(numRows - 1, 0, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(numRows - 1, numColumns - 1, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(0, numColumns - 3, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(0, numColumns - 2, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(0, numColumns - 1, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(1, numColumns - 3, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(1, numColumns - 2, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(1, numColumns - 1, numRows, numColumns)) {
currentByte |= 1;
}
return currentByte;
}
/**
* Reads the 8 bits of the special corner condition 4.
*
* See ISO 16022:2006, Figure F.6
*
* @param numRows Number of rows in the mapping matrix
* @param numColumns Number of columns in the mapping matrix
* @return byte from the Corner condition 4
*/
private int readCorner4(int numRows, int numColumns) {
int currentByte = 0;
if (readModule(numRows - 3, 0, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(numRows - 2, 0, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(numRows - 1, 0, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(0, numColumns - 2, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(0, numColumns - 1, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(1, numColumns - 1, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(2, numColumns - 1, numRows, numColumns)) {
currentByte |= 1;
}
currentByte <<= 1;
if (readModule(3, numColumns - 1, numRows, numColumns)) {
currentByte |= 1;
}
return currentByte;
}
/**
* Extracts the data region from a {@link BitMatrix} that contains
* alignment patterns.
*
* @param bitMatrix Original {@link BitMatrix} with alignment patterns
* @return BitMatrix that has the alignment patterns removed
*/
private BitMatrix extractDataRegion(BitMatrix bitMatrix) {
int symbolSizeRows = version.getSymbolSizeRows();
int symbolSizeColumns = version.getSymbolSizeColumns();
if (bitMatrix.getHeight() != symbolSizeRows) {
throw new IllegalArgumentException("Dimension of bitMarix must match the version size");
}
int dataRegionSizeRows = version.getDataRegionSizeRows();
int dataRegionSizeColumns = version.getDataRegionSizeColumns();
int numDataRegionsRow = symbolSizeRows / dataRegionSizeRows;
int numDataRegionsColumn = symbolSizeColumns / dataRegionSizeColumns;
int sizeDataRegionRow = numDataRegionsRow * dataRegionSizeRows;
int sizeDataRegionColumn = numDataRegionsColumn * dataRegionSizeColumns;
BitMatrix bitMatrixWithoutAlignment = new BitMatrix(sizeDataRegionColumn, sizeDataRegionRow);
for (int dataRegionRow = 0; dataRegionRow < numDataRegionsRow; ++dataRegionRow) {
int dataRegionRowOffset = dataRegionRow * dataRegionSizeRows;
for (int dataRegionColumn = 0; dataRegionColumn < numDataRegionsColumn; ++dataRegionColumn) {
int dataRegionColumnOffset = dataRegionColumn * dataRegionSizeColumns;
for (int i = 0; i < dataRegionSizeRows; ++i) {
int readRowOffset = dataRegionRow * (dataRegionSizeRows + 2) + 1 + i;
int writeRowOffset = dataRegionRowOffset + i;
for (int j = 0; j < dataRegionSizeColumns; ++j) {
int readColumnOffset = dataRegionColumn * (dataRegionSizeColumns + 2) + 1 + j;
if (bitMatrix.get(readColumnOffset, readRowOffset)) {
int writeColumnOffset = dataRegionColumnOffset + j;
bitMatrixWithoutAlignment.set(writeColumnOffset, writeRowOffset);
}
}
}
}
}
return bitMatrixWithoutAlignment;
}
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