/** * Decodes a Data Matrix Code represented as a {@link BitMatrix}. A 1 or "true" is taken to mean a * black module. * * @param bits booleans representing white/black Data Matrix Code modules * @return text and bytes encoded within the Data Matrix Code * @throws FormatException if the Data Matrix Code cannot be decoded * @throws ChecksumException if error correction fails */ public DecoderResult decode(BitMatrix bits) throws FormatException, ChecksumException { // Construct a parser and read version, error-correction level BitMatrixParser parser = new BitMatrixParser(bits); Version version = parser.getVersion(); // Read codewords byte[] codewords = parser.readCodewords(); // Separate into data blocks DataBlock[] dataBlocks = DataBlock.getDataBlocks(codewords, version); // Count total number of data bytes int totalBytes = 0; for (int i = 0; i < dataBlocks.length; i++) { totalBytes += dataBlocks[i].getNumDataCodewords(); } byte[] resultBytes = new byte[totalBytes]; int resultOffset = 0; // Error-correct and copy data blocks together into a stream of bytes for (int j = 0; j < dataBlocks.length; j++) { DataBlock dataBlock = dataBlocks[j]; byte[] codewordBytes = dataBlock.getCodewords(); int numDataCodewords = dataBlock.getNumDataCodewords(); correctErrors(codewordBytes, numDataCodewords); for (int i = 0; i < numDataCodewords; i++) { resultBytes[resultOffset++] = codewordBytes[i]; } } // Decode the contents of that stream of bytes return DecodedBitStreamParser.decode(resultBytes); }
private DecoderResult decode(BitMatrixParser parser, Map<DecodeHintType, ?> hints) throws FormatException, ChecksumException { Version version = parser.readVersion(); ErrorCorrectionLevel ecLevel = parser.readFormatInformation().getErrorCorrectionLevel(); // Read codewords byte[] codewords = parser.readCodewords(); // Separate into data blocks DataBlock[] dataBlocks = DataBlock.getDataBlocks(codewords, version, ecLevel); // Count total number of data bytes int totalBytes = 0; for (DataBlock dataBlock : dataBlocks) { totalBytes += dataBlock.getNumDataCodewords(); } byte[] resultBytes = new byte[totalBytes]; int resultOffset = 0; // Error-correct and copy data blocks together into a stream of bytes for (DataBlock dataBlock : dataBlocks) { byte[] codewordBytes = dataBlock.getCodewords(); int numDataCodewords = dataBlock.getNumDataCodewords(); correctErrors(codewordBytes, numDataCodewords); for (int i = 0; i < numDataCodewords; i++) { resultBytes[resultOffset++] = codewordBytes[i]; } } // Decode the contents of that stream of bytes return DecodedBitStreamParser.decode(resultBytes, version, ecLevel, hints); }
/** * Decodes a PDF417 Code represented as a {@link BitMatrix}. A 1 or "true" is taken to mean a * black module. * * @param bits booleans representing white/black PDF417 Code modules * @return text and bytes encoded within the PDF417 Code * @throws FormatException if the PDF417 Code cannot be decoded */ public DecoderResult decode(BitMatrix bits) throws FormatException { // Construct a parser to read the data codewords and error-correction level BitMatrixParser parser = new BitMatrixParser(bits); int[] codewords = parser.readCodewords(); if (codewords == null || codewords.length == 0) { throw FormatException.getFormatInstance(); } int ecLevel = parser.getECLevel(); int numECCodewords = 1 << (ecLevel + 1); int[] erasures = parser.getErasures(); correctErrors(codewords, erasures, numECCodewords); verifyCodewordCount(codewords, numECCodewords); // Decode the codewords return DecodedBitStreamParser.decode(codewords); }
/** * Decodes a QR Code represented as a {@link BitMatrix}. A 1 or "true" is taken to mean a black * module. * * @param bits booleans representing white/black QR Code modules * @param hints decoding hints that should be used to influence decoding * @return text and bytes encoded within the QR Code * @throws FormatException if the QR Code cannot be decoded * @throws ChecksumException if error correction fails */ public DecoderResult decode(BitMatrix bits, Map<DecodeHintType, ?> hints) throws FormatException, ChecksumException { // Construct a parser and read version, error-correction level BitMatrixParser parser = new BitMatrixParser(bits); FormatException fe = null; ChecksumException ce = null; try { return decode(parser, hints); } catch (FormatException e) { fe = e; } catch (ChecksumException e) { ce = e; } try { // Revert the bit matrix parser.remask(); // Will be attempting a mirrored reading of the version and format info. parser.setMirror(true); // Preemptively read the version. parser.readVersion(); // Preemptively read the format information. parser.readFormatInformation(); /* * Since we're here, this means we have successfully detected some kind * of version and format information when mirrored. This is a good sign, * that the QR code may be mirrored, and we should try once more with a * mirrored content. */ // Prepare for a mirrored reading. parser.mirror(); DecoderResult result = decode(parser, hints); // Success! Notify the caller that the code was mirrored. result.setOther(new QRCodeDecoderMetaData(true)); return result; } catch (FormatException | ChecksumException e) { // Throw the exception from the original reading if (fe != null) { throw fe; } if (ce != null) { throw ce; } throw e; } }