/** * <p>Reads the bits in the {@link BitMatrix} representing the finder pattern in the * correct order in order to reconstitute the codewords bytes contained within the * QR Code.</p> * * @return bytes encoded within the QR Code * @throws ReaderException if the exact number of bytes expected is not read */ public sbyte[] readCodewords() { FormatInformation formatInfo = readFormatInformation(); Version version = readVersion(); // Get the data mask for the format used in this QR Code. This will exclude // some bits from reading as we wind through the bit matrix. DataMask dataMask = DataMask.forReference((int)formatInfo.getDataMask()); int dimension = bitMatrix.getDimension(); dataMask.unmaskBitMatrix(bitMatrix.getBits(), dimension); BitMatrix functionPattern = version.buildFunctionPattern(); bool readingUp = true; sbyte[] result = new sbyte[version.getTotalCodewords()]; int resultOffset = 0; int currentByte = 0; int bitsRead = 0; // Read columns in pairs, from right to left for (int j = dimension - 1; j > 0; j -= 2) { if (j == 6) { // Skip whole column with vertical alignment pattern; // saves time and makes the other code proceed more cleanly j--; } // Read alternatingly from bottom to top then top to bottom for (int count = 0; count < dimension; count++) { int i = readingUp ? dimension - 1 - count : count; for (int col = 0; col < 2; col++) { // Ignore bits covered by the function pattern if (!functionPattern.get(i, j - col)) { // Read a bit bitsRead++; currentByte <<= 1; if (bitMatrix.get(i, j - col)) { currentByte |= 1; } // If we've made a whole byte, save it off if (bitsRead == 8) { result[resultOffset++] = (sbyte)currentByte; bitsRead = 0; currentByte = 0; } } } } readingUp = !readingUp; // switch directions } if (resultOffset != version.getTotalCodewords()) { throw new ReaderException(); } return(result); }