/// <summary> Interleave "bits" with corresponding error correction bytes. On success, store the result in /// "result". The interleave rule is complicated. See 8.6 of JISX0510:2004 (p.37) for details. /// </summary> internal static void interleaveWithECBytes(BitVector bits, int numTotalBytes, int numDataBytes, int numRSBlocks, BitVector result) { // "bits" must have "getNumDataBytes" bytes of data. if (bits.sizeInBytes() != numDataBytes) { throw new WriterException("Number of bits and data bytes does not match"); } // Step 1. Divide data bytes into blocks and generate error correction bytes for them. We'll // store the divided data bytes blocks and error correction bytes blocks into "blocks". int dataBytesOffset = 0; int maxNumDataBytes = 0; int maxNumEcBytes = 0; // Since, we know the number of reedsolmon blocks, we can initialize the vector with the number. System.Collections.Generic.List<Object> blocks = new System.Collections.Generic.List<Object>(numRSBlocks); for (int i = 0; i < numRSBlocks; ++i) { int[] numDataBytesInBlock = new int[1]; int[] numEcBytesInBlock = new int[1]; getNumDataBytesAndNumECBytesForBlockID(numTotalBytes, numDataBytes, numRSBlocks, i, numDataBytesInBlock, numEcBytesInBlock); ByteArray dataBytes = new ByteArray(); dataBytes.set_Renamed(bits.Array, dataBytesOffset, numDataBytesInBlock[0]); ByteArray ecBytes = generateECBytes(dataBytes, numEcBytesInBlock[0]); blocks.Add(new BlockPair(dataBytes, ecBytes)); maxNumDataBytes = System.Math.Max(maxNumDataBytes, dataBytes.size()); maxNumEcBytes = System.Math.Max(maxNumEcBytes, ecBytes.size()); dataBytesOffset += numDataBytesInBlock[0]; } if (numDataBytes != dataBytesOffset) { throw new WriterException("Data bytes does not match offset"); } // First, place data blocks. for (int i = 0; i < maxNumDataBytes; ++i) { for (int j = 0; j < blocks.Count; ++j) { ByteArray dataBytes = ((BlockPair) blocks[j]).DataBytes; if (i < dataBytes.size()) { result.appendBits(dataBytes.at(i), 8); } } } // Then, place error correction blocks. for (int i = 0; i < maxNumEcBytes; ++i) { for (int j = 0; j < blocks.Count; ++j) { ByteArray ecBytes = ((BlockPair) blocks[j]).ErrorCorrectionBytes; if (i < ecBytes.size()) { result.appendBits(ecBytes.at(i), 8); } } } if (numTotalBytes != result.sizeInBytes()) { // Should be same. throw new WriterException("Interleaving error: " + numTotalBytes + " and " + result.sizeInBytes() + " differ."); } }
/// <summary> Terminate bits as described in 8.4.8 and 8.4.9 of JISX0510:2004 (p.24).</summary> internal static void terminateBits(int numDataBytes, BitVector bits) { int capacity = numDataBytes << 3; if (bits.size() > capacity) { throw new WriterException("data bits cannot fit in the QR Code" + bits.size() + " > " + capacity); } // Append termination bits. See 8.4.8 of JISX0510:2004 (p.24) for details. // TODO: srowen says we can remove this for loop, since the 4 terminator bits are optional if // the last byte has less than 4 bits left. So it amounts to padding the last byte with zeroes // either way. for (int i = 0; i < 4 && bits.size() < capacity; ++i) { bits.appendBit(0); } int numBitsInLastByte = bits.size() % 8; // If the last byte isn't 8-bit aligned, we'll add padding bits. if (numBitsInLastByte > 0) { int numPaddingBits = 8 - numBitsInLastByte; for (int i = 0; i < numPaddingBits; ++i) { bits.appendBit(0); } } // Should be 8-bit aligned here. if (bits.size() % 8 != 0) { throw new WriterException("Number of bits is not a multiple of 8"); } // If we have more space, we'll fill the space with padding patterns defined in 8.4.9 (p.24). int numPaddingBytes = numDataBytes - bits.sizeInBytes(); for (int i = 0; i < numPaddingBytes; ++i) { if (i % 2 == 0) { bits.appendBits(0xec, 8); } else { bits.appendBits(0x11, 8); } } if (bits.size() != capacity) { throw new WriterException("Bits size does not equal capacity"); } }
public static void encode(System.String content, ErrorCorrectionLevel ecLevel, System.Collections.Generic.Dictionary<Object,Object> hints, QRCode qrCode) { System.String encoding = (hints != null && hints.ContainsKey(EncodeHintType.CHARACTER_SET))?(System.String) hints[EncodeHintType.CHARACTER_SET]:null; if (encoding == null) { encoding = DEFAULT_BYTE_MODE_ENCODING; } // Step 1: Choose the mode (encoding). Mode mode = chooseMode(content, encoding); // Step 2: Append "bytes" into "dataBits" in appropriate encoding. BitVector dataBits = new BitVector(); appendBytes(content, mode, dataBits, encoding); // Step 3: Initialize QR code that can contain "dataBits". int numInputBytes = dataBits.sizeInBytes(); initQRCode(numInputBytes, ecLevel, mode, qrCode); // Step 4: Build another bit vector that contains header and data. BitVector headerAndDataBits = new BitVector(); // Step 4.5: Append ECI message if applicable if (mode == Mode.BYTE && !DEFAULT_BYTE_MODE_ENCODING.Equals(encoding)) { CharacterSetECI eci = CharacterSetECI.getCharacterSetECIByName(encoding); if (eci != null) { appendECI(eci, headerAndDataBits); } } appendModeInfo(mode, headerAndDataBits); int numLetters = mode.Equals(Mode.BYTE)?dataBits.sizeInBytes():content.Length; appendLengthInfo(numLetters, qrCode.Version, mode, headerAndDataBits); headerAndDataBits.appendBitVector(dataBits); // Step 5: Terminate the bits properly. terminateBits(qrCode.NumDataBytes, headerAndDataBits); // Step 6: Interleave data bits with error correction code. BitVector finalBits = new BitVector(); interleaveWithECBytes(headerAndDataBits, qrCode.NumTotalBytes, qrCode.NumDataBytes, qrCode.NumRSBlocks, finalBits); // Step 7: Choose the mask pattern and set to "qrCode". ByteMatrix matrix = new ByteMatrix(qrCode.MatrixWidth, qrCode.MatrixWidth); qrCode.MaskPattern = chooseMaskPattern(finalBits, qrCode.ECLevel, qrCode.Version, matrix); // Step 8. Build the matrix and set it to "qrCode". MatrixUtil.buildMatrix(finalBits, qrCode.ECLevel, qrCode.Version, qrCode.MaskPattern, matrix); qrCode.Matrix = matrix; // Step 9. Make sure we have a valid QR Code. if (!qrCode.Valid) { throw new WriterException("Invalid QR code: " + qrCode.ToString()); } }