Exemplo n.º 1
0
        /// <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.");
            }
        }
Exemplo n.º 2
0
        internal static ByteArray generateECBytes(ByteArray dataBytes, int numEcBytesInBlock)
        {
            int numDataBytes = dataBytes.size();
            int[] toEncode = new int[numDataBytes + numEcBytesInBlock];
            for (int i = 0; i < numDataBytes; i++)
            {
                toEncode[i] = dataBytes.at(i);
            }
            new ReedSolomonEncoder(GF256.QR_CODE_FIELD).encode(toEncode, numEcBytesInBlock);

            ByteArray ecBytes = new ByteArray(numEcBytesInBlock);
            for (int i = 0; i < numEcBytesInBlock; i++)
            {
                ecBytes.set_Renamed(i, toEncode[numDataBytes + i]);
            }
            return ecBytes;
        }