| public toBytes ( int bitOffset, byte array, int offset, int numBytes ) : void | ||
| bitOffset | int | first bit to start writing |
| array | byte | array to write into. Bytes are written most-significant byte first. This is the opposite /// of the internal representation, which is exposed by BitArray |
| offset | int | position in array to start writing |
| numBytes | int | how many bytes to write |
| return | void | |
/// <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>
/// <param name="bits">The bits.</param>
/// <param name="numTotalBytes">The num total bytes.</param>
/// <param name="numDataBytes">The num data bytes.</param>
/// <param name="numRSBlocks">The num RS blocks.</param>
/// <returns></returns>
internal static BitArray interleaveWithECBytes(BitArray bits,
int numTotalBytes,
int numDataBytes,
int numRSBlocks)
{
// "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.
var blocks = new List<BlockPair>(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);
int size = numDataBytesInBlock[0];
byte[] dataBytes = new byte[size];
bits.toBytes(8 * dataBytesOffset, dataBytes, 0, size);
byte[] ecBytes = generateECBytes(dataBytes, numEcBytesInBlock[0]);
blocks.Add(new BlockPair(dataBytes, ecBytes));
maxNumDataBytes = Math.Max(maxNumDataBytes, size);
maxNumEcBytes = Math.Max(maxNumEcBytes, ecBytes.Length);
dataBytesOffset += numDataBytesInBlock[0];
}
if (numDataBytes != dataBytesOffset)
{
throw new WriterException("Data bytes does not match offset");
}
BitArray result = new BitArray();
// First, place data blocks.
for (int i = 0; i < maxNumDataBytes; ++i)
{
foreach (BlockPair block in blocks)
{
byte[] dataBytes = block.DataBytes;
if (i < dataBytes.Length)
{
result.appendBits(dataBytes[i], 8);
}
}
}
// Then, place error correction blocks.
for (int i = 0; i < maxNumEcBytes; ++i)
{
foreach (BlockPair block in blocks)
{
byte[] ecBytes = block.ErrorCorrectionBytes;
if (i < ecBytes.Length)
{
result.appendBits(ecBytes[i], 8);
}
}
}
if (numTotalBytes != result.SizeInBytes)
{ // Should be same.
throw new WriterException("Interleaving error: " + numTotalBytes + " and " +
result.SizeInBytes + " differ.");
}
return result;
}
private static BitArray interleaveWithECBytes(BitArray bits, int numTotalBytes, int numDataBytes, int numRSBlocks)
{
// 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.
var blocks = new List<Tuple<byte[], byte[]>>(numRSBlocks);
for (int i = 0; i < numRSBlocks; ++i)
{
int numDataBytesInBlock;
int numEcBytesInBlock;
getNumDataBytesAndNumECBytesForBlockID(
numTotalBytes, numDataBytes, numRSBlocks, i,
out numDataBytesInBlock, out numEcBytesInBlock);
byte[] dataBytes = new byte[numDataBytesInBlock];
bits.toBytes(8 * dataBytesOffset, dataBytes, 0, numDataBytesInBlock);
byte[] ecBytes = generateECBytes(dataBytes, numEcBytesInBlock);
blocks.Add(new Tuple<byte[], byte[]>(dataBytes, ecBytes));
maxNumDataBytes = Math.Max(maxNumDataBytes, numDataBytesInBlock);
maxNumEcBytes = Math.Max(maxNumEcBytes, ecBytes.Length);
dataBytesOffset += numEcBytesInBlock;
}
BitArray result = new BitArray();
// First, place data blocks.
for (int i = 0; i < maxNumDataBytes; ++i)
{
foreach (Tuple<byte[], byte[]> block in blocks)
{
byte[] dataBytes = block.Item1;
if (i < dataBytes.Length)
{
result.appendBits(dataBytes[i], 8);
}
}
}
// Then, place error correction blocks.
for (int i = 0; i < maxNumEcBytes; ++i)
{
foreach (Tuple<byte[], byte[]> block in blocks)
{
byte[] ecBytes = block.Item2;
if (i < ecBytes.Length)
{
result.appendBits(ecBytes[i], 8);
}
}
}
return result;
}