/// <summary>
/// Split and compress the complete virtual channel data into chunk data.
/// </summary>
/// <param name="completeData">The compete virtual channel data. This argument can be null.</param>
/// <returns>The splitted chunk data.</returns>
internal ChannelChunk[] SplitToChunks(byte[] completeData, int maxBit =16)
{
if (completeData == null || completeData.Length <= 0)
{
return null;
}
// calculate the number of the chunks
int chunkNum = (int)(completeData.Length / maxChunkSize);
if ((completeData.Length % maxChunkSize) != 0)
{
chunkNum++;
}
ChannelChunk[] chunks = new ChannelChunk[chunkNum];
uint chunkSize = maxChunkSize;
// fill the chunks except the last one
for (int i = 0; i < chunkNum; i++)
{
if (i == chunkNum - 1) // the last chunk
{
chunkSize = (uint)(completeData.Length - maxChunkSize * i);
}
byte[] chunkData = new byte[chunkSize];
Array.Copy(completeData, maxChunkSize * i, chunkData, 0, chunkSize);
chunks[i].channelPduHeader.length = (uint)completeData.Length;
if (mppcCompressor != null && channelOptions == Channel_Options.COMPRESS) // has compression
{
CompressMode flag;
chunks[i].chunkData = mppcCompressor.Compress(chunkData, out flag);
if ((flag & CompressMode.Compressed) == CompressMode.Compressed)
{
chunks[i].channelPduHeader.flags |= CHANNEL_PDU_HEADER_flags_Values.CHANNEL_PACKET_COMPRESSED;
}
if ((flag & CompressMode.Flush) == CompressMode.Flush)
{
chunks[i].channelPduHeader.flags |= CHANNEL_PDU_HEADER_flags_Values.CHANNEL_PACKET_FLUSHED;
}
if ((flag & CompressMode.SetToFront) == CompressMode.SetToFront)
{
chunks[i].channelPduHeader.flags |= CHANNEL_PDU_HEADER_flags_Values.CHANNEL_PACKET_AT_FRONT;
}
}
else // no compression
{
chunks[i].chunkData = chunkData;
}
}
// set the first chunk CHANNEL_FLAG_FIRST
chunks[0].channelPduHeader.flags |= CHANNEL_PDU_HEADER_flags_Values.CHANNEL_FLAG_FIRST;
// the last chunk
chunks[chunkNum - 1].channelPduHeader.flags |= CHANNEL_PDU_HEADER_flags_Values.CHANNEL_FLAG_LAST;
return chunks;
}
