public void Send(ICopyable data)
{
//We always use the fragmenting header to signal
//to the receiving end that we support (and want)
//fragmentation.
MemBlock rest = data as MemBlock;
if (null == rest)
{
rest = MemBlock.Copy(data);
}
int len = rest.Length;
if (len > MAX_SEND_SIZE)
{
throw new SendException(true,
System.String.Format("Packet too large: {0}, MaxSize = {1}", len,
MAX_SEND_SIZE));
}
uint crc32 = rest.Read <uint>(Crc32.ComputeChecksum);
//Avoid a RNG operation for now, might need to reconsider
//If we use RNG, we have to touch state, that has thread-safety issues
int id = _wrapped_sender.GetHashCode() ^ rest.GetHashCode();
byte[] header = new byte[HEADER_SIZE - 2];
int off = FragPType.CopyTo(header, 0);
NumberSerializer.WriteInt((int)crc32, header, off);
NumberSerializer.WriteInt(id, header, off + 4);
MemBlock header_mb = MemBlock.Reference(header);
ushort block = 0;
int blocksize = ComputeBlockSize(len);
while (rest.Length > 0)
{
int this_size = System.Math.Min(blocksize, rest.Length);
MemBlock this_block = rest.Slice(0, this_size);
rest = rest.Slice(this_size);
//Check to see if this is the last block:
if (rest.Length == 0)
{
block = (ushort)(block ^ (0x8000)); //Set the highest bit, this is last
}
byte[] block_b = new byte[2];
NumberSerializer.WriteShort((short)block, block_b, 0);
MemBlock block_mb = MemBlock.Reference(block_b);
_wrapped_sender.Send(new CopyList(header_mb, block_mb, this_block));
block += 1;
}
}
protected MemBlock DecodeAndClear(uint crc32, int id, ushort total)
{
ICopyable[] blocks = new ICopyable[total];
bool missing_block = false;
ushort last_idx = (ushort)(total - 1);
for (ushort i = 0; i < last_idx; i++)
{
var key = new Triple <uint, int, ushort>(crc32, id, i);
var this_block = (MemBlock)_fragments.Remove(key);
if (null != this_block)
{
blocks[i] = this_block;
}
else
{
//We are missing one:
missing_block = true;
break;
}
}
//Get the last one:
ushort last_id = (ushort)(last_idx ^ FragmentingSender.LAST_BLOCK_FLAG);
var lastkey = new Triple <uint, int, ushort>(crc32, id, last_id);
var last_block = (MemBlock)_fragments.Remove(lastkey);
blocks[last_idx] = last_block;
missing_block = missing_block || (null == last_block);
MemBlock result = null;
if (false == missing_block)
{
result = MemBlock.Concat(blocks);
uint crc32_ck = result.Read <uint>(Crc32.ComputeChecksum);
if (crc32_ck != crc32)
{
//Something went wrong:
result = null;
}
}
_frag_count.Remove(new Pair <uint, int>(crc32, id));
return(result);
}