void handleServerMessage(IAsyncResult result)
{
int receivedCount;
try
{
receivedCount = connection.Client.EndReceive(result);
}
catch
{
//if there was any issue reading the server text, ignore the message (what else can we do?)
return;
}
//0 bytes received means the server disconnected
if (receivedCount == 0)
{
this.Disconnect();
return;
}
//list of bytes which aren't telnet sequences
//ultimately, this will be the original buffer minus any telnet messages from the server
List <byte> contentBytes = this.telnetParser.HandleAndRemoveTelnetBytes(this.buffer, receivedCount);
//now we've filtered-out and responded accordingly to any telnet data.
//next, convert the actual MUD content of the message from ASCII to Unicode
string message = AsciiDecoder.AsciiToUnicode(contentBytes.ToArray(), contentBytes.Count);
//run the following on the main thread so that calling code doesn't have to think about threading
if (this.serverMessage != null)
{
List <MUDToken> runs = this.ansiParser.Translate(message, this, telnetParser, TextGrouping);
this.serverMessage(runs);
}
//now that we're done with this message, listen for the next message
connection.Client.BeginReceive(this.buffer, 0, this.buffer.Length, SocketFlags.None, new AsyncCallback(this.handleServerMessage), null);
}
public List <byte> HandleAndRemoveTelnetBytes(byte[] buffer, int receivedCount)
{
//list to hold any bytes which aren't telnet bytes (which will be most of the bytes)
List <byte> contentBytes = new List <byte>();
//we'll scan for telnet control sequences. anything NOT a telnet control sequence will be added to the contentBytes list for later processing.
int currentIndex = 0;
while (currentIndex < receivedCount)
{
//search for an IAC, which may signal the beginning of a telnet message
while (currentIndex < receivedCount && buffer[currentIndex] != (byte)Telnet.InterpretAsCommand)
{
contentBytes.Add(buffer[currentIndex]);
currentIndex++;
}
//if at the end of the data, stop. otherwise we've encountered an IAC and there should be at least one more byte here
if (++currentIndex == receivedCount)
{
break;
}
//read the next byte
byte secondByte = buffer[currentIndex];
//if another IAC, then this was just sequence IAC IAC, which is the escape sequence to represent byte value 255 (=IAC) in the content stream
if (secondByte == (byte)Telnet.InterpretAsCommand)
{
//write byte value 255 to the content stream and move on
contentBytes.Add(secondByte);
}
//otherwise we have a "real" telnet sequence, where the second byte is a command or negotiation
else
{
//DO
if (secondByte == (byte)Telnet.DO ||
secondByte == (byte)Telnet.DONT ||
secondByte == (byte)Telnet.WILL ||
secondByte == (byte)Telnet.WONT)
{
//what are we being told to do?
currentIndex++;
if (currentIndex == receivedCount)
{
break;
}
byte thirdByte = buffer[currentIndex];
if (secondByte == (byte)Telnet.WILL && thirdByte == (byte)Telnet.SuppressGoAhead)
{
this.sendTelnetBytes((byte)Telnet.DO, thirdByte);
}
}
//subnegotiations
else if (secondByte == (byte)Telnet.SubnegotiationBegin)
{
List <byte> subnegotiationBytes = new List <byte>();
//read until an IAC followed by an SE
while (currentIndex < receivedCount - 1 &&
!(buffer[currentIndex] == (byte)Telnet.InterpretAsCommand && buffer[currentIndex] == (byte)Telnet.SubnegotiationEnd))
{
subnegotiationBytes.Add(buffer[currentIndex]);
currentIndex++;
}
byte[] subnegotiationBytesArray = subnegotiationBytes.ToArray();
//append the content of the subnegotiation to the incoming message report string
AsciiDecoder.AsciiToUnicode(subnegotiationBytesArray, subnegotiationBytes.Count);
}
}
//move up to the next byte in the data
currentIndex++;
}
return(contentBytes);
}