Message Buffer for TCP Listener - vb.net

Question

I have a TCP Listener in a vb.net class that listens for data that another program sends out. The problem is it sends the data at a faster rate than my processing routine can process it. The routine will be about half way thru processing the last message and here comes another message on the listening port and it starts the processing without finishing the other message.
I want to add a message buffer so all incoming text strings are placed in a stack and when my processing routine gets done it will pull the next string out of the stack and work with it and then pull the next one until the stack is empty
I'm not sure of the best way to do this. I'm looking to see what someone thinks would be the best way to handle this.
TIA
Rick
Private Sub TCPListening()
Dim CommandString As String = ""
Dim ParamLength As Short
Dim ADIFStr As String = ""
Dim tmpStr As String = ""
Dim tmpBool As Boolean
Dim paramStr As String = ""
Dim xcvrfreq As String = ""
Dim xcvrmode As String = ""
Dim prsvsplit As String = ""
Dim Arr() As String
Dim decimalstr As String = Globalization.CultureInfo.CurrentCulture.NumberFormat.NumberDecimalSeparator
Dim thousandsstr As String = Globalization.CultureInfo.CurrentCulture.NumberFormat.NumberGroupSeparator
If ExternalTcpListener Is Nothing Then
ExternalTcpListener = New TcpListener(IPAddress.Parse(ExternalTCPIP), ExternalTCPPort)
ExternalTcpListener.Start()
End If
Try
Dim responseString As String = ""
Dim sendBytes As [Byte]()
Dim ExternaltcpClient As TcpClient = ExternalTcpListener.AcceptTcpClient()
While True
Debug.Print("Start While")
Dim networkStream As NetworkStream = ExternaltcpClient.GetStream()
Dim bytes(ExternaltcpClient.ReceiveBufferSize) As Byte
networkStream.Read(bytes, 0, CInt(ExternaltcpClient.ReceiveBufferSize))
Dim Sentdata As String = System.Text.Encoding.ASCII.GetString(bytes)
ttimer.start()
Sentdata = Replace(Sentdata, vbNullChar, "")
If Sentdata <> "" Then Debug.Print("SendData= " & Sentdata)
If InStrRev(Sentdata, "<command:") > 8 Then
'<command:10>CmdSetFreq<parameters:23><xcvrfreq:10> 7,185.000<command:10>CmdGetFreq<parameters:0>
'If multiple commands are recieved this section of the routine splits them up and processes each one as seperate commands.
Sentdata = Strings.Replace(Sentdata, "<command", "|<command")
Arr = Split(Sentdata, "|")
Debug.Print(" Arr=" & UBound(Arr))
For x = 1 To UBound(Arr)
Sentdata = Arr(x)
Debug.Print(" New " & Sentdata)
If InStr(Sentdata, "<command") Then
tmpStr = Sentdata
tmpStr = Right(Sentdata, Len(Sentdata) - 1)
CommandString = Extract(tmpStr, ">", "<")
ParamLength = Extract(Sentdata, "<parameters:", ">")
Select Case CommandString
Case "CmdSetFreqMode", "CmdQSXSplit", "CmdSetFreq", "CmdSetTXFreq", "CmdSetMode", "CmdSplit" ', "CmdTX", "CmdRX"
Station.ActiveWindow.SetExternalTCPCommandsInvoke(Sentdata)
'The above commands are processed and handled in EntryWindow.SetExternalTCPCommands
Case "CmdGetFreq"
'<command:10>CmdGetFreq<parameters:0>
Debug.Print("NI1Inside: " & CommandString & " " & Sentdata)
If ParamLength = 0 Then
tmpStr = Format(Val(Station.ActiveRadio.Frequency), "##,###.000")
responseString = "<CmdFreq:" & Len(tmpStr) & ">" & tmpStr
Debug.Print("[R1] " & responseString)
sendBytes = Encoding.ASCII.GetBytes(responseString)
networkStream.Write(sendBytes, 0, sendBytes.Length)
'LogError("CmdGetFreq1Response - ElapsedTime: " & ttimer.ElapsedMilliseconds)
End If
Case "CmdGetTXFreq"
'<command:12>CmdGetTXFreq<parameters:0>
Debug.Print("NIInside: " & CommandString & " " & Sentdata)
If ParamLength = 0 Then
tmpStr = Format(Val(Station.ActiveRadio.TXFreq), "##,###.000")
If Len(tmpStr) = 0 Then
responseString = "<CmdTXFreq:4>.000"
Else
responseString = "<CmdTXFreq:" & Len(tmpStr) & ">" & tmpStr
End If
Debug.Print("[R1] " & responseString)
sendBytes = Encoding.ASCII.GetBytes(responseString)
networkStream.Write(sendBytes, 0, sendBytes.Length)
'LogError("CmdGetTXFreq1Response - ElapsedTime: " & ttimer.ElapsedMilliseconds)
End If
end select
End If
Next
'End If
ElseIf InStr(Sentdata, "command") And InStrRev(Sentdata, "<command:") < 8 Then
'This section of the routine processes single commands that are sent via the Listener
tmpStr = Sentdata
tmpStr= Right(Sentdata, Len(Sentdata) - 1)
CommandString = Extract(tmpStr, ">", "<")
ParamLength = Extract(Sentdata, "parameters:", ">")
Select Case CommandString
Case "CmdSetFreqMode", "CmdQSXSplit", "CmdSetFreq", "CmdSetTXFreq", "CmdSetMode", "CmdSplit" ', "CmdTX", "CmdRX"
Station.ActiveWindow.SetExternalTCPCommandsInvoke(Sentdata)
'The above commands are processed and handled in EntryWindow.SetExternalTCPCommands
Case "CmdGetFreq"
'<command:10>CmdGetFreq<parameters:0>
Debug.Print("NI2Inside: " & CommandString & " " & Sentdata)
If ParamLength = 0 Then
tmpStr = Format(Val(Station.ActiveRadio.Frequency), "##,###.000")
responseString = "<CmdFreq:" & Len(tmpStr) & ">" & tmpStr
Debug.Print("[R] " & responseString)
sendBytes = Encoding.ASCII.GetBytes(responseString)
networkStream.Write(sendBytes, 0, sendBytes.Length)
'LogError("CmdGetFreqResponse - ElapsedTime: " & ttimer.ElapsedMilliseconds)
End If
Case "CmdGetTXFreq"
'<command:12>CmdGetTXFreq<parameters:0>
Debug.Print("NI2Inside: " & CommandString & " " & Sentdata)
If ParamLength = 0 Then
tmpStr = Format(Val(Station.ActiveRadio.TXFreq), "##,###.000")
If Len(tmpStr) = 0 Then
responseString = "<CmdTXFreq:4>.000"
Else
responseString = "<CmdTXFreq:" & Len(tmpStr) & ">" & tmpStr
End If
Debug.Print("[R] " & responseString)
sendBytes = Encoding.ASCII.GetBytes(responseString)
networkStream.Write(sendBytes, 0, sendBytes.Length)
'LogError("CmdGetTXFreqResponse - ElapsedTime: " & ttimer.ElapsedMilliseconds)
End If
There is alot of code missing but it gives you the general idea of what is happening.