WinSock, DataArrival and AnsiToRtf

I'm working on a Mud client (isn't everyone?), and after lots of frigging around I've created some subs/functions to convert an ANSI formatted string to an RTF formatted string. I've made a little test app which just takes ANSI formatted text in a TextBox and when a button is pressed converts it and writes it to a RichTextBox, and it works a treat.

Now I've added it to the mud client, and it works ok for small sections of data but when a large amount is sent in a large piece (I'm not sure if it's sent as one string or if it's several smaller strings and that's what's choking it up), it first displays the text correctly, the displays it again after the correct text with all the RTF formatting showing. This doesn't happen for smaller blocks of text (such as room descriptions, etc). If I turn off page-pausing in my mud character's configuration, then the whole lot coming down the tube at once causes the program to crash with a "Runtime Error 5: Invalid procedure call or argument."

I suspect these problems are the result of how I'm using the Winsock control rather than problems with my AnsiToRtf converter, since if I use an older version of the client (pre-ansi support) to do the same command then copy the ansi text to my test app, it handles it superbly.

Here are the relevant subs/functions (if you need to see more, just holler):

Private Sub Winsock1_DataArrival(ByVal bytesTotal As Long)
    Dim DataArrived As String
    Winsock1.GetData DataArrived, vbString
    If Not paused Then
        OutputText ParseData(DataArrived)
        DoTriggers DataArrived
    Else
        stringBuffer = stringBuffer & DataArrived
    End If
End Sub


Public Function ParseData(ByVal theText As String) As String
    Dim temp As String
    Dim i As Integer
    For i = 1 To Len(theText)
        Select Case Asc(Mid(theText, i, 1))
            Case 0      'null
            Case 1      'echo
                If processCommand Then
                    If theCommand = 251 Then
                        localEcho = False
                        processCommand = False
                        theCommand = -1
                    ElseIf theCommand = 252 Then
                        localEcho = True
                        processCommand = False
                        theCommand = -1
                    End If
                End If
            Case 7      'beep
                Beep
            Case 8      'backspace
            Case 9      'horizontal tab
                temp = temp & Chr(9)
            Case 10     'LF
                temp = temp & vbCrLf
            Case 11     'vertical tab
                temp = temp & vbCrLf & vbCrLf
            Case 12     'form feed
            Case 13     'CR
            Case 251    'will (option code)
                If processCommand Then theCommand = 251
            Case 252    'won't (option code)
                If processCommand Then theCommand = 252
            Case 255    'interpret as command (then one or two chars)
                If processCommand Then      ' if processCommand is already set,
                    temp = temp & Chr(255)  ' then it's an escape sequence for
                    processCommand = False  ' chr(255), so add it to the string.
                Else
                    processCommand = True   ' otherwise, it's an escape seq for
                End If                      ' a command.
            Case Else
                temp = temp & Mid(theText, i, 1)
                processCommand = False
                theCommand = -1
        End Select
    Next i
    ParseData = temp
End Function


Public Sub OutputText(ByVal theText As String)
    theText = "" & theText
    theText = AnsiToRtf(theText)
    OutputBox.SelStart = Len(OutputBox.Text)
    OutputBox.SelRTF = theText
    OutputBox.SelStart = Len(OutputBox.Text)
End Sub


Private Sub DoTriggers(ByVal theText As String)
    Dim i As Integer
    For i = 0 To numTriggers - 1
        If InStr(1, theText, GetTriggerByI(i).trigger, vbTextCompare) > 0 Then
            If GetTriggerByI(i).enabled Then SendData GetTriggerByI(i).action
        End If
    Next i
End Sub


Public Function AnsiToRtf(ByVal str As String) As String
    Dim s, c, a, r, cs As String
    Dim i, j, cc, csc As Integer
    Dim ac As AnsiCodeList
    Dim b As Boolean
    b = False
    cs = "{{\colortbl;\red255\green255\blue255;"
    csc = 2
    For i = 1 To Len(str)   ' do strings start at 0 or 1?
        r = "{\cf1 "
        c = Mid(str, i, 1)
        If c = Chr(27) Then
            r = "{"      ' stop rtf code building up over loop
            j = InStr(i, str, "m", vbTextCompare)  ' get index of end of string
'MsgBox "j=" & j
            a = Mid(str, i, (j - i) + 1)    ' get ansi code from string
            ac = GetCodes(a)
'MsgBox "acCount=" & ac.Count
            cc = GetColour(ac)
'MsgBox "cc=" & cc
            'r =        ' rtf code equivalent to 'a'
            If cc >= 0 And cc <= 15 Then    ' is it a valid colour?
                cs = cs & "\red" & GetColourByI(cc).Red & "\green" & GetColourByI(cc).Green & "\blue" & GetColourByI(cc).Blue & ";"
                r = r & "\cf" & csc & " "
                csc = csc + 1
                If b Then s = s & "}"    ' closes previous rtf code
            End If
   
            s = s & r   ' appends rtf code to new string
            i = j       ' go to next char after the code. the Next i line
                        ' will add 1 to this.
            b = True
       
        ElseIf c = Chr(13) Then
            If b Then
                s = s & "\par"  ' if it's inside {} it needs \par instead of vbcrlf
            End If
        ElseIf c = "\" Then
            c = "{\\}"
            s = s & c
        Else
            s = s & c ' if it's a normal character just append it to the new string
        End If
    Next i
    cs = cs & "}"   ' close colortbl string
    'if b then
    s = s & "}}"  ' if rtf has been opened, close it
    AnsiToRtf = cs & s   ' the new string
End Function



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I suspect that the problem is the DataArrival event being triggered faster than the data can be processed, but I have no idea how to test this, and for all I know the Winsock control deals with it automatically. It's just a suspicion of mine.

What do I need to do to stop long and/or rapid DataArrival events and subsequent actions from dropping dead?