[RB] Packet Builder

[Ryan Marcus]

This is my packet builder class, written in REALbasic. I hope this helps anybody who wants to use it. I should get my packet buffer posted soon..

Adding a byte:

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Sub InsertByte(data as integer)
subpacket = subpacket + ChrB(Data)
end sub


Adding a DWORD:

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Sub InsertDWORD(data as string)
subpacket = subpacket + MakeDWORD(data)
End Sub


Making a DWORD:

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Protected Function MakeDWORD(data as string) as string
  Dim tmp  as String
  Dim a  as String
  Dim B  as String
  Dim c  as String
  Dim D  as String
  DIM varMakeDWORD as String
  tmp = Right(chr(0) + chr(0) + chr(0) + chr(0) + chr(0) + chr(0) + chr(0) + chr(0) + tohex(Data), 8)
  a = Mid(tmp, 1, 2)
  B = Mid(tmp, 3, 2)
  c = Mid(tmp, 5, 2)
  D = Mid(tmp, 7, 2)
  varMakeDWORD=Chr(Val("&H" + D))
  varMakeDWORD= varMakeDWORD + Chr(Val("&H" + c))
  varMakeDWORD= varMakeDWORD + Chr(Val("&H" + B))
  varMakeDWORD= varMakeDWORD + Chr(Val("&H" + a))
  Return varMakeDWORD
End Function


Insert a string:

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Sub InsertString(data as string, NT as boolean)
  Select case NT
  case true
    subpacket = subpacket + data + chr(0)
  case false
    subpacket = subpacket + data
  end Select
End Sub


Insert a word:

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Sub InsertWORD(data as integer)
subpacket = subpacket + MakeWord(data)
End Sub


Make a word:

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Protected Function MakeWORD(data as integer) as string
  Dim tmp  as String
  Dim a  as String
  Dim B  as String
  DIM varMakeWORD as String
  tmp = Right(chr(0) + chr(0) + chr(0) + chr(0) + hex(Data), 4)
  a = Mid(tmp, 1, 2)
  B = Mid(tmp, 3, 2)
  varMakeWORD=Chr( Val("&H" + B) )
  varMakeWORD= varMakeWORD + Chr( Val("&H" + a) )
  Return varMakeWORD
End Function


To hex:

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Private Function ToHex(data as string) as string
  Dim i  as Integer
  DIM varToHex as String
  For i =  1 To Len(Data)
    varToHex= varToHex + Right("00" + hex(Asc(Mid(Data, i, 1))), 2)
  Next
  Return varToHex
End Function


Applying BNCS headers:

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Sub ApplyHeaders(MessageID as integer)
  headers = chr(&HFF) + chr(MessageID)
  headers = headers + MakeWord(LenB(subpacket) + lenB(Headers) + 2)
  subpacket = headers + subpacket
End Sub


Applying BNLS headers:

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Sub ApplyHeadersBNLS(MessageID as integer)
  headers = MakeWord(lenb(subpacket) + 3) // Include the WORD and the message id byte
  headers = headers + chr(MessageID)
  subpacket = headers + subpacket
End Sub


Getting the packet to write out:

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Function GetPacket() as string
return subpacket
End Function


You will need the following properties:
headers as string (Public)
subpacket as string (Public)


I hope these help!