binaryDecode with variable number of parameters

[Len Morgan]

Related to my problem with reading binary data from a socket, how do I
handle a variable number of numbers that will come in with binaryDecode?

>> To explain, I get a number in the packet header that tells me there are
>> x number of bytes to follow in this packet.  I know the first byte is a
>> remote ID and the second is a function code.  Based on the function
>> code, the number of two byte integers that follows is going to be (the
>> number of bytes in the message / 2) - 1 (for the function code and
>> remote ID).  One time there might be 2 integers to follow, another there
>> might be 10.  There is a "number of words" number that is part of the
>> command so I know how many words there will be but the binaryDecode
>> function requires that I specify a name for each variable that is going
>> to get a value.
>> Ideally, I'd like to put all of these words in an array so I can process
>> them, but this doesn't seem to be an option for the binaryDecode
>> command.  Should I build up a string that has
>> "...,var[0],var[1],...,var[x] in it to account for all the variables and
>> then use a "do" or "dispatch" to actually do the binaryDecode?
>> Also, if I use var[0], var[1], etc., do I need to create ALL of the
>> indexes first (for binaryDecode) or will just creating the first one
>> (var[0]) be sufficient?
> I think I'd do something like:
>
> read from socket for 1 bytes
> put it into tRemoteID
> read from socket for 1 bytes
> put it into tFunctionCode
> switch tFunctionCode
>    case kFunc1
>      put 2 into tWordCount
>      break
>    case kFunc2
>      put 10 into tWordCount
>      break
>    case -- ok - you get the idea
>      break
> end switch
> read from socket for (2*tWordCount) bytes
> put it into tData
> put binaryDecode("m3", tData, tSeq, tProto, tBytes) into tActual
> if tActual is not tWordCount then
>    -- oops
> end if
>
> ...and yes, you do need to have the maximum number of variables
> already defined. There's no penalty for having extra compartments in
> the binaryDecode line, but you don't want to have too few.
>
Thanks for the reply Mark but it's not quite the problem.  The order 
that the data comes in is:
tSequence, tProto, tBytes (all 16 bit), tRemoteID, tFunctionCode, xxxxx

After the function code, if you are doing a "write multiple registers" 
for example, you will have a beginning register, and the count of 
registers, followed by the actual data you are trying to write.  This is 
where things start to fall down for me because of this variable number 
of items and the requirement to have a predefined variable for each 
possible answer.  I know when I get to the data portion exactly how many 
registers I'm going to have to read (and therefore how many variables 
I'm going to need).  Based on your last paragraph though, it appears 
that I'll have to either have a separate case for each possible number 
of data words, or read them one at a time in a loop and assign them to a 
variable in the loop.  Neither of those is the optimal way to go but one 
must do what one must do.  :-)

Also, do you happen to know about using an array with only one index 
assigned and a "N*" for example in the format string?  Since the array 
exists already (and the first element I'd be assigning to) could I get 
away with passing an array NAME and have it create the extra elements or 
will that doom me to writing an "oops" handler?  I'm grabbing at straws 
here.  :-)

len morgan