[Discuss-gnuradio] Processing block with conditional number of output items

[Price, Nathan D. (S&T-Student)]

Hello all,


I'm  a grad student writing my first GNU Radio processing block, and I'm a 
little stuck.  I'm not sure how to tell GNU Radio the input output relationship 
of my block.

The block takes 2 inputs.  One is an index, and the other is data (I may use 
stream tags to indicate index in the future).  The block also has one output 
port of processed data.  The block needs to buffer a small history of inputs 
then search through for matching indexes.  When it finds a matching pair of 
indexes, it processes the 2 pieces of data corresponding to the two matching 
indexes (i.e. has the same position in the buffer) and produces 1 output.  The 
trouble is, there is no guarantee it will find a match.  The result is that 
sometimes there is no output, and sometimes there are multiple outputs.  I'm 
not sure how to setup GNU Radio's buffers to accommodate this.

I'm getting close to a solution, but I thought I'd ask here.  So, if I wanted 
to buffer say 8 index and 8 data items, and then arbitrarily pluck matching 
data from the input buffer to process and put on the output buffer, how would 
you recommend I go about it?

Thanks,
Nate