Re: [Discuss-gnuradio] Blocks with different input types

[Eric Blossom]

On Sun, Feb 18, 2007 at 04:37:10PM -0500, Achilleas Anastasopoulos wrote:
> Is it possible to generate a gnuradio block (gr_block)
> with two kinds of inputs (say, shorts and floats)?
> 
> Looking at the contructor, and the gr_io_signature class
> it is not clear how to do that...
> 
> gr_block::gr_block    (       const std::string &      name,
>               gr_io_signature_sptr    input_signature,
>               gr_io_signature_sptr    output_signature
>       )       [protected]
> 
> 
> Thanks
> Achilleas

It's not currently possible, though not too hard to add.
I agree that it would be useful.

The underlying code can deal with different types for the ports.  It
uses the port specific sizeof_stream_item(index) to retrieve the info.
The only thing missing is a way to build a gr_io_signature with different
types for the elements.

Why don't you take a look at the code in gr_io_signature.{h,cc}, and
let me know if you've got any questions about how to make the change.
There are a couple of ways it could go.  Probably the easiest is to
create a std::vector<size_t> indexed by stream index instead of just
using the same d_sizeof_stream_item for all of them.

Eric