Adding offset to 'Address

[Kim Rostgaard Christensen <krc@greenpc.dk>]

Hi

How does one go about setting a 'Address + (size of other record) to a 
record at runtime ?

In brief, I am switching over "Frametype" in a Ethernet frame record, to 
dynamically assign the next record by type (IPv4,IPv6,ARP, etc.)
My "datablob" is a *u_char from a imported C function.

So I have:

  Raw_Bytes : access Unsigned_Char
  for Ethernet_Header'Address use Raw_Bytes.all'Address;

and additionally need something like:
  for IP_Packet'Address use Raw_Bytes.all'Address + Ethernet_Header'Size;

Also, I am not confident that this _the_ solution, so other approaches 
are very welcome. For those curious about what it is all about, I ran a 
gnathtml on the source and made it available at 
http://krc.greenpc.dk/hovedopgave/html/index.htm

Regards
Kim Rostgaard Christensen