Porting from Modula-2 to Ada

[Manuel Collado <m.collado@lml.ls.fi.upm.es>]

We are porting some legacy Modula-2/C code to Ada. The code uses
low-level facilities from Modula-2 and C. We would like to port it to
clean Ada, without interfacing to C code. In addition we would like to
keep the old interface unchanged (if possible).

Al present we are looking for ways to manage memory and binary files as
arrays of bytes. The trouble is that Modula-2 allows the use of relaxed
ARRAY OF BYTE subprogram formal parameters, that are compatible with
actual parameters of any type. Example:

   PROCEDURE Xxx( raw: ARRAY OF BYTE );
      ...
   BEGIN
      FOR  k := 0 TO HIGH(raw) DO
         ... raw[k] ....
      END
   END Xxx;

   Num: INTEGER;
   ...
      Xxx( Num );
   ...


So far, my only porting scheme is to replace ARRAY OF BYTE parameters by
the pair (address, size), as follows:

   procedure Xxx (Raw_Address: System.Address; Raw_Size: Integer) ...

   Num: Integer;
   ...
      Xxx (Num'Address, Num'Size);
   ...

But this requires recoding every call to the procedure. Is there another
way to pass raw data without having to recode every call?

Thanks.
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