Re: Will Ada-95 Programs Written in MS Windows Run in MacOS and Linux Without Some Tweaking.

[Simon Wright <simon@pushface.org>]

Austin Obyrne <austin.obyrne@hotmail.com> writes:

> Could I ask you to start again and download "SureCrypt Cipher" from 
>
> http://www.adacryptpages.com

Things are not as good as I'd hoped.

The programs build OK (aside from a warning or two), but
general_decryption_program_mark_1 fails immediately with

   Execution terminated by unhandled exception
   Exception name: STORAGE_ERROR
   Message: stack overflow

at the start of the main program. This is usually a symptom of not
having enough stack space, caused (in your case) by having lots of large
arrays in the main program, not helped by initialising them - there was
a recent thread[1] here about this.

On the Mac there's a default stack limit of 8Mb; other OS's will have
different limits, if limits at all.

After poking at this for some time, there are two solutions:

(a) move all the array declarations to a package of their own (for
example, General_Decryption_Program_Mark_1_Arrays) and with/use it. The
arrays are no longer on the stack (I'm not sure about the initializers).

(b) increase the program's stack size. The help for gnatbind says I
could add the switch -d16m for a 16 Mb stack, but this had no effect;
instead, there's a Mac-specific way of doing this which I won't bore you
with.


Having got the program to start, I tried to decrypt the supplied
CipherTextFile_1.dat and got

   Execution terminated by unhandled exception
   Exception name: ADA.IO_EXCEPTIONS.DATA_ERROR

and as far as I can tell this was caused by the Windows line
terminator[2] in the data file; that's to say, when I removed the CR
character from the Windows CR/LF the program decoded correctly.

I'm not sure of the best way to get an Ada program not to care what sort
of input line terminators it's reading.

--S

[1]
https://groups.google.com/forum/?hl=en#!searchin/comp.lang.ada/large$20array%7Csort:date/comp.lang.ada/d-HSSQR9jHo/NjNp6cl6WaIJ
[2] http://en.wikipedia.org/wiki/Newline