Re: Efficiently setting up large quantities of constant data

["John B. Matthews" <nospam@nospam.com>]

In article <32di5rF3lj4ggU1@individual.net>,
 "Marc A. Criley" <mcNOSPAM@mckae.com> wrote:

> "Dr. Adrian Wrigley" <amtw@linuxchip.demon.co.uk.uk.uk> wrote:
> 
> > A similar question I have is how to link in regular files and access
> > their contents in Ada.
> >
> > For example, suppose I have a binary file "distances.dat" containing
> > the (road) distances between 1000 different cities.  This could be a 2MB
> > file computed by another application. How can I build a single executable
> > file containing the data and access it from the Ada code?
> >
> > I presume this needs to be done at the linker stage, but I don't
> > see any options to link in non-object files.  The obvious alternative
> > of distributing the data files separately and reading them in
> > is slower and much less tidy than having a single self-contained binary.
> 
> I don't know the answer to your real question about linking in such files,
> but the way we dealt with this problem _many_ years ago with some very large
> tables of math constants was to write a little tool that read in the file
> and then generated Ada source code that initialized a suitably defined data
> structure with the constants.  (And I don't think we used big aggregates,
> because they were...well...too big.  I think we had the tool generate
> thousands of assignment statements.)
> 
> The generated file was quite large and took awhile to compile (it was 1985
> after all :-), but it worked just fine for us.  Of course it was a one-shot
> effort as well, since math constants don't change very often, so YMMV if
> you're dealing with changing data.
> 
> Marc A. Criley
> McKae Technologies
> www.mckae.com

For several projects, we've used a script (SQL*Plus, PL/SQL, Java) 
to read from a database and generate executable code (Ada, Java). 
The script was part of the build, so each new release had the latest 
data.

-- 
John
jmatthews at wright dot edu
www dot wright dot edu/~john.matthews/