Re: Efficiently setting up large quantities of constant data

[Vinzent 'Gadget' Hoefler <nntp-2004-12@t-domaingrabbing.de>]

tmoran@acm.org wrote:

>>You could give "objcopy" a try. It can convert a binary file into an
>>object file which could then be linked normally.
>
>   You could also create an asm (remember that?) file with the data
> and link the resultant object file.

Yes. BTDT.

>   What's wrong with just creating an Ada source file with all the
>   constant data?

It's nothing wrong with it. But sometimes it just may seem a little bit
overkill to create source code from a binary to be compiled by a
compiler to get an object file to be linked by the linker when you can
create the needed object file in just one single, fast step with
bin2obj/objcopy. :)

> That would give you the advantage of the compiler doing the
> worrying about the data representation and layout and doing some
> checking that you are accessing things correctly.

Yes, agreed. If you really need this.

But if the file is essentially just an array of basic types I see not
much sense in doing all the steps mentioned above just to link a
lookup-table into the executable.

I mean, what kind of checking can the compiler do on a simple array of
integers?
Especially in the case when the program that writes the binary data uses
the same packages with the type declaration as the program where the
precomputed result is linked into?

Oh, and floating point data might be a little bit funny, if you convert
the binary result to textual representation, and then let the compiler
convert it back to its binary equivalent. ;-)


Vinzent.