missing ordinals in avifil32
Francois Gouget
fgouget at free.fr
Thu Sep 11 04:15:19 CDT 2003
On Wed, 10 Sep 2003, Alexandre Julliard wrote:
> Dave Miller <compsol at ptd.net> writes:
>
> > The first 59 ordinals seem to match in all windows versions. Add
> > ordinals to avifil32.spec to match windows.
>
> Unless ordinals are actually needed, it's better not to add them. In
> that case the functions are sorted so it's very likely that Windows is
> using automatic allocation too.
Yep, writing a script that detects whether Windows assigns a specific
ordinal to a function or not is tricky. There are two ways to detect
that and I think the best results can only be obtained by combining
them:
* first way is to check whether the ordinal associated to a given
function changes accross Windows versions. This is the technique Dave
used.
* the second would be to take all the functions in the dll, sort them
alphabetically, and check if their ordinals are in the expected order.
E.g. let's say you have:
function ordinal
A 2
B 4
C 3
Obviously at least one of these three functions is exported by
ordinal otherwise their ordinals would follow the alphabetical order and
always increment by 1. The tricky part is determining which API is
exported by ordinal. Here's a possible algorithm:
A has ordinal n. If B (the next function in alphabetical order) has
an ordinal different from n+1 then it's exported by ordinal. We then
consider all functions to be exported by ordinal until we find a
function with ordinal n+1.
The problem is that this algo breaks down if the firts function in
the dll is exported by ordinal and if there are holes in the ordinals.
In particular we are likely to find holes if some functions are exported
by ordinal (e.g. all functions 1-49 with ordinals < 100), and others not
(automatically assigned ordinals >100).
Maybe a simple enough solution in practice would be to start with the
last function in alphabetical order...
Note: I Wine's spec file it's not necessary to sort the functions that
don't have an ordinal. But it's much cleaner<g>.
--
Francois Gouget fgouget at free.fr http://fgouget.free.fr/
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