On 2009-11-03, at 1:01 PM, Andreas Raab wrote:

> John M McIntosh wrote:
>> I'm looking at the JPEG plugin and wondering?
>> (a) Should I convert that to using the os-x platforms JPEG  
>> implementation, versus our usage of the source from the  
>> "Independent JPEG Group's software"?
>
> Seems like a bad trade unless you want to severely rewrite the  
> plugin interface (making it effectively a new plugin). The current  
> interface is tied specifically to the IJGs implementation with  
> internal structures and functions being exposed fairly directly.

Yes, however in working with Sophie we noticed *most* interfacing is  
done via ImageReadWriter which supports a generic interface for  
creating or reading files or streams.
The choice of which class to use is based on iterating over the  
subclasses and asking who can do the work, it never appeared that  
people messed about with the JPEG read/write class other than
asking for magic decoding/encoding.

For Sophie we choose to override this and provided an interface that  
worked with Apple's quicktime for os-x and Windows to read *lots* of  
graphics formats and
provide us with a resulting form.

No doubt I could do the same given if os-x and some flavour of the VM  
then do a different call path.


>
>> (b) Should we consider upgrading the VMs from version "6b  27- 
>> Mar-1998"  to the more current "release 7 of 27-Jun-2009" since we  
>> store the source in the VM SVN tree at the moment.
>
> That sounds like a good idea.
>
>> I've not looked but
>> (a) Apple might have a private implementation that could be faster  
>> since it would likely use hardware vector services.
>
> Almost certainly. Intel's performance prims can make JPEG stuff  
> quite a bit faster already.
>
>> (b) Relying on the system libraries for conversion means fixes for  
>> security issues get prompt attention, versus our non-attention now.
>
> I'm not sure about this. The IJGs code has been quite robust and to  
> my knowledge no exploits have ever been published. OTOH, Microsofts  
> implementation seems to have been sucessfully attacked in the past,  
> so it's a bit questionable whether using the OS vendors  
> implementation would necessarily be more secure than the IJGs version.
>
> Cheers,
>  - Andreas

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John M. McIntosh <johnmci at smalltalkconsulting.com>   Twitter:   
squeaker68882
Corporate Smalltalk Consulting Ltd.  http://www.smalltalkconsulting.com
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