[Insight-developers] Small modification to ImportImageContainer

[Tom Vercauteren]

Thanks Bill for the very interesting pointer!

I think the patch really makes sense in that exact same scenario. If I
get it right, the factory basically loads a TestImportImageContainer
which is defined in itkFactoryTestLib.[h/cxx].

TestImportImageContainer inherits from ImportImageContainer and
redefines AllocateElements. IMHO, if allocation is redefined, it makes
sense to also redefine deallocation.

By enclosing all deallocation in one virtual function, this is what
the patch allows. Thus enabling for example the use of a
std::allocator instead of calling new and delete.

Tom

On Thu, Mar 19, 2009 at 16:51, Bill Lorensen <bill.lorensen at gmail.com> wrote:
> Tom,
>
> Another possibility is to use the object factory mechanism to provide
> an override to ImportImageContainer. The test
> Testing/Code.Common/itkObjectFactoryTest2.cxx shows how
> ImportImageContainer can be overriden.
>
> Bill
>
>
> On Thu, Mar 19, 2009 at 7:51 AM, Tom Vercauteren
> <tom.vercauteren at m4x.org> wrote:
>> Hi,
>>
>> At my company, we needed to have ITK images for which buffers are
>> ensured to be aligned (say on 8 bits). This can be done by overloading
>> itk::Image and itk::ImportImageContainer.
>>
>> However, it also requires a patch to ImportImageContainer for it to be
>> "overloadable". Basically, the attached patch only amounts to:
>> 1) Putting all the memory deallocation in a single virtual function
>> 2) Moving some member variables from private to protected
>>
>> There should be no backward compatibility issue with this. All unit
>> tests are still green on my computer.
>>
>>
>> By looking into ImportImageContainer, I also realized that Reserve is
>> wrong in the sense that it has a Resize semantics. This is similar to
>> the following VectorContainer and the MapContainer bug:
>> http://www.itk.org/Bug/view.php?id=2893
>>
>> Since it was decided not to fix bug 2893, I haven't fixed
>> ImportImageContainer::Reserve either but simply added some comments to
>> the file.
>>
>> Let me know if you see any potential problem with this patch.
>>
>> Thanks,
>> Tom
>>
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>