[fdo-users] How does FDO handle invalid fgf geometries?

[Jackie Ng]

I strongly suspected that it was some other error than running out of memory.

Good to know my suspicions are confirmed.

- Jackie


Dan Stoica wrote:
> 
> Did some investigations on this matter. Turns out that:
> 
> a) the polygon in question has a ring which is not closed.
> b) the geometry factory throws an appropriate exception "Open ring"
> c) the exception is not caught by GetText()
> d) for some odd reason the exception is turned into "memory allocation
> error"
> 
> Therefore, the quick solution for Jackie is to catch the exception.
> 
> Going forward, we might want to get rid of the 'is polygon closed?'
> test...
> 
> 
> Dan.
> 
> -----Original Message-----
> From: fdo-users-bounces at lists.osgeo.org
> [mailto:fdo-users-bounces at lists.osgeo.org] On Behalf Of Mateusz Loskot
> Sent: Thursday, August 21, 2008 10:51 AM
> To: FDO Users Mail List
> Subject: Re: [fdo-users] How does FDO handle invalid fgf geometries?
> 
> Jackie Ng wrote:
>> Hi All,
>>
>> How does FDO handle invalid FGF binary data?
> 
> Jackie,
> 
>  From my experience, I've observed that FDO does not strictly
> validate FGF/WKB input on geometry creation.
> Actually, GeometryFactory checks if WKB stream has minimal length of 9
> bytes and it does not prevent to create geometry from bytes stream of
> garbage.
> 
> Here is a small test of valid and invalid WKB input (see main function):
> 
> http://mateusz.loskot.net/tmp/fdo/test_geometry_factory.cpp.html
> 
> This is the result of 3 test cases included in the test:
> 
> Expected WKT: POINT(15.123 21.456)
> Output WKT  : POINT (-7.84591113289983e+298 0)
> 
> Expected WKT: POINT(15.123 21.456)
> Output WKT  : POINT (15.123 21.456)
> 
> *** FDO Error:
>    *** (.\Src\Geometry\Fgf\GeometryFactory.cpp: 568)
> FDO_1_INVALID_INPUT_ON_CLASS_CREATION
> 
> 
> Best regards,
> --
> Mateusz Loskot, http://mateusz.loskot.net
> Charter Member of OSGeo, http://osgeo.org
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> 

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