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

[Dan Stoica]

This is a bug and needs fixing. It is a bug because GetText() is supposed to do a simple dump. What a dump has to do with topological validation? None.

Therefore, filing a ticket is the right thing to do.

Dan.

-----Original Message-----
From: fdo-users-bounces at lists.osgeo.org [mailto:fdo-users-bounces at lists.osgeo.org] On Behalf Of Jackie Ng
Sent: Thursday, August 21, 2008 11:57 PM
To: fdo-users at lists.osgeo.org
Subject: RE: [fdo-users] How does FDO handle invalid fgf geometries?


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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