[geos-devel]createEmptyGeometry()

[strk at refractions.net]

On Fri, Mar 31, 2006 at 12:35:12PM +0200, strk at refractions.net wrote:
> On Fri, Mar 31, 2006 at 01:20:51AM +0200, Mateusz £oskot wrote:
> > Martin Davis wrote:
> > > I thought about this, but on the principal of Occam's Razor decided 
> > > just to use an empty GC.  This has the advantage that there are fewer
> > >  cases to handle for both developers and clients.
> > 
> > That's clear for me.
> > 
> > strk:
> > The only thing I'd do is to review current impl. of GEOS and see if
> > there are any possible runtime bugs.
> 
> Code is FULL of assumption about the fact that geometries 
> are not EMTPY... just took a look at LineString.cpp, and
> the CoordinateSequence pointer is dereferenced always w/out
> checks.
> Note that the same happens with JTS. Example:
> 
>   public Coordinate[] getCoordinates() {
>     return points.toCoordinateArray();
>  }
> 
> 'points' is not checked for being NULL.
> In other places it is.

...

Sorry, I had a closer look, at it seems that
LineString refuses to be contructed with a NULL
CoordinateSequence. It creates an *empty*
CoordinateSequence when passed NULL as arg.

Yet another useless waste of memory, similar
to the NULL Envelope and NULL Coordinate representations...

--strk;