[postgis-devel] ST_OrderingEquals and memcmp

Paul Ramsey pramsey at cleverelephant.ca
Mon Nov 17 09:03:49 PST 2014


There’s only one pad hole, it's for polygons with an odd number of rings. I don’t know why it wouldn’t be consistently zero’ed out, since the pad is set with 

		memset(loc, 0, sizeof(uint32_t));

P.


-- 
Paul Ramsey
http://cleverelephant.ca
http://postgis.net

On November 17, 2014 at 7:12:49 AM, Sandro Santilli (strk at keybit.net) wrote:

I was reading the implementation of ST_OrderingEquals and wondered  
why we're not using memcmp on the serialized memory.  

Saint testsuite revealed it can sometime fail.  
I guess the reason for that is some "holes" in the serialized format  
left for alignment purpose, does it sound correct ?  

Could we ensure serializers fill any hole to speedup identity checking ?  

--strk;  

() Free GIS & Flash consultant/developer  
/\ http://strk.keybit.net/services.html  
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