[Fwd: Re: [geos-devel] Benchmark between various geometry libraries]

[Martin Davis]

Hartmut Kaiser wrote:
>>     
>
> It's not that allocation is necessarily slow 
Well, compared to the JVM it is.  Java is amazingly fast at allocating 
objects. 

>
> Sharing is certainly a bit trickier this way, but allocating on the stack helps defining proper ownership of the data.
>   
For better or worse, JTS/GEOS already has well-defined sharing 
policies.  Performance-wise, it's probably for worse (in C land) - many 
of the intermediate data structures are designed to be usable on their 
own - which means that their components are shared.  And since they are 
mostly dynamic in nature, I think this implies that their component 
objects need to be heap allocated, correct?

Actually, I'm a bit puzzled by your code example.  If I understand it, 
you say that

{
       vector<bla> v;
       // use v
   }

results on stack-only memory usage.  But aren't vectors dynamically 
sized?  Doesn't the dynamically created memory get allocated from the 
heap? 

-- 
Martin Davis
Senior Technical Architect
Refractions Research, Inc.
(250) 383-3022




-- 
Martin Davis
Senior Technical Architect
Refractions Research, Inc.
(250) 383-3022