Le 12 juil. 2013 à 08:41, Vincent Habchi <vi...@macports.org> a écrit :

> Hi!
> 
> Sorry for this late answer, I was a bit swamped lately.
> 
>> NSData wouldn't let you, but NSMutableData would, with methods like 
>> appendBytes:length:, appendData:, increaseLengthBy:, etc.  The underlying 
>> buffer might have to move around if it cannot be extended in place, just as 
>> it would if you use C realloc() calls.
> 
> In fact, I overlooked that completely. I just fear building a buffer from 
> zero to something like 400,000 * 3 * 4 bytes = just under 5 MiB would imply 
> too many moves as you mention. 

If you know how large your data will be and want to avoid the realloc cost, you 
can just create your mutable data using -initWithCapacity: .
And even if the size end up to be larger than your initial capacity, the 
mutable data will do the right thing and increase the capacity.

> Now, I am anyway moving towards a binary file that would be fed directly into 
> the buffer rather than needing decoding, and partitioning it into several 
> chunks in order to optimize the number of triangles displayed. I think I’ll 
> use NSData to store these chunks.
> 
> Thanks to all for the precious help!
> Vincent
> 

-- Jean-Daniel





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