On Jun 18, 2008, at 2:50 PM, Quincey Morris wrote:
I suppose you could byte-move each group of 4 doubles in one NSData and give that to the archiver instead. Or do it further upstream and make a bigger array of numbers in a NSData. (But you'll have to deal with endianness and -- egads! -- floating point representation issues across architectures yourself.)Perhaps you could avoid the endianness and representation issues by archiving each group of 4 doubles (with a different archive object) into a NSData and give that to your main archiver. This sounds like it would be slow, but probably not as slow as what you already tried.
I just tried this. It is slower than saving XML (around 10 seconds), which is orders of magnitudes faster than without this "optimization".
One problem is that each 4 double value object gets blown up to 307 bytes when in its NSData container. That makes the overall file increase from 18MB to 38MB. That's a bit of a problem and compressing the data won't make things faster, so that's not an option.
I'll try the further upstream approach, it should lower the memory impact but I will pay for that with much slower performance - I'll report back how that turns out.
Probably the real answer is that NSKeyedArchiver isn't designed to handle such large numbers of objects efficiently.
It's more like "lots of numbers" rather than "lots of objects". It doesn't matter whether the doubles are located in separate objects or not. Iit would be nice to see a warning in the documentation if such a design limitation really exists - it may be a bug.
Anyway thanks for your input! Regards Markus -- __________________________________________ Markus Spoettl
smime.p7s
Description: S/MIME cryptographic signature
_______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [EMAIL PROTECTED]
