Marcel, NOW we're talking. This has really been such an eye-opening thread.
Now it's googling time to try to figure out how to search for a string in there. Thanks! On Wed, Apr 15, 2009 at 7:01 PM, WT <[email protected]> wrote: > Hi Marcel, > > that's quite impressive. On the simulator on my machine, it took 0.007 > seconds, consistently. Learned something new with your message. Thanks! > > Wagner > > On Apr 16, 2009, at 12:35 AM, Marcel Weiher wrote: > > I would do the following: >> >> 1. map the file into memory using -[NSData dataWithContentsOfMappedFile:] >> (or mmap() if you really want to) >> 2. Do not convert to individual objects for the words >> 3. get the pointer to the raw bytes >> 4. search using a little bit of plain old C (assuming you're OK with >> encodings) >> >> >> Memory mapping will be essentially instantaneous, with the I/O performed >> on-demand when its actually needed (or you can pre-heat the data, for >> example in a background thread). More importantly, you will be doing good >> things for memory consumption, because the mapped memory can be released to >> the OS without having to kill your app in low-memory situations (without >> paging it out on Mac OS X, but the iPhone doesn't page memory out). >> >> I added an implementation of this approach to the testing program provided >> by Wagner (thanks!) and it loads + counts the words in 0.084 seconds on the >> device. That's anywhere from around 50 - 100 times faster than the other >> methods implemented in DictTest (plist / xml / txt ). On the simulator, it >> runs in 0.043 seconds, so around 30-40 times faster than the other methods. >> >> Download can be found here: >> >> http://www.metaobject.com/downloads/Objective-C/DictTest.tgz >> >> You mentioned that you were OK with search performance, so I won't go into >> that. >> >> Cheers, >> >> Marcel >> > _______________________________________________ > > Cocoa-dev mailing list ([email protected]) > > 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/vardpenguin%40gmail.com > > This email sent to [email protected] > _______________________________________________ Cocoa-dev mailing list ([email protected]) 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]
