On Thu, Jul 2, 2009 at 10:15, Laszlo KREKACS<[email protected]> wrote: > On Thu, Jul 2, 2009 at 8:42 AM, Alexander Shulgin<[email protected]> > wrote: >> I fail to see how is this true for normal tar files (vs. data read >> from pipe). Can you elaborate please? > > Yepp, of course;) > [snip] > > Simplification of tar archive: > [1. file header][1. file][2.file header][2. file][3. file header][3. file] > > So how you read the third file from the archive? You read the file until the > [3. file header], your test is successfull (is it the right file?), > and you read the > file itself. You see? You have read the whole file, just accessing the > last item inside.
Yes, but is lseek(2) banned on neo? This is what I was talking about then mentioned normal files (i.e. not pipes). :) >> Pardon my ignorance, but wouldn't zip -0 do the trick for your purpose? :) > > It will do more or less, however there are three main problems with it: > > 1. you can only obtain the whole file from the archive. So you cant > read a part of the file. So if you packed lets say a 700MB file to zip, > you run out of memory on neo. > At least this is the case on standard python zipfile module. > > 2. There is no random access feature, at > least not in standard python modules. > 3. There are significant processor time wasted when accessing to a file > (many computation required). Btw, it needs to benchmark on the neo, how > worse is it. OK, I see now. Thanks for explanation. -- Cheers, Alex _______________________________________________ Openmoko community mailing list [email protected] http://lists.openmoko.org/mailman/listinfo/community
