John Darrington <[EMAIL PROTECTED]> writes: > On Mon, Jun 05, 2006 at 05:38:53PM -0700, Ben Pfaff wrote: > John Darrington <[EMAIL PROTECTED]> writes: > > > If you're able and willing to write a random access casereader, then > > that will certainly make the gui code simpler. I've got a change > > almost ready to commit, which will remove the GUI's hard limit on the > > number of variables. The next major step for the GUI is to unlimit > > the number of cases. So I'm just about ready to use such casereader. > > > > > > My idea of the interface would be something along the lines of the > > following, but you may have better ideas. > > Here's an implementation with a different interface. If you like > it, I'll check it in. Let me know. > > I suppose I can use it. I'd be immediately following every call to > casereader_seek with a call to casereader_read. In many, but not all, > instances the GUI will be reading sequentially. So the reader will > already be pointing to the seeked position. Will your implementation > behave optimally in this situation?
Well, not the one I posted, but I took a few minutes to optimize it and it should now be OK. I figured that sequential access starting at a random position would be the norm, hence the preference for a "seek" function. > Also, when scrolling backwards there'll be a lot of seeking to > 2 positions preceding the current position. Is it worth having > some means of hinting to the casereader that the next read will > probably be the case preceeding the case currently being read, > instead of the following one? > > On the other hand perhaps we should leave such optimisations until we > know they're justified. I doubt the value of trying to optimize this case unless it's a real problem. I'm not even sure what I'd do to optimize it. -- Ben Pfaff email: [EMAIL PROTECTED] web: http://benpfaff.org _______________________________________________ pspp-dev mailing list [email protected] http://lists.gnu.org/mailman/listinfo/pspp-dev
