No comment/interest? I am assuming this is the right list to send this sort of crap to. Correct me if I am wrong.
If the fix is incorrect I would appreciate pointers. Thanks, --patrick On Tue, Dec 07, 2010 at 11:58:39PM -0800, patrick keshishian wrote: > Hello, > > I work with a lot of sources that have strange formatting > (as do you no doubt). I noticed that sometimes changing the > tabstop value in search of a reasonable display vi would > crash. > > Took me a bit to figure out the reproducible steps to be > able to come up with a fix. > > Steps to reproduce the crash. Reproducible on i386, amd64, > and macppc: > > 1. Imagine a file edited with a small tabstop value (say 2 > or 3) containing lines long enough so they wrap in default > tabstop (8), but possibly not in the smaller tabstop values. > > 2. While tabstop set to 8, position one of the wrapping lines > such that the beginning of said line is off screen and the > tail end of the wrapped portion is the first line on the > screen with the cursor positioned on same first line. > > 3. Change tabstop to 2 (or 3). > Assuming there were more lines below the line your cursor > is on, you will notice a drawing glitch where only the > top line is redrawn and the rest of the screen is blanked > out. > > 4. If at this point you press ^B (page backwards) vi will > core dump. > > A visual of what I experience (series of five screen-shots): > http://sidster.com/scratch/nvi/ > > > The patch below resets the HMAP->soff (screen offset of line) > to 1 if the number of lines HMAP->lno spans has changed and is > now less than HMAP->soff. This essentially forces the entire > line to be redrawn at the top of the screen, avoids the redraw > glitch and eventual crash. > > Comments? > > --patrick > > > Index: vi/vs_smap.c > =================================================================== > RCS file: /cvs/obsd/src/usr.bin/vi/vi/vs_smap.c,v > retrieving revision 1.7 > diff -u -p vi/vs_smap.c > --- vi/vs_smap.c 27 Oct 2009 23:59:49 -0000 1.7 > +++ vi/vs_smap.c 8 Dec 2010 06:22:09 -0000 > @@ -224,6 +224,17 @@ top: HMAP->lno = lno; > HMAP->coff = 0; > HMAP->soff = 1; > } > + else { > + /* > + * If number of lines HMAP->lno (top line) spans > + * changed due to, say reformatting, and now is > + * fewer than HMAP->soff, reset so the line is > + * redrawn at the top of the screen. > + */ > + cnt = vs_screens(sp, HMAP->lno, NULL); > + if (cnt < HMAP->soff) > + HMAP->soff = 1; > + } > /* If we fail, just punt. */ > for (p = HMAP, cnt = sp->t_rows; --cnt; ++p) > if (vs_sm_next(sp, p, p + 1))
