Corrections for 20020914

[Philippe Blain]

>From Philippe Blain, Bordeaux, FRANCE.
My old computer: P133 - 8,4 Go - 32 Mo Red Hat Linux 7.0

To maintainers of 'ncurses'.(and to Mr Dickey)
Subject: Corrections for ncurses-5.2-20020914+

Here are some problems I found :

----------------------------------------------------------------------------
File : ncurses/base/lib_overlay.c

Function overlap() :

That internal function used by overlay() and overwrite() is false.
Code is incomplete.
There is no mention of intersection of source and dest in the code.
What happens if windows DO NOT overlap ?
Some coordinates are computed relatives to their windows, but never test if
overlapping really is. Just supposed it is.

Should be something like that :

static int overlap (const WINDOW * const s, WINDOW * const d, int const
flag)
{
    int sx1, sy1, sx2, sy2, dx1, dy1, dx2, dy2;
    int sminrow, smincol, dminrow, dmincol, dmaxrow, dmaxcol;

    T(("overlap : sby %d, sbx %d, smy %d, smx %d, dby %d, dbx %d, dmy %d,
        dmx %d", s->_begy, s->_begx, s->_maxy, s->_maxx, d->_begy, d->_begx,
        d->_maxy, d->_maxx));

    if (!s || !d) returnCode (ERR);

    sx1 = s->_begx;
    sy1 = s->_begy;
    sx2 = sx1 + s->_maxx;
    sy2 = sy1 + s->_maxy;

    dx1 = d->_begx;
    dy1 = d->_begy;
    dx2 = dx1 + d->_maxx;
    dy2 = dy1 + d->_maxy;

    if (dx2 < sx1 || dx1 > sx2 || dy2 < sy1 || dy1 > sy2) {
        returnCode (ERR);  /* No intersection */
    }
    else {
        sminrow = max (sy1, dy1) - s->_begy;
        smincol = max (sx1, dx1) - s->_begx;
        dminrow = max (sy1, dy1) - d->_begy;
        dmincol = max (sx1, dx1) - d->_begx;
        dmaxrow = min (sy2, dy2) - d->_begy;
        dmaxcol = min (sx2, dx2) - d->_begx;

        return (copywin
            (s, d, sminrow, smincol, dminrow, dmincol, dmaxrow, dmaxcol,
flag));
    }
}

----------------------------------------------------------------------------
File : ncurses/base/lib_overlay.c

Function copywin() , line 155:

    ..............
        if (touched) {
==>         touchline(dst, 0, getmaxy(dst));
        }
    }
    T(("finished copywin"));
    returnCode(OK);
}

Think it can be replaced more efficiently by :
    touchline(dst, dminrow, (dmaxrow - dminrow + 1), 1);

----------------------------------------------------------------------------
- Philippe