problems with old c code with new ncurses version (ldat struct) - c

Question

I have a problem with some code using curses after upgrading to a new server and thus also new software like libs, headers and such.
The problem is the use of the ldat struct fields "firstchar", "lastchar" and "text" which in the the newer versions of curses.h is hidden in the curses.priv.h and therefore they are not resolved.
I could really use some pointers as to how I might be able to resolve these issues.
The code below indicates the use of the struct fields, but it just a part of the complete code as it several thousand lines...
If there is need for additional code I can add this.
I might also add that I have not made this program myself, I'm just responsible for making it work with our new server...
int
update_window(changed, dw, sw, win_shared)
bool *changed;
WINDOW *dw; /* Destination window */
window_t *sw; /* Source window */
bool win_shared;
{
int y, x;
int yind, nx, first, last;
chtype *pd, *ps; /* pd = pointer destination, ps = pointer source */
int nscrolls; /* Number of scrolls to make */
if(! sw->changed) {
*changed = FALSE;
return(0);
}
/****************************************
* Determine number of times window is
* scrolled since last update
****************************************/
nscrolls = sw->scrollcount; if(nscrolls >= sw->ny)
nscrolls = 0;
sw->scrollcount = 0L;
dw->_flags = _HASMOVED;
dw->_cury = sw->cury;
dw->_curx = sw->curx;
if(nscrolls > 0) {
/* Don't copy lines that is scolled away */
for(y = nscrolls; y < sw->ny; y++) {
yind = GETYIND(y - nscrolls, sw->toprow, sw->ny);
if(sw->lastch[yind] != _NOCHANGE) {
first = dw->_line[y].firstchar = sw->firstch[yind];
last = dw->_line[y].lastchar = sw->lastch[yind];
ps = &sw->screen[yind][first];
pd = (chtype *)&dw->_line[y].text[first];
nx = last - first + 1;
LOOPDN(x, nx)
d++ = *ps++;
if(! win_shared) {
sw->firstch[yind] = sw->nx;
sw->lastch[yind] = _NOCHANGE;
}
}
}
} else {
LOOPUP(y, sw->ny) {
yind = GETYIND(y, sw->toprow, sw->ny);
if(sw->lastch[yind] != _NOCHANGE) {
first = dw->_line[y].firstchar = sw->firstch[yind];
last = dw->_line[y].lastchar = sw->lastch[yind];
ps = &sw->screen[yind][first];
pd = (chtype *)&dw->_line[y].text[first];
nx = last - first + 1;
LOOPDN(x, nx)
*pd++ = *ps++;
if(! win_shared) {
sw->firstch[yind] = sw->nx;
sw->lastch[yind] = _NOCHANGE;
}
}
}
if(! win_shared)
sw->changed = FALSE;
}
*changed = TRUE;
return(nscrolls);
}
I appreciate all the help I can get!

Answer 1

The members of struct ldat were made private in June 2001. Reading the function and its mention of scrolls hints that it is writing a portion of some window used to imitate scrolling (by writing a set of lines to the real window), and attempting to bypass the ncurses logic which checks for changed lines.
For a function like that, the only solution is to determine what the developer was trying to do, and write a new function which does this — using the library functions provided.