/* go to the top of the history buffer */
void
sc_hist_end(scr_stat *scp)
{
scp->history_pos = sc_vtb_pos(scp->history, sc_vtb_tail(scp->history),
scp->xsize*scp->ysize);
history_to_screen(scp);
}
/* restore the screen by copying from the history buffer */
int
sc_hist_restore(scr_stat *scp)
{
int ret;
if (scp->history_pos != sc_vtb_tail(scp->history)) {
scp->history_pos = sc_vtb_tail(scp->history);
history_to_screen(scp);
ret = 0;
} else {
ret = 1;
}
sc_vtb_seek(scp->history, sc_vtb_pos(scp->history,
sc_vtb_tail(scp->history),
-scp->xsize*scp->ysize));
return ret;
}
/* move one line down */
int
sc_hist_down_line(scr_stat *scp)
{
if (scp->history_pos == sc_vtb_tail(scp->history))
return -1;
scp->history_pos = sc_vtb_pos(scp->history, scp->history_pos,
scp->xsize);
history_to_screen(scp);
return 0;
}
static void
copy_history(sc_vtb_t *from, sc_vtb_t *to)
{
int lines;
int cols;
int cols1;
int cols2;
int pos;
int i;
lines = sc_vtb_rows(from);
cols1 = sc_vtb_cols(from);
cols2 = sc_vtb_cols(to);
cols = imin(cols1, cols2);
pos = sc_vtb_tail(from);
for (i = 0; i < lines; ++i) {
sc_vtb_append(from, pos, to, cols);
if (cols < cols2)
sc_vtb_seek(to, sc_vtb_pos(to,
sc_vtb_tail(to),
cols2 - cols));
pos = sc_vtb_pos(from, pos, cols1);
}
}
/* allocate a history buffer */
int
sc_alloc_history_buffer(scr_stat *scp, int lines, int prev_ysize, int wait)
{
/*
* syscons unconditionally allocates buffers up to
* SC_HISTORY_SIZE lines or scp->ysize lines, whichever
* is larger. A value greater than that is allowed,
* subject to extra_history_size.
*/
sc_vtb_t *history;
sc_vtb_t *prev_history;
int cur_lines; /* current buffer size */
int min_lines; /* guaranteed buffer size */
int delta; /* lines to put back */
if (lines <= 0)
lines = SC_HISTORY_SIZE; /* use the default value */
/* make it at least as large as the screen size */
lines = imax(lines, scp->ysize);
/* remove the history buffer while we update it */
history = prev_history = scp->history;
scp->history = NULL;
/* calculate the amount of lines to put back to extra_history_size */
delta = 0;
if (prev_history) {
cur_lines = sc_vtb_rows(history);
min_lines = imax(SC_HISTORY_SIZE, prev_ysize);
if (cur_lines > min_lines)
delta = cur_lines - min_lines;
}
/* lines up to min_lines are always allowed. */
min_lines = imax(SC_HISTORY_SIZE, scp->ysize);
if (lines > min_lines) {
if (lines - min_lines > extra_history_size + delta) {
/* too many lines are requested */
scp->history = prev_history;
return EINVAL;
}
}
/* allocate a new buffer */
history = (sc_vtb_t *)malloc(sizeof(*history),
M_DEVBUF,
(wait) ? M_WAITOK : M_NOWAIT);
if (history != NULL) {
if (lines > min_lines)
extra_history_size -= lines - min_lines;
/* XXX error check? */
sc_vtb_init(history, VTB_RINGBUFFER, scp->xsize, lines,
NULL, wait);
/* FIXME: XXX no good? */
sc_vtb_clear(history, scp->sc->scr_map[0x20],
SC_NORM_ATTR << 8);
if (prev_history != NULL)
copy_history(prev_history, history);
scp->history_pos = sc_vtb_tail(history);
} else {
scp->history_pos = 0;
}
/* destroy the previous buffer */
if (prev_history != NULL) {
extra_history_size += delta;
sc_vtb_destroy(prev_history);
free(prev_history, M_DEVBUF);
}
scp->history = history;
return 0;
}
/* go to the tail of the history buffer */
void
sc_hist_home(scr_stat *scp)
{
scp->history_pos = sc_vtb_tail(scp->history);
history_to_screen(scp);
}
/* copy entire screen into the top of the history buffer */
void
sc_hist_save(scr_stat *scp)
{
sc_vtb_append(&scp->vtb, 0, scp->history, scp->xsize*scp->ysize);
scp->history_pos = sc_vtb_tail(scp->history);
}
/* Restore old_ysize lines from the tail of the history buffer */
void
sc_hist_getback(scr_stat *scp, int old_ysize)
{
scp->history_pos = sc_vtb_tail(scp->history);
history_to_screen_lines(scp, old_ysize);
}
