* Copyright (c) 1983 Regents of the University of California.
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by the University of California, Berkeley. The name of the
* University may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
static char sccsid
[] = "@(#)wwupdate.c 3.26 (Berkeley) %G%";
register char *t1
= wwtouched
+ top
, *t2
= wwtouched
+ bot
;
scan_top
= top
= t1
- wwtouched
- 1;
scan_bot
= bot
= t2
- wwtouched
+ 1;
if (scan_bot
- scan_top
> 1 &&
(tt
.tt_clreos
!= 0 || tt
.tt_clear
!= 0)) {
int st
= tt
.tt_clreos
!= 0 ? scan_top
: 0;
* t1 is one past the first touched row,
* t2 is on the last touched row.
for (t1
--, n
= 1; t1
< t2
;)
* If we can't clreos then we try for clearing
if (check_clreos
= n
* 10 > (wwnrow
- st
) * 9) {
if (tt
.tt_clreol
== 0 && !check_clreos
)
for (i
= scan_top
, touched
= &wwtouched
[i
], upd
= &wwupd
[i
];
register union ww_char
*ns
, *os
;
if (!check_clreos
&& !*touched
)
* The cost of clearing is:
* The cost of straight update is, more or less:
* We clear if nblank - nsame > X
* X is the clreol overhead.
* So we make gain = nblank - nsame.
if ((--ns
)->c_w
== (--os
)->c_w
)
upd
->best_gain
= best_gain
;
upd
->best_col
= best_col
;
register struct ww_update
*u
;
register simple_gain
= 0;
* gain is the advantage of clearing all the lines.
* best_gain is the advantage of clearing to eos
* at best_row and u->best_col.
* simple_gain is the advantage of using only clreol.
* We use g > best_gain because u->best_col can be
* undefined when u->best_gain is 0 so we can't use it.
for (j
= scan_bot
- 1, u
= wwupd
+ j
; j
>= top
; j
--, u
--) {
register g
= gain
+ u
->best_gain
;
if (tt
.tt_clreol
!= 0 && u
->best_gain
> 4)
simple_gain
+= u
->best_gain
- 4;
if (gain
> simple_gain
&& gain
> 4) {
if (best_gain
> simple_gain
&& best_gain
> 4) {
xxclreos(i
, j
= wwupd
[i
].best_col
);
wwnupdclreosline
+= wwnrow
- i
;
register union ww_char
*os
= &wwos
[i
][j
];
for (j
= wwncol
- j
; --j
>= 0;)
wwtouched
[i
++] |= WWU_TOUCHED
;
for (i
= top
, touched
= &wwtouched
[i
], upd
= &wwupd
[i
]; i
< bot
;
register union ww_char
*os
, *ns
;
if (tt
.tt_clreol
!= 0 && upd
->best_gain
> 4) {
xxclreol(i
, j
= upd
->best_col
);
for (os
= &wwos
[i
][j
], j
= wwncol
- j
; --j
>= 0;)
for (j
= 0; j
< wwncol
;) {
char buf
[512]; /* > wwncol */
for (; j
++ < wwncol
&& ns
++->c_w
== os
++->c_w
;)
while (j
< wwncol
&& ns
->c_m
== m
) {
if (ns
->c_w
== os
->c_w
) {
&& i
== wwnrow
- 1 && q
- buf
+ c
== wwncol
) {
xxinschar(i
, c
, *buf
, m
);
xxwrite(i
, c
- 1, buf
, 1, m
);
} else if (tt
.tt_insspace
) {
xxwrite(i
, c
, buf
, 1, m
);
xxwrite(i
, c
- 1, buf
, 1, m
);
xxwrite(i
, c
- 1, &ns
[-2].c_c
,
xxwrite(i
, c
, buf
, q
- buf
, m
);