2 * Copyright (c) 1983, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
6 * Edward Wang at The University of California, Berkeley.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 static char sccsid[] = "@(#)wwupdate.c 8.1 (Berkeley) 6/6/93";
39 static char rcsid[] = "@(#)$FreeBSD$";
50 struct ww_update *upd;
51 char check_clreos = 0;
52 int scan_top, scan_bot;
56 register char *t1 = wwtouched + top, *t2 = wwtouched + bot;
64 scan_top = top = t1 - wwtouched - 1;
65 scan_bot = bot = t2 - wwtouched + 1;
66 if (scan_bot - scan_top > 1 &&
67 (tt.tt_clreos != 0 || tt.tt_clear != 0)) {
68 int st = tt.tt_clreos != 0 ? scan_top : 0;
71 * t1 is one past the first touched row,
72 * t2 is on the last touched row.
74 for (t1--, n = 1; t1 < t2;)
78 * If we can't clreos then we try for clearing
81 if (check_clreos = n * 10 > (wwnrow - st) * 9) {
87 if (tt.tt_clreol == 0 && !check_clreos)
89 for (i = scan_top, touched = &wwtouched[i], upd = &wwupd[i];
91 i++, touched++, upd++) {
93 register best_gain = 0;
95 register union ww_char *ns, *os;
99 if (!check_clreos && !*touched)
107 * The cost of clearing is:
109 * The cost of straight update is, more or less:
111 * We clear if nblank - nsame > X
112 * X is the clreol overhead.
113 * So we make gain = nblank - nsame.
115 if ((--ns)->c_w == (--os)->c_w)
121 if (gain > best_gain) {
126 upd->best_gain = best_gain;
127 upd->best_col = best_col;
131 register struct ww_update *u;
133 register best_gain = 0;
135 register simple_gain = 0;
139 * gain is the advantage of clearing all the lines.
140 * best_gain is the advantage of clearing to eos
141 * at best_row and u->best_col.
142 * simple_gain is the advantage of using only clreol.
143 * We use g > best_gain because u->best_col can be
144 * undefined when u->best_gain is 0 so we can't use it.
146 for (j = scan_bot - 1, u = wwupd + j; j >= top; j--, u--) {
147 register g = gain + u->best_gain;
154 if (tt.tt_clreol != 0 && u->best_gain > 4)
155 simple_gain += u->best_gain - 4;
157 if (tt.tt_clreos == 0) {
158 if (gain > simple_gain && gain > 4) {
166 if (best_gain > simple_gain && best_gain > 4) {
168 xxclreos(i, j = wwupd[i].best_col);
174 wwnupdclreosline += wwnrow - i;
176 while (i < scan_bot) {
177 register union ww_char *os = &wwos[i][j];
179 for (j = wwncol - j; --j >= 0;)
181 wwtouched[i++] |= WWU_TOUCHED;
189 for (i = top, touched = &wwtouched[i], upd = &wwupd[i]; i < bot;
190 i++, touched++, upd++) {
191 register union ww_char *os, *ns;
199 if (tt.tt_clreol != 0 && upd->best_gain > 4) {
201 xxclreol(i, j = upd->best_col);
202 for (os = &wwos[i][j], j = wwncol - j; --j >= 0;)
208 for (j = 0; j < wwncol;) {
209 register char *p, *q;
213 char buf[512]; /* > wwncol */
216 for (; j++ < wwncol && ns++->c_w == os++->c_w;)
227 while (j < wwncol && ns->c_m == m) {
229 if (ns->c_w == os->c_w) {
243 if (!wwwrap || i != wwnrow - 1 || c + n != wwncol)
244 xxwrite(i, c, buf, n, m);
245 else if (tt.tt_inschar || tt.tt_insspace) {
251 xxwrite(i, c, buf, n, m);
254 xxinschar(i, c, ns[-2].c_c,
258 xxwrite(i, c, &ns[-2].c_c, 1,
263 xxwrite(i, c, buf, n, m);
265 *touched = WWU_TOUCHED;