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
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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
36 * @(#)wwupdate.c 8.1 (Berkeley) 6/6/93
37 * $FreeBSD: src/usr.bin/window/wwupdate.c,v 1.1.1.1.14.1 2001/05/17 09:45:02 obrien Exp $
38 * $DragonFly: src/usr.bin/window/wwupdate.c,v 1.2 2003/06/17 04:29:34 dillon Exp $
49 struct ww_update *upd;
50 char check_clreos = 0;
51 int scan_top, scan_bot;
55 register char *t1 = wwtouched + top, *t2 = wwtouched + bot;
63 scan_top = top = t1 - wwtouched - 1;
64 scan_bot = bot = t2 - wwtouched + 1;
65 if (scan_bot - scan_top > 1 &&
66 (tt.tt_clreos != 0 || tt.tt_clear != 0)) {
67 int st = tt.tt_clreos != 0 ? scan_top : 0;
70 * t1 is one past the first touched row,
71 * t2 is on the last touched row.
73 for (t1--, n = 1; t1 < t2;)
77 * If we can't clreos then we try for clearing
80 if (check_clreos = n * 10 > (wwnrow - st) * 9) {
86 if (tt.tt_clreol == 0 && !check_clreos)
88 for (i = scan_top, touched = &wwtouched[i], upd = &wwupd[i];
90 i++, touched++, upd++) {
92 register best_gain = 0;
94 register union ww_char *ns, *os;
98 if (!check_clreos && !*touched)
106 * The cost of clearing is:
108 * The cost of straight update is, more or less:
110 * We clear if nblank - nsame > X
111 * X is the clreol overhead.
112 * So we make gain = nblank - nsame.
114 if ((--ns)->c_w == (--os)->c_w)
120 if (gain > best_gain) {
125 upd->best_gain = best_gain;
126 upd->best_col = best_col;
130 register struct ww_update *u;
132 register best_gain = 0;
134 register simple_gain = 0;
138 * gain is the advantage of clearing all the lines.
139 * best_gain is the advantage of clearing to eos
140 * at best_row and u->best_col.
141 * simple_gain is the advantage of using only clreol.
142 * We use g > best_gain because u->best_col can be
143 * undefined when u->best_gain is 0 so we can't use it.
145 for (j = scan_bot - 1, u = wwupd + j; j >= top; j--, u--) {
146 register g = gain + u->best_gain;
153 if (tt.tt_clreol != 0 && u->best_gain > 4)
154 simple_gain += u->best_gain - 4;
156 if (tt.tt_clreos == 0) {
157 if (gain > simple_gain && gain > 4) {
165 if (best_gain > simple_gain && best_gain > 4) {
167 xxclreos(i, j = wwupd[i].best_col);
173 wwnupdclreosline += wwnrow - i;
175 while (i < scan_bot) {
176 register union ww_char *os = &wwos[i][j];
178 for (j = wwncol - j; --j >= 0;)
180 wwtouched[i++] |= WWU_TOUCHED;
188 for (i = top, touched = &wwtouched[i], upd = &wwupd[i]; i < bot;
189 i++, touched++, upd++) {
190 register union ww_char *os, *ns;
198 if (tt.tt_clreol != 0 && upd->best_gain > 4) {
200 xxclreol(i, j = upd->best_col);
201 for (os = &wwos[i][j], j = wwncol - j; --j >= 0;)
207 for (j = 0; j < wwncol;) {
208 register char *p, *q;
212 char buf[512]; /* > wwncol */
215 for (; j++ < wwncol && ns++->c_w == os++->c_w;)
226 while (j < wwncol && ns->c_m == m) {
228 if (ns->c_w == os->c_w) {
242 if (!wwwrap || i != wwnrow - 1 || c + n != wwncol)
243 xxwrite(i, c, buf, n, m);
244 else if (tt.tt_inschar || tt.tt_insspace) {
250 xxwrite(i, c, buf, n, m);
253 xxinschar(i, c, ns[-2].c_c,
257 xxwrite(i, c, &ns[-2].c_c, 1,
262 xxwrite(i, c, buf, n, m);
264 *touched = WWU_TOUCHED;