1 /* @(#)wwupdate.c 8.1 (Berkeley) 6/6/93 */
2 /* $NetBSD: wwupdate.c,v 1.6 2003/08/07 11:17:46 agc Exp $ */
5 * Copyright (c) 1983, 1993
6 * The Regents of the University of California. All rights reserved.
8 * This code is derived from software contributed to Berkeley by
9 * Edward Wang at The University of California, Berkeley.
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
41 wwupdate1(int top, int bot)
46 struct ww_update *upd;
47 char check_clreos = 0;
48 int scan_top, scan_bot;
52 char *t1 = wwtouched + top, *t2 = wwtouched + bot;
60 scan_top = top = t1 - wwtouched - 1;
61 scan_bot = bot = t2 - wwtouched + 1;
62 if (scan_bot - scan_top > 1 &&
63 (tt.tt_clreos != 0 || tt.tt_clear != 0)) {
64 int st = tt.tt_clreos != 0 ? scan_top : 0;
67 * t1 is one past the first touched row,
68 * t2 is on the last touched row.
70 for (t1--, n = 1; t1 < t2;)
74 * If we can't clreos then we try for clearing
77 if ((check_clreos = n * 10 > (wwnrow - st) * 9)) {
83 if (tt.tt_clreol == 0 && !check_clreos)
85 for (i = scan_top, touched = &wwtouched[i], upd = &wwupd[i];
87 i++, touched++, upd++) {
91 union ww_char *ns, *os;
95 if (!check_clreos && !*touched)
103 * The cost of clearing is:
105 * The cost of straight update is, more or less:
107 * We clear if nblank - nsame > X
108 * X is the clreol overhead.
109 * So we make gain = nblank - nsame.
111 if ((--ns)->c_w == (--os)->c_w)
117 if (gain > best_gain) {
122 upd->best_gain = best_gain;
123 upd->best_col = best_col;
135 * gain is the advantage of clearing all the lines.
136 * best_gain is the advantage of clearing to eos
137 * at best_row and u->best_col.
138 * simple_gain is the advantage of using only clreol.
139 * We use g > best_gain because u->best_col can be
140 * undefined when u->best_gain is 0 so we can't use it.
142 for (j = scan_bot - 1, u = wwupd + j; j >= top; j--, u--) {
143 int g = gain + u->best_gain;
150 if (tt.tt_clreol != 0 && u->best_gain > 4)
151 simple_gain += u->best_gain - 4;
153 if (tt.tt_clreos == 0) {
154 if (gain > simple_gain && gain > 4) {
162 if (best_gain > simple_gain && best_gain > 4) {
164 xxclreos(i, j = wwupd[i].best_col);
170 wwnupdclreosline += wwnrow - i;
172 while (i < scan_bot) {
173 union ww_char *os = &wwos[i][j];
175 for (j = wwncol - j; --j >= 0;)
177 wwtouched[i++] |= WWU_TOUCHED;
185 for (i = top, touched = &wwtouched[i], upd = &wwupd[i]; i < bot;
186 i++, touched++, upd++) {
187 union ww_char *os, *ns;
195 if (tt.tt_clreol != 0 && upd->best_gain > 4) {
197 xxclreol(i, j = upd->best_col);
198 for (os = &wwos[i][j], j = wwncol - j; --j >= 0;)
204 for (j = 0; j < wwncol;) {
209 char buf[512]; /* > wwncol */
212 for (; j++ < wwncol && ns++->c_w == os++->c_w;)
223 while (j < wwncol && ns->c_m == m) {
225 if (ns->c_w == os->c_w) {
239 if (!wwwrap || i != wwnrow - 1 || c + n != wwncol)
240 xxwrite(i, c, buf, n, m);
241 else if (tt.tt_inschar || tt.tt_insspace) {
247 xxwrite(i, c, buf, n, m);
250 xxinschar(i, c, ns[-2].c_c,
254 xxwrite(i, c, &ns[-2].c_c, 1,
259 xxwrite(i, c, buf, n, m);
261 *touched = WWU_TOUCHED;