1 /* @(#)wwupdate.c 8.1 (Berkeley) 6/6/93 */
2 /* $NetBSD: wwupdate.c,v 1.6 2003/08/07 11:17:46 agc Exp $ */
3
4 /*
5 * Copyright (c) 1983, 1993
6 * The Regents of the University of California. All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * Edward Wang at The University of California, Berkeley.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
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.
22 *
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
33 * SUCH DAMAGE.
34 */
35
36 #include "ww.h"
37 #include "tt.h"
38 #include "xx.h"
39
40 void
wwupdate1(int top,int bot)41 wwupdate1(int top, int bot)
42 {
43 int i;
44 int j;
45 char *touched;
46 struct ww_update *upd;
47 char check_clreos = 0;
48 int scan_top, scan_bot;
49
50 wwnupdate++;
51 {
52 char *t1 = wwtouched + top, *t2 = wwtouched + bot;
53 int n;
54
55 while (!*t1++)
56 if (t1 == t2)
57 return;
58 while (!*--t2)
59 ;
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;
65
66 /*
67 * t1 is one past the first touched row,
68 * t2 is on the last touched row.
69 */
70 for (t1--, n = 1; t1 < t2;)
71 if (*t1++)
72 n++;
73 /*
74 * If we can't clreos then we try for clearing
75 * the whole screen.
76 */
77 if ((check_clreos = n * 10 > (wwnrow - st) * 9)) {
78 scan_top = st;
79 scan_bot = wwnrow;
80 }
81 }
82 }
83 if (tt.tt_clreol == 0 && !check_clreos)
84 goto simple;
85 for (i = scan_top, touched = &wwtouched[i], upd = &wwupd[i];
86 i < scan_bot;
87 i++, touched++, upd++) {
88 int gain = 0;
89 int best_gain = 0;
90 int best_col = 0;
91 union ww_char *ns, *os;
92
93 if (wwinterrupt())
94 return;
95 if (!check_clreos && !*touched)
96 continue;
97 wwnupdscan++;
98 j = wwncol;
99 ns = &wwns[i][j];
100 os = &wwos[i][j];
101 while (--j >= 0) {
102 /*
103 * The cost of clearing is:
104 * ncol - nblank + X
105 * The cost of straight update is, more or less:
106 * ncol - nsame
107 * We clear if nblank - nsame > X
108 * X is the clreol overhead.
109 * So we make gain = nblank - nsame.
110 */
111 if ((--ns)->c_w == (--os)->c_w)
112 gain--;
113 else
114 best_gain--;
115 if (ns->c_w == ' ')
116 gain++;
117 if (gain > best_gain) {
118 best_col = j;
119 best_gain = gain;
120 }
121 }
122 upd->best_gain = best_gain;
123 upd->best_col = best_col;
124 upd->gain = gain;
125 }
126 if (check_clreos) {
127 struct ww_update *u;
128 int gain = 0;
129 int best_gain = 0;
130 int best_row = 0;
131 int simple_gain = 0;
132 char didit = 0;
133
134 /*
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.
141 */
142 for (j = scan_bot - 1, u = wwupd + j; j >= top; j--, u--) {
143 int g = gain + u->best_gain;
144
145 if (g > best_gain) {
146 best_gain = g;
147 best_row = j;
148 }
149 gain += u->gain;
150 if (tt.tt_clreol != 0 && u->best_gain > 4)
151 simple_gain += u->best_gain - 4;
152 }
153 if (tt.tt_clreos == 0) {
154 if (gain > simple_gain && gain > 4) {
155 xxclear();
156 i = top = scan_top;
157 bot = scan_bot;
158 j = 0;
159 didit = 1;
160 }
161 } else
162 if (best_gain > simple_gain && best_gain > 4) {
163 i = best_row;
164 xxclreos(i, j = wwupd[i].best_col);
165 bot = scan_bot;
166 didit = 1;
167 }
168 if (didit) {
169 wwnupdclreos++;
170 wwnupdclreosline += wwnrow - i;
171 u = wwupd + i;
172 while (i < scan_bot) {
173 union ww_char *os = &wwos[i][j];
174
175 for (j = wwncol - j; --j >= 0;)
176 os++->c_w = ' ';
177 wwtouched[i++] |= WWU_TOUCHED;
178 u++->best_gain = 0;
179 j = 0;
180 }
181 } else
182 wwnupdclreosmiss++;
183 }
184 simple:
185 for (i = top, touched = &wwtouched[i], upd = &wwupd[i]; i < bot;
186 i++, touched++, upd++) {
187 union ww_char *os, *ns;
188 char didit;
189
190 if (!*touched)
191 continue;
192 *touched = 0;
193 wwnupdline++;
194 didit = 0;
195 if (tt.tt_clreol != 0 && upd->best_gain > 4) {
196 wwnupdclreol++;
197 xxclreol(i, j = upd->best_col);
198 for (os = &wwos[i][j], j = wwncol - j; --j >= 0;)
199 os++->c_w = ' ';
200 didit = 1;
201 }
202 ns = wwns[i];
203 os = wwos[i];
204 for (j = 0; j < wwncol;) {
205 char *p, *q;
206 char m;
207 int c;
208 int n;
209 char buf[512]; /* > wwncol */
210 union ww_char lastc;
211
212 for (; j++ < wwncol && ns++->c_w == os++->c_w;)
213 ;
214 if (j > wwncol)
215 break;
216 p = buf;
217 m = ns[-1].c_m;
218 c = j - 1;
219 os[-1] = ns[-1];
220 *p++ = ns[-1].c_c;
221 n = 5;
222 q = p;
223 while (j < wwncol && ns->c_m == m) {
224 *p++ = ns->c_c;
225 if (ns->c_w == os->c_w) {
226 if (--n <= 0)
227 break;
228 os++;
229 ns++;
230 } else {
231 n = 5;
232 q = p;
233 lastc = *os;
234 *os++ = *ns++;
235 }
236 j++;
237 }
238 n = q - buf;
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) {
242 if (n > 1) {
243 q[-2] = q[-1];
244 n--;
245 } else
246 c--;
247 xxwrite(i, c, buf, n, m);
248 c += n - 1;
249 if (tt.tt_inschar)
250 xxinschar(i, c, ns[-2].c_c,
251 ns[-2].c_m);
252 else {
253 xxinsspace(i, c);
254 xxwrite(i, c, &ns[-2].c_c, 1,
255 ns[-2].c_m);
256 }
257 } else {
258 if (--n)
259 xxwrite(i, c, buf, n, m);
260 os[-1] = lastc;
261 *touched = WWU_TOUCHED;
262 }
263 didit = 1;
264 }
265 if (!didit)
266 wwnupdmiss++;
267 }
268 }
269