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1.1 root 1: /*
2: * Copyright (c) 1983 Regents of the University of California.
3: * All rights reserved.
4: *
5: * This code is derived from software contributed to Berkeley by
6: * Edward Wang at The University of California, Berkeley.
7: *
8: * Redistribution and use in source and binary forms are permitted provided
9: * that: (1) source distributions retain this entire copyright notice and
10: * comment, and (2) distributions including binaries display the following
11: * acknowledgement: ``This product includes software developed by the
12: * University of California, Berkeley and its contributors'' in the
13: * documentation or other materials provided with the distribution and in
14: * all advertising materials mentioning features or use of this software.
15: * Neither the name of the University nor the names of its contributors may
16: * be used to endorse or promote products derived from this software without
17: * specific prior written permission.
18: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
19: * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
20: * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
21: */
22:
23: #ifndef lint
24: static char sccsid[] = "@(#)wwupdate.c 3.29 (Berkeley) 6/6/90";
25: #endif /* not lint */
26:
27: #include "ww.h"
28: #include "tt.h"
29:
30: wwupdate1(top, bot)
31: {
32: int i;
33: register j;
34: char *touched;
35: struct ww_update *upd;
36: char check_clreos = 0;
37: int scan_top, scan_bot;
38:
39: wwnupdate++;
40: {
41: register char *t1 = wwtouched + top, *t2 = wwtouched + bot;
42: register n;
43:
44: while (!*t1++)
45: if (t1 == t2)
46: return;
47: while (!*--t2)
48: ;
49: scan_top = top = t1 - wwtouched - 1;
50: scan_bot = bot = t2 - wwtouched + 1;
51: if (scan_bot - scan_top > 1 &&
52: (tt.tt_clreos != 0 || tt.tt_clear != 0)) {
53: int st = tt.tt_clreos != 0 ? scan_top : 0;
54:
55: /*
56: * t1 is one past the first touched row,
57: * t2 is on the last touched row.
58: */
59: for (t1--, n = 1; t1 < t2;)
60: if (*t1++)
61: n++;
62: /*
63: * If we can't clreos then we try for clearing
64: * the whole screen.
65: */
66: if (check_clreos = n * 10 > (wwnrow - st) * 9) {
67: scan_top = st;
68: scan_bot = wwnrow;
69: }
70: }
71: }
72: if (tt.tt_clreol == 0 && !check_clreos)
73: goto simple;
74: for (i = scan_top, touched = &wwtouched[i], upd = &wwupd[i];
75: i < scan_bot;
76: i++, touched++, upd++) {
77: register gain = 0;
78: register best_gain = 0;
79: register best_col;
80: register union ww_char *ns, *os;
81:
82: if (wwinterrupt())
83: return;
84: if (!check_clreos && !*touched)
85: continue;
86: wwnupdscan++;
87: j = wwncol;
88: ns = &wwns[i][j];
89: os = &wwos[i][j];
90: while (--j >= 0) {
91: /*
92: * The cost of clearing is:
93: * ncol - nblank + X
94: * The cost of straight update is, more or less:
95: * ncol - nsame
96: * We clear if nblank - nsame > X
97: * X is the clreol overhead.
98: * So we make gain = nblank - nsame.
99: */
100: if ((--ns)->c_w == (--os)->c_w)
101: gain--;
102: else
103: best_gain--;
104: if (ns->c_w == ' ')
105: gain++;
106: if (gain > best_gain) {
107: best_col = j;
108: best_gain = gain;
109: }
110: }
111: upd->best_gain = best_gain;
112: upd->best_col = best_col;
113: upd->gain = gain;
114: }
115: if (check_clreos) {
116: register struct ww_update *u;
117: register gain = 0;
118: register best_gain = 0;
119: int best_row;
120: register simple_gain = 0;
121: char didit = 0;
122:
123: /*
124: * gain is the advantage of clearing all the lines.
125: * best_gain is the advantage of clearing to eos
126: * at best_row and u->best_col.
127: * simple_gain is the advantage of using only clreol.
128: * We use g > best_gain because u->best_col can be
129: * undefined when u->best_gain is 0 so we can't use it.
130: */
131: for (j = scan_bot - 1, u = wwupd + j; j >= top; j--, u--) {
132: register g = gain + u->best_gain;
133:
134: if (g > best_gain) {
135: best_gain = g;
136: best_row = j;
137: }
138: gain += u->gain;
139: if (tt.tt_clreol != 0 && u->best_gain > 4)
140: simple_gain += u->best_gain - 4;
141: }
142: if (tt.tt_clreos == 0) {
143: if (gain > simple_gain && gain > 4) {
144: xxclear();
145: i = top = scan_top;
146: bot = scan_bot;
147: j = 0;
148: didit = 1;
149: }
150: } else
151: if (best_gain > simple_gain && best_gain > 4) {
152: i = best_row;
153: xxclreos(i, j = wwupd[i].best_col);
154: bot = scan_bot;
155: didit = 1;
156: }
157: if (didit) {
158: wwnupdclreos++;
159: wwnupdclreosline += wwnrow - i;
160: u = wwupd + i;
161: while (i < scan_bot) {
162: register union ww_char *os = &wwos[i][j];
163:
164: for (j = wwncol - j; --j >= 0;)
165: os++->c_w = ' ';
166: wwtouched[i++] |= WWU_TOUCHED;
167: u++->best_gain = 0;
168: j = 0;
169: }
170: } else
171: wwnupdclreosmiss++;
172: }
173: simple:
174: for (i = top, touched = &wwtouched[i], upd = &wwupd[i]; i < bot;
175: i++, touched++, upd++) {
176: register union ww_char *os, *ns;
177: char didit;
178:
179: if (!*touched)
180: continue;
181: *touched = 0;
182: wwnupdline++;
183: didit = 0;
184: if (tt.tt_clreol != 0 && upd->best_gain > 4) {
185: wwnupdclreol++;
186: xxclreol(i, j = upd->best_col);
187: for (os = &wwos[i][j], j = wwncol - j; --j >= 0;)
188: os++->c_w = ' ';
189: didit = 1;
190: }
191: ns = wwns[i];
192: os = wwos[i];
193: for (j = 0; j < wwncol;) {
194: register char *p, *q;
195: char m;
196: int c;
197: register n;
198: char buf[512]; /* > wwncol */
199: union ww_char lastc;
200:
201: for (; j++ < wwncol && ns++->c_w == os++->c_w;)
202: ;
203: if (j > wwncol)
204: break;
205: p = buf;
206: m = ns[-1].c_m;
207: c = j - 1;
208: os[-1] = ns[-1];
209: *p++ = ns[-1].c_c;
210: n = 5;
211: q = p;
212: while (j < wwncol && ns->c_m == m) {
213: *p++ = ns->c_c;
214: if (ns->c_w == os->c_w) {
215: if (--n <= 0)
216: break;
217: os++;
218: ns++;
219: } else {
220: n = 5;
221: q = p;
222: lastc = *os;
223: *os++ = *ns++;
224: }
225: j++;
226: }
227: n = q - buf;
228: if (!wwwrap || i != wwnrow - 1 || c + n != wwncol)
229: xxwrite(i, c, buf, n, m);
230: else if (tt.tt_inschar || tt.tt_insspace) {
231: if (n > 1) {
232: q[-2] = q[-1];
233: n--;
234: } else
235: c--;
236: xxwrite(i, c, buf, n, m);
237: c += n - 1;
238: if (tt.tt_inschar)
239: xxinschar(i, c, ns[-2].c_c,
240: ns[-2].c_m);
241: else {
242: xxinsspace(i, c);
243: xxwrite(i, c, &ns[-2].c_c, 1,
244: ns[-2].c_m);
245: }
246: } else {
247: if (--n)
248: xxwrite(i, c, buf, n, m);
249: os[-1] = lastc;
250: *touched = WWU_TOUCHED;
251: }
252: didit = 1;
253: }
254: if (!didit)
255: wwnupdmiss++;
256: }
257: }
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