usr.bin/window/wwupdate.c

   1 /*      $NetBSD: wwupdate.c,v 1.6 2003/08/07 11:17:46 agc Exp $ */
   2
   3 /*
   4  * Copyright (c) 1983, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Edward Wang at The University of California, Berkeley.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #include <sys/cdefs.h>
  36 #ifndef lint
  37 #if 0
  38 static char sccsid[] = "@(#)wwupdate.c  8.1 (Berkeley) 6/6/93";
  39 #else
  40 __RCSID("$NetBSD: wwupdate.c,v 1.6 2003/08/07 11:17:46 agc Exp $");
  41 #endif
  42 #endif /* not lint */
  43
  44 #include "ww.h"
  45 #include "tt.h"
  46 #include "xx.h"
  47
  48 void
  49 wwupdate1(int top, int bot)
  50 {
  51         int i;
  52         int j;
  53         char *touched;
  54         struct ww_update *upd;
  55         char check_clreos = 0;
  56         int scan_top, scan_bot;
  57
  58         wwnupdate++;
  59         {
  60                 char *t1 = wwtouched + top, *t2 = wwtouched + bot;
  61                 int n;
  62
  63                 while (!*t1++)
  64                         if (t1 == t2)
  65                                 return;
  66                 while (!*--t2)
  67                         ;
  68                 scan_top = top = t1 - wwtouched - 1;
  69                 scan_bot = bot = t2 - wwtouched + 1;
  70                 if (scan_bot - scan_top > 1 &&
  71                     (tt.tt_clreos != 0 || tt.tt_clear != 0)) {
  72                         int st = tt.tt_clreos != 0 ? scan_top : 0;
  73
  74                         /*
  75                          * t1 is one past the first touched row,
  76                          * t2 is on the last touched row.
  77                          */
  78                         for (t1--, n = 1; t1 < t2;)
  79                                 if (*t1++)
  80                                         n++;
  81                         /*
  82                          * If we can't clreos then we try for clearing
  83                          * the whole screen.
  84                          */
  85                         if ((check_clreos = n * 10 > (wwnrow - st) * 9)) {
  86                                 scan_top = st;
  87                                 scan_bot = wwnrow;
  88                         }
  89                 }
  90         }
  91         if (tt.tt_clreol == 0 && !check_clreos)
  92                 goto simple;
  93         for (i = scan_top, touched = &wwtouched[i], upd = &wwupd[i];
  94              i < scan_bot;
  95              i++, touched++, upd++) {
  96                 int gain = 0;
  97                 int best_gain = 0;
  98                 int best_col = 0;
  99                 union ww_char *ns, *os;
 100
 101                 if (wwinterrupt())
 102                         return;
 103                 if (!check_clreos && !*touched)
 104                         continue;
 105                 wwnupdscan++;
 106                 j = wwncol;
 107                 ns = &wwns[i][j];
 108                 os = &wwos[i][j];
 109                 while (--j >= 0) {
 110                         /*
 111                          * The cost of clearing is:
 112                          *      ncol - nblank + X
 113                          * The cost of straight update is, more or less:
 114                          *      ncol - nsame
 115                          * We clear if  nblank - nsame > X
 116                          * X is the clreol overhead.
 117                          * So we make gain = nblank - nsame.
 118                          */
 119                         if ((--ns)->c_w == (--os)->c_w)
 120                                 gain--;
 121                         else
 122                                 best_gain--;
 123                         if (ns->c_w == ' ')
 124                                 gain++;
 125                         if (gain > best_gain) {
 126                                 best_col = j;
 127                                 best_gain = gain;
 128                         }
 129                 }
 130                 upd->best_gain = best_gain;
 131                 upd->best_col = best_col;
 132                 upd->gain = gain;
 133         }
 134         if (check_clreos) {
 135                 struct ww_update *u;
 136                 int gain = 0;
 137                 int best_gain = 0;
 138                 int best_row = 0;
 139                 int simple_gain = 0;
 140                 char didit = 0;
 141
 142                 /*
 143                  * gain is the advantage of clearing all the lines.
 144                  * best_gain is the advantage of clearing to eos
 145                  * at best_row and u->best_col.
 146                  * simple_gain is the advantage of using only clreol.
 147                  * We use g > best_gain because u->best_col can be
 148                  * undefined when u->best_gain is 0 so we can't use it.
 149                  */
 150                 for (j = scan_bot - 1, u = wwupd + j; j >= top; j--, u--) {
 151                         int g = gain + u->best_gain;
 152
 153                         if (g > best_gain) {
 154                                 best_gain = g;
 155                                 best_row = j;
 156                         }
 157                         gain += u->gain;
 158                         if (tt.tt_clreol != 0 && u->best_gain > 4)
 159                                 simple_gain += u->best_gain - 4;
 160                 }
 161                 if (tt.tt_clreos == 0) {
 162                         if (gain > simple_gain && gain > 4) {
 163                                 xxclear();
 164                                 i = top = scan_top;
 165                                 bot = scan_bot;
 166                                 j = 0;
 167                                 didit = 1;
 168                         }
 169                 } else
 170                         if (best_gain > simple_gain && best_gain > 4) {
 171                                 i = best_row;
 172                                 xxclreos(i, j = wwupd[i].best_col);
 173                                 bot = scan_bot;
 174                                 didit = 1;
 175                         }
 176                 if (didit) {
 177                         wwnupdclreos++;
 178                         wwnupdclreosline += wwnrow - i;
 179                         u = wwupd + i;
 180                         while (i < scan_bot) {
 181                                 union ww_char *os = &wwos[i][j];
 182
 183                                 for (j = wwncol - j; --j >= 0;)
 184                                         os++->c_w = ' ';
 185                                 wwtouched[i++] |= WWU_TOUCHED;
 186                                 u++->best_gain = 0;
 187                                 j = 0;
 188                         }
 189                 } else
 190                         wwnupdclreosmiss++;
 191         }
 192 simple:
 193         for (i = top, touched = &wwtouched[i], upd = &wwupd[i]; i < bot;
 194              i++, touched++, upd++) {
 195                 union ww_char *os, *ns;
 196                 char didit;
 197
 198                 if (!*touched)
 199                         continue;
 200                 *touched = 0;
 201                 wwnupdline++;
 202                 didit = 0;
 203                 if (tt.tt_clreol != 0 && upd->best_gain > 4) {
 204                         wwnupdclreol++;
 205                         xxclreol(i, j = upd->best_col);
 206                         for (os = &wwos[i][j], j = wwncol - j; --j >= 0;)
 207                                 os++->c_w = ' ';
 208                         didit = 1;
 209                 }
 210                 ns = wwns[i];
 211                 os = wwos[i];
 212                 for (j = 0; j < wwncol;) {
 213                         char *p, *q;
 214                         char m;
 215                         int c;
 216                         int n;
 217                         char buf[512];                  /* > wwncol */
 218                         union ww_char lastc;
 219
 220                         for (; j++ < wwncol && ns++->c_w == os++->c_w;)
 221                                 ;
 222                         if (j > wwncol)
 223                                 break;
 224                         p = buf;
 225                         m = ns[-1].c_m;
 226                         c = j - 1;
 227                         os[-1] = ns[-1];
 228                         *p++ = ns[-1].c_c;
 229                         n = 5;
 230                         q = p;
 231                         while (j < wwncol && ns->c_m == m) {
 232                                 *p++ = ns->c_c;
 233                                 if (ns->c_w == os->c_w) {
 234                                         if (--n <= 0)
 235                                                 break;
 236                                         os++;
 237                                         ns++;
 238                                 } else {
 239                                         n = 5;
 240                                         q = p;
 241                                         lastc = *os;
 242                                         *os++ = *ns++;
 243                                 }
 244                                 j++;
 245                         }
 246                         n = q - buf;
 247                         if (!wwwrap || i != wwnrow - 1 || c + n != wwncol)
 248                                 xxwrite(i, c, buf, n, m);
 249                         else if (tt.tt_inschar || tt.tt_insspace) {
 250                                 if (n > 1) {
 251                                         q[-2] = q[-1];
 252                                         n--;
 253                                 } else
 254                                         c--;
 255                                 xxwrite(i, c, buf, n, m);
 256                                 c += n - 1;
 257                                 if (tt.tt_inschar)
 258                                         xxinschar(i, c, ns[-2].c_c,
 259                                                 ns[-2].c_m);
 260                                 else {
 261                                         xxinsspace(i, c);
 262                                         xxwrite(i, c, &ns[-2].c_c, 1,
 263                                                 ns[-2].c_m);
 264                                 }
 265                         } else {
 266                                 if (--n)
 267                                         xxwrite(i, c, buf, n, m);
 268                                 os[-1] = lastc;
 269                                 *touched = WWU_TOUCHED;
 270                         }
 271                         didit = 1;
 272                 }
 273                 if (!didit)
 274                         wwnupdmiss++;
 275         }
 276 }