window/wwupdate.c

   1 /*      $NetBSD: wwupdate.c,v 1.4 1997/11/21 08:37:59 lukem 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. All advertising materials mentioning features or use of this software
  19  *    must display the following acknowledgement:
  20  *      This product includes software developed by the University of
  21  *      California, Berkeley and its contributors.
  22  * 4. Neither the name of the University nor the names of its contributors
  23  *    may be used to endorse or promote products derived from this software
  24  *    without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  36  * SUCH DAMAGE.
  37  */
  38
  39 #include <sys/cdefs.h>
  40 #ifndef lint
  41 #if 0
  42 static char sccsid[] = "@(#)wwupdate.c  8.1 (Berkeley) 6/6/93";
  43 #else
  44 __RCSID("$NetBSD: wwupdate.c,v 1.4 1997/11/21 08:37:59 lukem Exp $");
  45 #endif
  46 #endif /* not lint */
  47
  48 #include "ww.h"
  49 #include "tt.h"
  50 #include "xx.h"
  51
  52 void
  53 wwupdate1(top, bot)
  54         int top, bot;
  55 {
  56         int i;
  57         int j;
  58         char *touched;
  59         struct ww_update *upd;
  60         char check_clreos = 0;
  61         int scan_top, scan_bot;
  62
  63         wwnupdate++;
  64         {
  65                 char *t1 = wwtouched + top, *t2 = wwtouched + bot;
  66                 int n;
  67
  68                 while (!*t1++)
  69                         if (t1 == t2)
  70                                 return;
  71                 while (!*--t2)
  72                         ;
  73                 scan_top = top = t1 - wwtouched - 1;
  74                 scan_bot = bot = t2 - wwtouched + 1;
  75                 if (scan_bot - scan_top > 1 &&
  76                     (tt.tt_clreos != 0 || tt.tt_clear != 0)) {
  77                         int st = tt.tt_clreos != 0 ? scan_top : 0;
  78
  79                         /*
  80                          * t1 is one past the first touched row,
  81                          * t2 is on the last touched row.
  82                          */
  83                         for (t1--, n = 1; t1 < t2;)
  84                                 if (*t1++)
  85                                         n++;
  86                         /*
  87                          * If we can't clreos then we try for clearing
  88                          * the whole screen.
  89                          */
  90                         if ((check_clreos = n * 10 > (wwnrow - st) * 9)) {
  91                                 scan_top = st;
  92                                 scan_bot = wwnrow;
  93                         }
  94                 }
  95         }
  96         if (tt.tt_clreol == 0 && !check_clreos)
  97                 goto simple;
  98         for (i = scan_top, touched = &wwtouched[i], upd = &wwupd[i];
  99              i < scan_bot;
 100              i++, touched++, upd++) {
 101                 int gain = 0;
 102                 int best_gain = 0;
 103                 int best_col = 0;
 104                 union ww_char *ns, *os;
 105
 106                 if (wwinterrupt())
 107                         return;
 108                 if (!check_clreos && !*touched)
 109                         continue;
 110                 wwnupdscan++;
 111                 j = wwncol;
 112                 ns = &wwns[i][j];
 113                 os = &wwos[i][j];
 114                 while (--j >= 0) {
 115                         /*
 116                          * The cost of clearing is:
 117                          *      ncol - nblank + X
 118                          * The cost of straight update is, more or less:
 119                          *      ncol - nsame
 120                          * We clear if  nblank - nsame > X
 121                          * X is the clreol overhead.
 122                          * So we make gain = nblank - nsame.
 123                          */
 124                         if ((--ns)->c_w == (--os)->c_w)
 125                                 gain--;
 126                         else
 127                                 best_gain--;
 128                         if (ns->c_w == ' ')
 129                                 gain++;
 130                         if (gain > best_gain) {
 131                                 best_col = j;
 132                                 best_gain = gain;
 133                         }
 134                 }
 135                 upd->best_gain = best_gain;
 136                 upd->best_col = best_col;
 137                 upd->gain = gain;
 138         }
 139         if (check_clreos) {
 140                 struct ww_update *u;
 141                 int gain = 0;
 142                 int best_gain = 0;
 143                 int best_row = 0;
 144                 int simple_gain = 0;
 145                 char didit = 0;
 146
 147                 /*
 148                  * gain is the advantage of clearing all the lines.
 149                  * best_gain is the advantage of clearing to eos
 150                  * at best_row and u->best_col.
 151                  * simple_gain is the advantage of using only clreol.
 152                  * We use g > best_gain because u->best_col can be
 153                  * undefined when u->best_gain is 0 so we can't use it.
 154                  */
 155                 for (j = scan_bot - 1, u = wwupd + j; j >= top; j--, u--) {
 156                         int g = gain + u->best_gain;
 157
 158                         if (g > best_gain) {
 159                                 best_gain = g;
 160                                 best_row = j;
 161                         }
 162                         gain += u->gain;
 163                         if (tt.tt_clreol != 0 && u->best_gain > 4)
 164                                 simple_gain += u->best_gain - 4;
 165                 }
 166                 if (tt.tt_clreos == 0) {
 167                         if (gain > simple_gain && gain > 4) {
 168                                 xxclear();
 169                                 i = top = scan_top;
 170                                 bot = scan_bot;
 171                                 j = 0;
 172                                 didit = 1;
 173                         }
 174                 } else
 175                         if (best_gain > simple_gain && best_gain > 4) {
 176                                 i = best_row;
 177                                 xxclreos(i, j = wwupd[i].best_col);
 178                                 bot = scan_bot;
 179                                 didit = 1;
 180                         }
 181                 if (didit) {
 182                         wwnupdclreos++;
 183                         wwnupdclreosline += wwnrow - i;
 184                         u = wwupd + i;
 185                         while (i < scan_bot) {
 186                                 union ww_char *os = &wwos[i][j];
 187
 188                                 for (j = wwncol - j; --j >= 0;)
 189                                         os++->c_w = ' ';
 190                                 wwtouched[i++] |= WWU_TOUCHED;
 191                                 u++->best_gain = 0;
 192                                 j = 0;
 193                         }
 194                 } else
 195                         wwnupdclreosmiss++;
 196         }
 197 simple:
 198         for (i = top, touched = &wwtouched[i], upd = &wwupd[i]; i < bot;
 199              i++, touched++, upd++) {
 200                 union ww_char *os, *ns;
 201                 char didit;
 202
 203                 if (!*touched)
 204                         continue;
 205                 *touched = 0;
 206                 wwnupdline++;
 207                 didit = 0;
 208                 if (tt.tt_clreol != 0 && upd->best_gain > 4) {
 209                         wwnupdclreol++;
 210                         xxclreol(i, j = upd->best_col);
 211                         for (os = &wwos[i][j], j = wwncol - j; --j >= 0;)
 212                                 os++->c_w = ' ';
 213                         didit = 1;
 214                 }
 215                 ns = wwns[i];
 216                 os = wwos[i];
 217                 for (j = 0; j < wwncol;) {
 218                         char *p, *q;
 219                         char m;
 220                         int c;
 221                         int n;
 222                         char buf[512];                  /* > wwncol */
 223                         union ww_char lastc;
 224
 225                         for (; j++ < wwncol && ns++->c_w == os++->c_w;)
 226                                 ;
 227                         if (j > wwncol)
 228                                 break;
 229                         p = buf;
 230                         m = ns[-1].c_m;
 231                         c = j - 1;
 232                         os[-1] = ns[-1];
 233                         *p++ = ns[-1].c_c;
 234                         n = 5;
 235                         q = p;
 236                         while (j < wwncol && ns->c_m == m) {
 237                                 *p++ = ns->c_c;
 238                                 if (ns->c_w == os->c_w) {
 239                                         if (--n <= 0)
 240                                                 break;
 241                                         os++;
 242                                         ns++;
 243                                 } else {
 244                                         n = 5;
 245                                         q = p;
 246                                         lastc = *os;
 247                                         *os++ = *ns++;
 248                                 }
 249                                 j++;
 250                         }
 251                         n = q - buf;
 252                         if (!wwwrap || i != wwnrow - 1 || c + n != wwncol)
 253                                 xxwrite(i, c, buf, n, m);
 254                         else if (tt.tt_inschar || tt.tt_insspace) {
 255                                 if (n > 1) {
 256                                         q[-2] = q[-1];
 257                                         n--;
 258                                 } else
 259                                         c--;
 260                                 xxwrite(i, c, buf, n, m);
 261                                 c += n - 1;
 262                                 if (tt.tt_inschar)
 263                                         xxinschar(i, c, ns[-2].c_c,
 264                                                 ns[-2].c_m);
 265                                 else {
 266                                         xxinsspace(i, c);
 267                                         xxwrite(i, c, &ns[-2].c_c, 1,
 268                                                 ns[-2].c_m);
 269                                 }
 270                         } else {
 271                                 if (--n)
 272                                         xxwrite(i, c, buf, n, m);
 273                                 os[-1] = lastc;
 274                                 *touched = WWU_TOUCHED;
 275                         }
 276                         didit = 1;
 277                 }
 278                 if (!didit)
 279                         wwnupdmiss++;
 280         }
 281 }