usr.bin/window/wwupdate.c

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