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  * @(#)wwupdate.c       8.1 (Berkeley) 6/6/93
  37  * $FreeBSD: src/usr.bin/window/wwupdate.c,v 1.1.1.1.14.1 2001/05/17 09:45:02 obrien Exp $
  38  * $DragonFly: src/usr.bin/window/wwupdate.c,v 1.2 2003/06/17 04:29:34 dillon Exp $
  39  */
  40
  41 #include "ww.h"
  42 #include "tt.h"
  43
  44 wwupdate1(top, bot)
  45 {
  46         int i;
  47         register j;
  48         char *touched;
  49         struct ww_update *upd;
  50         char check_clreos = 0;
  51         int scan_top, scan_bot;
  52
  53         wwnupdate++;
  54         {
  55                 register char *t1 = wwtouched + top, *t2 = wwtouched + bot;
  56                 register n;
  57
  58                 while (!*t1++)
  59                         if (t1 == t2)
  60                                 return;
  61                 while (!*--t2)
  62                         ;
  63                 scan_top = top = t1 - wwtouched - 1;
  64                 scan_bot = bot = t2 - wwtouched + 1;
  65                 if (scan_bot - scan_top > 1 &&
  66                     (tt.tt_clreos != 0 || tt.tt_clear != 0)) {
  67                         int st = tt.tt_clreos != 0 ? scan_top : 0;
  68
  69                         /*
  70                          * t1 is one past the first touched row,
  71                          * t2 is on the last touched row.
  72                          */
  73                         for (t1--, n = 1; t1 < t2;)
  74                                 if (*t1++)
  75                                         n++;
  76                         /*
  77                          * If we can't clreos then we try for clearing
  78                          * the whole screen.
  79                          */
  80                         if (check_clreos = n * 10 > (wwnrow - st) * 9) {
  81                                 scan_top = st;
  82                                 scan_bot = wwnrow;
  83                         }
  84                 }
  85         }
  86         if (tt.tt_clreol == 0 && !check_clreos)
  87                 goto simple;
  88         for (i = scan_top, touched = &wwtouched[i], upd = &wwupd[i];
  89              i < scan_bot;
  90              i++, touched++, upd++) {
  91                 register gain = 0;
  92                 register best_gain = 0;
  93                 register best_col;
  94                 register union ww_char *ns, *os;
  95
  96                 if (wwinterrupt())
  97                         return;
  98                 if (!check_clreos && !*touched)
  99                         continue;
 100                 wwnupdscan++;
 101                 j = wwncol;
 102                 ns = &wwns[i][j];
 103                 os = &wwos[i][j];
 104                 while (--j >= 0) {
 105                         /*
 106                          * The cost of clearing is:
 107                          *      ncol - nblank + X
 108                          * The cost of straight update is, more or less:
 109                          *      ncol - nsame
 110                          * We clear if  nblank - nsame > X
 111                          * X is the clreol overhead.
 112                          * So we make gain = nblank - nsame.
 113                          */
 114                         if ((--ns)->c_w == (--os)->c_w)
 115                                 gain--;
 116                         else
 117                                 best_gain--;
 118                         if (ns->c_w == ' ')
 119                                 gain++;
 120                         if (gain > best_gain) {
 121                                 best_col = j;
 122                                 best_gain = gain;
 123                         }
 124                 }
 125                 upd->best_gain = best_gain;
 126                 upd->best_col = best_col;
 127                 upd->gain = gain;
 128         }
 129         if (check_clreos) {
 130                 register struct ww_update *u;
 131                 register gain = 0;
 132                 register best_gain = 0;
 133                 int best_row;
 134                 register simple_gain = 0;
 135                 char didit = 0;
 136
 137                 /*
 138                  * gain is the advantage of clearing all the lines.
 139                  * best_gain is the advantage of clearing to eos
 140                  * at best_row and u->best_col.
 141                  * simple_gain is the advantage of using only clreol.
 142                  * We use g > best_gain because u->best_col can be
 143                  * undefined when u->best_gain is 0 so we can't use it.
 144                  */
 145                 for (j = scan_bot - 1, u = wwupd + j; j >= top; j--, u--) {
 146                         register g = gain + u->best_gain;
 147
 148                         if (g > best_gain) {
 149                                 best_gain = g;
 150                                 best_row = j;
 151                         }
 152                         gain += u->gain;
 153                         if (tt.tt_clreol != 0 && u->best_gain > 4)
 154                                 simple_gain += u->best_gain - 4;
 155                 }
 156                 if (tt.tt_clreos == 0) {
 157                         if (gain > simple_gain && gain > 4) {
 158                                 xxclear();
 159                                 i = top = scan_top;
 160                                 bot = scan_bot;
 161                                 j = 0;
 162                                 didit = 1;
 163                         }
 164                 } else
 165                         if (best_gain > simple_gain && best_gain > 4) {
 166                                 i = best_row;
 167                                 xxclreos(i, j = wwupd[i].best_col);
 168                                 bot = scan_bot;
 169                                 didit = 1;
 170                         }
 171                 if (didit) {
 172                         wwnupdclreos++;
 173                         wwnupdclreosline += wwnrow - i;
 174                         u = wwupd + i;
 175                         while (i < scan_bot) {
 176                                 register union ww_char *os = &wwos[i][j];
 177
 178                                 for (j = wwncol - j; --j >= 0;)
 179                                         os++->c_w = ' ';
 180                                 wwtouched[i++] |= WWU_TOUCHED;
 181                                 u++->best_gain = 0;
 182                                 j = 0;
 183                         }
 184                 } else
 185                         wwnupdclreosmiss++;
 186         }
 187 simple:
 188         for (i = top, touched = &wwtouched[i], upd = &wwupd[i]; i < bot;
 189              i++, touched++, upd++) {
 190                 register union ww_char *os, *ns;
 191                 char didit;
 192
 193                 if (!*touched)
 194                         continue;
 195                 *touched = 0;
 196                 wwnupdline++;
 197                 didit = 0;
 198                 if (tt.tt_clreol != 0 && upd->best_gain > 4) {
 199                         wwnupdclreol++;
 200                         xxclreol(i, j = upd->best_col);
 201                         for (os = &wwos[i][j], j = wwncol - j; --j >= 0;)
 202                                 os++->c_w = ' ';
 203                         didit = 1;
 204                 }
 205                 ns = wwns[i];
 206                 os = wwos[i];
 207                 for (j = 0; j < wwncol;) {
 208                         register char *p, *q;
 209                         char m;
 210                         int c;
 211                         register n;
 212                         char buf[512];                  /* > wwncol */
 213                         union ww_char lastc;
 214
 215                         for (; j++ < wwncol && ns++->c_w == os++->c_w;)
 216                                 ;
 217                         if (j > wwncol)
 218                                 break;
 219                         p = buf;
 220                         m = ns[-1].c_m;
 221                         c = j - 1;
 222                         os[-1] = ns[-1];
 223                         *p++ = ns[-1].c_c;
 224                         n = 5;
 225                         q = p;
 226                         while (j < wwncol && ns->c_m == m) {
 227                                 *p++ = ns->c_c;
 228                                 if (ns->c_w == os->c_w) {
 229                                         if (--n <= 0)
 230                                                 break;
 231                                         os++;
 232                                         ns++;
 233                                 } else {
 234                                         n = 5;
 235                                         q = p;
 236                                         lastc = *os;
 237                                         *os++ = *ns++;
 238                                 }
 239                                 j++;
 240                         }
 241                         n = q - buf;
 242                         if (!wwwrap || i != wwnrow - 1 || c + n != wwncol)
 243                                 xxwrite(i, c, buf, n, m);
 244                         else if (tt.tt_inschar || tt.tt_insspace) {
 245                                 if (n > 1) {
 246                                         q[-2] = q[-1];
 247                                         n--;
 248                                 } else
 249                                         c--;
 250                                 xxwrite(i, c, buf, n, m);
 251                                 c += n - 1;
 252                                 if (tt.tt_inschar)
 253                                         xxinschar(i, c, ns[-2].c_c,
 254                                                 ns[-2].c_m);
 255                                 else {
 256                                         xxinsspace(i, c);
 257                                         xxwrite(i, c, &ns[-2].c_c, 1,
 258                                                 ns[-2].c_m);
 259                                 }
 260                         } else {
 261                                 if (--n)
 262                                         xxwrite(i, c, buf, n, m);
 263                                 os[-1] = lastc;
 264                                 *touched = WWU_TOUCHED;
 265                         }
 266                         didit = 1;
 267                 }
 268                 if (!didit)
 269                         wwnupdmiss++;
 270         }
 271 }