src/cm.c

   1 /* Cursor motion subroutines for GNU Emacs.
   2    Copyright (C) 1985, 1995 Free Software Foundation, Inc.
   3     based primarily on public domain code written by Chris Torek
   4
   5 This file is part of GNU Emacs.
   6
   7 GNU Emacs is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2, or (at your option)
  10 any later version.
  11
  12 GNU Emacs is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GNU Emacs; see the file COPYING.  If not, write to
  19 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  20 Boston, MA 02111-1307, USA.  */
  21
  22
  23 #include <config.h>
  24 #include <stdio.h>
  25 #include "cm.h"
  26 #include "termhooks.h"
  27
  28 #define BIG     9999            /* 9999 good on VAXen.  For 16 bit machines
  29                                    use about 2000.... */
  30
  31 char *tgoto ();
  32
  33 extern char *BC, *UP;
  34
  35 int cost;               /* sums up costs */
  36
  37 /* ARGSUSED */
  38 evalcost (c)
  39      char c;
  40 {
  41   cost++;
  42   return c;
  43 }
  44
  45 cmputc (c)
  46      char c;
  47 {
  48   if (termscript)
  49     fputc (c & 0177, termscript);
  50   putchar (c & 0177);
  51   return c;
  52 }
  53
  54 /* NEXT TWO ARE DONE WITH MACROS */
  55 #if 0
  56 /*
  57  * Assume the cursor is at row row, column col.  Normally used only after
  58  * clearing the screen, when the cursor is at (0, 0), but what the heck,
  59  * let's let the guy put it anywhere.
  60  */
  61
  62 static
  63 at (row, col) {
  64     curY = row;
  65     curX = col;
  66 }
  67
  68 /*
  69  * Add n columns to the current cursor position.
  70  */
  71
  72 static
  73 addcol (n) {
  74     curX += n;
  75
  76     /*
  77      * If cursor hit edge of screen, what happened?
  78      * N.B.: DO NOT!! write past edge of screen.  If you do, you
  79      * deserve what you get.  Furthermore, on terminals with
  80      * autowrap (but not magicwrap), don't write in the last column
  81      * of the last line.
  82      */
  83
  84     if (curX == Wcm.cm_cols) {
  85         /*
  86          * Well, if magicwrap, still there, past the edge of the
  87          * screen (!).  If autowrap, on the col 0 of the next line.
  88          * Otherwise on last column.
  89          */
  90
  91         if (Wcm.cm_magicwrap)
  92             ;                   /* "limbo" */
  93         else if (Wcm.cm_autowrap) {
  94             curX = 0;
  95             curY++;             /* Beware end of screen! */
  96         }
  97         else
  98             curX--;
  99     }
 100 }
 101 #endif
 102
 103 /*
 104  * Terminals with magicwrap (xn) don't all behave identically.
 105  * The VT100 leaves the cursor in the last column but will wrap before
 106  * printing the next character.  I hear that the Concept terminal does
 107  * the wrap immediately but ignores the next newline it sees.  And some
 108  * terminals just have buggy firmware, and think that the cursor is still
 109  * in limbo if we use direct cursor addressing from the phantom column.
 110  * The only guaranteed safe thing to do is to emit a CRLF immediately
 111  * after we reach the last column; this takes us to a known state.
 112  */
 113 void
 114 cmcheckmagic ()
 115 {
 116   if (curX == FrameCols)
 117     {
 118       if (!MagicWrap || curY >= FrameRows - 1)
 119         abort ();
 120       if (termscript)
 121         putc ('\r', termscript);
 122       putchar ('\r');
 123       if (termscript)
 124         putc ('\n', termscript);
 125       putchar ('\n');
 126       curX = 0;
 127       curY++;
 128     }
 129 }
 130
 131
 132 /*
 133  * (Re)Initialize the cost factors, given the output speed of the terminal
 134  * in the variable ospeed.  (Note: this holds B300, B9600, etc -- ie stuff
 135  * out of <sgtty.h>.)
 136  */
 137
 138 cmcostinit ()
 139 {
 140     char *p;
 141
 142 #define COST(x,e)       (x ? (cost = 0, tputs (x, 1, e), cost) : BIG)
 143 #define CMCOST(x,e)     ((x == 0) ? BIG : (p = tgoto(x, 0, 0), COST(p ,e)))
 144
 145     Wcm.cc_up =         COST (Wcm.cm_up, evalcost);
 146     Wcm.cc_down =       COST (Wcm.cm_down, evalcost);
 147     Wcm.cc_left =       COST (Wcm.cm_left, evalcost);
 148     Wcm.cc_right =      COST (Wcm.cm_right, evalcost);
 149     Wcm.cc_home =       COST (Wcm.cm_home, evalcost);
 150     Wcm.cc_cr =         COST (Wcm.cm_cr, evalcost);
 151     Wcm.cc_ll =         COST (Wcm.cm_ll, evalcost);
 152     Wcm.cc_tab =        Wcm.cm_tabwidth ? COST (Wcm.cm_tab, evalcost) : BIG;
 153
 154     /*
 155      * These last three are actually minimum costs.  When (if) they are
 156      * candidates for the least-cost motion, the real cost is computed.
 157      * (Note that "0" is the assumed to generate the minimum cost.
 158      * While this is not necessarily true, I have yet to see a terminal
 159      * for which is not; all the terminals that have variable-cost
 160      * cursor motion seem to take straight numeric values.  --ACT)
 161      */
 162
 163     Wcm.cc_abs =  CMCOST (Wcm.cm_abs, evalcost);
 164     Wcm.cc_habs = CMCOST (Wcm.cm_habs, evalcost);
 165     Wcm.cc_vabs = CMCOST (Wcm.cm_vabs, evalcost);
 166
 167 #undef CMCOST
 168 #undef COST
 169 }
 170
 171 /*
 172  * Calculate the cost to move from (srcy, srcx) to (dsty, dstx) using
 173  * up and down, and left and right, motions, and tabs.  If doit is set
 174  * actually perform the motion.
 175  */
 176
 177 static
 178 calccost (srcy, srcx, dsty, dstx, doit)
 179 {
 180     register int    deltay,
 181                     deltax,
 182                     c,
 183                     totalcost;
 184     int     ntabs,
 185             n2tabs,
 186             tabx,
 187             tab2x,
 188             tabcost;
 189     register char  *p;
 190
 191     /* If have just wrapped on a terminal with xn,
 192        don't believe the cursor position: give up here
 193        and force use of absolute positioning.  */
 194
 195     if (curX == Wcm.cm_cols)
 196       goto fail;
 197
 198     totalcost = 0;
 199     if ((deltay = dsty - srcy) == 0)
 200         goto x;
 201     if (deltay < 0)
 202         p = Wcm.cm_up, c = Wcm.cc_up, deltay = -deltay;
 203     else
 204         p = Wcm.cm_down, c = Wcm.cc_down;
 205     if (c == BIG) {             /* caint get thar from here */
 206         if (doit)
 207             printf ("OOPS");
 208         return c;
 209     }
 210     totalcost = c * deltay;
 211     if (doit)
 212         while (--deltay >= 0)
 213             tputs (p, 1, cmputc);
 214 x:
 215     if ((deltax = dstx - srcx) == 0)
 216         goto done;
 217     if (deltax < 0) {
 218         p = Wcm.cm_left, c = Wcm.cc_left, deltax = -deltax;
 219         goto dodelta;           /* skip all the tab junk */
 220     }
 221     /* Tabs (the toughie) */
 222     if (Wcm.cc_tab >= BIG || !Wcm.cm_usetabs)
 223         goto olddelta;          /* forget it! */
 224
 225     /*
 226      * ntabs is # tabs towards but not past dstx; n2tabs is one more
 227      * (ie past dstx), but this is only valid if that is not past the
 228      * right edge of the screen.  We can check that at the same time
 229      * as we figure out where we would be if we use the tabs (which
 230      * we will put into tabx (for ntabs) and tab2x (for n2tabs)).
 231      */
 232
 233     ntabs = (deltax + srcx % Wcm.cm_tabwidth) / Wcm.cm_tabwidth;
 234     n2tabs = ntabs + 1;
 235     tabx = (srcx / Wcm.cm_tabwidth + ntabs) * Wcm.cm_tabwidth;
 236     tab2x = tabx + Wcm.cm_tabwidth;
 237
 238     if (tab2x >= Wcm.cm_cols)   /* too far (past edge) */
 239         n2tabs = 0;
 240
 241     /*
 242      * Now set tabcost to the cost for using ntabs, and c to the cost
 243      * for using n2tabs, then pick the minimum.
 244      */
 245
 246                    /* cost for ntabs     +    cost for right motion */
 247     tabcost = ntabs ? ntabs * Wcm.cc_tab + (dstx - tabx) * Wcm.cc_right
 248                     : BIG;
 249
 250                    /* cost for n2tabs    +    cost for left motion */
 251     c = n2tabs  ?    n2tabs * Wcm.cc_tab + (tab2x - dstx) * Wcm.cc_left
 252                 : BIG;
 253
 254     if (c < tabcost)            /* then cheaper to overshoot & back up */
 255         ntabs = n2tabs, tabcost = c, tabx = tab2x;
 256
 257     if (tabcost >= BIG)         /* caint use tabs */
 258         goto newdelta;
 259
 260     /*
 261      * See if tabcost is less than just moving right
 262      */
 263
 264     if (tabcost < (deltax * Wcm.cc_right)) {
 265         totalcost += tabcost;   /* use the tabs */
 266         if (doit)
 267             while (--ntabs >= 0)
 268                 tputs (Wcm.cm_tab, 1, cmputc);
 269         srcx = tabx;
 270     }
 271
 272     /*
 273      * Now might as well just recompute the delta.
 274      */
 275
 276 newdelta:
 277     if ((deltax = dstx - srcx) == 0)
 278         goto done;
 279 olddelta:
 280     if (deltax > 0)
 281         p = Wcm.cm_right, c = Wcm.cc_right;
 282     else
 283         p = Wcm.cm_left, c = Wcm.cc_left, deltax = -deltax;
 284
 285 dodelta:
 286     if (c == BIG) {             /* caint get thar from here */
 287 fail:
 288         if (doit)
 289             printf ("OOPS");
 290         return BIG;
 291     }
 292     totalcost += c * deltax;
 293     if (doit)
 294         while (--deltax >= 0)
 295             tputs (p, 1, cmputc);
 296 done:
 297     return totalcost;
 298 }
 299
 300 #if 0
 301 losecursor ()
 302 {
 303   curY = -1;
 304 }
 305 #endif
 306
 307 #define USEREL  0
 308 #define USEHOME 1
 309 #define USELL   2
 310 #define USECR   3
 311
 312 cmgoto (row, col)
 313 {
 314     int     homecost,
 315             crcost,
 316             llcost,
 317             relcost,
 318             directcost;
 319     int     use;
 320     char   *p,
 321            *dcm;
 322
 323   /* First the degenerate case */
 324   if (row == curY && col == curX) /* already there */
 325     return;
 326
 327   if (curY >= 0 && curX >= 0)
 328     {
 329       /* We may have quick ways to go to the upper-left, bottom-left,
 330        * start-of-line, or start-of-next-line.  Or it might be best to
 331        * start where we are.  Examine the options, and pick the cheapest.
 332        */
 333
 334       relcost = calccost (curY, curX, row, col, 0);
 335       use = USEREL;
 336       if ((homecost = Wcm.cc_home) < BIG)
 337           homecost += calccost (0, 0, row, col, 0);
 338       if (homecost < relcost)
 339           relcost = homecost, use = USEHOME;
 340       if ((llcost = Wcm.cc_ll) < BIG)
 341           llcost += calccost (Wcm.cm_rows - 1, 0, row, col, 0);
 342       if (llcost < relcost)
 343           relcost = llcost, use = USELL;
 344       if ((crcost = Wcm.cc_cr) < BIG) {
 345           if (Wcm.cm_autolf)
 346               if (curY + 1 >= Wcm.cm_rows)
 347                   crcost = BIG;
 348               else
 349                   crcost += calccost (curY + 1, 0, row, col, 0);
 350           else
 351               crcost += calccost (curY, 0, row, col, 0);
 352       }
 353       if (crcost < relcost)
 354           relcost = crcost, use = USECR;
 355       directcost = Wcm.cc_abs, dcm = Wcm.cm_abs;
 356       if (row == curY && Wcm.cc_habs < BIG)
 357           directcost = Wcm.cc_habs, dcm = Wcm.cm_habs;
 358       else if (col == curX && Wcm.cc_vabs < BIG)
 359           directcost = Wcm.cc_vabs, dcm = Wcm.cm_vabs;
 360     }
 361   else
 362     {
 363       directcost = 0, relcost = 100000;
 364       dcm = Wcm.cm_abs;
 365     }
 366
 367   /*
 368    * In the following comparison, the = in <= is because when the costs
 369    * are the same, it looks nicer (I think) to move directly there.
 370    */
 371   if (directcost <= relcost)
 372     {
 373       /* compute REAL direct cost */
 374       cost = 0;
 375       p = dcm == Wcm.cm_habs ? tgoto (dcm, row, col) :
 376                                tgoto (dcm, col, row);
 377       tputs (p, 1, evalcost);
 378       if (cost <= relcost)
 379         {       /* really is cheaper */
 380           tputs (p, 1, cmputc);
 381           curY = row, curX = col;
 382           return;
 383         }
 384     }
 385
 386   switch (use)
 387     {
 388     case USEHOME:
 389       tputs (Wcm.cm_home, 1, cmputc);
 390       curY = 0, curX = 0;
 391       break;
 392
 393     case USELL:
 394       tputs (Wcm.cm_ll, 1, cmputc);
 395       curY = Wcm.cm_rows - 1, curX = 0;
 396       break;
 397
 398     case USECR:
 399       tputs (Wcm.cm_cr, 1, cmputc);
 400       if (Wcm.cm_autolf)
 401         curY++;
 402       curX = 0;
 403       break;
 404     }
 405
 406   (void) calccost (curY, curX, row, col, 1);
 407   curY = row, curX = col;
 408 }
 409
 410 /* Clear out all terminal info.
 411    Used before copying into it the info on the actual terminal.
 412  */
 413
 414 Wcm_clear ()
 415 {
 416   bzero (&Wcm, sizeof Wcm);
 417   UP = 0;
 418   BC = 0;
 419 }
 420
 421 /*
 422  * Initialized stuff
 423  * Return 0 if can do CM.
 424  * Return -1 if cannot.
 425  * Return -2 if size not specified.
 426  */
 427
 428 Wcm_init ()
 429 {
 430 #if 0
 431   if (Wcm.cm_abs && !Wcm.cm_ds)
 432     return 0;
 433 #endif
 434   if (Wcm.cm_abs)
 435     return 0;
 436   /* Require up and left, and, if no absolute, down and right */
 437   if (!Wcm.cm_up || !Wcm.cm_left)
 438     return - 1;
 439   if (!Wcm.cm_abs && (!Wcm.cm_down || !Wcm.cm_right))
 440     return - 1;
 441   /* Check that we know the size of the screen.... */
 442   if (Wcm.cm_rows <= 0 || Wcm.cm_cols <= 0)
 443     return - 2;
 444   return 0;
 445 }