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 #ifdef HAVE_TERMCAP_H
  29 #include <termcap.h>
  30 #endif
  31
  32 #define BIG     9999            /* 9999 good on VAXen.  For 16 bit machines
  33                                    use about 2000.... */
  34
  35 char *tgoto ();
  36
  37 extern char *BC, *UP;
  38
  39 int cost;               /* sums up costs */
  40
  41 /* ARGSUSED */
  42 int
  43 evalcost (c)
  44      char c;
  45 {
  46   cost++;
  47   return c;
  48 }
  49
  50 int
  51 cmputc (c)
  52      char c;
  53 {
  54   if (termscript)
  55     fputc (c & 0177, termscript);
  56   putchar (c & 0177);
  57   return c;
  58 }
  59
  60 /* NEXT TWO ARE DONE WITH MACROS */
  61 #if 0
  62 /*
  63  * Assume the cursor is at row row, column col.  Normally used only after
  64  * clearing the screen, when the cursor is at (0, 0), but what the heck,
  65  * let's let the guy put it anywhere.
  66  */
  67
  68 static
  69 at (row, col) {
  70     curY = row;
  71     curX = col;
  72 }
  73
  74 /*
  75  * Add n columns to the current cursor position.
  76  */
  77
  78 static
  79 addcol (n) {
  80     curX += n;
  81
  82     /*
  83      * If cursor hit edge of screen, what happened?
  84      * N.B.: DO NOT!! write past edge of screen.  If you do, you
  85      * deserve what you get.  Furthermore, on terminals with
  86      * autowrap (but not magicwrap), don't write in the last column
  87      * of the last line.
  88      */
  89
  90     if (curX == Wcm.cm_cols) {
  91         /*
  92          * Well, if magicwrap, still there, past the edge of the
  93          * screen (!).  If autowrap, on the col 0 of the next line.
  94          * Otherwise on last column.
  95          */
  96
  97         if (Wcm.cm_magicwrap)
  98             ;                   /* "limbo" */
  99         else if (Wcm.cm_autowrap) {
 100             curX = 0;
 101             curY++;             /* Beware end of screen! */
 102         }
 103         else
 104             curX--;
 105     }
 106 }
 107 #endif
 108
 109 /*
 110  * Terminals with magicwrap (xn) don't all behave identically.
 111  * The VT100 leaves the cursor in the last column but will wrap before
 112  * printing the next character.  I hear that the Concept terminal does
 113  * the wrap immediately but ignores the next newline it sees.  And some
 114  * terminals just have buggy firmware, and think that the cursor is still
 115  * in limbo if we use direct cursor addressing from the phantom column.
 116  * The only guaranteed safe thing to do is to emit a CRLF immediately
 117  * after we reach the last column; this takes us to a known state.
 118  */
 119 void
 120 cmcheckmagic ()
 121 {
 122   if (curX == FrameCols)
 123     {
 124       if (!MagicWrap || curY >= FrameRows - 1)
 125         abort ();
 126       if (termscript)
 127         putc ('\r', termscript);
 128       putchar ('\r');
 129       if (termscript)
 130         putc ('\n', termscript);
 131       putchar ('\n');
 132       curX = 0;
 133       curY++;
 134     }
 135 }
 136
 137
 138 /*
 139  * (Re)Initialize the cost factors, given the output speed of the terminal
 140  * in the variable ospeed.  (Note: this holds B300, B9600, etc -- ie stuff
 141  * out of <sgtty.h>.)
 142  */
 143
 144 void
 145 cmcostinit ()
 146 {
 147     char *p;
 148
 149 #define COST(x,e)       (x ? (cost = 0, tputs (x, 1, e), cost) : BIG)
 150 #define CMCOST(x,e)     ((x == 0) ? BIG : (p = tgoto(x, 0, 0), COST(p ,e)))
 151
 152     Wcm.cc_up =         COST (Wcm.cm_up, evalcost);
 153     Wcm.cc_down =       COST (Wcm.cm_down, evalcost);
 154     Wcm.cc_left =       COST (Wcm.cm_left, evalcost);
 155     Wcm.cc_right =      COST (Wcm.cm_right, evalcost);
 156     Wcm.cc_home =       COST (Wcm.cm_home, evalcost);
 157     Wcm.cc_cr =         COST (Wcm.cm_cr, evalcost);
 158     Wcm.cc_ll =         COST (Wcm.cm_ll, evalcost);
 159     Wcm.cc_tab =        Wcm.cm_tabwidth ? COST (Wcm.cm_tab, evalcost) : BIG;
 160
 161     /*
 162      * These last three are actually minimum costs.  When (if) they are
 163      * candidates for the least-cost motion, the real cost is computed.
 164      * (Note that "0" is the assumed to generate the minimum cost.
 165      * While this is not necessarily true, I have yet to see a terminal
 166      * for which is not; all the terminals that have variable-cost
 167      * cursor motion seem to take straight numeric values.  --ACT)
 168      */
 169
 170     Wcm.cc_abs =  CMCOST (Wcm.cm_abs, evalcost);
 171     Wcm.cc_habs = CMCOST (Wcm.cm_habs, evalcost);
 172     Wcm.cc_vabs = CMCOST (Wcm.cm_vabs, evalcost);
 173
 174 #undef CMCOST
 175 #undef COST
 176 }
 177
 178 /*
 179  * Calculate the cost to move from (srcy, srcx) to (dsty, dstx) using
 180  * up and down, and left and right, motions, and tabs.  If doit is set
 181  * actually perform the motion.
 182  */
 183
 184 static int
 185 calccost (srcy, srcx, dsty, dstx, doit)
 186 {
 187     register int    deltay,
 188                     deltax,
 189                     c,
 190                     totalcost;
 191     int     ntabs,
 192             n2tabs,
 193             tabx,
 194             tab2x,
 195             tabcost;
 196     register char  *p;
 197
 198     /* If have just wrapped on a terminal with xn,
 199        don't believe the cursor position: give up here
 200        and force use of absolute positioning.  */
 201
 202     if (curX == Wcm.cm_cols)
 203       goto fail;
 204
 205     totalcost = 0;
 206     if ((deltay = dsty - srcy) == 0)
 207         goto x;
 208     if (deltay < 0)
 209         p = Wcm.cm_up, c = Wcm.cc_up, deltay = -deltay;
 210     else
 211         p = Wcm.cm_down, c = Wcm.cc_down;
 212     if (c == BIG) {             /* caint get thar from here */
 213         if (doit)
 214             printf ("OOPS");
 215         return c;
 216     }
 217     totalcost = c * deltay;
 218     if (doit)
 219         while (--deltay >= 0)
 220             tputs (p, 1, cmputc);
 221 x:
 222     if ((deltax = dstx - srcx) == 0)
 223         goto done;
 224     if (deltax < 0) {
 225         p = Wcm.cm_left, c = Wcm.cc_left, deltax = -deltax;
 226         goto dodelta;           /* skip all the tab junk */
 227     }
 228     /* Tabs (the toughie) */
 229     if (Wcm.cc_tab >= BIG || !Wcm.cm_usetabs)
 230         goto olddelta;          /* forget it! */
 231
 232     /*
 233      * ntabs is # tabs towards but not past dstx; n2tabs is one more
 234      * (ie past dstx), but this is only valid if that is not past the
 235      * right edge of the screen.  We can check that at the same time
 236      * as we figure out where we would be if we use the tabs (which
 237      * we will put into tabx (for ntabs) and tab2x (for n2tabs)).
 238      */
 239
 240     ntabs = (deltax + srcx % Wcm.cm_tabwidth) / Wcm.cm_tabwidth;
 241     n2tabs = ntabs + 1;
 242     tabx = (srcx / Wcm.cm_tabwidth + ntabs) * Wcm.cm_tabwidth;
 243     tab2x = tabx + Wcm.cm_tabwidth;
 244
 245     if (tab2x >= Wcm.cm_cols)   /* too far (past edge) */
 246         n2tabs = 0;
 247
 248     /*
 249      * Now set tabcost to the cost for using ntabs, and c to the cost
 250      * for using n2tabs, then pick the minimum.
 251      */
 252
 253                    /* cost for ntabs     +    cost for right motion */
 254     tabcost = ntabs ? ntabs * Wcm.cc_tab + (dstx - tabx) * Wcm.cc_right
 255                     : BIG;
 256
 257                    /* cost for n2tabs    +    cost for left motion */
 258     c = n2tabs  ?    n2tabs * Wcm.cc_tab + (tab2x - dstx) * Wcm.cc_left
 259                 : BIG;
 260
 261     if (c < tabcost)            /* then cheaper to overshoot & back up */
 262         ntabs = n2tabs, tabcost = c, tabx = tab2x;
 263
 264     if (tabcost >= BIG)         /* caint use tabs */
 265         goto newdelta;
 266
 267     /*
 268      * See if tabcost is less than just moving right
 269      */
 270
 271     if (tabcost < (deltax * Wcm.cc_right)) {
 272         totalcost += tabcost;   /* use the tabs */
 273         if (doit)
 274             while (--ntabs >= 0)
 275                 tputs (Wcm.cm_tab, 1, cmputc);
 276         srcx = tabx;
 277     }
 278
 279     /*
 280      * Now might as well just recompute the delta.
 281      */
 282
 283 newdelta:
 284     if ((deltax = dstx - srcx) == 0)
 285         goto done;
 286 olddelta:
 287     if (deltax > 0)
 288         p = Wcm.cm_right, c = Wcm.cc_right;
 289     else
 290         p = Wcm.cm_left, c = Wcm.cc_left, deltax = -deltax;
 291
 292 dodelta:
 293     if (c == BIG) {             /* caint get thar from here */
 294 fail:
 295         if (doit)
 296             printf ("OOPS");
 297         return BIG;
 298     }
 299     totalcost += c * deltax;
 300     if (doit)
 301         while (--deltax >= 0)
 302             tputs (p, 1, cmputc);
 303 done:
 304     return totalcost;
 305 }
 306
 307 #if 0
 308 losecursor ()
 309 {
 310   curY = -1;
 311 }
 312 #endif
 313
 314 #define USEREL  0
 315 #define USEHOME 1
 316 #define USELL   2
 317 #define USECR   3
 318
 319 void
 320 cmgoto (row, col)
 321 {
 322     int     homecost,
 323             crcost,
 324             llcost,
 325             relcost,
 326             directcost;
 327     int     use;
 328     char   *p,
 329            *dcm;
 330
 331   /* First the degenerate case */
 332   if (row == curY && col == curX) /* already there */
 333     return;
 334
 335   if (curY >= 0 && curX >= 0)
 336     {
 337       /* We may have quick ways to go to the upper-left, bottom-left,
 338        * start-of-line, or start-of-next-line.  Or it might be best to
 339        * start where we are.  Examine the options, and pick the cheapest.
 340        */
 341
 342       relcost = calccost (curY, curX, row, col, 0);
 343       use = USEREL;
 344       if ((homecost = Wcm.cc_home) < BIG)
 345           homecost += calccost (0, 0, row, col, 0);
 346       if (homecost < relcost)
 347           relcost = homecost, use = USEHOME;
 348       if ((llcost = Wcm.cc_ll) < BIG)
 349           llcost += calccost (Wcm.cm_rows - 1, 0, row, col, 0);
 350       if (llcost < relcost)
 351           relcost = llcost, use = USELL;
 352       if ((crcost = Wcm.cc_cr) < BIG) {
 353           if (Wcm.cm_autolf)
 354               if (curY + 1 >= Wcm.cm_rows)
 355                   crcost = BIG;
 356               else
 357                   crcost += calccost (curY + 1, 0, row, col, 0);
 358           else
 359               crcost += calccost (curY, 0, row, col, 0);
 360       }
 361       if (crcost < relcost)
 362           relcost = crcost, use = USECR;
 363       directcost = Wcm.cc_abs, dcm = Wcm.cm_abs;
 364       if (row == curY && Wcm.cc_habs < BIG)
 365           directcost = Wcm.cc_habs, dcm = Wcm.cm_habs;
 366       else if (col == curX && Wcm.cc_vabs < BIG)
 367           directcost = Wcm.cc_vabs, dcm = Wcm.cm_vabs;
 368     }
 369   else
 370     {
 371       directcost = 0, relcost = 100000;
 372       dcm = Wcm.cm_abs;
 373     }
 374
 375   /*
 376    * In the following comparison, the = in <= is because when the costs
 377    * are the same, it looks nicer (I think) to move directly there.
 378    */
 379   if (directcost <= relcost)
 380     {
 381       /* compute REAL direct cost */
 382       cost = 0;
 383       p = dcm == Wcm.cm_habs ? tgoto (dcm, row, col) :
 384                                tgoto (dcm, col, row);
 385       tputs (p, 1, evalcost);
 386       if (cost <= relcost)
 387         {       /* really is cheaper */
 388           tputs (p, 1, cmputc);
 389           curY = row, curX = col;
 390           return;
 391         }
 392     }
 393
 394   switch (use)
 395     {
 396     case USEHOME:
 397       tputs (Wcm.cm_home, 1, cmputc);
 398       curY = 0, curX = 0;
 399       break;
 400
 401     case USELL:
 402       tputs (Wcm.cm_ll, 1, cmputc);
 403       curY = Wcm.cm_rows - 1, curX = 0;
 404       break;
 405
 406     case USECR:
 407       tputs (Wcm.cm_cr, 1, cmputc);
 408       if (Wcm.cm_autolf)
 409         curY++;
 410       curX = 0;
 411       break;
 412     }
 413
 414   (void) calccost (curY, curX, row, col, 1);
 415   curY = row, curX = col;
 416 }
 417
 418 /* Clear out all terminal info.
 419    Used before copying into it the info on the actual terminal.
 420  */
 421
 422 void
 423 Wcm_clear ()
 424 {
 425   bzero (&Wcm, sizeof Wcm);
 426   UP = 0;
 427   BC = 0;
 428 }
 429
 430 /*
 431  * Initialized stuff
 432  * Return 0 if can do CM.
 433  * Return -1 if cannot.
 434  * Return -2 if size not specified.
 435  */
 436
 437 int
 438 Wcm_init ()
 439 {
 440 #if 0
 441   if (Wcm.cm_abs && !Wcm.cm_ds)
 442     return 0;
 443 #endif
 444   if (Wcm.cm_abs)
 445     return 0;
 446   /* Require up and left, and, if no absolute, down and right */
 447   if (!Wcm.cm_up || !Wcm.cm_left)
 448     return - 1;
 449   if (!Wcm.cm_abs && (!Wcm.cm_down || !Wcm.cm_right))
 450     return - 1;
 451   /* Check that we know the size of the screen.... */
 452   if (Wcm.cm_rows <= 0 || Wcm.cm_cols <= 0)
 453     return - 2;
 454   return 0;
 455 }