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 #else
  31 extern void tputs P_ ((const char *, int, int (*)(int)));
  32 extern char *tgoto P_ ((const char *, int, int));
  33 #endif
  34
  35 #define BIG     9999            /* 9999 good on VAXen.  For 16 bit machines
  36                                    use about 2000.... */
  37
  38 extern char *BC, *UP;
  39
  40 int cost;               /* sums up costs */
  41
  42 /* ARGSUSED */
  43 int
  44 evalcost (c)
  45      char c;
  46 {
  47   cost++;
  48   return c;
  49 }
  50
  51 int
  52 cmputc (c)
  53      char c;
  54 {
  55   if (termscript)
  56     fputc (c & 0177, termscript);
  57   putchar (c & 0177);
  58   return c;
  59 }
  60
  61 /* NEXT TWO ARE DONE WITH MACROS */
  62 #if 0
  63 /*
  64  * Assume the cursor is at row row, column col.  Normally used only after
  65  * clearing the screen, when the cursor is at (0, 0), but what the heck,
  66  * let's let the guy put it anywhere.
  67  */
  68
  69 static
  70 at (row, col) {
  71     curY = row;
  72     curX = col;
  73 }
  74
  75 /*
  76  * Add n columns to the current cursor position.
  77  */
  78
  79 static
  80 addcol (n) {
  81     curX += n;
  82
  83     /*
  84      * If cursor hit edge of screen, what happened?
  85      * N.B.: DO NOT!! write past edge of screen.  If you do, you
  86      * deserve what you get.  Furthermore, on terminals with
  87      * autowrap (but not magicwrap), don't write in the last column
  88      * of the last line.
  89      */
  90
  91     if (curX == Wcm.cm_cols) {
  92         /*
  93          * Well, if magicwrap, still there, past the edge of the
  94          * screen (!).  If autowrap, on the col 0 of the next line.
  95          * Otherwise on last column.
  96          */
  97
  98         if (Wcm.cm_magicwrap)
  99             ;                   /* "limbo" */
 100         else if (Wcm.cm_autowrap) {
 101             curX = 0;
 102             curY++;             /* Beware end of screen! */
 103         }
 104         else
 105             curX--;
 106     }
 107 }
 108 #endif
 109
 110 /*
 111  * Terminals with magicwrap (xn) don't all behave identically.
 112  * The VT100 leaves the cursor in the last column but will wrap before
 113  * printing the next character.  I hear that the Concept terminal does
 114  * the wrap immediately but ignores the next newline it sees.  And some
 115  * terminals just have buggy firmware, and think that the cursor is still
 116  * in limbo if we use direct cursor addressing from the phantom column.
 117  * The only guaranteed safe thing to do is to emit a CRLF immediately
 118  * after we reach the last column; this takes us to a known state.
 119  */
 120 void
 121 cmcheckmagic ()
 122 {
 123   if (curX == FrameCols)
 124     {
 125       if (!MagicWrap || curY >= FrameRows - 1)
 126         abort ();
 127       if (termscript)
 128         putc ('\r', termscript);
 129       putchar ('\r');
 130       if (termscript)
 131         putc ('\n', termscript);
 132       putchar ('\n');
 133       curX = 0;
 134       curY++;
 135     }
 136 }
 137
 138
 139 /*
 140  * (Re)Initialize the cost factors, given the output speed of the terminal
 141  * in the variable ospeed.  (Note: this holds B300, B9600, etc -- ie stuff
 142  * out of <sgtty.h>.)
 143  */
 144
 145 void
 146 cmcostinit ()
 147 {
 148     char *p;
 149
 150 #define COST(x,e)       (x ? (cost = 0, tputs (x, 1, e), cost) : BIG)
 151 #define CMCOST(x,e)     ((x == 0) ? BIG : (p = tgoto(x, 0, 0), COST(p ,e)))
 152
 153     Wcm.cc_up =         COST (Wcm.cm_up, evalcost);
 154     Wcm.cc_down =       COST (Wcm.cm_down, evalcost);
 155     Wcm.cc_left =       COST (Wcm.cm_left, evalcost);
 156     Wcm.cc_right =      COST (Wcm.cm_right, evalcost);
 157     Wcm.cc_home =       COST (Wcm.cm_home, evalcost);
 158     Wcm.cc_cr =         COST (Wcm.cm_cr, evalcost);
 159     Wcm.cc_ll =         COST (Wcm.cm_ll, evalcost);
 160     Wcm.cc_tab =        Wcm.cm_tabwidth ? COST (Wcm.cm_tab, evalcost) : BIG;
 161
 162     /*
 163      * These last three are actually minimum costs.  When (if) they are
 164      * candidates for the least-cost motion, the real cost is computed.
 165      * (Note that "0" is the assumed to generate the minimum cost.
 166      * While this is not necessarily true, I have yet to see a terminal
 167      * for which is not; all the terminals that have variable-cost
 168      * cursor motion seem to take straight numeric values.  --ACT)
 169      */
 170
 171     Wcm.cc_abs =  CMCOST (Wcm.cm_abs, evalcost);
 172     Wcm.cc_habs = CMCOST (Wcm.cm_habs, evalcost);
 173     Wcm.cc_vabs = CMCOST (Wcm.cm_vabs, evalcost);
 174
 175 #undef CMCOST
 176 #undef COST
 177 }
 178
 179 /*
 180  * Calculate the cost to move from (srcy, srcx) to (dsty, dstx) using
 181  * up and down, and left and right, motions, and tabs.  If doit is set
 182  * actually perform the motion.
 183  */
 184
 185 static int
 186 calccost (srcy, srcx, dsty, dstx, doit)
 187 {
 188     register int    deltay,
 189                     deltax,
 190                     c,
 191                     totalcost;
 192     int     ntabs,
 193             n2tabs,
 194             tabx,
 195             tab2x,
 196             tabcost;
 197     register char  *p;
 198
 199     /* If have just wrapped on a terminal with xn,
 200        don't believe the cursor position: give up here
 201        and force use of absolute positioning.  */
 202
 203     if (curX == Wcm.cm_cols)
 204       goto fail;
 205
 206     totalcost = 0;
 207     if ((deltay = dsty - srcy) == 0)
 208         goto x;
 209     if (deltay < 0)
 210         p = Wcm.cm_up, c = Wcm.cc_up, deltay = -deltay;
 211     else
 212         p = Wcm.cm_down, c = Wcm.cc_down;
 213     if (c == BIG) {             /* caint get thar from here */
 214         if (doit)
 215             printf ("OOPS");
 216         return c;
 217     }
 218     totalcost = c * deltay;
 219     if (doit)
 220         while (--deltay >= 0)
 221             tputs (p, 1, cmputc);
 222 x:
 223     if ((deltax = dstx - srcx) == 0)
 224         goto done;
 225     if (deltax < 0) {
 226         p = Wcm.cm_left, c = Wcm.cc_left, deltax = -deltax;
 227         goto dodelta;           /* skip all the tab junk */
 228     }
 229     /* Tabs (the toughie) */
 230     if (Wcm.cc_tab >= BIG || !Wcm.cm_usetabs)
 231         goto olddelta;          /* forget it! */
 232
 233     /*
 234      * ntabs is # tabs towards but not past dstx; n2tabs is one more
 235      * (ie past dstx), but this is only valid if that is not past the
 236      * right edge of the screen.  We can check that at the same time
 237      * as we figure out where we would be if we use the tabs (which
 238      * we will put into tabx (for ntabs) and tab2x (for n2tabs)).
 239      */
 240
 241     ntabs = (deltax + srcx % Wcm.cm_tabwidth) / Wcm.cm_tabwidth;
 242     n2tabs = ntabs + 1;
 243     tabx = (srcx / Wcm.cm_tabwidth + ntabs) * Wcm.cm_tabwidth;
 244     tab2x = tabx + Wcm.cm_tabwidth;
 245
 246     if (tab2x >= Wcm.cm_cols)   /* too far (past edge) */
 247         n2tabs = 0;
 248
 249     /*
 250      * Now set tabcost to the cost for using ntabs, and c to the cost
 251      * for using n2tabs, then pick the minimum.
 252      */
 253
 254                    /* cost for ntabs     +    cost for right motion */
 255     tabcost = ntabs ? ntabs * Wcm.cc_tab + (dstx - tabx) * Wcm.cc_right
 256                     : BIG;
 257
 258                    /* cost for n2tabs    +    cost for left motion */
 259     c = n2tabs  ?    n2tabs * Wcm.cc_tab + (tab2x - dstx) * Wcm.cc_left
 260                 : BIG;
 261
 262     if (c < tabcost)            /* then cheaper to overshoot & back up */
 263         ntabs = n2tabs, tabcost = c, tabx = tab2x;
 264
 265     if (tabcost >= BIG)         /* caint use tabs */
 266         goto newdelta;
 267
 268     /*
 269      * See if tabcost is less than just moving right
 270      */
 271
 272     if (tabcost < (deltax * Wcm.cc_right)) {
 273         totalcost += tabcost;   /* use the tabs */
 274         if (doit)
 275             while (--ntabs >= 0)
 276                 tputs (Wcm.cm_tab, 1, cmputc);
 277         srcx = tabx;
 278     }
 279
 280     /*
 281      * Now might as well just recompute the delta.
 282      */
 283
 284 newdelta:
 285     if ((deltax = dstx - srcx) == 0)
 286         goto done;
 287 olddelta:
 288     if (deltax > 0)
 289         p = Wcm.cm_right, c = Wcm.cc_right;
 290     else
 291         p = Wcm.cm_left, c = Wcm.cc_left, deltax = -deltax;
 292
 293 dodelta:
 294     if (c == BIG) {             /* caint get thar from here */
 295 fail:
 296         if (doit)
 297             printf ("OOPS");
 298         return BIG;
 299     }
 300     totalcost += c * deltax;
 301     if (doit)
 302         while (--deltax >= 0)
 303             tputs (p, 1, cmputc);
 304 done:
 305     return totalcost;
 306 }
 307
 308 #if 0
 309 losecursor ()
 310 {
 311   curY = -1;
 312 }
 313 #endif
 314
 315 #define USEREL  0
 316 #define USEHOME 1
 317 #define USELL   2
 318 #define USECR   3
 319
 320 void
 321 cmgoto (row, col)
 322 {
 323     int     homecost,
 324             crcost,
 325             llcost,
 326             relcost,
 327             directcost;
 328     int     use;
 329     char   *p,
 330            *dcm;
 331
 332   /* First the degenerate case */
 333   if (row == curY && col == curX) /* already there */
 334     return;
 335
 336   if (curY >= 0 && curX >= 0)
 337     {
 338       /* We may have quick ways to go to the upper-left, bottom-left,
 339        * start-of-line, or start-of-next-line.  Or it might be best to
 340        * start where we are.  Examine the options, and pick the cheapest.
 341        */
 342
 343       relcost = calccost (curY, curX, row, col, 0);
 344       use = USEREL;
 345       if ((homecost = Wcm.cc_home) < BIG)
 346           homecost += calccost (0, 0, row, col, 0);
 347       if (homecost < relcost)
 348           relcost = homecost, use = USEHOME;
 349       if ((llcost = Wcm.cc_ll) < BIG)
 350           llcost += calccost (Wcm.cm_rows - 1, 0, row, col, 0);
 351       if (llcost < relcost)
 352           relcost = llcost, use = USELL;
 353       if ((crcost = Wcm.cc_cr) < BIG) {
 354           if (Wcm.cm_autolf)
 355               if (curY + 1 >= Wcm.cm_rows)
 356                   crcost = BIG;
 357               else
 358                   crcost += calccost (curY + 1, 0, row, col, 0);
 359           else
 360               crcost += calccost (curY, 0, row, col, 0);
 361       }
 362       if (crcost < relcost)
 363           relcost = crcost, use = USECR;
 364       directcost = Wcm.cc_abs, dcm = Wcm.cm_abs;
 365       if (row == curY && Wcm.cc_habs < BIG)
 366           directcost = Wcm.cc_habs, dcm = Wcm.cm_habs;
 367       else if (col == curX && Wcm.cc_vabs < BIG)
 368           directcost = Wcm.cc_vabs, dcm = Wcm.cm_vabs;
 369     }
 370   else
 371     {
 372       directcost = 0, relcost = 100000;
 373       dcm = Wcm.cm_abs;
 374     }
 375
 376   /*
 377    * In the following comparison, the = in <= is because when the costs
 378    * are the same, it looks nicer (I think) to move directly there.
 379    */
 380   if (directcost <= relcost)
 381     {
 382       /* compute REAL direct cost */
 383       cost = 0;
 384       p = dcm == Wcm.cm_habs ? tgoto (dcm, row, col) :
 385                                tgoto (dcm, col, row);
 386       tputs (p, 1, evalcost);
 387       if (cost <= relcost)
 388         {       /* really is cheaper */
 389           tputs (p, 1, cmputc);
 390           curY = row, curX = col;
 391           return;
 392         }
 393     }
 394
 395   switch (use)
 396     {
 397     case USEHOME:
 398       tputs (Wcm.cm_home, 1, cmputc);
 399       curY = 0, curX = 0;
 400       break;
 401
 402     case USELL:
 403       tputs (Wcm.cm_ll, 1, cmputc);
 404       curY = Wcm.cm_rows - 1, curX = 0;
 405       break;
 406
 407     case USECR:
 408       tputs (Wcm.cm_cr, 1, cmputc);
 409       if (Wcm.cm_autolf)
 410         curY++;
 411       curX = 0;
 412       break;
 413     }
 414
 415   (void) calccost (curY, curX, row, col, 1);
 416   curY = row, curX = col;
 417 }
 418
 419 /* Clear out all terminal info.
 420    Used before copying into it the info on the actual terminal.
 421  */
 422
 423 void
 424 Wcm_clear ()
 425 {
 426   bzero (&Wcm, sizeof Wcm);
 427   UP = 0;
 428   BC = 0;
 429 }
 430
 431 /*
 432  * Initialized stuff
 433  * Return 0 if can do CM.
 434  * Return -1 if cannot.
 435  * Return -2 if size not specified.
 436  */
 437
 438 int
 439 Wcm_init ()
 440 {
 441 #if 0
 442   if (Wcm.cm_abs && !Wcm.cm_ds)
 443     return 0;
 444 #endif
 445   if (Wcm.cm_abs)
 446     return 0;
 447   /* Require up and left, and, if no absolute, down and right */
 448   if (!Wcm.cm_up || !Wcm.cm_left)
 449     return - 1;
 450   if (!Wcm.cm_abs && (!Wcm.cm_down || !Wcm.cm_right))
 451     return - 1;
 452   /* Check that we know the size of the screen.... */
 453   if (Wcm.cm_rows <= 0 || Wcm.cm_cols <= 0)
 454     return - 2;
 455   return 0;
 456 }