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
  26 /* For CURTTY */
  27 #include "lisp.h"
  28 #include "frame.h"
  29
  30 #include "cm.h"
  31 #include "termhooks.h"
  32 #include "termchar.h"
  33
  34
  35 /* For now, don't try to include termcap.h.  On some systems,
  36    configure finds a non-standard termcap.h that the main build
  37    won't find.  */
  38
  39 #if defined HAVE_TERMCAP_H && 0
  40 #include <termcap.h>
  41 #else
  42 extern void tputs P_ ((const char *, int, int (*)(int)));
  43 extern char *tgoto P_ ((const char *, int, int));
  44 #endif
  45
  46 #define BIG     9999            /* 9999 good on VAXen.  For 16 bit machines
  47                                    use about 2000.... */
  48
  49 extern char *BC, *UP;
  50
  51
  52 int cost;               /* sums up costs */
  53
  54 /* ARGSUSED */
  55 int
  56 evalcost (c)
  57      char c;
  58 {
  59   cost++;
  60   return c;
  61 }
  62
  63 /* The terminal to use for low-level output. */
  64 struct tty_display_info *current_tty;
  65
  66 int
  67 cmputc (c)
  68      char c;
  69 {
  70   if (TTY_TERMSCRIPT (current_tty))
  71     putc (c & 0177, TTY_TERMSCRIPT (current_tty));
  72   putc (c & 0177, TTY_OUTPUT (current_tty));
  73   return c;
  74 }
  75
  76 /* NEXT TWO ARE DONE WITH MACROS */
  77 #if 0
  78 /*
  79  * Assume the cursor is at row row, column col.  Normally used only after
  80  * clearing the screen, when the cursor is at (0, 0), but what the heck,
  81  * let's let the guy put it anywhere.
  82  */
  83
  84 static
  85 at (tty, row, col) {
  86   curY (tty) = row;
  87   curX (tty)  = col;
  88 }
  89
  90 /*
  91  * Add n columns to the current cursor position.
  92  */
  93
  94 static
  95 addcol (tty, n) {
  96   curX (tty) += n;
  97
  98     /*
  99      * If cursor hit edge of screen, what happened?
 100      * N.B.: DO NOT!! write past edge of screen.  If you do, you
 101      * deserve what you get.  Furthermore, on terminals with
 102      * autowrap (but not magicwrap), don't write in the last column
 103      * of the last line.
 104      */
 105
 106   if (curX (tty) == tty->Wcm->cm_cols) {
 107         /*
 108          * Well, if magicwrap, still there, past the edge of the
 109          * screen (!).  If autowrap, on the col 0 of the next line.
 110          * Otherwise on last column.
 111          */
 112
 113         if (tty->Wcm->cm_magicwrap)
 114             ;                   /* "limbo" */
 115         else if (tty->Wcm->cm_autowrap) {
 116           curX (tty) = 0;
 117           curY (tty) ++;                /* Beware end of screen! */
 118         }
 119         else
 120           curX (tty)--;
 121     }
 122 }
 123 #endif
 124
 125 /*
 126  * Terminals with magicwrap (xn) don't all behave identically.
 127  * The VT100 leaves the cursor in the last column but will wrap before
 128  * printing the next character.  I hear that the Concept terminal does
 129  * the wrap immediately but ignores the next newline it sees.  And some
 130  * terminals just have buggy firmware, and think that the cursor is still
 131  * in limbo if we use direct cursor addressing from the phantom column.
 132  * The only guaranteed safe thing to do is to emit a CRLF immediately
 133  * after we reach the last column; this takes us to a known state.
 134  */
 135 void
 136 cmcheckmagic (struct tty_display_info *tty)
 137 {
 138   if (curX (tty) == FrameCols (tty))
 139     {
 140       if (!MagicWrap (tty) || curY (tty) >= FrameRows (tty) - 1)
 141         abort ();
 142       if (TTY_TERMSCRIPT (tty))
 143         putc ('\r', TTY_TERMSCRIPT (tty));
 144       putc ('\r', TTY_OUTPUT (tty));
 145       if (TTY_TERMSCRIPT (tty))
 146         putc ('\n', TTY_TERMSCRIPT (tty));
 147       putc ('\n', TTY_OUTPUT (tty));
 148       curX (tty) = 0;
 149       curY (tty)++;
 150     }
 151 }
 152
 153
 154 /*
 155  * (Re)Initialize the cost factors, given the output speed of the terminal
 156  * in the variable ospeed.  (Note: this holds B300, B9600, etc -- ie stuff
 157  * out of <sgtty.h>.)
 158  */
 159
 160 void
 161 cmcostinit (struct tty_display_info *tty)
 162 {
 163     char *p;
 164
 165 #define COST(x,e)       (x ? (cost = 0, tputs (x, 1, e), cost) : BIG)
 166 #define CMCOST(x,e)     ((x == 0) ? BIG : (p = tgoto(x, 0, 0), COST(p ,e)))
 167
 168     tty->Wcm->cc_up =    COST (tty->Wcm->cm_up, evalcost);
 169     tty->Wcm->cc_down =  COST (tty->Wcm->cm_down, evalcost);
 170     tty->Wcm->cc_left =  COST (tty->Wcm->cm_left, evalcost);
 171     tty->Wcm->cc_right = COST (tty->Wcm->cm_right, evalcost);
 172     tty->Wcm->cc_home =  COST (tty->Wcm->cm_home, evalcost);
 173     tty->Wcm->cc_cr =    COST (tty->Wcm->cm_cr, evalcost);
 174     tty->Wcm->cc_ll =    COST (tty->Wcm->cm_ll, evalcost);
 175     tty->Wcm->cc_tab =   tty->Wcm->cm_tabwidth ? COST (tty->Wcm->cm_tab, evalcost) : BIG;
 176
 177     /*
 178      * These last three are actually minimum costs.  When (if) they are
 179      * candidates for the least-cost motion, the real cost is computed.
 180      * (Note that "0" is the assumed to generate the minimum cost.
 181      * While this is not necessarily true, I have yet to see a terminal
 182      * for which is not; all the terminals that have variable-cost
 183      * cursor motion seem to take straight numeric values.  --ACT)
 184      */
 185
 186     tty->Wcm->cc_abs =  CMCOST (tty->Wcm->cm_abs, evalcost);
 187     tty->Wcm->cc_habs = CMCOST (tty->Wcm->cm_habs, evalcost);
 188     tty->Wcm->cc_vabs = CMCOST (tty->Wcm->cm_vabs, evalcost);
 189
 190 #undef CMCOST
 191 #undef COST
 192 }
 193
 194 /*
 195  * Calculate the cost to move from (srcy, srcx) to (dsty, dstx) using
 196  * up and down, and left and right, motions, and tabs.  If doit is set
 197  * actually perform the motion.
 198  */
 199
 200 static int
 201 calccost (struct tty_display_info *tty,
 202           int srcy, int srcx, int dsty, int dstx, int doit)
 203 {
 204     register int    deltay,
 205                     deltax,
 206                     c,
 207                     totalcost;
 208     int     ntabs,
 209             n2tabs,
 210             tabx,
 211             tab2x,
 212             tabcost;
 213     register char  *p;
 214
 215     /* If have just wrapped on a terminal with xn,
 216        don't believe the cursor position: give up here
 217        and force use of absolute positioning.  */
 218
 219     if (curX (tty) == tty->Wcm->cm_cols)
 220       goto fail;
 221
 222     totalcost = 0;
 223     if ((deltay = dsty - srcy) == 0)
 224         goto x;
 225     if (deltay < 0)
 226         p = tty->Wcm->cm_up, c = tty->Wcm->cc_up, deltay = -deltay;
 227     else
 228         p = tty->Wcm->cm_down, c = tty->Wcm->cc_down;
 229     if (c == BIG) {             /* caint get thar from here */
 230         if (doit)
 231             printf ("OOPS");
 232         return c;
 233     }
 234     totalcost = c * deltay;
 235     if (doit)
 236         while (--deltay >= 0)
 237           emacs_tputs (tty, p, 1, cmputc);
 238 x:
 239     if ((deltax = dstx - srcx) == 0)
 240         goto done;
 241     if (deltax < 0) {
 242         p = tty->Wcm->cm_left, c = tty->Wcm->cc_left, deltax = -deltax;
 243         goto dodelta;           /* skip all the tab junk */
 244     }
 245     /* Tabs (the toughie) */
 246     if (tty->Wcm->cc_tab >= BIG || !tty->Wcm->cm_usetabs)
 247         goto olddelta;          /* forget it! */
 248
 249     /*
 250      * ntabs is # tabs towards but not past dstx; n2tabs is one more
 251      * (ie past dstx), but this is only valid if that is not past the
 252      * right edge of the screen.  We can check that at the same time
 253      * as we figure out where we would be if we use the tabs (which
 254      * we will put into tabx (for ntabs) and tab2x (for n2tabs)).
 255      */
 256
 257     ntabs = (deltax + srcx % tty->Wcm->cm_tabwidth) / tty->Wcm->cm_tabwidth;
 258     n2tabs = ntabs + 1;
 259     tabx = (srcx / tty->Wcm->cm_tabwidth + ntabs) * tty->Wcm->cm_tabwidth;
 260     tab2x = tabx + tty->Wcm->cm_tabwidth;
 261
 262     if (tab2x >= tty->Wcm->cm_cols)     /* too far (past edge) */
 263         n2tabs = 0;
 264
 265     /*
 266      * Now set tabcost to the cost for using ntabs, and c to the cost
 267      * for using n2tabs, then pick the minimum.
 268      */
 269
 270                    /* cost for ntabs     +    cost for right motion */
 271     tabcost = ntabs ? ntabs * tty->Wcm->cc_tab + (dstx - tabx) * tty->Wcm->cc_right
 272                     : BIG;
 273
 274                    /* cost for n2tabs    +    cost for left motion */
 275     c = n2tabs  ?    n2tabs * tty->Wcm->cc_tab + (tab2x - dstx) * tty->Wcm->cc_left
 276                 : BIG;
 277
 278     if (c < tabcost)            /* then cheaper to overshoot & back up */
 279         ntabs = n2tabs, tabcost = c, tabx = tab2x;
 280
 281     if (tabcost >= BIG)         /* caint use tabs */
 282         goto newdelta;
 283
 284     /*
 285      * See if tabcost is less than just moving right
 286      */
 287
 288     if (tabcost < (deltax * tty->Wcm->cc_right)) {
 289         totalcost += tabcost;   /* use the tabs */
 290         if (doit)
 291             while (--ntabs >= 0)
 292               emacs_tputs (tty, tty->Wcm->cm_tab, 1, cmputc);
 293         srcx = tabx;
 294     }
 295
 296     /*
 297      * Now might as well just recompute the delta.
 298      */
 299
 300 newdelta:
 301     if ((deltax = dstx - srcx) == 0)
 302         goto done;
 303 olddelta:
 304     if (deltax > 0)
 305         p = tty->Wcm->cm_right, c = tty->Wcm->cc_right;
 306     else
 307         p = tty->Wcm->cm_left, c = tty->Wcm->cc_left, deltax = -deltax;
 308
 309 dodelta:
 310     if (c == BIG) {             /* caint get thar from here */
 311 fail:
 312         if (doit)
 313             printf ("OOPS");
 314         return BIG;
 315     }
 316     totalcost += c * deltax;
 317     if (doit)
 318         while (--deltax >= 0)
 319           emacs_tputs (tty, p, 1, cmputc);
 320 done:
 321     return totalcost;
 322 }
 323
 324 #if 0
 325 losecursor ()
 326 {
 327   curY = -1;
 328 }
 329 #endif
 330
 331 #define USEREL  0
 332 #define USEHOME 1
 333 #define USELL   2
 334 #define USECR   3
 335
 336 void
 337 cmgoto (tty, row, col)
 338      struct tty_display_info *tty;
 339      int row, col;
 340 {
 341     int     homecost,
 342             crcost,
 343             llcost,
 344             relcost,
 345             directcost;
 346     int     use;
 347     char   *p,
 348            *dcm;
 349
 350   /* First the degenerate case */
 351     if (row == curY (tty) && col == curX (tty)) /* already there */
 352     return;
 353
 354     if (curY (tty) >= 0 && curX (tty) >= 0)
 355     {
 356       /* We may have quick ways to go to the upper-left, bottom-left,
 357        * start-of-line, or start-of-next-line.  Or it might be best to
 358        * start where we are.  Examine the options, and pick the cheapest.
 359        */
 360
 361       relcost = calccost (tty, curY (tty), curX (tty), row, col, 0);
 362       use = USEREL;
 363       if ((homecost = tty->Wcm->cc_home) < BIG)
 364           homecost += calccost (tty, 0, 0, row, col, 0);
 365       if (homecost < relcost)
 366           relcost = homecost, use = USEHOME;
 367       if ((llcost = tty->Wcm->cc_ll) < BIG)
 368           llcost += calccost (tty, tty->Wcm->cm_rows - 1, 0, row, col, 0);
 369       if (llcost < relcost)
 370           relcost = llcost, use = USELL;
 371       if ((crcost = tty->Wcm->cc_cr) < BIG) {
 372           if (tty->Wcm->cm_autolf)
 373             if (curY (tty) + 1 >= tty->Wcm->cm_rows)
 374                 crcost = BIG;
 375               else
 376                 crcost += calccost (tty, curY (tty) + 1, 0, row, col, 0);
 377           else
 378             crcost += calccost (tty, curY (tty), 0, row, col, 0);
 379       }
 380       if (crcost < relcost)
 381           relcost = crcost, use = USECR;
 382       directcost = tty->Wcm->cc_abs, dcm = tty->Wcm->cm_abs;
 383       if (row == curY (tty) && tty->Wcm->cc_habs < BIG)
 384           directcost = tty->Wcm->cc_habs, dcm = tty->Wcm->cm_habs;
 385       else if (col == curX (tty) && tty->Wcm->cc_vabs < BIG)
 386           directcost = tty->Wcm->cc_vabs, dcm = tty->Wcm->cm_vabs;
 387     }
 388   else
 389     {
 390       directcost = 0, relcost = 100000;
 391       dcm = tty->Wcm->cm_abs;
 392     }
 393
 394   /*
 395    * In the following comparison, the = in <= is because when the costs
 396    * are the same, it looks nicer (I think) to move directly there.
 397    */
 398   if (directcost <= relcost)
 399     {
 400       /* compute REAL direct cost */
 401       cost = 0;
 402       p = dcm == tty->Wcm->cm_habs
 403         ? tgoto (dcm, row, col)
 404         : tgoto (dcm, col, row);
 405       emacs_tputs (tty, p, 1, evalcost);
 406       if (cost <= relcost)
 407         {       /* really is cheaper */
 408           emacs_tputs (tty, p, 1, cmputc);
 409           curY (tty) = row, curX (tty) = col;
 410           return;
 411         }
 412     }
 413
 414   switch (use)
 415     {
 416     case USEHOME:
 417       emacs_tputs (tty, tty->Wcm->cm_home, 1, cmputc);
 418       curY (tty) = 0, curX (tty) = 0;
 419       break;
 420
 421     case USELL:
 422       emacs_tputs (tty, tty->Wcm->cm_ll, 1, cmputc);
 423       curY (tty) = tty->Wcm->cm_rows - 1, curX (tty) = 0;
 424       break;
 425
 426     case USECR:
 427       emacs_tputs (tty, tty->Wcm->cm_cr, 1, cmputc);
 428       if (tty->Wcm->cm_autolf)
 429         curY (tty)++;
 430       curX (tty) = 0;
 431       break;
 432     }
 433
 434   (void) calccost (tty, curY (tty), curX (tty), row, col, 1);
 435   curY (tty) = row, curX (tty) = col;
 436 }
 437
 438 /* Clear out all terminal info.
 439    Used before copying into it the info on the actual terminal.
 440  */
 441
 442 void
 443 Wcm_clear (struct tty_display_info *tty)
 444 {
 445   bzero (tty->Wcm, sizeof (struct cm));
 446   UP = 0;
 447   BC = 0;
 448 }
 449
 450 /*
 451  * Initialized stuff
 452  * Return 0 if can do CM.
 453  * Return -1 if cannot.
 454  * Return -2 if size not specified.
 455  */
 456
 457 int
 458 Wcm_init (struct tty_display_info *tty)
 459 {
 460 #if 0
 461   if (tty->Wcm->cm_abs && !tty->Wcm->cm_ds)
 462     return 0;
 463 #endif
 464   if (tty->Wcm->cm_abs)
 465     return 0;
 466   /* Require up and left, and, if no absolute, down and right */
 467   if (!tty->Wcm->cm_up || !tty->Wcm->cm_left)
 468     return - 1;
 469   if (!tty->Wcm->cm_abs && (!tty->Wcm->cm_down || !tty->Wcm->cm_right))
 470     return - 1;
 471   /* Check that we know the size of the screen.... */
 472   if (tty->Wcm->cm_rows <= 0 || tty->Wcm->cm_cols <= 0)
 473     return - 2;
 474   return 0;
 475 }
 476
 477 /* arch-tag: bcf64c02-00f6-44ef-94b6-c56eab5b3dc4
 478    (do not change this comment) */