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