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_display_info *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   if (putc (c & 0177, TTY_OUTPUT (current_tty)) == EOF)
  74       abort ();                 /* XXX For testing only! */
  75   return c;
  76 }
  77
  78 /* NEXT TWO ARE DONE WITH MACROS */
  79 #if 0
  80 /*
  81  * Assume the cursor is at row row, column col.  Normally used only after
  82  * clearing the screen, when the cursor is at (0, 0), but what the heck,
  83  * let's let the guy put it anywhere.
  84  */
  85
  86 static
  87 at (tty, row, col) {
  88   curY (tty) = row;
  89   curX (tty)  = col;
  90 }
  91
  92 /*
  93  * Add n columns to the current cursor position.
  94  */
  95
  96 static
  97 addcol (tty, n) {
  98   curX (tty) += n;
  99
 100     /*
 101      * If cursor hit edge of screen, what happened?
 102      * N.B.: DO NOT!! write past edge of screen.  If you do, you
 103      * deserve what you get.  Furthermore, on terminals with
 104      * autowrap (but not magicwrap), don't write in the last column
 105      * of the last line.
 106      */
 107
 108   if (curX (tty) == tty->Wcm->cm_cols) {
 109         /*
 110          * Well, if magicwrap, still there, past the edge of the
 111          * screen (!).  If autowrap, on the col 0 of the next line.
 112          * Otherwise on last column.
 113          */
 114
 115         if (tty->Wcm->cm_magicwrap)
 116             ;                   /* "limbo" */
 117         else if (tty->Wcm->cm_autowrap) {
 118           curX (tty) = 0;
 119           curY (tty) ++;                /* Beware end of screen! */
 120         }
 121         else
 122           curX (tty)--;
 123     }
 124 }
 125 #endif
 126
 127 /*
 128  * Terminals with magicwrap (xn) don't all behave identically.
 129  * The VT100 leaves the cursor in the last column but will wrap before
 130  * printing the next character.  I hear that the Concept terminal does
 131  * the wrap immediately but ignores the next newline it sees.  And some
 132  * terminals just have buggy firmware, and think that the cursor is still
 133  * in limbo if we use direct cursor addressing from the phantom column.
 134  * The only guaranteed safe thing to do is to emit a CRLF immediately
 135  * after we reach the last column; this takes us to a known state.
 136  */
 137 void
 138 cmcheckmagic (struct tty_display_info *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_display_info *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_display_info *tty,
 204           int srcy, int srcx, int dsty, int dstx, int doit)
 205 {
 206     register int    deltay,
 207                     deltax,
 208                     c,
 209                     totalcost;
 210     int     ntabs,
 211             n2tabs,
 212             tabx,
 213             tab2x,
 214             tabcost;
 215     register char  *p;
 216
 217     /* If have just wrapped on a terminal with xn,
 218        don't believe the cursor position: give up here
 219        and force use of absolute positioning.  */
 220
 221     if (curX (tty) == tty->Wcm->cm_cols)
 222       goto fail;
 223
 224     totalcost = 0;
 225     if ((deltay = dsty - srcy) == 0)
 226         goto x;
 227     if (deltay < 0)
 228         p = tty->Wcm->cm_up, c = tty->Wcm->cc_up, deltay = -deltay;
 229     else
 230         p = tty->Wcm->cm_down, c = tty->Wcm->cc_down;
 231     if (c == BIG) {             /* caint get thar from here */
 232         if (doit)
 233             printf ("OOPS");
 234         return c;
 235     }
 236     totalcost = c * deltay;
 237     if (doit)
 238         while (--deltay >= 0)
 239           emacs_tputs (tty, p, 1, cmputc);
 240 x:
 241     if ((deltax = dstx - srcx) == 0)
 242         goto done;
 243     if (deltax < 0) {
 244         p = tty->Wcm->cm_left, c = tty->Wcm->cc_left, deltax = -deltax;
 245         goto dodelta;           /* skip all the tab junk */
 246     }
 247     /* Tabs (the toughie) */
 248     if (tty->Wcm->cc_tab >= BIG || !tty->Wcm->cm_usetabs)
 249         goto olddelta;          /* forget it! */
 250
 251     /*
 252      * ntabs is # tabs towards but not past dstx; n2tabs is one more
 253      * (ie past dstx), but this is only valid if that is not past the
 254      * right edge of the screen.  We can check that at the same time
 255      * as we figure out where we would be if we use the tabs (which
 256      * we will put into tabx (for ntabs) and tab2x (for n2tabs)).
 257      */
 258
 259     ntabs = (deltax + srcx % tty->Wcm->cm_tabwidth) / tty->Wcm->cm_tabwidth;
 260     n2tabs = ntabs + 1;
 261     tabx = (srcx / tty->Wcm->cm_tabwidth + ntabs) * tty->Wcm->cm_tabwidth;
 262     tab2x = tabx + tty->Wcm->cm_tabwidth;
 263
 264     if (tab2x >= tty->Wcm->cm_cols)     /* too far (past edge) */
 265         n2tabs = 0;
 266
 267     /*
 268      * Now set tabcost to the cost for using ntabs, and c to the cost
 269      * for using n2tabs, then pick the minimum.
 270      */
 271
 272                    /* cost for ntabs     +    cost for right motion */
 273     tabcost = ntabs ? ntabs * tty->Wcm->cc_tab + (dstx - tabx) * tty->Wcm->cc_right
 274                     : BIG;
 275
 276                    /* cost for n2tabs    +    cost for left motion */
 277     c = n2tabs  ?    n2tabs * tty->Wcm->cc_tab + (tab2x - dstx) * tty->Wcm->cc_left
 278                 : BIG;
 279
 280     if (c < tabcost)            /* then cheaper to overshoot & back up */
 281         ntabs = n2tabs, tabcost = c, tabx = tab2x;
 282
 283     if (tabcost >= BIG)         /* caint use tabs */
 284         goto newdelta;
 285
 286     /*
 287      * See if tabcost is less than just moving right
 288      */
 289
 290     if (tabcost < (deltax * tty->Wcm->cc_right)) {
 291         totalcost += tabcost;   /* use the tabs */
 292         if (doit)
 293             while (--ntabs >= 0)
 294               emacs_tputs (tty, tty->Wcm->cm_tab, 1, cmputc);
 295         srcx = tabx;
 296     }
 297
 298     /*
 299      * Now might as well just recompute the delta.
 300      */
 301
 302 newdelta:
 303     if ((deltax = dstx - srcx) == 0)
 304         goto done;
 305 olddelta:
 306     if (deltax > 0)
 307         p = tty->Wcm->cm_right, c = tty->Wcm->cc_right;
 308     else
 309         p = tty->Wcm->cm_left, c = tty->Wcm->cc_left, deltax = -deltax;
 310
 311 dodelta:
 312     if (c == BIG) {             /* caint get thar from here */
 313 fail:
 314         if (doit)
 315             printf ("OOPS");
 316         return BIG;
 317     }
 318     totalcost += c * deltax;
 319     if (doit)
 320         while (--deltax >= 0)
 321           emacs_tputs (tty, p, 1, cmputc);
 322 done:
 323     return totalcost;
 324 }
 325
 326 #if 0
 327 losecursor ()
 328 {
 329   curY = -1;
 330 }
 331 #endif
 332
 333 #define USEREL  0
 334 #define USEHOME 1
 335 #define USELL   2
 336 #define USECR   3
 337
 338 void
 339 cmgoto (tty, row, col)
 340      struct tty_display_info *tty;
 341      int row, col;
 342 {
 343     int     homecost,
 344             crcost,
 345             llcost,
 346             relcost,
 347             directcost;
 348     int     use;
 349     char   *p,
 350            *dcm;
 351
 352   /* First the degenerate case */
 353     if (row == curY (tty) && col == curX (tty)) /* already there */
 354     return;
 355
 356     if (curY (tty) >= 0 && curX (tty) >= 0)
 357     {
 358       /* We may have quick ways to go to the upper-left, bottom-left,
 359        * start-of-line, or start-of-next-line.  Or it might be best to
 360        * start where we are.  Examine the options, and pick the cheapest.
 361        */
 362
 363       relcost = calccost (tty, curY (tty), curX (tty), row, col, 0);
 364       use = USEREL;
 365       if ((homecost = tty->Wcm->cc_home) < BIG)
 366           homecost += calccost (tty, 0, 0, row, col, 0);
 367       if (homecost < relcost)
 368           relcost = homecost, use = USEHOME;
 369       if ((llcost = tty->Wcm->cc_ll) < BIG)
 370           llcost += calccost (tty, tty->Wcm->cm_rows - 1, 0, row, col, 0);
 371       if (llcost < relcost)
 372           relcost = llcost, use = USELL;
 373       if ((crcost = tty->Wcm->cc_cr) < BIG) {
 374           if (tty->Wcm->cm_autolf)
 375             if (curY (tty) + 1 >= tty->Wcm->cm_rows)
 376                 crcost = BIG;
 377               else
 378                 crcost += calccost (tty, curY (tty) + 1, 0, row, col, 0);
 379           else
 380             crcost += calccost (tty, curY (tty), 0, row, col, 0);
 381       }
 382       if (crcost < relcost)
 383           relcost = crcost, use = USECR;
 384       directcost = tty->Wcm->cc_abs, dcm = tty->Wcm->cm_abs;
 385       if (row == curY (tty) && tty->Wcm->cc_habs < BIG)
 386           directcost = tty->Wcm->cc_habs, dcm = tty->Wcm->cm_habs;
 387       else if (col == curX (tty) && tty->Wcm->cc_vabs < BIG)
 388           directcost = tty->Wcm->cc_vabs, dcm = tty->Wcm->cm_vabs;
 389     }
 390   else
 391     {
 392       directcost = 0, relcost = 100000;
 393       dcm = tty->Wcm->cm_abs;
 394     }
 395
 396   /*
 397    * In the following comparison, the = in <= is because when the costs
 398    * are the same, it looks nicer (I think) to move directly there.
 399    */
 400   if (directcost <= relcost)
 401     {
 402       /* compute REAL direct cost */
 403       cost = 0;
 404       p = dcm == tty->Wcm->cm_habs
 405         ? tgoto (dcm, row, col)
 406         : tgoto (dcm, col, row);
 407       emacs_tputs (tty, p, 1, evalcost);
 408       if (cost <= relcost)
 409         {       /* really is cheaper */
 410           emacs_tputs (tty, p, 1, cmputc);
 411           curY (tty) = row, curX (tty) = col;
 412           return;
 413         }
 414     }
 415
 416   switch (use)
 417     {
 418     case USEHOME:
 419       emacs_tputs (tty, tty->Wcm->cm_home, 1, cmputc);
 420       curY (tty) = 0, curX (tty) = 0;
 421       break;
 422
 423     case USELL:
 424       emacs_tputs (tty, tty->Wcm->cm_ll, 1, cmputc);
 425       curY (tty) = tty->Wcm->cm_rows - 1, curX (tty) = 0;
 426       break;
 427
 428     case USECR:
 429       emacs_tputs (tty, tty->Wcm->cm_cr, 1, cmputc);
 430       if (tty->Wcm->cm_autolf)
 431         curY (tty)++;
 432       curX (tty) = 0;
 433       break;
 434     }
 435
 436   (void) calccost (tty, curY (tty), curX (tty), row, col, 1);
 437   curY (tty) = row, curX (tty) = col;
 438 }
 439
 440 /* Clear out all terminal info.
 441    Used before copying into it the info on the actual terminal.
 442  */
 443
 444 void
 445 Wcm_clear (struct tty_display_info *tty)
 446 {
 447   bzero (tty->Wcm, sizeof (struct cm));
 448   UP = 0;
 449   BC = 0;
 450 }
 451
 452 /*
 453  * Initialized stuff
 454  * Return 0 if can do CM.
 455  * Return -1 if cannot.
 456  * Return -2 if size not specified.
 457  */
 458
 459 int
 460 Wcm_init (struct tty_display_info *tty)
 461 {
 462 #if 0
 463   if (tty->Wcm->cm_abs && !tty->Wcm->cm_ds)
 464     return 0;
 465 #endif
 466   if (tty->Wcm->cm_abs)
 467     return 0;
 468   /* Require up and left, and, if no absolute, down and right */
 469   if (!tty->Wcm->cm_up || !tty->Wcm->cm_left)
 470     return - 1;
 471   if (!tty->Wcm->cm_abs && (!tty->Wcm->cm_down || !tty->Wcm->cm_right))
 472     return - 1;
 473   /* Check that we know the size of the screen.... */
 474   if (tty->Wcm->cm_rows <= 0 || tty->Wcm->cm_cols <= 0)
 475     return - 2;
 476   return 0;
 477 }
 478
 479 /* arch-tag: bcf64c02-00f6-44ef-94b6-c56eab5b3dc4
 480    (do not change this comment) */