src/cm.c

   1 /* Cursor motion subroutines for GNU Emacs.
   2    Copyright (C) 1985, 1995, 2001, 2002, 2003, 2004,
   3                  2005, 2006, 2007, 2008, 2009, 2010  Free Software Foundation, Inc.
   4     based primarily on public domain code written by Chris Torek
   5
   6 This file is part of GNU Emacs.
   7
   8 GNU Emacs is free software: you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation, either version 3 of the License, or
  11 (at your option) any later version.
  12
  13 GNU Emacs is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21
  22 #include <config.h>
  23 #include <stdio.h>
  24 #include <setjmp.h>
  25
  26 #include "lisp.h"
  27 #include "frame.h"
  28 #include "cm.h"
  29 #include "termhooks.h"
  30 #include "termchar.h"
  31
  32
  33 /* For now, don't try to include termcap.h.  On some systems,
  34    configure finds a non-standard termcap.h that the main build
  35    won't find.  */
  36
  37 #if defined HAVE_TERMCAP_H && 0
  38 #include <termcap.h>
  39 #else
  40 extern void tputs P_ ((const char *, int, int (*)(int)));
  41 extern char *tgoto P_ ((const char *, int, int));
  42 #endif
  43
  44 #define BIG     9999            /* 9999 good on VAXen.  For 16 bit machines
  45                                    use about 2000.... */
  46
  47 extern char *BC, *UP;
  48
  49 int cost;               /* sums up costs */
  50
  51 /* ARGSUSED */
  52 int
  53 evalcost (c)
  54      char c;
  55 {
  56   cost++;
  57   return c;
  58 }
  59
  60 /* The terminal to use for low-level output. */
  61 struct tty_display_info *current_tty;
  62
  63 int
  64 cmputc (c)
  65      char c;
  66 {
  67   if (current_tty->termscript)
  68     putc (c & 0177, current_tty->termscript);
  69   putc (c & 0177, current_tty->output);
  70   return c;
  71 }
  72
  73 /* NEXT TWO ARE DONE WITH MACROS */
  74 #if 0
  75 /*
  76  * Assume the cursor is at row row, column col.  Normally used only after
  77  * clearing the screen, when the cursor is at (0, 0), but what the heck,
  78  * let's let the guy put it anywhere.
  79  */
  80
  81 static
  82 at (tty, row, col) {
  83   curY (tty) = row;
  84   curX (tty)  = col;
  85 }
  86
  87 /*
  88  * Add n columns to the current cursor position.
  89  */
  90
  91 static
  92 addcol (tty, n) {
  93   curX (tty) += n;
  94
  95     /*
  96      * If cursor hit edge of screen, what happened?
  97      * N.B.: DO NOT!! write past edge of screen.  If you do, you
  98      * deserve what you get.  Furthermore, on terminals with
  99      * autowrap (but not magicwrap), don't write in the last column
 100      * of the last line.
 101      */
 102
 103   if (curX (tty) == tty->Wcm->cm_cols) {
 104         /*
 105          * Well, if magicwrap, still there, past the edge of the
 106          * screen (!).  If autowrap, on the col 0 of the next line.
 107          * Otherwise on last column.
 108          */
 109
 110         if (tty->Wcm->cm_magicwrap)
 111             ;                   /* "limbo" */
 112         else if (tty->Wcm->cm_autowrap) {
 113           curX (tty) = 0;
 114           curY (tty) ++;                /* Beware end of screen! */
 115         }
 116         else
 117           curX (tty)--;
 118     }
 119 }
 120 #endif
 121
 122 /*
 123  * Terminals with magicwrap (xn) don't all behave identically.
 124  * The VT100 leaves the cursor in the last column but will wrap before
 125  * printing the next character.  I hear that the Concept terminal does
 126  * the wrap immediately but ignores the next newline it sees.  And some
 127  * terminals just have buggy firmware, and think that the cursor is still
 128  * in limbo if we use direct cursor addressing from the phantom column.
 129  * The only guaranteed safe thing to do is to emit a CRLF immediately
 130  * after we reach the last column; this takes us to a known state.
 131  */
 132 void
 133 cmcheckmagic (struct tty_display_info *tty)
 134 {
 135   if (curX (tty) == FrameCols (tty))
 136     {
 137       if (!MagicWrap (tty) || curY (tty) >= FrameRows (tty) - 1)
 138         abort ();
 139       if (tty->termscript)
 140         putc ('\r', tty->termscript);
 141       putc ('\r', tty->output);
 142       if (tty->termscript)
 143         putc ('\n', tty->termscript);
 144       putc ('\n', tty->output);
 145       curX (tty) = 0;
 146       curY (tty)++;
 147     }
 148 }
 149
 150
 151 /*
 152  * (Re)Initialize the cost factors, given the output speed of the terminal
 153  * in the variable ospeed.  (Note: this holds B300, B9600, etc -- ie stuff
 154  * out of <sgtty.h>.)
 155  */
 156
 157 void
 158 cmcostinit (struct tty_display_info *tty)
 159 {
 160     char *p;
 161
 162 #define COST(x,e)       (x ? (cost = 0, tputs (x, 1, e), cost) : BIG)
 163 #define CMCOST(x,e)     ((x == 0) ? BIG : (p = tgoto(x, 0, 0), COST(p ,e)))
 164
 165     tty->Wcm->cc_up =    COST (tty->Wcm->cm_up, evalcost);
 166     tty->Wcm->cc_down =  COST (tty->Wcm->cm_down, evalcost);
 167     tty->Wcm->cc_left =  COST (tty->Wcm->cm_left, evalcost);
 168     tty->Wcm->cc_right = COST (tty->Wcm->cm_right, evalcost);
 169     tty->Wcm->cc_home =  COST (tty->Wcm->cm_home, evalcost);
 170     tty->Wcm->cc_cr =    COST (tty->Wcm->cm_cr, evalcost);
 171     tty->Wcm->cc_ll =    COST (tty->Wcm->cm_ll, evalcost);
 172     tty->Wcm->cc_tab =   tty->Wcm->cm_tabwidth ? COST (tty->Wcm->cm_tab, evalcost) : BIG;
 173
 174     /*
 175      * These last three are actually minimum costs.  When (if) they are
 176      * candidates for the least-cost motion, the real cost is computed.
 177      * (Note that "0" is the assumed to generate the minimum cost.
 178      * While this is not necessarily true, I have yet to see a terminal
 179      * for which is not; all the terminals that have variable-cost
 180      * cursor motion seem to take straight numeric values.  --ACT)
 181      */
 182
 183     tty->Wcm->cc_abs =  CMCOST (tty->Wcm->cm_abs, evalcost);
 184     tty->Wcm->cc_habs = CMCOST (tty->Wcm->cm_habs, evalcost);
 185     tty->Wcm->cc_vabs = CMCOST (tty->Wcm->cm_vabs, evalcost);
 186
 187 #undef CMCOST
 188 #undef COST
 189 }
 190
 191 /*
 192  * Calculate the cost to move from (srcy, srcx) to (dsty, dstx) using
 193  * up and down, and left and right, motions, and tabs.  If doit is set
 194  * actually perform the motion.
 195  */
 196
 197 static int
 198 calccost (struct tty_display_info *tty,
 199           int srcy, int srcx, int dsty, int dstx, int doit)
 200 {
 201     register int    deltay,
 202                     deltax,
 203                     c,
 204                     totalcost;
 205     int     ntabs,
 206             n2tabs,
 207             tabx,
 208             tab2x,
 209             tabcost;
 210     register char  *p;
 211
 212     /* If have just wrapped on a terminal with xn,
 213        don't believe the cursor position: give up here
 214        and force use of absolute positioning.  */
 215
 216     if (curX (tty) == tty->Wcm->cm_cols)
 217       goto fail;
 218
 219     totalcost = 0;
 220     if ((deltay = dsty - srcy) == 0)
 221         goto x;
 222     if (deltay < 0)
 223         p = tty->Wcm->cm_up, c = tty->Wcm->cc_up, deltay = -deltay;
 224     else
 225         p = tty->Wcm->cm_down, c = tty->Wcm->cc_down;
 226     if (c == BIG) {             /* caint get thar from here */
 227         if (doit)
 228             printf ("OOPS");
 229         return c;
 230     }
 231     totalcost = c * deltay;
 232     if (doit)
 233         while (--deltay >= 0)
 234           emacs_tputs (tty, p, 1, cmputc);
 235 x:
 236     if ((deltax = dstx - srcx) == 0)
 237         goto done;
 238     if (deltax < 0) {
 239         p = tty->Wcm->cm_left, c = tty->Wcm->cc_left, deltax = -deltax;
 240         goto dodelta;           /* skip all the tab junk */
 241     }
 242     /* Tabs (the toughie) */
 243     if (tty->Wcm->cc_tab >= BIG || !tty->Wcm->cm_usetabs)
 244         goto olddelta;          /* forget it! */
 245
 246     /*
 247      * ntabs is # tabs towards but not past dstx; n2tabs is one more
 248      * (ie past dstx), but this is only valid if that is not past the
 249      * right edge of the screen.  We can check that at the same time
 250      * as we figure out where we would be if we use the tabs (which
 251      * we will put into tabx (for ntabs) and tab2x (for n2tabs)).
 252      */
 253
 254     ntabs = (deltax + srcx % tty->Wcm->cm_tabwidth) / tty->Wcm->cm_tabwidth;
 255     n2tabs = ntabs + 1;
 256     tabx = (srcx / tty->Wcm->cm_tabwidth + ntabs) * tty->Wcm->cm_tabwidth;
 257     tab2x = tabx + tty->Wcm->cm_tabwidth;
 258
 259     if (tab2x >= tty->Wcm->cm_cols)     /* too far (past edge) */
 260         n2tabs = 0;
 261
 262     /*
 263      * Now set tabcost to the cost for using ntabs, and c to the cost
 264      * for using n2tabs, then pick the minimum.
 265      */
 266
 267                    /* cost for ntabs           +    cost for right motion */
 268     tabcost = ntabs ? ntabs * tty->Wcm->cc_tab + (dstx - tabx) * tty->Wcm->cc_right
 269                     : BIG;
 270
 271                    /* cost for n2tabs          +    cost for left motion */
 272     c = n2tabs  ?    n2tabs * tty->Wcm->cc_tab + (tab2x - dstx) * tty->Wcm->cc_left
 273                 : BIG;
 274
 275     if (c < tabcost)            /* then cheaper to overshoot & back up */
 276         ntabs = n2tabs, tabcost = c, tabx = tab2x;
 277
 278     if (tabcost >= BIG)         /* caint use tabs */
 279         goto newdelta;
 280
 281     /*
 282      * See if tabcost is less than just moving right
 283      */
 284
 285     if (tabcost < (deltax * tty->Wcm->cc_right)) {
 286         totalcost += tabcost;   /* use the tabs */
 287         if (doit)
 288             while (--ntabs >= 0)
 289               emacs_tputs (tty, tty->Wcm->cm_tab, 1, cmputc);
 290         srcx = tabx;
 291     }
 292
 293     /*
 294      * Now might as well just recompute the delta.
 295      */
 296
 297 newdelta:
 298     if ((deltax = dstx - srcx) == 0)
 299         goto done;
 300 olddelta:
 301     if (deltax > 0)
 302         p = tty->Wcm->cm_right, c = tty->Wcm->cc_right;
 303     else
 304         p = tty->Wcm->cm_left, c = tty->Wcm->cc_left, deltax = -deltax;
 305
 306 dodelta:
 307     if (c == BIG) {             /* caint get thar from here */
 308 fail:
 309         if (doit)
 310             printf ("OOPS");
 311         return BIG;
 312     }
 313     totalcost += c * deltax;
 314     if (doit)
 315         while (--deltax >= 0)
 316           emacs_tputs (tty, p, 1, cmputc);
 317 done:
 318     return totalcost;
 319 }
 320
 321 #if 0
 322 losecursor ()
 323 {
 324   curY = -1;
 325 }
 326 #endif
 327
 328 #define USEREL  0
 329 #define USEHOME 1
 330 #define USELL   2
 331 #define USECR   3
 332
 333 void
 334 cmgoto (tty, row, col)
 335      struct tty_display_info *tty;
 336      int row, col;
 337 {
 338     int     homecost,
 339             crcost,
 340             llcost,
 341             relcost,
 342             directcost;
 343     int     use;
 344     char   *p,
 345            *dcm;
 346
 347   /* First the degenerate case */
 348     if (row == curY (tty) && col == curX (tty)) /* already there */
 349     return;
 350
 351     if (curY (tty) >= 0 && curX (tty) >= 0)
 352     {
 353       /* We may have quick ways to go to the upper-left, bottom-left,
 354        * start-of-line, or start-of-next-line.  Or it might be best to
 355        * start where we are.  Examine the options, and pick the cheapest.
 356        */
 357
 358       relcost = calccost (tty, curY (tty), curX (tty), row, col, 0);
 359       use = USEREL;
 360       if ((homecost = tty->Wcm->cc_home) < BIG)
 361           homecost += calccost (tty, 0, 0, row, col, 0);
 362       if (homecost < relcost)
 363           relcost = homecost, use = USEHOME;
 364       if ((llcost = tty->Wcm->cc_ll) < BIG)
 365           llcost += calccost (tty, tty->Wcm->cm_rows - 1, 0, row, col, 0);
 366       if (llcost < relcost)
 367           relcost = llcost, use = USELL;
 368       if ((crcost = tty->Wcm->cc_cr) < BIG) {
 369           if (tty->Wcm->cm_autolf)
 370             if (curY (tty) + 1 >= tty->Wcm->cm_rows)
 371                 crcost = BIG;
 372               else
 373                 crcost += calccost (tty, curY (tty) + 1, 0, row, col, 0);
 374           else
 375             crcost += calccost (tty, curY (tty), 0, row, col, 0);
 376       }
 377       if (crcost < relcost)
 378           relcost = crcost, use = USECR;
 379       directcost = tty->Wcm->cc_abs, dcm = tty->Wcm->cm_abs;
 380       if (row == curY (tty) && tty->Wcm->cc_habs < BIG)
 381           directcost = tty->Wcm->cc_habs, dcm = tty->Wcm->cm_habs;
 382       else if (col == curX (tty) && tty->Wcm->cc_vabs < BIG)
 383           directcost = tty->Wcm->cc_vabs, dcm = tty->Wcm->cm_vabs;
 384     }
 385   else
 386     {
 387       directcost = 0, relcost = 100000;
 388       dcm = tty->Wcm->cm_abs;
 389     }
 390
 391   /*
 392    * In the following comparison, the = in <= is because when the costs
 393    * are the same, it looks nicer (I think) to move directly there.
 394    */
 395   if (directcost <= relcost)
 396     {
 397       /* compute REAL direct cost */
 398       cost = 0;
 399       p = (dcm == tty->Wcm->cm_habs
 400            ? tgoto (dcm, row, col)
 401            : tgoto (dcm, col, row));
 402       emacs_tputs (tty, p, 1, evalcost);
 403       if (cost <= relcost)
 404         {       /* really is cheaper */
 405           emacs_tputs (tty, p, 1, cmputc);
 406           curY (tty) = row, curX (tty) = col;
 407           return;
 408         }
 409     }
 410
 411   switch (use)
 412     {
 413     case USEHOME:
 414       emacs_tputs (tty, tty->Wcm->cm_home, 1, cmputc);
 415       curY (tty) = 0, curX (tty) = 0;
 416       break;
 417
 418     case USELL:
 419       emacs_tputs (tty, tty->Wcm->cm_ll, 1, cmputc);
 420       curY (tty) = tty->Wcm->cm_rows - 1, curX (tty) = 0;
 421       break;
 422
 423     case USECR:
 424       emacs_tputs (tty, tty->Wcm->cm_cr, 1, cmputc);
 425       if (tty->Wcm->cm_autolf)
 426         curY (tty)++;
 427       curX (tty) = 0;
 428       break;
 429     }
 430
 431   (void) calccost (tty, curY (tty), curX (tty), row, col, 1);
 432   curY (tty) = row, curX (tty) = col;
 433 }
 434
 435 /* Clear out all terminal info.
 436    Used before copying into it the info on the actual terminal.
 437  */
 438
 439 void
 440 Wcm_clear (struct tty_display_info *tty)
 441 {
 442   bzero (tty->Wcm, sizeof (struct cm));
 443   UP = 0;
 444   BC = 0;
 445 }
 446
 447 /*
 448  * Initialized stuff
 449  * Return 0 if can do CM.
 450  * Return -1 if cannot.
 451  * Return -2 if size not specified.
 452  */
 453
 454 int
 455 Wcm_init (struct tty_display_info *tty)
 456 {
 457 #if 0
 458   if (tty->Wcm->cm_abs && !tty->Wcm->cm_ds)
 459     return 0;
 460 #endif
 461   if (tty->Wcm->cm_abs)
 462     return 0;
 463   /* Require up and left, and, if no absolute, down and right */
 464   if (!tty->Wcm->cm_up || !tty->Wcm->cm_left)
 465     return - 1;
 466   if (!tty->Wcm->cm_abs && (!tty->Wcm->cm_down || !tty->Wcm->cm_right))
 467     return - 1;
 468   /* Check that we know the size of the screen.... */
 469   if (tty->Wcm->cm_rows <= 0 || tty->Wcm->cm_cols <= 0)
 470     return - 2;
 471   return 0;
 472 }
 473
 474 /* arch-tag: bcf64c02-00f6-44ef-94b6-c56eab5b3dc4
 475    (do not change this comment) */