src/cm.c

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