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