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, or (at your option)
  11 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; see the file COPYING.  If not, write to
  20 the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  21 Boston, MA 02110-1301, USA.  */
  22
  23
  24 #include <config.h>
  25 #include <stdio.h>
  26
  27 #include "lisp.h"
  28 #include "frame.h"
  29 #include "cm.h"
  30 #include "termhooks.h"
  31 #include "termchar.h"
  32
  33
  34 /* For now, don't try to include termcap.h.  On some systems,
  35    configure finds a non-standard termcap.h that the main build
  36    won't find.  */
  37
  38 #if defined HAVE_TERMCAP_H && 0
  39 #include <termcap.h>
  40 #else
  41 extern void tputs P_ ((const char *, int, int (*)(int)));
  42 extern char *tgoto P_ ((const char *, int, int));
  43 #endif
  44
  45 #define BIG     9999            /* 9999 good on VAXen.  For 16 bit machines
  46                                    use about 2000.... */
  47
  48 extern char *BC, *UP;
  49
  50 int cost;               /* sums up costs */
  51
  52 /* ARGSUSED */
  53 int
  54 evalcost (c)
  55      char c;
  56 {
  57   cost++;
  58   return c;
  59 }
  60
  61 /* The terminal to use for low-level output. */
  62 struct tty_display_info *current_tty;
  63
  64 int
  65 cmputc (c)
  66      char c;
  67 {
  68   if (current_tty->termscript)
  69     putc (c & 0177, current_tty->termscript);
  70   putc (c & 0177, current_tty->output);
  71   return c;
  72 }
  73
  74 /* NEXT TWO ARE DONE WITH MACROS */
  75 #if 0
  76 /*
  77  * Assume the cursor is at row row, column col.  Normally used only after
  78  * clearing the screen, when the cursor is at (0, 0), but what the heck,
  79  * let's let the guy put it anywhere.
  80  */
  81
  82 static
  83 at (tty, row, col) {
  84   curY (tty) = row;
  85   curX (tty)  = col;
  86 }
  87
  88 /*
  89  * Add n columns to the current cursor position.
  90  */
  91
  92 static
  93 addcol (tty, n) {
  94   curX (tty) += n;
  95
  96     /*
  97      * If cursor hit edge of screen, what happened?
  98      * N.B.: DO NOT!! write past edge of screen.  If you do, you
  99      * deserve what you get.  Furthermore, on terminals with
 100      * autowrap (but not magicwrap), don't write in the last column
 101      * of the last line.
 102      */
 103
 104   if (curX (tty) == tty->Wcm->cm_cols) {
 105         /*
 106          * Well, if magicwrap, still there, past the edge of the
 107          * screen (!).  If autowrap, on the col 0 of the next line.
 108          * Otherwise on last column.
 109          */
 110
 111         if (tty->Wcm->cm_magicwrap)
 112             ;                   /* "limbo" */
 113         else if (tty->Wcm->cm_autowrap) {
 114           curX (tty) = 0;
 115           curY (tty) ++;                /* Beware end of screen! */
 116         }
 117         else
 118           curX (tty)--;
 119     }
 120 }
 121 #endif
 122
 123 /*
 124  * Terminals with magicwrap (xn) don't all behave identically.
 125  * The VT100 leaves the cursor in the last column but will wrap before
 126  * printing the next character.  I hear that the Concept terminal does
 127  * the wrap immediately but ignores the next newline it sees.  And some
 128  * terminals just have buggy firmware, and think that the cursor is still
 129  * in limbo if we use direct cursor addressing from the phantom column.
 130  * The only guaranteed safe thing to do is to emit a CRLF immediately
 131  * after we reach the last column; this takes us to a known state.
 132  */
 133 void
 134 cmcheckmagic (struct tty_display_info *tty)
 135 {
 136   if (curX (tty) == FrameCols (tty))
 137     {
 138       if (!MagicWrap (tty) || curY (tty) >= FrameRows (tty) - 1)
 139         abort ();
 140       if (tty->termscript)
 141         putc ('\r', tty->termscript);
 142       putc ('\r', tty->output);
 143       if (tty->termscript)
 144         putc ('\n', tty->termscript);
 145       putc ('\n', tty->output);
 146       curX (tty) = 0;
 147       curY (tty)++;
 148     }
 149 }
 150
 151
 152 /*
 153  * (Re)Initialize the cost factors, given the output speed of the terminal
 154  * in the variable ospeed.  (Note: this holds B300, B9600, etc -- ie stuff
 155  * out of <sgtty.h>.)
 156  */
 157
 158 void
 159 cmcostinit (struct tty_display_info *tty)
 160 {
 161     char *p;
 162
 163 #define COST(x,e)       (x ? (cost = 0, tputs (x, 1, e), cost) : BIG)
 164 #define CMCOST(x,e)     ((x == 0) ? BIG : (p = tgoto(x, 0, 0), COST(p ,e)))
 165
 166     tty->Wcm->cc_up =    COST (tty->Wcm->cm_up, evalcost);
 167     tty->Wcm->cc_down =  COST (tty->Wcm->cm_down, evalcost);
 168     tty->Wcm->cc_left =  COST (tty->Wcm->cm_left, evalcost);
 169     tty->Wcm->cc_right = COST (tty->Wcm->cm_right, evalcost);
 170     tty->Wcm->cc_home =  COST (tty->Wcm->cm_home, evalcost);
 171     tty->Wcm->cc_cr =    COST (tty->Wcm->cm_cr, evalcost);
 172     tty->Wcm->cc_ll =    COST (tty->Wcm->cm_ll, evalcost);
 173     tty->Wcm->cc_tab =   tty->Wcm->cm_tabwidth ? COST (tty->Wcm->cm_tab, evalcost) : BIG;
 174
 175     /*
 176      * These last three are actually minimum costs.  When (if) they are
 177      * candidates for the least-cost motion, the real cost is computed.
 178      * (Note that "0" is the assumed to generate the minimum cost.
 179      * While this is not necessarily true, I have yet to see a terminal
 180      * for which is not; all the terminals that have variable-cost
 181      * cursor motion seem to take straight numeric values.  --ACT)
 182      */
 183
 184     tty->Wcm->cc_abs =  CMCOST (tty->Wcm->cm_abs, evalcost);
 185     tty->Wcm->cc_habs = CMCOST (tty->Wcm->cm_habs, evalcost);
 186     tty->Wcm->cc_vabs = CMCOST (tty->Wcm->cm_vabs, evalcost);
 187
 188 #undef CMCOST
 189 #undef COST
 190 }
 191
 192 /*
 193  * Calculate the cost to move from (srcy, srcx) to (dsty, dstx) using
 194  * up and down, and left and right, motions, and tabs.  If doit is set
 195  * actually perform the motion.
 196  */
 197
 198 static int
 199 calccost (struct tty_display_info *tty,
 200           int srcy, int srcx, int dsty, int dstx, int doit)
 201 {
 202     register int    deltay,
 203                     deltax,
 204                     c,
 205                     totalcost;
 206     int     ntabs,
 207             n2tabs,
 208             tabx,
 209             tab2x,
 210             tabcost;
 211     register char  *p;
 212
 213     /* If have just wrapped on a terminal with xn,
 214        don't believe the cursor position: give up here
 215        and force use of absolute positioning.  */
 216
 217     if (curX (tty) == tty->Wcm->cm_cols)
 218       goto fail;
 219
 220     totalcost = 0;
 221     if ((deltay = dsty - srcy) == 0)
 222         goto x;
 223     if (deltay < 0)
 224         p = tty->Wcm->cm_up, c = tty->Wcm->cc_up, deltay = -deltay;
 225     else
 226         p = tty->Wcm->cm_down, c = tty->Wcm->cc_down;
 227     if (c == BIG) {             /* caint get thar from here */
 228         if (doit)
 229             printf ("OOPS");
 230         return c;
 231     }
 232     totalcost = c * deltay;
 233     if (doit)
 234         while (--deltay >= 0)
 235           emacs_tputs (tty, p, 1, cmputc);
 236 x:
 237     if ((deltax = dstx - srcx) == 0)
 238         goto done;
 239     if (deltax < 0) {
 240         p = tty->Wcm->cm_left, c = tty->Wcm->cc_left, deltax = -deltax;
 241         goto dodelta;           /* skip all the tab junk */
 242     }
 243     /* Tabs (the toughie) */
 244     if (tty->Wcm->cc_tab >= BIG || !tty->Wcm->cm_usetabs)
 245         goto olddelta;          /* forget it! */
 246
 247     /*
 248      * ntabs is # tabs towards but not past dstx; n2tabs is one more
 249      * (ie past dstx), but this is only valid if that is not past the
 250      * right edge of the screen.  We can check that at the same time
 251      * as we figure out where we would be if we use the tabs (which
 252      * we will put into tabx (for ntabs) and tab2x (for n2tabs)).
 253      */
 254
 255     ntabs = (deltax + srcx % tty->Wcm->cm_tabwidth) / tty->Wcm->cm_tabwidth;
 256     n2tabs = ntabs + 1;
 257     tabx = (srcx / tty->Wcm->cm_tabwidth + ntabs) * tty->Wcm->cm_tabwidth;
 258     tab2x = tabx + tty->Wcm->cm_tabwidth;
 259
 260     if (tab2x >= tty->Wcm->cm_cols)     /* too far (past edge) */
 261         n2tabs = 0;
 262
 263     /*
 264      * Now set tabcost to the cost for using ntabs, and c to the cost
 265      * for using n2tabs, then pick the minimum.
 266      */
 267
 268                    /* cost for ntabs           +    cost for right motion */
 269     tabcost = ntabs ? ntabs * tty->Wcm->cc_tab + (dstx - tabx) * tty->Wcm->cc_right
 270                     : BIG;
 271
 272                    /* cost for n2tabs          +    cost for left motion */
 273     c = n2tabs  ?    n2tabs * tty->Wcm->cc_tab + (tab2x - dstx) * tty->Wcm->cc_left
 274                 : BIG;
 275
 276     if (c < tabcost)            /* then cheaper to overshoot & back up */
 277         ntabs = n2tabs, tabcost = c, tabx = tab2x;
 278
 279     if (tabcost >= BIG)         /* caint use tabs */
 280         goto newdelta;
 281
 282     /*
 283      * See if tabcost is less than just moving right
 284      */
 285
 286     if (tabcost < (deltax * tty->Wcm->cc_right)) {
 287         totalcost += tabcost;   /* use the tabs */
 288         if (doit)
 289             while (--ntabs >= 0)
 290               emacs_tputs (tty, tty->Wcm->cm_tab, 1, cmputc);
 291         srcx = tabx;
 292     }
 293
 294     /*
 295      * Now might as well just recompute the delta.
 296      */
 297
 298 newdelta:
 299     if ((deltax = dstx - srcx) == 0)
 300         goto done;
 301 olddelta:
 302     if (deltax > 0)
 303         p = tty->Wcm->cm_right, c = tty->Wcm->cc_right;
 304     else
 305         p = tty->Wcm->cm_left, c = tty->Wcm->cc_left, deltax = -deltax;
 306
 307 dodelta:
 308     if (c == BIG) {             /* caint get thar from here */
 309 fail:
 310         if (doit)
 311             printf ("OOPS");
 312         return BIG;
 313     }
 314     totalcost += c * deltax;
 315     if (doit)
 316         while (--deltax >= 0)
 317           emacs_tputs (tty, p, 1, cmputc);
 318 done:
 319     return totalcost;
 320 }
 321
 322 #if 0
 323 losecursor ()
 324 {
 325   curY = -1;
 326 }
 327 #endif
 328
 329 #define USEREL  0
 330 #define USEHOME 1
 331 #define USELL   2
 332 #define USECR   3
 333
 334 void
 335 cmgoto (tty, row, col)
 336      struct tty_display_info *tty;
 337      int row, col;
 338 {
 339     int     homecost,
 340             crcost,
 341             llcost,
 342             relcost,
 343             directcost;
 344     int     use;
 345     char   *p,
 346            *dcm;
 347
 348   /* First the degenerate case */
 349     if (row == curY (tty) && col == curX (tty)) /* already there */
 350     return;
 351
 352     if (curY (tty) >= 0 && curX (tty) >= 0)
 353     {
 354       /* We may have quick ways to go to the upper-left, bottom-left,
 355        * start-of-line, or start-of-next-line.  Or it might be best to
 356        * start where we are.  Examine the options, and pick the cheapest.
 357        */
 358
 359       relcost = calccost (tty, curY (tty), curX (tty), row, col, 0);
 360       use = USEREL;
 361       if ((homecost = tty->Wcm->cc_home) < BIG)
 362           homecost += calccost (tty, 0, 0, row, col, 0);
 363       if (homecost < relcost)
 364           relcost = homecost, use = USEHOME;
 365       if ((llcost = tty->Wcm->cc_ll) < BIG)
 366           llcost += calccost (tty, tty->Wcm->cm_rows - 1, 0, row, col, 0);
 367       if (llcost < relcost)
 368           relcost = llcost, use = USELL;
 369       if ((crcost = tty->Wcm->cc_cr) < BIG) {
 370           if (tty->Wcm->cm_autolf)
 371             if (curY (tty) + 1 >= tty->Wcm->cm_rows)
 372                 crcost = BIG;
 373               else
 374                 crcost += calccost (tty, curY (tty) + 1, 0, row, col, 0);
 375           else
 376             crcost += calccost (tty, curY (tty), 0, row, col, 0);
 377       }
 378       if (crcost < relcost)
 379           relcost = crcost, use = USECR;
 380       directcost = tty->Wcm->cc_abs, dcm = tty->Wcm->cm_abs;
 381       if (row == curY (tty) && tty->Wcm->cc_habs < BIG)
 382           directcost = tty->Wcm->cc_habs, dcm = tty->Wcm->cm_habs;
 383       else if (col == curX (tty) && tty->Wcm->cc_vabs < BIG)
 384           directcost = tty->Wcm->cc_vabs, dcm = tty->Wcm->cm_vabs;
 385     }
 386   else
 387     {
 388       directcost = 0, relcost = 100000;
 389       dcm = tty->Wcm->cm_abs;
 390     }
 391
 392   /*
 393    * In the following comparison, the = in <= is because when the costs
 394    * are the same, it looks nicer (I think) to move directly there.
 395    */
 396   if (directcost <= relcost)
 397     {
 398       /* compute REAL direct cost */
 399       cost = 0;
 400       p = (dcm == tty->Wcm->cm_habs
 401            ? tgoto (dcm, row, col)
 402            : tgoto (dcm, col, row));
 403       emacs_tputs (tty, p, 1, evalcost);
 404       if (cost <= relcost)
 405         {       /* really is cheaper */
 406           emacs_tputs (tty, p, 1, cmputc);
 407           curY (tty) = row, curX (tty) = col;
 408           return;
 409         }
 410     }
 411
 412   switch (use)
 413     {
 414     case USEHOME:
 415       emacs_tputs (tty, tty->Wcm->cm_home, 1, cmputc);
 416       curY (tty) = 0, curX (tty) = 0;
 417       break;
 418
 419     case USELL:
 420       emacs_tputs (tty, tty->Wcm->cm_ll, 1, cmputc);
 421       curY (tty) = tty->Wcm->cm_rows - 1, curX (tty) = 0;
 422       break;
 423
 424     case USECR:
 425       emacs_tputs (tty, tty->Wcm->cm_cr, 1, cmputc);
 426       if (tty->Wcm->cm_autolf)
 427         curY (tty)++;
 428       curX (tty) = 0;
 429       break;
 430     }
 431
 432   (void) calccost (tty, curY (tty), curX (tty), row, col, 1);
 433   curY (tty) = row, curX (tty) = col;
 434 }
 435
 436 /* Clear out all terminal info.
 437    Used before copying into it the info on the actual terminal.
 438  */
 439
 440 void
 441 Wcm_clear (struct tty_display_info *tty)
 442 {
 443   bzero (tty->Wcm, sizeof (struct cm));
 444   UP = 0;
 445   BC = 0;
 446 }
 447
 448 /*
 449  * Initialized stuff
 450  * Return 0 if can do CM.
 451  * Return -1 if cannot.
 452  * Return -2 if size not specified.
 453  */
 454
 455 int
 456 Wcm_init (struct tty_display_info *tty)
 457 {
 458 #if 0
 459   if (tty->Wcm->cm_abs && !tty->Wcm->cm_ds)
 460     return 0;
 461 #endif
 462   if (tty->Wcm->cm_abs)
 463     return 0;
 464   /* Require up and left, and, if no absolute, down and right */
 465   if (!tty->Wcm->cm_up || !tty->Wcm->cm_left)
 466     return - 1;
 467   if (!tty->Wcm->cm_abs && (!tty->Wcm->cm_down || !tty->Wcm->cm_right))
 468     return - 1;
 469   /* Check that we know the size of the screen.... */
 470   if (tty->Wcm->cm_rows <= 0 || tty->Wcm->cm_cols <= 0)
 471     return - 2;
 472   return 0;
 473 }
 474
 475 /* arch-tag: bcf64c02-00f6-44ef-94b6-c56eab5b3dc4
 476    (do not change this comment) */