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