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      int srcy, srcx, dsty, dstx, doit;
 192 {
 193     register int    deltay,
 194                     deltax,
 195                     c,
 196                     totalcost;
 197     int     ntabs,
 198             n2tabs,
 199             tabx,
 200             tab2x,
 201             tabcost;
 202     register char  *p;
 203
 204     /* If have just wrapped on a terminal with xn,
 205        don't believe the cursor position: give up here
 206        and force use of absolute positioning.  */
 207
 208     if (curX == Wcm.cm_cols)
 209       goto fail;
 210
 211     totalcost = 0;
 212     if ((deltay = dsty - srcy) == 0)
 213         goto x;
 214     if (deltay < 0)
 215         p = Wcm.cm_up, c = Wcm.cc_up, deltay = -deltay;
 216     else
 217         p = Wcm.cm_down, c = Wcm.cc_down;
 218     if (c == BIG) {             /* caint get thar from here */
 219         if (doit)
 220             printf ("OOPS");
 221         return c;
 222     }
 223     totalcost = c * deltay;
 224     if (doit)
 225         while (--deltay >= 0)
 226             tputs (p, 1, cmputc);
 227 x:
 228     if ((deltax = dstx - srcx) == 0)
 229         goto done;
 230     if (deltax < 0) {
 231         p = Wcm.cm_left, c = Wcm.cc_left, deltax = -deltax;
 232         goto dodelta;           /* skip all the tab junk */
 233     }
 234     /* Tabs (the toughie) */
 235     if (Wcm.cc_tab >= BIG || !Wcm.cm_usetabs)
 236         goto olddelta;          /* forget it! */
 237
 238     /*
 239      * ntabs is # tabs towards but not past dstx; n2tabs is one more
 240      * (ie past dstx), but this is only valid if that is not past the
 241      * right edge of the screen.  We can check that at the same time
 242      * as we figure out where we would be if we use the tabs (which
 243      * we will put into tabx (for ntabs) and tab2x (for n2tabs)).
 244      */
 245
 246     ntabs = (deltax + srcx % Wcm.cm_tabwidth) / Wcm.cm_tabwidth;
 247     n2tabs = ntabs + 1;
 248     tabx = (srcx / Wcm.cm_tabwidth + ntabs) * Wcm.cm_tabwidth;
 249     tab2x = tabx + Wcm.cm_tabwidth;
 250
 251     if (tab2x >= Wcm.cm_cols)   /* too far (past edge) */
 252         n2tabs = 0;
 253
 254     /*
 255      * Now set tabcost to the cost for using ntabs, and c to the cost
 256      * for using n2tabs, then pick the minimum.
 257      */
 258
 259                    /* cost for ntabs     +    cost for right motion */
 260     tabcost = ntabs ? ntabs * Wcm.cc_tab + (dstx - tabx) * Wcm.cc_right
 261                     : BIG;
 262
 263                    /* cost for n2tabs    +    cost for left motion */
 264     c = n2tabs  ?    n2tabs * Wcm.cc_tab + (tab2x - dstx) * Wcm.cc_left
 265                 : BIG;
 266
 267     if (c < tabcost)            /* then cheaper to overshoot & back up */
 268         ntabs = n2tabs, tabcost = c, tabx = tab2x;
 269
 270     if (tabcost >= BIG)         /* caint use tabs */
 271         goto newdelta;
 272
 273     /*
 274      * See if tabcost is less than just moving right
 275      */
 276
 277     if (tabcost < (deltax * Wcm.cc_right)) {
 278         totalcost += tabcost;   /* use the tabs */
 279         if (doit)
 280             while (--ntabs >= 0)
 281                 tputs (Wcm.cm_tab, 1, cmputc);
 282         srcx = tabx;
 283     }
 284
 285     /*
 286      * Now might as well just recompute the delta.
 287      */
 288
 289 newdelta:
 290     if ((deltax = dstx - srcx) == 0)
 291         goto done;
 292 olddelta:
 293     if (deltax > 0)
 294         p = Wcm.cm_right, c = Wcm.cc_right;
 295     else
 296         p = Wcm.cm_left, c = Wcm.cc_left, deltax = -deltax;
 297
 298 dodelta:
 299     if (c == BIG) {             /* caint get thar from here */
 300 fail:
 301         if (doit)
 302             printf ("OOPS");
 303         return BIG;
 304     }
 305     totalcost += c * deltax;
 306     if (doit)
 307         while (--deltax >= 0)
 308             tputs (p, 1, cmputc);
 309 done:
 310     return totalcost;
 311 }
 312
 313 #if 0
 314 losecursor ()
 315 {
 316   curY = -1;
 317 }
 318 #endif
 319
 320 #define USEREL  0
 321 #define USEHOME 1
 322 #define USELL   2
 323 #define USECR   3
 324
 325 void
 326 cmgoto (row, col)
 327      int row, col;
 328 {
 329     int     homecost,
 330             crcost,
 331             llcost,
 332             relcost,
 333             directcost;
 334     int     use;
 335     char   *p,
 336            *dcm;
 337
 338   /* First the degenerate case */
 339   if (row == curY && col == curX) /* already there */
 340     return;
 341
 342   if (curY >= 0 && curX >= 0)
 343     {
 344       /* We may have quick ways to go to the upper-left, bottom-left,
 345        * start-of-line, or start-of-next-line.  Or it might be best to
 346        * start where we are.  Examine the options, and pick the cheapest.
 347        */
 348
 349       relcost = calccost (curY, curX, row, col, 0);
 350       use = USEREL;
 351       if ((homecost = Wcm.cc_home) < BIG)
 352           homecost += calccost (0, 0, row, col, 0);
 353       if (homecost < relcost)
 354           relcost = homecost, use = USEHOME;
 355       if ((llcost = Wcm.cc_ll) < BIG)
 356           llcost += calccost (Wcm.cm_rows - 1, 0, row, col, 0);
 357       if (llcost < relcost)
 358           relcost = llcost, use = USELL;
 359       if ((crcost = Wcm.cc_cr) < BIG) {
 360           if (Wcm.cm_autolf)
 361               if (curY + 1 >= Wcm.cm_rows)
 362                   crcost = BIG;
 363               else
 364                   crcost += calccost (curY + 1, 0, row, col, 0);
 365           else
 366               crcost += calccost (curY, 0, row, col, 0);
 367       }
 368       if (crcost < relcost)
 369           relcost = crcost, use = USECR;
 370       directcost = Wcm.cc_abs, dcm = Wcm.cm_abs;
 371       if (row == curY && Wcm.cc_habs < BIG)
 372           directcost = Wcm.cc_habs, dcm = Wcm.cm_habs;
 373       else if (col == curX && Wcm.cc_vabs < BIG)
 374           directcost = Wcm.cc_vabs, dcm = Wcm.cm_vabs;
 375     }
 376   else
 377     {
 378       directcost = 0, relcost = 100000;
 379       dcm = Wcm.cm_abs;
 380     }
 381
 382   /*
 383    * In the following comparison, the = in <= is because when the costs
 384    * are the same, it looks nicer (I think) to move directly there.
 385    */
 386   if (directcost <= relcost)
 387     {
 388       /* compute REAL direct cost */
 389       cost = 0;
 390       p = dcm == Wcm.cm_habs ? tgoto (dcm, row, col) :
 391                                tgoto (dcm, col, row);
 392       tputs (p, 1, evalcost);
 393       if (cost <= relcost)
 394         {       /* really is cheaper */
 395           tputs (p, 1, cmputc);
 396           curY = row, curX = col;
 397           return;
 398         }
 399     }
 400
 401   switch (use)
 402     {
 403     case USEHOME:
 404       tputs (Wcm.cm_home, 1, cmputc);
 405       curY = 0, curX = 0;
 406       break;
 407
 408     case USELL:
 409       tputs (Wcm.cm_ll, 1, cmputc);
 410       curY = Wcm.cm_rows - 1, curX = 0;
 411       break;
 412
 413     case USECR:
 414       tputs (Wcm.cm_cr, 1, cmputc);
 415       if (Wcm.cm_autolf)
 416         curY++;
 417       curX = 0;
 418       break;
 419     }
 420
 421   (void) calccost (curY, curX, row, col, 1);
 422   curY = row, curX = col;
 423 }
 424
 425 /* Clear out all terminal info.
 426    Used before copying into it the info on the actual terminal.
 427  */
 428
 429 void
 430 Wcm_clear ()
 431 {
 432   bzero (&Wcm, sizeof Wcm);
 433   UP = 0;
 434   BC = 0;
 435 }
 436
 437 /*
 438  * Initialized stuff
 439  * Return 0 if can do CM.
 440  * Return -1 if cannot.
 441  * Return -2 if size not specified.
 442  */
 443
 444 int
 445 Wcm_init ()
 446 {
 447 #if 0
 448   if (Wcm.cm_abs && !Wcm.cm_ds)
 449     return 0;
 450 #endif
 451   if (Wcm.cm_abs)
 452     return 0;
 453   /* Require up and left, and, if no absolute, down and right */
 454   if (!Wcm.cm_up || !Wcm.cm_left)
 455     return - 1;
 456   if (!Wcm.cm_abs && (!Wcm.cm_down || !Wcm.cm_right))
 457     return - 1;
 458   /* Check that we know the size of the screen.... */
 459   if (Wcm.cm_rows <= 0 || Wcm.cm_cols <= 0)
 460     return - 2;
 461   return 0;
 462 }