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