src/cm.c

   1 /* Cursor motion subroutines for GNU Emacs.
   2    Copyright (C) 1985 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, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  20
  21
  22 #include <config.h>
  23 #include <stdio.h>
  24 #include "cm.h"
  25 #include "termhooks.h"
  26
  27 #define BIG     9999            /* 9999 good on VAXen.  For 16 bit machines
  28                                    use about 2000.... */
  29
  30 char *tgoto ();
  31
  32 extern char *BC, *UP;
  33
  34 int cost;               /* sums up costs */
  35
  36 /* ARGSUSED */
  37 evalcost (c)
  38      char c;
  39 {
  40   cost++;
  41   return c;
  42 }
  43
  44 cmputc (c)
  45      char c;
  46 {
  47   if (termscript)
  48     fputc (c & 0177, termscript);
  49   putchar (c & 0177);
  50   return c;
  51 }
  52
  53 /* NEXT TWO ARE DONE WITH MACROS */
  54 #if 0
  55 /*
  56  * Assume the cursor is at row row, column col.  Normally used only after
  57  * clearing the screen, when the cursor is at (0, 0), but what the heck,
  58  * let's let the guy put it anywhere.
  59  */
  60
  61 static
  62 at (row, col) {
  63     curY = row;
  64     curX = col;
  65 }
  66
  67 /*
  68  * Add n columns to the current cursor position.
  69  */
  70
  71 static
  72 addcol (n) {
  73     curX += n;
  74
  75     /*
  76      * If cursor hit edge of screen, what happened?
  77      * N.B.: DO NOT!! write past edge of screen.  If you do, you
  78      * deserve what you get.  Furthermore, on terminals with
  79      * autowrap (but not magicwrap), don't write in the last column
  80      * of the last line.
  81      */
  82
  83     if (curX == Wcm.cm_cols) {
  84         /*
  85          * Well, if magicwrap, still there, past the edge of the
  86          * screen (!).  If autowrap, on the col 0 of the next line.
  87          * Otherwise on last column.
  88          */
  89
  90         if (Wcm.cm_magicwrap)
  91             ;                   /* "limbo" */
  92         else if (Wcm.cm_autowrap) {
  93             curX = 0;
  94             curY++;             /* Beware end of screen! */
  95         }
  96         else
  97             curX--;
  98     }
  99 }
 100 #endif
 101
 102 /*
 103  * (Re)Initialize the cost factors, given the output speed of the terminal
 104  * in the variable ospeed.  (Note: this holds B300, B9600, etc -- ie stuff
 105  * out of <sgtty.h>.)
 106  */
 107
 108 cmcostinit ()
 109 {
 110     char *p;
 111
 112 #define COST(x,e)       (x ? (cost = 0, tputs (x, 1, e), cost) : BIG)
 113 #define CMCOST(x,e)     ((x == 0) ? BIG : (p = tgoto(x, 0, 0), COST(p ,e)))
 114
 115     Wcm.cc_up =         COST (Wcm.cm_up, evalcost);
 116     Wcm.cc_down =       COST (Wcm.cm_down, evalcost);
 117     Wcm.cc_left =       COST (Wcm.cm_left, evalcost);
 118     Wcm.cc_right =      COST (Wcm.cm_right, evalcost);
 119     Wcm.cc_home =       COST (Wcm.cm_home, evalcost);
 120     Wcm.cc_cr =         COST (Wcm.cm_cr, evalcost);
 121     Wcm.cc_ll =         COST (Wcm.cm_ll, evalcost);
 122     Wcm.cc_tab =        Wcm.cm_tabwidth ? COST (Wcm.cm_tab, evalcost) : BIG;
 123
 124     /*
 125      * These last three are actually minimum costs.  When (if) they are
 126      * candidates for the least-cost motion, the real cost is computed.
 127      * (Note that "0" is the assumed to generate the minimum cost.
 128      * While this is not necessarily true, I have yet to see a terminal
 129      * for which is not; all the terminals that have variable-cost
 130      * cursor motion seem to take straight numeric values.  --ACT)
 131      */
 132
 133     Wcm.cc_abs =  CMCOST (Wcm.cm_abs, evalcost);
 134     Wcm.cc_habs = CMCOST (Wcm.cm_habs, evalcost);
 135     Wcm.cc_vabs = CMCOST (Wcm.cm_vabs, evalcost);
 136
 137 #undef CMCOST
 138 #undef COST
 139 }
 140
 141 /*
 142  * Calculate the cost to move from (srcy, srcx) to (dsty, dstx) using
 143  * up and down, and left and right, motions, and tabs.  If doit is set
 144  * actually perform the motion.
 145  */
 146
 147 static
 148 calccost (srcy, srcx, dsty, dstx, doit)
 149 {
 150     register int    deltay,
 151                     deltax,
 152                     c,
 153                     totalcost;
 154     int     ntabs,
 155             n2tabs,
 156             tabx,
 157             tab2x,
 158             tabcost;
 159     register char  *p;
 160
 161     /* If have just wrapped on a terminal with xn,
 162        don't believe the cursor position: give up here
 163        and force use of absolute positioning.  */
 164
 165     if (curX == Wcm.cm_cols)
 166       goto fail;
 167
 168     totalcost = 0;
 169     if ((deltay = dsty - srcy) == 0)
 170         goto x;
 171     if (deltay < 0)
 172         p = Wcm.cm_up, c = Wcm.cc_up, deltay = -deltay;
 173     else
 174         p = Wcm.cm_down, c = Wcm.cc_down;
 175     if (c == BIG) {             /* caint get thar from here */
 176         if (doit)
 177             printf ("OOPS");
 178         return c;
 179     }
 180     totalcost = c * deltay;
 181     if (doit)
 182         while (--deltay >= 0)
 183             tputs (p, 1, cmputc);
 184 x:
 185     if ((deltax = dstx - srcx) == 0)
 186         goto done;
 187     if (deltax < 0) {
 188         p = Wcm.cm_left, c = Wcm.cc_left, deltax = -deltax;
 189         goto dodelta;           /* skip all the tab junk */
 190     }
 191     /* Tabs (the toughie) */
 192     if (Wcm.cc_tab >= BIG || !Wcm.cm_usetabs)
 193         goto olddelta;          /* forget it! */
 194
 195     /*
 196      * ntabs is # tabs towards but not past dstx; n2tabs is one more
 197      * (ie past dstx), but this is only valid if that is not past the
 198      * right edge of the screen.  We can check that at the same time
 199      * as we figure out where we would be if we use the tabs (which
 200      * we will put into tabx (for ntabs) and tab2x (for n2tabs)).
 201      */
 202
 203     ntabs = (deltax + srcx % Wcm.cm_tabwidth) / Wcm.cm_tabwidth;
 204     n2tabs = ntabs + 1;
 205     tabx = (srcx / Wcm.cm_tabwidth + ntabs) * Wcm.cm_tabwidth;
 206     tab2x = tabx + Wcm.cm_tabwidth;
 207
 208     if (tab2x >= Wcm.cm_cols)   /* too far (past edge) */
 209         n2tabs = 0;
 210
 211     /*
 212      * Now set tabcost to the cost for using ntabs, and c to the cost
 213      * for using n2tabs, then pick the minimum.
 214      */
 215
 216                    /* cost for ntabs     +    cost for right motion */
 217     tabcost = ntabs ? ntabs * Wcm.cc_tab + (dstx - tabx) * Wcm.cc_right
 218                     : BIG;
 219
 220                    /* cost for n2tabs    +    cost for left motion */
 221     c = n2tabs  ?    n2tabs * Wcm.cc_tab + (tab2x - dstx) * Wcm.cc_left
 222                 : BIG;
 223
 224     if (c < tabcost)            /* then cheaper to overshoot & back up */
 225         ntabs = n2tabs, tabcost = c, tabx = tab2x;
 226
 227     if (tabcost >= BIG)         /* caint use tabs */
 228         goto newdelta;
 229
 230     /*
 231      * See if tabcost is less than just moving right
 232      */
 233
 234     if (tabcost < (deltax * Wcm.cc_right)) {
 235         totalcost += tabcost;   /* use the tabs */
 236         if (doit)
 237             while (--ntabs >= 0)
 238                 tputs (Wcm.cm_tab, 1, cmputc);
 239         srcx = tabx;
 240     }
 241
 242     /*
 243      * Now might as well just recompute the delta.
 244      */
 245
 246 newdelta:
 247     if ((deltax = dstx - srcx) == 0)
 248         goto done;
 249 olddelta:
 250     if (deltax > 0)
 251         p = Wcm.cm_right, c = Wcm.cc_right;
 252     else
 253         p = Wcm.cm_left, c = Wcm.cc_left, deltax = -deltax;
 254
 255 dodelta:
 256     if (c == BIG) {             /* caint get thar from here */
 257 fail:
 258         if (doit)
 259             printf ("OOPS");
 260         return BIG;
 261     }
 262     totalcost += c * deltax;
 263     if (doit)
 264         while (--deltax >= 0)
 265             tputs (p, 1, cmputc);
 266 done:
 267     return totalcost;
 268 }
 269
 270 #if 0
 271 losecursor ()
 272 {
 273   curY = -1;
 274 }
 275 #endif
 276
 277 #define USEREL  0
 278 #define USEHOME 1
 279 #define USELL   2
 280 #define USECR   3
 281
 282 cmgoto (row, col)
 283 {
 284     int     homecost,
 285             crcost,
 286             llcost,
 287             relcost,
 288             directcost;
 289     int     use;
 290     char   *p,
 291            *dcm;
 292
 293   /* First the degenerate case */
 294   if (row == curY && col == curX) /* already there */
 295     return;
 296
 297   if (curY >= 0 && curX >= 0)
 298     {
 299       /* We may have quick ways to go to the upper-left, bottom-left,
 300        * start-of-line, or start-of-next-line.  Or it might be best to
 301        * start where we are.  Examine the options, and pick the cheapest.
 302        */
 303
 304       relcost = calccost (curY, curX, row, col, 0);
 305       use = USEREL;
 306       if ((homecost = Wcm.cc_home) < BIG)
 307           homecost += calccost (0, 0, row, col, 0);
 308       if (homecost < relcost)
 309           relcost = homecost, use = USEHOME;
 310       if ((llcost = Wcm.cc_ll) < BIG)
 311           llcost += calccost (Wcm.cm_rows - 1, 0, row, col, 0);
 312       if (llcost < relcost)
 313           relcost = llcost, use = USELL;
 314       if ((crcost = Wcm.cc_cr) < BIG) {
 315           if (Wcm.cm_autolf)
 316               if (curY + 1 >= Wcm.cm_rows)
 317                   crcost = BIG;
 318               else
 319                   crcost += calccost (curY + 1, 0, row, col, 0);
 320           else
 321               crcost += calccost (curY, 0, row, col, 0);
 322       }
 323       if (crcost < relcost)
 324           relcost = crcost, use = USECR;
 325       directcost = Wcm.cc_abs, dcm = Wcm.cm_abs;
 326       if (row == curY && Wcm.cc_habs < BIG)
 327           directcost = Wcm.cc_habs, dcm = Wcm.cm_habs;
 328       else if (col == curX && Wcm.cc_vabs < BIG)
 329           directcost = Wcm.cc_vabs, dcm = Wcm.cm_vabs;
 330     }
 331   else
 332     {
 333       directcost = 0, relcost = 100000;
 334       dcm = Wcm.cm_abs;
 335     }
 336
 337   /*
 338    * In the following comparison, the = in <= is because when the costs
 339    * are the same, it looks nicer (I think) to move directly there.
 340    */
 341   if (directcost <= relcost)
 342     {
 343       /* compute REAL direct cost */
 344       cost = 0;
 345       p = dcm == Wcm.cm_habs ? tgoto (dcm, row, col) :
 346                                tgoto (dcm, col, row);
 347       tputs (p, 1, evalcost);
 348       if (cost <= relcost)
 349         {       /* really is cheaper */
 350           tputs (p, 1, cmputc);
 351           curY = row, curX = col;
 352           return;
 353         }
 354     }
 355
 356   switch (use)
 357     {
 358     case USEHOME:
 359       tputs (Wcm.cm_home, 1, cmputc);
 360       curY = 0, curX = 0;
 361       break;
 362
 363     case USELL:
 364       tputs (Wcm.cm_ll, 1, cmputc);
 365       curY = Wcm.cm_rows - 1, curX = 0;
 366       break;
 367
 368     case USECR:
 369       tputs (Wcm.cm_cr, 1, cmputc);
 370       if (Wcm.cm_autolf)
 371         curY++;
 372       curX = 0;
 373       break;
 374     }
 375
 376   (void) calccost (curY, curX, row, col, 1);
 377   curY = row, curX = col;
 378 }
 379
 380 /* Clear out all terminal info.
 381    Used before copying into it the info on the actual terminal.
 382  */
 383
 384 Wcm_clear ()
 385 {
 386   bzero (&Wcm, sizeof Wcm);
 387   UP = 0;
 388   BC = 0;
 389 }
 390
 391 /*
 392  * Initialized stuff
 393  * Return 0 if can do CM.
 394  * Return -1 if cannot.
 395  * Return -2 if size not specified.
 396  */
 397
 398 Wcm_init ()
 399 {
 400 #if 0
 401   if (Wcm.cm_abs && !Wcm.cm_ds)
 402     return 0;
 403 #endif
 404   if (Wcm.cm_abs)
 405     return 0;
 406   /* Require up and left, and, if no absolute, down and right */
 407   if (!Wcm.cm_up || !Wcm.cm_left)
 408     return - 1;
 409   if (!Wcm.cm_abs && (!Wcm.cm_down || !Wcm.cm_right))
 410     return - 1;
 411   /* Check that we know the size of the screen.... */
 412   if (Wcm.cm_rows <= 0 || Wcm.cm_cols <= 0)
 413     return - 2;
 414   return 0;
 415 }