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[emacs.git] / src / cm.c
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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
5 This file is part of GNU Emacs.
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.
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.
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. */
23 #include <config.h>
24 #include <stdio.h>
25 #include "cm.h"
26 #include "termhooks.h"
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. */
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
39 #define BIG 9999 /* 9999 good on VAXen. For 16 bit machines
40 use about 2000.... */
42 extern char *BC, *UP;
44 int cost; /* sums up costs */
46 /* ARGSUSED */
47 int
48 evalcost (c)
49 char c;
51 cost++;
52 return c;
55 int
56 cmputc (c)
57 char c;
59 if (termscript)
60 fputc (c & 0177, termscript);
61 putchar (c & 0177);
62 return c;
65 /* NEXT TWO ARE DONE WITH MACROS */
66 #if 0
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.
73 static
74 at (row, col) {
75 curY = row;
76 curX = col;
80 * Add n columns to the current cursor position.
83 static
84 addcol (n) {
85 curX += n;
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.
95 if (curX == Wcm.cm_cols) {
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.
102 if (Wcm.cm_magicwrap)
103 ; /* "limbo" */
104 else if (Wcm.cm_autowrap) {
105 curX = 0;
106 curY++; /* Beware end of screen! */
108 else
109 curX--;
112 #endif
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.
124 void
125 cmcheckmagic ()
127 if (curX == FrameCols)
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++;
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>.)
149 void
150 cmcostinit ()
152 char *p;
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)))
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;
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)
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);
179 #undef CMCOST
180 #undef COST
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.
189 static int
190 calccost (srcy, srcx, dsty, dstx, doit)
192 register int deltay,
193 deltax,
195 totalcost;
196 int ntabs,
197 n2tabs,
198 tabx,
199 tab2x,
200 tabcost;
201 register char *p;
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. */
207 if (curX == Wcm.cm_cols)
208 goto fail;
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;
222 totalcost = c * deltay;
223 if (doit)
224 while (--deltay >= 0)
225 tputs (p, 1, cmputc);
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 */
233 /* Tabs (the toughie) */
234 if (Wcm.cc_tab >= BIG || !Wcm.cm_usetabs)
235 goto olddelta; /* forget it! */
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)).
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;
250 if (tab2x >= Wcm.cm_cols) /* too far (past edge) */
251 n2tabs = 0;
254 * Now set tabcost to the cost for using ntabs, and c to the cost
255 * for using n2tabs, then pick the minimum.
258 /* cost for ntabs + cost for right motion */
259 tabcost = ntabs ? ntabs * Wcm.cc_tab + (dstx - tabx) * Wcm.cc_right
260 : BIG;
262 /* cost for n2tabs + cost for left motion */
263 c = n2tabs ? n2tabs * Wcm.cc_tab + (tab2x - dstx) * Wcm.cc_left
264 : BIG;
266 if (c < tabcost) /* then cheaper to overshoot & back up */
267 ntabs = n2tabs, tabcost = c, tabx = tab2x;
269 if (tabcost >= BIG) /* caint use tabs */
270 goto newdelta;
273 * See if tabcost is less than just moving right
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;
285 * Now might as well just recompute the delta.
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;
297 dodelta:
298 if (c == BIG) { /* caint get thar from here */
299 fail:
300 if (doit)
301 printf ("OOPS");
302 return BIG;
304 totalcost += c * deltax;
305 if (doit)
306 while (--deltax >= 0)
307 tputs (p, 1, cmputc);
308 done:
309 return totalcost;
312 #if 0
313 losecursor ()
315 curY = -1;
317 #endif
319 #define USEREL 0
320 #define USEHOME 1
321 #define USELL 2
322 #define USECR 3
324 void
325 cmgoto (row, col)
327 int homecost,
328 crcost,
329 llcost,
330 relcost,
331 directcost;
332 int use;
333 char *p,
334 *dcm;
336 /* First the degenerate case */
337 if (row == curY && col == curX) /* already there */
338 return;
340 if (curY >= 0 && curX >= 0)
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.
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);
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;
374 else
376 directcost = 0, relcost = 100000;
377 dcm = Wcm.cm_abs;
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.
384 if (directcost <= relcost)
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;
399 switch (use)
401 case USEHOME:
402 tputs (Wcm.cm_home, 1, cmputc);
403 curY = 0, curX = 0;
404 break;
406 case USELL:
407 tputs (Wcm.cm_ll, 1, cmputc);
408 curY = Wcm.cm_rows - 1, curX = 0;
409 break;
411 case USECR:
412 tputs (Wcm.cm_cr, 1, cmputc);
413 if (Wcm.cm_autolf)
414 curY++;
415 curX = 0;
416 break;
419 (void) calccost (curY, curX, row, col, 1);
420 curY = row, curX = col;
423 /* Clear out all terminal info.
424 Used before copying into it the info on the actual terminal.
427 void
428 Wcm_clear ()
430 bzero (&Wcm, sizeof Wcm);
431 UP = 0;
432 BC = 0;
436 * Initialized stuff
437 * Return 0 if can do CM.
438 * Return -1 if cannot.
439 * Return -2 if size not specified.
443 Wcm_init ()
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;