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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, 2001-2016 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 3 of the License, or (at
10 your option) 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. If not, see <http://www.gnu.org/licenses/>. */
21 #include <config.h>
22 #include <stdio.h>
24 #include "lisp.h"
25 #include "cm.h"
26 #include "termchar.h"
27 #include "tparam.h"
29 #define BIG 9999 /* Good on 32-bit hosts. */
31 int cost; /* sums up costs */
33 /* ARGSUSED */
34 int
35 evalcost (int c)
37 cost++;
38 return c;
41 /* The terminal to use for low-level output. */
42 struct tty_display_info *current_tty;
44 int
45 cmputc (int c)
47 if (current_tty->termscript)
48 putc (c & 0177, current_tty->termscript);
49 putc (c & 0177, current_tty->output);
50 return c;
53 /* NEXT TWO ARE DONE WITH MACROS */
54 #if 0
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.
61 static
62 at (tty, row, col) {
63 curY (tty) = row;
64 curX (tty) = col;
68 * Add n columns to the current cursor position.
71 static
72 addcol (tty, n) {
73 curX (tty) += n;
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.
83 if (curX (tty) == tty->Wcm->cm_cols) {
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.
90 if (tty->Wcm->cm_magicwrap)
91 ; /* "limbo" */
92 else if (tty->Wcm->cm_autowrap) {
93 curX (tty) = 0;
94 curY (tty) ++; /* Beware end of screen! */
96 else
97 curX (tty)--;
100 #endif
103 * Terminals with magicwrap (xn) don't all behave identically.
104 * The VT100 leaves the cursor in the last column but will wrap before
105 * printing the next character. I hear that the Concept terminal does
106 * the wrap immediately but ignores the next newline it sees. And some
107 * terminals just have buggy firmware, and think that the cursor is still
108 * in limbo if we use direct cursor addressing from the phantom column.
109 * The only guaranteed safe thing to do is to emit a CRLF immediately
110 * after we reach the last column; this takes us to a known state.
112 void
113 cmcheckmagic (struct tty_display_info *tty)
115 if (curX (tty) == FrameCols (tty))
117 if (!MagicWrap (tty) || curY (tty) >= FrameRows (tty) - 1)
118 emacs_abort ();
119 if (tty->termscript)
120 putc ('\r', tty->termscript);
121 putc ('\r', tty->output);
122 if (tty->termscript)
123 putc ('\n', tty->termscript);
124 putc ('\n', tty->output);
125 curX (tty) = 0;
126 curY (tty)++;
132 * (Re)Initialize the cost factors, given the output speed of the terminal
133 * in the variable ospeed. (Note: this holds B300, B9600, etc -- ie stuff
134 * out of <sgtty.h>.)
137 void
138 cmcostinit (struct tty_display_info *tty)
140 char *p;
142 #define COST(x,e) (x ? (cost = 0, tputs (x, 1, e), cost) : BIG)
143 #define CMCOST(x,e) ((x == 0) ? BIG : (p = tgoto(x, 0, 0), COST(p ,e)))
145 tty->Wcm->cc_up = COST (tty->Wcm->cm_up, evalcost);
146 tty->Wcm->cc_down = COST (tty->Wcm->cm_down, evalcost);
147 tty->Wcm->cc_left = COST (tty->Wcm->cm_left, evalcost);
148 tty->Wcm->cc_right = COST (tty->Wcm->cm_right, evalcost);
149 tty->Wcm->cc_home = COST (tty->Wcm->cm_home, evalcost);
150 tty->Wcm->cc_cr = COST (tty->Wcm->cm_cr, evalcost);
151 tty->Wcm->cc_ll = COST (tty->Wcm->cm_ll, evalcost);
152 tty->Wcm->cc_tab = tty->Wcm->cm_tabwidth ? COST (tty->Wcm->cm_tab, evalcost) : BIG;
155 * These last three are actually minimum costs. When (if) they are
156 * candidates for the least-cost motion, the real cost is computed.
157 * (Note that "0" is the assumed to generate the minimum cost.
158 * While this is not necessarily true, I have yet to see a terminal
159 * for which is not; all the terminals that have variable-cost
160 * cursor motion seem to take straight numeric values. --ACT)
163 tty->Wcm->cc_abs = CMCOST (tty->Wcm->cm_abs, evalcost);
164 tty->Wcm->cc_habs = CMCOST (tty->Wcm->cm_habs, evalcost);
165 tty->Wcm->cc_vabs = CMCOST (tty->Wcm->cm_vabs, evalcost);
167 #undef CMCOST
168 #undef COST
172 * Calculate the cost to move from (srcy, srcx) to (dsty, dstx) using
173 * up and down, and left and right, motions, and tabs. If doit is set
174 * actually perform the motion.
177 static int
178 calccost (struct tty_display_info *tty,
179 int srcy, int srcx, int dsty, int dstx, int doit)
181 register int deltay,
182 deltax,
184 totalcost;
185 int ntabs,
186 n2tabs,
187 tabx,
188 tab2x,
189 tabcost;
190 register const char *p;
192 /* If have just wrapped on a terminal with xn,
193 don't believe the cursor position: give up here
194 and force use of absolute positioning. */
196 if (curX (tty) == tty->Wcm->cm_cols)
197 goto fail;
199 totalcost = 0;
200 if ((deltay = dsty - srcy) == 0)
201 goto x;
202 if (deltay < 0)
203 p = tty->Wcm->cm_up, c = tty->Wcm->cc_up, deltay = -deltay;
204 else
205 p = tty->Wcm->cm_down, c = tty->Wcm->cc_down;
206 if (c == BIG) { /* caint get thar from here */
207 if (doit)
208 printf ("OOPS");
209 return c;
211 totalcost = c * deltay;
212 if (doit)
214 emacs_tputs (tty, p, 1, cmputc);
215 while (--deltay > 0);
217 if ((deltax = dstx - srcx) == 0)
218 goto done;
219 if (deltax < 0) {
220 p = tty->Wcm->cm_left, c = tty->Wcm->cc_left, deltax = -deltax;
221 goto dodelta; /* skip all the tab junk */
223 /* Tabs (the toughie) */
224 if (tty->Wcm->cc_tab >= BIG || !tty->Wcm->cm_usetabs)
225 goto olddelta; /* forget it! */
228 * ntabs is # tabs towards but not past dstx; n2tabs is one more
229 * (ie past dstx), but this is only valid if that is not past the
230 * right edge of the screen. We can check that at the same time
231 * as we figure out where we would be if we use the tabs (which
232 * we will put into tabx (for ntabs) and tab2x (for n2tabs)).
235 ntabs = (deltax + srcx % tty->Wcm->cm_tabwidth) / tty->Wcm->cm_tabwidth;
236 n2tabs = ntabs + 1;
237 tabx = (srcx / tty->Wcm->cm_tabwidth + ntabs) * tty->Wcm->cm_tabwidth;
238 tab2x = tabx + tty->Wcm->cm_tabwidth;
240 if (tab2x >= tty->Wcm->cm_cols) /* too far (past edge) */
241 n2tabs = 0;
244 * Now set tabcost to the cost for using ntabs, and c to the cost
245 * for using n2tabs, then pick the minimum.
248 /* cost for ntabs + cost for right motion */
249 tabcost = ntabs ? ntabs * tty->Wcm->cc_tab + (dstx - tabx) * tty->Wcm->cc_right
250 : BIG;
252 /* cost for n2tabs + cost for left motion */
253 c = n2tabs ? n2tabs * tty->Wcm->cc_tab + (tab2x - dstx) * tty->Wcm->cc_left
254 : BIG;
256 if (c < tabcost) /* then cheaper to overshoot & back up */
257 ntabs = n2tabs, tabcost = c, tabx = tab2x;
259 if (tabcost >= BIG) /* caint use tabs */
260 goto newdelta;
263 * See if tabcost is less than just moving right
266 if (tabcost < (deltax * tty->Wcm->cc_right)) {
267 totalcost += tabcost; /* use the tabs */
268 if (doit)
269 while (--ntabs >= 0)
270 emacs_tputs (tty, tty->Wcm->cm_tab, 1, cmputc);
271 srcx = tabx;
275 * Now might as well just recompute the delta.
278 newdelta:
279 if ((deltax = dstx - srcx) == 0)
280 goto done;
281 olddelta:
282 if (deltax > 0)
283 p = tty->Wcm->cm_right, c = tty->Wcm->cc_right;
284 else
285 p = tty->Wcm->cm_left, c = tty->Wcm->cc_left, deltax = -deltax;
287 dodelta:
288 if (c == BIG) { /* caint get thar from here */
289 fail:
290 if (doit)
291 printf ("OOPS");
292 return BIG;
294 totalcost += c * deltax;
295 if (doit)
297 emacs_tputs (tty, p, 1, cmputc);
298 while (--deltax > 0);
299 done:
300 return totalcost;
303 #if 0
304 void
305 losecursor (void)
307 curY = -1;
309 #endif
311 #define USEREL 0
312 #define USEHOME 1
313 #define USELL 2
314 #define USECR 3
316 void
317 cmgoto (struct tty_display_info *tty, int row, int col)
319 int homecost,
320 crcost,
321 llcost,
322 relcost,
323 directcost;
324 int use UNINIT;
325 char *p;
326 const char *dcm;
328 /* First the degenerate case */
329 if (row == curY (tty) && col == curX (tty)) /* already there */
330 return;
332 if (curY (tty) >= 0 && curX (tty) >= 0)
334 /* We may have quick ways to go to the upper-left, bottom-left,
335 * start-of-line, or start-of-next-line. Or it might be best to
336 * start where we are. Examine the options, and pick the cheapest.
339 relcost = calccost (tty, curY (tty), curX (tty), row, col, 0);
340 use = USEREL;
341 if ((homecost = tty->Wcm->cc_home) < BIG)
342 homecost += calccost (tty, 0, 0, row, col, 0);
343 if (homecost < relcost)
344 relcost = homecost, use = USEHOME;
345 if ((llcost = tty->Wcm->cc_ll) < BIG)
346 llcost += calccost (tty, tty->Wcm->cm_rows - 1, 0, row, col, 0);
347 if (llcost < relcost)
348 relcost = llcost, use = USELL;
349 if ((crcost = tty->Wcm->cc_cr) < BIG) {
350 if (tty->Wcm->cm_autolf)
351 if (curY (tty) + 1 >= tty->Wcm->cm_rows)
352 crcost = BIG;
353 else
354 crcost += calccost (tty, curY (tty) + 1, 0, row, col, 0);
355 else
356 crcost += calccost (tty, curY (tty), 0, row, col, 0);
358 if (crcost < relcost)
359 relcost = crcost, use = USECR;
360 directcost = tty->Wcm->cc_abs, dcm = tty->Wcm->cm_abs;
361 if (row == curY (tty) && tty->Wcm->cc_habs < BIG)
362 directcost = tty->Wcm->cc_habs, dcm = tty->Wcm->cm_habs;
363 else if (col == curX (tty) && tty->Wcm->cc_vabs < BIG)
364 directcost = tty->Wcm->cc_vabs, dcm = tty->Wcm->cm_vabs;
366 else
368 directcost = 0, relcost = 100000;
369 dcm = tty->Wcm->cm_abs;
373 * In the following comparison, the = in <= is because when the costs
374 * are the same, it looks nicer (I think) to move directly there.
376 if (directcost <= relcost)
378 /* compute REAL direct cost */
379 cost = 0;
380 p = (dcm == tty->Wcm->cm_habs
381 ? tgoto (dcm, row, col)
382 : tgoto (dcm, col, row));
383 emacs_tputs (tty, p, 1, evalcost);
384 if (cost <= relcost)
385 { /* really is cheaper */
386 emacs_tputs (tty, p, 1, cmputc);
387 curY (tty) = row, curX (tty) = col;
388 return;
392 switch (use)
394 case USEHOME:
395 emacs_tputs (tty, tty->Wcm->cm_home, 1, cmputc);
396 curY (tty) = 0, curX (tty) = 0;
397 break;
399 case USELL:
400 emacs_tputs (tty, tty->Wcm->cm_ll, 1, cmputc);
401 curY (tty) = tty->Wcm->cm_rows - 1, curX (tty) = 0;
402 break;
404 case USECR:
405 emacs_tputs (tty, tty->Wcm->cm_cr, 1, cmputc);
406 if (tty->Wcm->cm_autolf)
407 curY (tty)++;
408 curX (tty) = 0;
409 break;
412 (void) calccost (tty, curY (tty), curX (tty), row, col, 1);
413 curY (tty) = row, curX (tty) = col;
416 /* Clear out all terminal info.
417 Used before copying into it the info on the actual terminal.
420 void
421 Wcm_clear (struct tty_display_info *tty)
423 memset (tty->Wcm, 0, sizeof (struct cm));
424 UP = 0;
425 BC = 0;
429 * Initialized stuff
430 * Return 0 if can do CM.
431 * Return -1 if cannot.
432 * Return -2 if size not specified.
436 Wcm_init (struct tty_display_info *tty)
438 #if 0
439 if (tty->Wcm->cm_abs && !tty->Wcm->cm_ds)
440 return 0;
441 #endif
442 if (tty->Wcm->cm_abs)
443 return 0;
444 /* Require up and left, and, if no absolute, down and right */
445 if (!tty->Wcm->cm_up || !tty->Wcm->cm_left)
446 return - 1;
447 if (!tty->Wcm->cm_abs && (!tty->Wcm->cm_down || !tty->Wcm->cm_right))
448 return - 1;
449 /* Check that we know the size of the screen.... */
450 if (tty->Wcm->cm_rows <= 0 || tty->Wcm->cm_cols <= 0)
451 return - 2;
452 return 0;