1 /* Cursor motion subroutines for GNU Emacs.
2 Copyright (C) 1985, 1995, 2001-2017 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/>. */
29 #define BIG 9999 /* Good on 32-bit hosts. */
31 int cost
; /* sums up costs */
41 /* The terminal to use for low-level output. */
42 struct tty_display_info
*current_tty
;
47 if (current_tty
->termscript
)
48 putc (c
& 0177, current_tty
->termscript
);
49 putc (c
& 0177, current_tty
->output
);
53 /* NEXT TWO ARE DONE WITH MACROS */
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.
68 * Add n columns to the current cursor position.
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
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
)
92 else if (tty
->Wcm
->cm_autowrap
) {
94 curY (tty
) ++; /* Beware end of screen! */
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.
113 cmcheckmagic (struct tty_display_info
*tty
)
115 if (curX (tty
) == FrameCols (tty
))
117 if (!MagicWrap (tty
) || curY (tty
) >= FrameRows (tty
) - 1)
120 putc ('\r', tty
->termscript
);
121 putc ('\r', tty
->output
);
123 putc ('\n', tty
->termscript
);
124 putc ('\n', tty
->output
);
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
138 cmcostinit (struct tty_display_info
*tty
)
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
);
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.
178 calccost (struct tty_display_info
*tty
,
179 int srcy
, int srcx
, int dsty
, int dstx
, int doit
)
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
)
200 if ((deltay
= dsty
- srcy
) == 0)
203 p
= tty
->Wcm
->cm_up
, c
= tty
->Wcm
->cc_up
, deltay
= -deltay
;
205 p
= tty
->Wcm
->cm_down
, c
= tty
->Wcm
->cc_down
;
206 if (c
== BIG
) { /* caint get thar from here */
211 totalcost
= c
* deltay
;
214 emacs_tputs (tty
, p
, 1, cmputc
);
215 while (--deltay
> 0);
217 if ((deltax
= dstx
- srcx
) == 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
;
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) */
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
252 /* cost for n2tabs + cost for left motion */
253 c
= n2tabs
? n2tabs
* tty
->Wcm
->cc_tab
+ (tab2x
- dstx
) * tty
->Wcm
->cc_left
256 if (c
< tabcost
) /* then cheaper to overshoot & back up */
257 ntabs
= n2tabs
, tabcost
= c
, tabx
= tab2x
;
259 if (tabcost
>= BIG
) /* caint use tabs */
263 * See if tabcost is less than just moving right
266 if (tabcost
< (deltax
* tty
->Wcm
->cc_right
)) {
267 totalcost
+= tabcost
; /* use the tabs */
270 emacs_tputs (tty
, tty
->Wcm
->cm_tab
, 1, cmputc
);
275 * Now might as well just recompute the delta.
279 if ((deltax
= dstx
- srcx
) == 0)
283 p
= tty
->Wcm
->cm_right
, c
= tty
->Wcm
->cc_right
;
285 p
= tty
->Wcm
->cm_left
, c
= tty
->Wcm
->cc_left
, deltax
= -deltax
;
288 if (c
== BIG
) { /* caint get thar from here */
294 totalcost
+= c
* deltax
;
297 emacs_tputs (tty
, p
, 1, cmputc
);
298 while (--deltax
> 0);
317 cmgoto (struct tty_display_info
*tty
, int row
, int col
)
324 int use
IF_LINT (= 0);
328 /* First the degenerate case */
329 if (row
== curY (tty
) && col
== curX (tty
)) /* already there */
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);
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
)
354 crcost
+= calccost (tty
, curY (tty
) + 1, 0, row
, col
, 0);
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
;
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 */
380 p
= (dcm
== tty
->Wcm
->cm_habs
381 ? tgoto (dcm
, row
, col
)
382 : tgoto (dcm
, col
, row
));
383 emacs_tputs (tty
, p
, 1, evalcost
);
385 { /* really is cheaper */
386 emacs_tputs (tty
, p
, 1, cmputc
);
387 curY (tty
) = row
, curX (tty
) = col
;
395 emacs_tputs (tty
, tty
->Wcm
->cm_home
, 1, cmputc
);
396 curY (tty
) = 0, curX (tty
) = 0;
400 emacs_tputs (tty
, tty
->Wcm
->cm_ll
, 1, cmputc
);
401 curY (tty
) = tty
->Wcm
->cm_rows
- 1, curX (tty
) = 0;
405 emacs_tputs (tty
, tty
->Wcm
->cm_cr
, 1, cmputc
);
406 if (tty
->Wcm
->cm_autolf
)
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.
421 Wcm_clear (struct tty_display_info
*tty
)
423 memset (tty
->Wcm
, 0, sizeof (struct cm
));
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
)
439 if (tty
->Wcm
->cm_abs
&& !tty
->Wcm
->cm_ds
)
442 if (tty
->Wcm
->cm_abs
)
444 /* Require up and left, and, if no absolute, down and right */
445 if (!tty
->Wcm
->cm_up
|| !tty
->Wcm
->cm_left
)
447 if (!tty
->Wcm
->cm_abs
&& (!tty
->Wcm
->cm_down
|| !tty
->Wcm
->cm_right
))
449 /* Check that we know the size of the screen.... */
450 if (tty
->Wcm
->cm_rows
<= 0 || tty
->Wcm
->cm_cols
<= 0)