xref: /netbsd-src/games/atc/input.c (revision 1182a44c59cae4d586117d55eca24b4b8b173211)
1 /*	$NetBSD: input.c,v 1.30 2021/05/02 12:50:43 rillig Exp $	*/
2 
3 /*-
4  * Copyright (c) 1990, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Ed James.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 /*
36  * Copyright (c) 1987 by Ed James, UC Berkeley.  All rights reserved.
37  *
38  * Copy permission is hereby granted provided that this notice is
39  * retained on all partial or complete copies.
40  *
41  * For more info on this and all of my stuff, mail edjames@berkeley.edu.
42  */
43 
44 #include <sys/cdefs.h>
45 #ifndef lint
46 #if 0
47 static char sccsid[] = "@(#)input.c	8.1 (Berkeley) 5/31/93";
48 #else
49 __RCSID("$NetBSD: input.c,v 1.30 2021/05/02 12:50:43 rillig Exp $");
50 #endif
51 #endif /* not lint */
52 
53 #include <sys/types.h>
54 #include <sys/wait.h>
55 #include <stdio.h>
56 #include <stdlib.h>
57 #include <string.h>
58 #include <unistd.h>
59 #include <termios.h>
60 #include <ctype.h>
61 #include <assert.h>
62 #include <math.h>
63 
64 #include "pathnames.h"
65 #include "def.h"
66 #include "struct.h"
67 #include "extern.h"
68 #include "tunable.h"
69 
70 static void rezero(void);
71 static void noise(void);
72 static int gettoken(void);
73 static const char *setplane(int);
74 static const char *turn(int);
75 static const char *circle(int);
76 static const char *left(int);
77 static const char *right(int);
78 static const char *Left(int);
79 static const char *Right(int);
80 static const char *delayb(int);
81 static const char *beacon(int);
82 static const char *ex_it(int);
83 static const char *airport(int);
84 static const char *climb(int);
85 static const char *descend(int);
86 static const char *setalt(int);
87 static const char *setrelalt(int);
88 static const char *benum(int);
89 static const char *to_dir(int);
90 static const char *rel_dir(int);
91 static const char *mark(int);
92 static const char *unmark(int);
93 static const char *ignore(int);
94 
95 
96 
97 #define MAXRULES	6
98 #define MAXDEPTH	15
99 
100 #define RETTOKEN	'\n'
101 #define REDRAWTOKEN	'\014'	/* CTRL(L) */
102 #define	SHELLTOKEN	'!'
103 #define HELPTOKEN	'?'
104 #define ALPHATOKEN	256
105 #define NUMTOKEN	257
106 
107 typedef struct {
108 	int	token;
109 	int	to_state;
110 	const char	*str;
111 	const char	*(*func)(int);
112 } RULE;
113 
114 typedef struct {
115 	int	num_rules;
116 	RULE	*rule;
117 } STATE;
118 
119 typedef struct {
120 	char	str[20];
121 	int	state;
122 	int	rule;
123 	int	ch;
124 	int	pos;
125 } STACK;
126 
127 #define T_RULE		stack[level].rule
128 #define T_STATE		stack[level].state
129 #define T_STR		stack[level].str
130 #define T_POS		stack[level].pos
131 #define	T_CH		stack[level].ch
132 
133 #define NUMELS(a)	(sizeof (a) / sizeof (*(a)))
134 
135 #define NUMSTATES	NUMELS(st)
136 
137 static
138 RULE	state0[] = {	{ ALPHATOKEN,	1,	"%c:",		setplane},
139 			{ RETTOKEN,	-1,	"",		NULL	},
140 			{ HELPTOKEN,	12,	" [a-z]<ret>",	NULL	}},
141 	state1[] = {	{ 't',		2,	" turn",	turn	},
142 			{ 'a',		3,	" altitude:",	NULL	},
143 			{ 'c',		4,	" circle",	circle	},
144 			{ 'm',		7,	" mark",	mark	},
145 			{ 'u',		7,	" unmark",	unmark	},
146 			{ 'i',		7,	" ignore",	ignore	},
147 			{ HELPTOKEN,	12,	" tacmui",	NULL	}},
148 	state2[] = {	{ 'l',		6,	" left",	left	},
149 			{ 'r',		6,	" right",	right	},
150 			{ 'L',		4,	" left 90",	Left	},
151 			{ 'R',		4,	" right 90",	Right	},
152 			{ 't',		11,	" towards",	NULL	},
153 			{ 'w',		4,	" to 0",	to_dir	},
154 			{ 'e',		4,	" to 45",	to_dir	},
155 			{ 'd',		4,	" to 90",	to_dir	},
156 			{ 'c',		4,	" to 135",	to_dir	},
157 			{ 'x',		4,	" to 180",	to_dir	},
158 			{ 'z',		4,	" to 225",	to_dir	},
159 			{ 'a',		4,	" to 270",	to_dir	},
160 			{ 'q',		4,	" to 315",	to_dir	},
161 			{ HELPTOKEN,	12,	" lrLRt<dir>",	NULL	}},
162 	state3[] = {	{ '+',		10,	" climb",	climb	},
163 			{ 'c',		10,	" climb",	climb	},
164 			{ '-',		10,	" descend",	descend	},
165 			{ 'd',		10,	" descend",	descend	},
166 			{ NUMTOKEN,	7,	" %c000 feet",	setalt	},
167 			{ HELPTOKEN,	12,	" +-cd[0-9]",	NULL	}},
168 	state4[] = {	{ '@',		9,	" at",		NULL	},
169 			{ 'a',		9,	" at",		NULL	},
170 			{ RETTOKEN,	-1,	"",		NULL	},
171 			{ HELPTOKEN,	12,	" @a<ret>",	NULL	}},
172 	state5[] = {	{ NUMTOKEN,	7,	"%c",		delayb	},
173 			{ HELPTOKEN,	12,	" [0-9]",	NULL	}},
174 	state6[] = {	{ '@',		9,	" at",		NULL	},
175 			{ 'a',		9,	" at",		NULL	},
176 			{ 'w',		4,	" 0",		rel_dir	},
177 			{ 'e',		4,	" 45",		rel_dir	},
178 			{ 'd',		4,	" 90",		rel_dir	},
179 			{ 'c',		4,	" 135",		rel_dir	},
180 			{ 'x',		4,	" 180",		rel_dir	},
181 			{ 'z',		4,	" 225",		rel_dir	},
182 			{ 'a',		4,	" 270",		rel_dir	},
183 			{ 'q',		4,	" 315",		rel_dir	},
184 			{ RETTOKEN,	-1,	"",		NULL	},
185 			{ HELPTOKEN,	12,	" @a<dir><ret>",NULL	}},
186 	state7[] = {	{ RETTOKEN,	-1,	"",		NULL	},
187 			{ HELPTOKEN,	12,	" <ret>",	NULL	}},
188 	state8[] = {	{ NUMTOKEN,	4,	"%c",		benum	},
189 			{ HELPTOKEN,	12,	" [0-9]",	NULL	}},
190 	state9[] = {	{ 'b',		5,	" beacon #",	NULL	},
191 			{ '*',		5,	" beacon #",	NULL	},
192 			{ HELPTOKEN,	12,	" b*",		NULL	}},
193 	state10[] = {	{ NUMTOKEN,	7,	" %c000 ft",	setrelalt},
194 			{ HELPTOKEN,	12,	" [0-9]",	NULL	}},
195 	state11[] = {	{ 'b',		8,	" beacon #",	beacon	},
196 			{ '*',		8,	" beacon #",	beacon	},
197 			{ 'e',		8,	" exit #",	ex_it	},
198 			{ 'a',		8,	" airport #",	airport	},
199 			{ HELPTOKEN,	12,	" b*ea",	NULL	}},
200 	state12[] = {	{ -1,		-1,	"",		NULL	}};
201 
202 #define DEF_STATE(s)	{ NUMELS(s),	(s)	}
203 
204 static STATE st[] = {
205 	DEF_STATE(state0), DEF_STATE(state1), DEF_STATE(state2),
206 	DEF_STATE(state3), DEF_STATE(state4), DEF_STATE(state5),
207 	DEF_STATE(state6), DEF_STATE(state7), DEF_STATE(state8),
208 	DEF_STATE(state9), DEF_STATE(state10), DEF_STATE(state11),
209 	DEF_STATE(state12)
210 };
211 
212 static PLANE p;
213 static STACK stack[MAXDEPTH];
214 static int level;
215 static int tval;
216 static int dir;
217 static enum places dest_type;
218 static unsigned dest_no;
219 
220 static int
pop(void)221 pop(void)
222 {
223 	if (level == 0)
224 		return (-1);
225 	level--;
226 
227 	ioclrtoeol(T_POS);
228 
229 	(void)strcpy(T_STR, "");
230 	T_RULE = -1;
231 	T_CH = -1;
232 	return (0);
233 }
234 
235 static void
rezero(void)236 rezero(void)
237 {
238 	iomove(0);
239 
240 	level = 0;
241 	T_STATE = 0;
242 	T_RULE = -1;
243 	T_CH = -1;
244 	T_POS = 0;
245 	(void)strcpy(T_STR, "");
246 }
247 
248 static void
push(int ruleno,int ch)249 push(int ruleno, int ch)
250 {
251 	int	newstate, newpos;
252 
253 	assert(level < (MAXDEPTH - 1));
254 	(void)snprintf(T_STR, sizeof(T_STR),
255 		st[T_STATE].rule[ruleno].str, tval);
256 	T_RULE = ruleno;
257 	T_CH = ch;
258 	newstate = st[T_STATE].rule[ruleno].to_state;
259 	newpos = T_POS + strlen(T_STR);
260 
261 	ioaddstr(T_POS, T_STR);
262 
263 	if (level == 0)
264 		ioclrtobot();
265 	level++;
266 	T_STATE = newstate;
267 	T_POS = newpos;
268 	T_RULE = -1;
269 	(void)strcpy(T_STR, "");
270 }
271 
272 int
getcommand(void)273 getcommand(void)
274 {
275 	int	c, i, done;
276 	const char	*s, *(*func)(int);
277 	PLANE	*pp;
278 
279 	rezero();
280 
281 	do {
282 		c = gettoken();
283 		if (c == tty_new.c_cc[VERASE]) {
284 			if (pop() < 0)
285 				noise();
286 		} else if (c == tty_new.c_cc[VKILL]) {
287 			while (pop() >= 0)
288 				;
289 		} else {
290 			done = 0;
291 			for (i = 0; i < st[T_STATE].num_rules; i++) {
292 				if (st[T_STATE].rule[i].token == c ||
293 				    st[T_STATE].rule[i].token == tval) {
294 					push(i, (c >= ALPHATOKEN) ? tval : c);
295 					done = 1;
296 					break;
297 				}
298 			}
299 			if (!done)
300 				noise();
301 		}
302 	} while (T_STATE != -1);
303 
304 	if (level == 1)
305 		return (1);	/* forced update */
306 
307 	dest_type = T_NODEST;
308 
309 	for (i = 0; i < level; i++) {
310 		func = st[stack[i].state].rule[stack[i].rule].func;
311 		if (func != NULL)
312 			if ((s = (*func)(stack[i].ch)) != NULL) {
313 				ioerror(stack[i].pos,
314 				    (int)strlen(stack[i].str), s);
315 				return (-1);
316 			}
317 	}
318 
319 	pp = findplane(p.plane_no);
320 	if (pp->new_altitude != p.new_altitude)
321 		pp->new_altitude = p.new_altitude;
322 	else if (pp->status != p.status)
323 		pp->status = p.status;
324 	else {
325 		pp->new_dir = p.new_dir;
326 		pp->delayd = p.delayd;
327 		pp->delayd_no = p.delayd_no;
328 	}
329 	return (0);
330 }
331 
332 static void
noise(void)333 noise(void)
334 {
335 	(void)putchar('\07');
336 	(void)fflush(stdout);
337 }
338 
339 static int
gettoken(void)340 gettoken(void)
341 {
342 	while ((tval = getAChar()) == REDRAWTOKEN || tval == SHELLTOKEN)
343 	{
344 		if (tval == SHELLTOKEN)
345 		{
346 #ifdef BSD
347 			struct itimerval	itv;
348 			itv.it_value.tv_sec = 0;
349 			itv.it_value.tv_usec = 0;
350 			(void)setitimer(ITIMER_REAL, &itv, NULL);
351 #endif
352 #ifdef SYSV
353 			int aval;
354 			aval = alarm(0);
355 #endif
356 			if (fork() == 0)	/* child */
357 			{
358 				char *shell, *base;
359 
360 				done_screen();
361 
362 						 /* run user's favorite shell */
363 				if ((shell = getenv("SHELL")) != NULL)
364 				{
365 					base = strrchr(shell, '/');
366 					if (base == NULL)
367 						base = shell;
368 					else
369 						base++;
370 					(void)execl(shell, base, (char *) 0);
371 				}
372 				else
373 					(void)execl(_PATH_BSHELL, "sh",
374 					    (char *) 0);
375 
376 				exit(0);	/* oops */
377 			}
378 
379 			(void)wait(0);
380 			(void)tcsetattr(fileno(stdin), TCSADRAIN, &tty_new);
381 #ifdef BSD
382 			itv.it_value.tv_sec = 0;
383 			itv.it_value.tv_usec = 1;
384 			itv.it_interval.tv_sec = sp->update_secs;
385 			itv.it_interval.tv_usec = 0;
386 			(void)setitimer(ITIMER_REAL, &itv, NULL);
387 #endif
388 #ifdef SYSV
389 			alarm(aval);
390 #endif
391 		}
392 		(void)redraw();
393 	}
394 
395 	if (isdigit(tval))
396 		return (NUMTOKEN);
397 	else if (isalpha(tval))
398 		return (ALPHATOKEN);
399 	else
400 		return (tval);
401 }
402 
403 static const char *
setplane(int c)404 setplane(int c)
405 {
406 	PLANE	*pp;
407 
408 	pp = findplane(number(c));
409 	if (pp == NULL)
410 		return ("Unknown Plane");
411 	(void)memcpy(&p, pp, sizeof (p));
412 	p.delayd = false;
413 	return (NULL);
414 }
415 
416 /* ARGSUSED */
417 static const char *
turn(int c __unused)418 turn(int c __unused)
419 {
420 	if (p.altitude == 0)
421 		return ("Planes at airports may not change direction");
422 	return (NULL);
423 }
424 
425 /* ARGSUSED */
426 static const char *
circle(int c __unused)427 circle(int c __unused)
428 {
429 	if (p.altitude == 0)
430 		return ("Planes cannot circle on the ground");
431 	p.new_dir = MAXDIR;
432 	return (NULL);
433 }
434 
435 /* ARGSUSED */
436 static const char *
left(int c __unused)437 left(int c __unused)
438 {
439 	dir = D_LEFT;
440 	p.new_dir = p.dir - 1;
441 	if (p.new_dir < 0)
442 		p.new_dir += MAXDIR;
443 	return (NULL);
444 }
445 
446 /* ARGSUSED */
447 static const char *
right(int c __unused)448 right(int c __unused)
449 {
450 	dir = D_RIGHT;
451 	p.new_dir = p.dir + 1;
452 	if (p.new_dir >= MAXDIR)
453 		p.new_dir -= MAXDIR;
454 	return (NULL);
455 }
456 
457 /* ARGSUSED */
458 static const char *
Left(int c __unused)459 Left(int c __unused)
460 {
461 	p.new_dir = p.dir - 2;
462 	if (p.new_dir < 0)
463 		p.new_dir += MAXDIR;
464 	return (NULL);
465 }
466 
467 /* ARGSUSED */
468 static const char *
Right(int c __unused)469 Right(int c __unused)
470 {
471 	p.new_dir = p.dir + 2;
472 	if (p.new_dir >= MAXDIR)
473 		p.new_dir -= MAXDIR;
474 	return (NULL);
475 }
476 
477 static const char *
delayb(int ch)478 delayb(int ch)
479 {
480 	int	xdiff, ydiff;
481 	unsigned bn;
482 
483 	bn = ch -= '0';
484 
485 	if (bn >= sp->num_beacons)
486 		return ("Unknown beacon");
487 	xdiff = sp->beacon[bn].x - p.xpos;
488 	xdiff = SGN(xdiff);
489 	ydiff = sp->beacon[bn].y - p.ypos;
490 	ydiff = SGN(ydiff);
491 	if (xdiff != displacement[p.dir].dx || ydiff != displacement[p.dir].dy)
492 		return ("Beacon is not in flight path");
493 	p.delayd = true;
494 	p.delayd_no = bn;
495 
496 	if (dest_type != T_NODEST) {
497 		switch (dest_type) {
498 		case T_BEACON:
499 			xdiff = sp->beacon[dest_no].x - sp->beacon[bn].x;
500 			ydiff = sp->beacon[dest_no].y - sp->beacon[bn].y;
501 			break;
502 		case T_EXIT:
503 			xdiff = sp->exit[dest_no].x - sp->beacon[bn].x;
504 			ydiff = sp->exit[dest_no].y - sp->beacon[bn].y;
505 			break;
506 		case T_AIRPORT:
507 			xdiff = sp->airport[dest_no].x - sp->beacon[bn].x;
508 			ydiff = sp->airport[dest_no].y - sp->beacon[bn].y;
509 			break;
510 		default:
511 			return ("Bad case in delayb!  Get help!");
512 		}
513 		if (xdiff == 0 && ydiff == 0)
514 			return ("Would already be there");
515 		p.new_dir = DIR_FROM_DXDY(xdiff, ydiff);
516 		if (p.new_dir == p.dir)
517 			return ("Already going in that direction");
518 	}
519 	return (NULL);
520 }
521 
522 /* ARGSUSED */
523 static const char *
beacon(int c __unused)524 beacon(int c __unused)
525 {
526 	dest_type = T_BEACON;
527 	return (NULL);
528 }
529 
530 /* ARGSUSED */
531 static const char *
ex_it(int c __unused)532 ex_it(int c __unused)
533 {
534 	dest_type = T_EXIT;
535 	return (NULL);
536 }
537 
538 /* ARGSUSED */
539 static const char *
airport(int c __unused)540 airport(int c __unused)
541 {
542 	dest_type = T_AIRPORT;
543 	return (NULL);
544 }
545 
546 /* ARGSUSED */
547 static const char *
climb(int c __unused)548 climb(int c __unused)
549 {
550 	dir = D_UP;
551 	return (NULL);
552 }
553 
554 /* ARGSUSED */
555 static const char *
descend(int c __unused)556 descend(int c __unused)
557 {
558 	dir = D_DOWN;
559 	return (NULL);
560 }
561 
562 static const char *
setalt(int c)563 setalt(int c)
564 {
565 	int newalt = c - '0';
566 	if ((p.altitude == newalt) && (p.new_altitude == p.altitude))
567 		return ("Already at that altitude");
568 	if (p.new_altitude == newalt) {
569 		return ("Already going to that altitude");
570 	}
571 	p.new_altitude = newalt;
572 	return (NULL);
573 }
574 
575 static const char *
setrelalt(int c)576 setrelalt(int c)
577 {
578 	int newalt;
579 
580 	if (c == 0)
581 		return ("altitude not changed");
582 
583 	switch (dir) {
584 	case D_UP:
585 		newalt = p.altitude + c - '0';
586 		break;
587 	case D_DOWN:
588 		newalt = p.altitude - (c - '0');
589 		break;
590 	default:
591 		return ("Unknown case in setrelalt!  Get help!");
592 	}
593 
594 	if (p.new_altitude == newalt)
595 		return ("Already going to that altitude");
596 
597 	p.new_altitude = newalt;
598 
599 	if (p.new_altitude < 0)
600 		return ("Altitude would be too low");
601 	else if (p.new_altitude > 9)
602 		return ("Altitude would be too high");
603 	return (NULL);
604 }
605 
606 static const char *
benum(int ch)607 benum(int ch)
608 {
609 	unsigned n;
610 
611 	n = ch - '0';
612 	dest_no = n;
613 
614 	switch (dest_type) {
615 	case T_BEACON:
616 		if (n >= sp->num_beacons)
617 			return ("Unknown beacon");
618 		p.new_dir = DIR_FROM_DXDY(sp->beacon[n].x - p.xpos,
619 			sp->beacon[n].y - p.ypos);
620 		break;
621 	case T_EXIT:
622 		if (n >= sp->num_exits)
623 			return ("Unknown exit");
624 		p.new_dir = DIR_FROM_DXDY(sp->exit[n].x - p.xpos,
625 			sp->exit[n].y - p.ypos);
626 		break;
627 	case T_AIRPORT:
628 		if (n >= sp->num_airports)
629 			return ("Unknown airport");
630 		p.new_dir = DIR_FROM_DXDY(sp->airport[n].x - p.xpos,
631 			sp->airport[n].y - p.ypos);
632 		break;
633 	default:
634 		return ("Unknown case in benum!  Get help!");
635 	}
636 	return (NULL);
637 }
638 
639 static const char *
to_dir(int c)640 to_dir(int c)
641 {
642 	p.new_dir = dir_no(c);
643 	return (NULL);
644 }
645 
646 static const char *
rel_dir(int c)647 rel_dir(int c)
648 {
649 	int	angle;
650 
651 	angle = dir_no(c);
652 	switch (dir) {
653 	case D_LEFT:
654 		p.new_dir = p.dir - angle;
655 		if (p.new_dir < 0)
656 			p.new_dir += MAXDIR;
657 		break;
658 	case D_RIGHT:
659 		p.new_dir = p.dir + angle;
660 		if (p.new_dir >= MAXDIR)
661 			p.new_dir -= MAXDIR;
662 		break;
663 	default:
664 		return ("Bizarre direction in rel_dir!  Get help!");
665 	}
666 	return (NULL);
667 }
668 
669 /* ARGSUSED */
670 static const char *
mark(int c __unused)671 mark(int c __unused)
672 {
673 	if (p.altitude == 0)
674 		return ("Cannot mark planes on the ground");
675 	if (p.status == S_MARKED)
676 		return ("Already marked");
677 	p.status = S_MARKED;
678 	return (NULL);
679 }
680 
681 /* ARGSUSED */
682 static const char *
unmark(int c __unused)683 unmark(int c __unused)
684 {
685 	if (p.altitude == 0)
686 		return ("Cannot unmark planes on the ground");
687 	if (p.status == S_UNMARKED)
688 		return ("Already unmarked");
689 	p.status = S_UNMARKED;
690 	return (NULL);
691 }
692 
693 /* ARGSUSED */
694 static const char *
ignore(int c __unused)695 ignore(int c __unused)
696 {
697 	if (p.altitude == 0)
698 		return ("Cannot ignore planes on the ground");
699 	if (p.status == S_IGNORED)
700 		return ("Already ignored");
701 	p.status = S_IGNORED;
702 	return (NULL);
703 }
704 
705 int
dir_no(int ch)706 dir_no(int ch)
707 {
708 	int	dirno;
709 
710 	dirno = -1;
711 	switch (ch) {
712 	case 'w':	dirno = 0;	break;
713 	case 'e':	dirno = 1;	break;
714 	case 'd':	dirno = 2;	break;
715 	case 'c':	dirno = 3;	break;
716 	case 'x':	dirno = 4;	break;
717 	case 'z':	dirno = 5;	break;
718 	case 'a':	dirno = 6;	break;
719 	case 'q':	dirno = 7;	break;
720 	default:
721 		(void)fprintf(stderr, "bad character in dir_no\n");
722 		break;
723 	}
724 	return (dirno);
725 }
726