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input.c revision 1.5
      1  1.5      tls /*	$NetBSD: input.c,v 1.5 1997/01/13 06:50:25 tls Exp $	*/
      2  1.3      cgd 
      3  1.1      cgd /*-
      4  1.3      cgd  * Copyright (c) 1990, 1993
      5  1.3      cgd  *	The Regents of the University of California.  All rights reserved.
      6  1.1      cgd  *
      7  1.1      cgd  * This code is derived from software contributed to Berkeley by
      8  1.1      cgd  * Ed James.
      9  1.1      cgd  *
     10  1.1      cgd  * Redistribution and use in source and binary forms, with or without
     11  1.1      cgd  * modification, are permitted provided that the following conditions
     12  1.1      cgd  * are met:
     13  1.1      cgd  * 1. Redistributions of source code must retain the above copyright
     14  1.1      cgd  *    notice, this list of conditions and the following disclaimer.
     15  1.1      cgd  * 2. Redistributions in binary form must reproduce the above copyright
     16  1.1      cgd  *    notice, this list of conditions and the following disclaimer in the
     17  1.1      cgd  *    documentation and/or other materials provided with the distribution.
     18  1.1      cgd  * 3. All advertising materials mentioning features or use of this software
     19  1.1      cgd  *    must display the following acknowledgement:
     20  1.1      cgd  *	This product includes software developed by the University of
     21  1.1      cgd  *	California, Berkeley and its contributors.
     22  1.1      cgd  * 4. Neither the name of the University nor the names of its contributors
     23  1.1      cgd  *    may be used to endorse or promote products derived from this software
     24  1.1      cgd  *    without specific prior written permission.
     25  1.1      cgd  *
     26  1.1      cgd  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     27  1.1      cgd  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     28  1.1      cgd  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     29  1.1      cgd  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     30  1.1      cgd  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     31  1.1      cgd  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     32  1.1      cgd  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     33  1.1      cgd  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     34  1.1      cgd  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     35  1.1      cgd  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     36  1.1      cgd  * SUCH DAMAGE.
     37  1.1      cgd  */
     38  1.1      cgd 
     39  1.1      cgd /*
     40  1.1      cgd  * Copyright (c) 1987 by Ed James, UC Berkeley.  All rights reserved.
     41  1.1      cgd  *
     42  1.1      cgd  * Copy permission is hereby granted provided that this notice is
     43  1.1      cgd  * retained on all partial or complete copies.
     44  1.1      cgd  *
     45  1.1      cgd  * For more info on this and all of my stuff, mail edjames (at) berkeley.edu.
     46  1.1      cgd  */
     47  1.1      cgd 
     48  1.1      cgd #ifndef lint
     49  1.3      cgd #if 0
     50  1.3      cgd static char sccsid[] = "@(#)input.c	8.1 (Berkeley) 5/31/93";
     51  1.3      cgd #else
     52  1.5      tls static char rcsid[] = "$NetBSD: input.c,v 1.5 1997/01/13 06:50:25 tls Exp $";
     53  1.3      cgd #endif
     54  1.1      cgd #endif not lint
     55  1.1      cgd 
     56  1.1      cgd #include "include.h"
     57  1.1      cgd #include "pathnames.h"
     58  1.1      cgd 
     59  1.1      cgd #define MAXRULES	6
     60  1.1      cgd #define MAXDEPTH	15
     61  1.1      cgd 
     62  1.1      cgd #define RETTOKEN	'\n'
     63  1.1      cgd #ifdef SYSV
     64  1.1      cgd #define CRTOKEN		'\r'
     65  1.1      cgd #endif
     66  1.1      cgd #define REDRAWTOKEN	'\014'	/* CTRL(L) */
     67  1.1      cgd #define	SHELLTOKEN	'!'
     68  1.1      cgd #define HELPTOKEN	'?'
     69  1.1      cgd #define ALPHATOKEN	256
     70  1.1      cgd #define NUMTOKEN	257
     71  1.1      cgd 
     72  1.1      cgd typedef struct {
     73  1.1      cgd 	int	token;
     74  1.1      cgd 	int	to_state;
     75  1.1      cgd 	char	*str;
     76  1.1      cgd 	char	*(*func)();
     77  1.1      cgd } RULE;
     78  1.1      cgd 
     79  1.1      cgd typedef struct {
     80  1.1      cgd 	int	num_rules;
     81  1.1      cgd 	RULE	*rule;
     82  1.1      cgd } STATE;
     83  1.1      cgd 
     84  1.1      cgd typedef struct {
     85  1.1      cgd 	char	str[20];
     86  1.1      cgd 	int	state;
     87  1.1      cgd 	int	rule;
     88  1.1      cgd 	int	ch;
     89  1.1      cgd 	int	pos;
     90  1.1      cgd } STACK;
     91  1.1      cgd 
     92  1.1      cgd #define T_RULE		stack[level].rule
     93  1.1      cgd #define T_STATE		stack[level].state
     94  1.1      cgd #define T_STR		stack[level].str
     95  1.1      cgd #define T_POS		stack[level].pos
     96  1.1      cgd #define	T_CH		stack[level].ch
     97  1.1      cgd 
     98  1.1      cgd #define NUMELS(a)	(sizeof (a) / sizeof (*(a)))
     99  1.1      cgd 
    100  1.1      cgd #define NUMSTATES	NUMELS(st)
    101  1.1      cgd 
    102  1.1      cgd char	*setplane(), *circle(), *left(), *right(), *Left(), *Right(),
    103  1.1      cgd 	*beacon(), *ex_it(), *climb(), *descend(), *setalt(), *setrelalt(),
    104  1.1      cgd 	*benum(), *to_dir(), *rel_dir(), *delayb(), *mark(), *unmark(),
    105  1.1      cgd 	*airport(), *turn(), *ignore();
    106  1.1      cgd 
    107  1.1      cgd RULE	state0[] = {	{ ALPHATOKEN,	1,	"%c:",		setplane},
    108  1.1      cgd 			{ RETTOKEN,	-1,	"",		NULL	},
    109  1.1      cgd #ifdef SYSV
    110  1.1      cgd 			{ CRTOKEN,	-1,	"",		NULL	},
    111  1.1      cgd #endif
    112  1.1      cgd 			{ HELPTOKEN,	12,	" [a-z]<ret>",	NULL	}},
    113  1.1      cgd 	state1[] = {	{ 't',		2,	" turn",	turn	},
    114  1.1      cgd 			{ 'a',		3,	" altitude:",	NULL	},
    115  1.1      cgd 			{ 'c',		4,	" circle",	circle	},
    116  1.1      cgd 			{ 'm',		7,	" mark",	mark	},
    117  1.1      cgd 			{ 'u',		7,	" unmark",	unmark	},
    118  1.1      cgd 			{ 'i',		7,	" ignore",	ignore	},
    119  1.1      cgd 			{ HELPTOKEN,	12,	" tacmui",	NULL	}},
    120  1.1      cgd 	state2[] = {	{ 'l',		6,	" left",	left	},
    121  1.1      cgd 			{ 'r',		6,	" right",	right	},
    122  1.1      cgd 			{ 'L',		4,	" left 90",	Left	},
    123  1.1      cgd 			{ 'R',		4,	" right 90",	Right	},
    124  1.1      cgd 			{ 't',		11,	" towards",	NULL	},
    125  1.1      cgd 			{ 'w',		4,	" to 0",	to_dir	},
    126  1.1      cgd 			{ 'e',		4,	" to 45",	to_dir	},
    127  1.1      cgd 			{ 'd',		4,	" to 90",	to_dir	},
    128  1.1      cgd 			{ 'c',		4,	" to 135",	to_dir	},
    129  1.1      cgd 			{ 'x',		4,	" to 180",	to_dir	},
    130  1.1      cgd 			{ 'z',		4,	" to 225",	to_dir	},
    131  1.1      cgd 			{ 'a',		4,	" to 270",	to_dir	},
    132  1.1      cgd 			{ 'q',		4,	" to 315",	to_dir	},
    133  1.1      cgd 			{ HELPTOKEN,	12,	" lrLRt<dir>",	NULL	}},
    134  1.1      cgd 	state3[] = {	{ '+',		10,	" climb",	climb	},
    135  1.1      cgd 			{ 'c',		10,	" climb",	climb	},
    136  1.1      cgd 			{ '-',		10,	" descend",	descend	},
    137  1.1      cgd 			{ 'd',		10,	" descend",	descend	},
    138  1.1      cgd 			{ NUMTOKEN,	7,	" %c000 feet",	setalt	},
    139  1.1      cgd 			{ HELPTOKEN,	12,	" +-cd[0-9]",	NULL	}},
    140  1.1      cgd 	state4[] = {	{ '@',		9,	" at",		NULL	},
    141  1.1      cgd 			{ 'a',		9,	" at",		NULL	},
    142  1.1      cgd 			{ RETTOKEN,	-1,	"",		NULL	},
    143  1.1      cgd #ifdef SYSV
    144  1.1      cgd 			{ CRTOKEN,	-1,	"",		NULL	},
    145  1.1      cgd #endif
    146  1.1      cgd 			{ HELPTOKEN,	12,	" @a<ret>",	NULL	}},
    147  1.1      cgd 	state5[] = {	{ NUMTOKEN,	7,	"%c",		delayb	},
    148  1.1      cgd 			{ HELPTOKEN,	12,	" [0-9]",	NULL	}},
    149  1.1      cgd 	state6[] = {	{ '@',		9,	" at",		NULL	},
    150  1.1      cgd 			{ 'a',		9,	" at",		NULL	},
    151  1.1      cgd 			{ 'w',		4,	" 0",		rel_dir	},
    152  1.1      cgd 			{ 'e',		4,	" 45",		rel_dir	},
    153  1.1      cgd 			{ 'd',		4,	" 90",		rel_dir	},
    154  1.1      cgd 			{ 'c',		4,	" 135",		rel_dir	},
    155  1.1      cgd 			{ 'x',		4,	" 180",		rel_dir	},
    156  1.1      cgd 			{ 'z',		4,	" 225",		rel_dir	},
    157  1.1      cgd 			{ 'a',		4,	" 270",		rel_dir	},
    158  1.1      cgd 			{ 'q',		4,	" 315",		rel_dir	},
    159  1.1      cgd 			{ RETTOKEN,	-1,	"",		NULL	},
    160  1.1      cgd #ifdef SYSV
    161  1.1      cgd 			{ CRTOKEN,	-1,	"",		NULL	},
    162  1.1      cgd #endif
    163  1.1      cgd 			{ HELPTOKEN,	12,	" @a<dir><ret>",NULL	}},
    164  1.1      cgd 	state7[] = {	{ RETTOKEN,	-1,	"",		NULL	},
    165  1.1      cgd #ifdef SYSV
    166  1.1      cgd 	            	{ CRTOKEN,	-1,	"",		NULL	},
    167  1.1      cgd #endif
    168  1.1      cgd 			{ HELPTOKEN,	12,	" <ret>",	NULL	}},
    169  1.1      cgd 	state8[] = {	{ NUMTOKEN,	4,	"%c",		benum	},
    170  1.1      cgd 			{ HELPTOKEN,	12,	" [0-9]",	NULL	}},
    171  1.1      cgd 	state9[] = {	{ 'b',		5,	" beacon #",	NULL	},
    172  1.1      cgd 			{ '*',		5,	" beacon #",	NULL	},
    173  1.1      cgd 			{ HELPTOKEN,	12,	" b*",		NULL	}},
    174  1.1      cgd 	state10[] = {	{ NUMTOKEN,	7,	" %c000 ft",	setrelalt},
    175  1.1      cgd 			{ HELPTOKEN,	12,	" [0-9]",	NULL	}},
    176  1.1      cgd 	state11[] = {	{ 'b',		8,	" beacon #",	beacon	},
    177  1.1      cgd 			{ '*',		8,	" beacon #",	beacon	},
    178  1.1      cgd 			{ 'e',		8,	" exit #",	ex_it	},
    179  1.1      cgd 			{ 'a',		8,	" airport #",	airport	},
    180  1.1      cgd 			{ HELPTOKEN,	12,	" b*ea",	NULL	}},
    181  1.1      cgd 	state12[] = {	{ -1,		-1,	"",		NULL	}};
    182  1.1      cgd 
    183  1.1      cgd #define DEF_STATE(s)	{ NUMELS(s),	(s)	}
    184  1.1      cgd 
    185  1.1      cgd STATE	st[] = {
    186  1.1      cgd 	DEF_STATE(state0), DEF_STATE(state1), DEF_STATE(state2),
    187  1.1      cgd 	DEF_STATE(state3), DEF_STATE(state4), DEF_STATE(state5),
    188  1.1      cgd 	DEF_STATE(state6), DEF_STATE(state7), DEF_STATE(state8),
    189  1.1      cgd 	DEF_STATE(state9), DEF_STATE(state10), DEF_STATE(state11),
    190  1.1      cgd 	DEF_STATE(state12)
    191  1.1      cgd };
    192  1.1      cgd 
    193  1.1      cgd PLANE	p;
    194  1.1      cgd STACK	stack[MAXDEPTH];
    195  1.1      cgd int	level;
    196  1.1      cgd int	tval;
    197  1.1      cgd int	dest_type, dest_no, dir;
    198  1.1      cgd 
    199  1.1      cgd pop()
    200  1.1      cgd {
    201  1.1      cgd 	if (level == 0)
    202  1.1      cgd 		return (-1);
    203  1.1      cgd 	level--;
    204  1.1      cgd 
    205  1.1      cgd 	ioclrtoeol(T_POS);
    206  1.1      cgd 
    207  1.1      cgd 	strcpy(T_STR, "");
    208  1.1      cgd 	T_RULE = -1;
    209  1.1      cgd 	T_CH = -1;
    210  1.1      cgd 	return (0);
    211  1.1      cgd }
    212  1.1      cgd 
    213  1.1      cgd rezero()
    214  1.1      cgd {
    215  1.1      cgd 	iomove(0);
    216  1.1      cgd 
    217  1.1      cgd 	level = 0;
    218  1.1      cgd 	T_STATE = 0;
    219  1.1      cgd 	T_RULE = -1;
    220  1.1      cgd 	T_CH = -1;
    221  1.1      cgd 	T_POS = 0;
    222  1.1      cgd 	strcpy(T_STR, "");
    223  1.1      cgd }
    224  1.1      cgd 
    225  1.1      cgd push(ruleno, ch)
    226  1.1      cgd {
    227  1.1      cgd 	int	newstate, newpos;
    228  1.1      cgd 
    229  1.1      cgd 	(void)sprintf(T_STR, st[T_STATE].rule[ruleno].str, tval);
    230  1.1      cgd 	T_RULE = ruleno;
    231  1.1      cgd 	T_CH = ch;
    232  1.1      cgd 	newstate = st[T_STATE].rule[ruleno].to_state;
    233  1.1      cgd 	newpos = T_POS + strlen(T_STR);
    234  1.1      cgd 
    235  1.1      cgd 	ioaddstr(T_POS, T_STR);
    236  1.1      cgd 
    237  1.1      cgd 	if (level == 0)
    238  1.1      cgd 		ioclrtobot();
    239  1.1      cgd 	level++;
    240  1.1      cgd 	T_STATE = newstate;
    241  1.1      cgd 	T_POS = newpos;
    242  1.1      cgd 	T_RULE = -1;
    243  1.1      cgd 	strcpy(T_STR, "");
    244  1.1      cgd }
    245  1.1      cgd 
    246  1.1      cgd getcommand()
    247  1.1      cgd {
    248  1.1      cgd 	int	c, i, done;
    249  1.1      cgd 	char	*s, *(*func)();
    250  1.1      cgd 	PLANE	*pp;
    251  1.1      cgd 
    252  1.1      cgd 	rezero();
    253  1.1      cgd 
    254  1.1      cgd 	do {
    255  1.1      cgd 		c = gettoken();
    256  1.4  mycroft 		if (c == tty_new.c_cc[VERASE]) {
    257  1.1      cgd 			if (pop() < 0)
    258  1.1      cgd 				noise();
    259  1.4  mycroft 		} else if (c == tty_new.c_cc[VKILL]) {
    260  1.1      cgd 			while (pop() >= 0)
    261  1.1      cgd 				;
    262  1.1      cgd 		} else {
    263  1.1      cgd 			done = 0;
    264  1.1      cgd 			for (i = 0; i < st[T_STATE].num_rules; i++) {
    265  1.1      cgd 				if (st[T_STATE].rule[i].token == c ||
    266  1.1      cgd 				    st[T_STATE].rule[i].token == tval) {
    267  1.1      cgd 					push(i, (c >= ALPHATOKEN) ? tval : c);
    268  1.1      cgd 					done = 1;
    269  1.1      cgd 					break;
    270  1.1      cgd 				}
    271  1.1      cgd 			}
    272  1.1      cgd 			if (!done)
    273  1.1      cgd 				noise();
    274  1.1      cgd 		}
    275  1.1      cgd 	} while (T_STATE != -1);
    276  1.1      cgd 
    277  1.1      cgd 	if (level == 1)
    278  1.1      cgd 		return (1);	/* forced update */
    279  1.1      cgd 
    280  1.1      cgd 	dest_type = T_NODEST;
    281  1.1      cgd 
    282  1.1      cgd 	for (i = 0; i < level; i++) {
    283  1.1      cgd 		func = st[stack[i].state].rule[stack[i].rule].func;
    284  1.1      cgd 		if (func != NULL)
    285  1.1      cgd 			if ((s = (*func)(stack[i].ch)) != NULL) {
    286  1.1      cgd 				ioerror(stack[i].pos, strlen(stack[i].str), s);
    287  1.1      cgd 				return (-1);
    288  1.1      cgd 			}
    289  1.1      cgd 	}
    290  1.1      cgd 
    291  1.1      cgd 	pp = findplane(p.plane_no);
    292  1.1      cgd 	if (pp->new_altitude != p.new_altitude)
    293  1.1      cgd 		pp->new_altitude = p.new_altitude;
    294  1.1      cgd 	else if (pp->status != p.status)
    295  1.1      cgd 		pp->status = p.status;
    296  1.1      cgd 	else {
    297  1.1      cgd 		pp->new_dir = p.new_dir;
    298  1.1      cgd 		pp->delayd = p.delayd;
    299  1.1      cgd 		pp->delayd_no = p.delayd_no;
    300  1.1      cgd 	}
    301  1.1      cgd 	return (0);
    302  1.1      cgd }
    303  1.1      cgd 
    304  1.1      cgd noise()
    305  1.1      cgd {
    306  1.1      cgd 	putchar('\07');
    307  1.1      cgd 	fflush(stdout);
    308  1.1      cgd }
    309  1.1      cgd 
    310  1.1      cgd gettoken()
    311  1.1      cgd {
    312  1.1      cgd 	while ((tval = getAChar()) == REDRAWTOKEN || tval == SHELLTOKEN)
    313  1.1      cgd 	{
    314  1.1      cgd 		if (tval == SHELLTOKEN)
    315  1.1      cgd 		{
    316  1.1      cgd #ifdef BSD
    317  1.1      cgd 			struct itimerval	itv;
    318  1.1      cgd 			itv.it_value.tv_sec = 0;
    319  1.1      cgd 			itv.it_value.tv_usec = 0;
    320  1.1      cgd 			setitimer(ITIMER_REAL, &itv, NULL);
    321  1.1      cgd #endif
    322  1.1      cgd #ifdef SYSV
    323  1.1      cgd 			int aval;
    324  1.1      cgd 			aval = alarm(0);
    325  1.1      cgd #endif
    326  1.1      cgd 			if (fork() == 0)	/* child */
    327  1.1      cgd 			{
    328  1.1      cgd 				char *shell, *base, *getenv(), *strrchr();
    329  1.1      cgd 
    330  1.1      cgd 				setuid(getuid()); /* turn off setuid bit */
    331  1.1      cgd 				done_screen();
    332  1.1      cgd 
    333  1.1      cgd 						 /* run user's favorite shell */
    334  1.1      cgd 				if ((shell = getenv("SHELL")) != NULL)
    335  1.1      cgd 				{
    336  1.1      cgd 					base = strrchr(shell, '/');
    337  1.1      cgd 					if (base == NULL)
    338  1.1      cgd 						base = shell;
    339  1.1      cgd 					else
    340  1.1      cgd 						base++;
    341  1.1      cgd 					execl(shell, base, 0);
    342  1.1      cgd 				}
    343  1.1      cgd 				else
    344  1.1      cgd 					execl(_PATH_BSHELL, "sh", 0);
    345  1.1      cgd 
    346  1.1      cgd 				exit(0);	/* oops */
    347  1.1      cgd 			}
    348  1.1      cgd 
    349  1.1      cgd 			wait(0);
    350  1.4  mycroft 			tcsetattr(fileno(stdin), TCSADRAIN, &tty_new);
    351  1.1      cgd #ifdef BSD
    352  1.1      cgd 			itv.it_value.tv_sec = 0;
    353  1.1      cgd 			itv.it_value.tv_usec = 1;
    354  1.1      cgd 			itv.it_interval.tv_sec = sp->update_secs;
    355  1.1      cgd 			itv.it_interval.tv_usec = 0;
    356  1.1      cgd 			setitimer(ITIMER_REAL, &itv, NULL);
    357  1.1      cgd #endif
    358  1.1      cgd #ifdef SYSV
    359  1.1      cgd 			alarm(aval);
    360  1.1      cgd #endif
    361  1.1      cgd 		}
    362  1.1      cgd 		redraw();
    363  1.1      cgd 	}
    364  1.1      cgd 
    365  1.1      cgd 	if (isdigit(tval))
    366  1.1      cgd 		return (NUMTOKEN);
    367  1.1      cgd 	else if (isalpha(tval))
    368  1.1      cgd 		return (ALPHATOKEN);
    369  1.1      cgd 	else
    370  1.1      cgd 		return (tval);
    371  1.1      cgd }
    372  1.1      cgd 
    373  1.1      cgd char	*
    374  1.1      cgd setplane(c)
    375  1.1      cgd {
    376  1.1      cgd 	PLANE	*pp;
    377  1.1      cgd 
    378  1.1      cgd 	pp = findplane(number(c));
    379  1.1      cgd 	if (pp == NULL)
    380  1.1      cgd 		return ("Unknown Plane");
    381  1.5      tls 	memcpy(&p, pp, sizeof (p));
    382  1.1      cgd 	p.delayd = 0;
    383  1.1      cgd 	return (NULL);
    384  1.1      cgd }
    385  1.1      cgd 
    386  1.1      cgd char	*
    387  1.1      cgd turn(c)
    388  1.1      cgd {
    389  1.1      cgd 	if (p.altitude == 0)
    390  1.1      cgd 		return ("Planes at airports may not change direction");
    391  1.1      cgd 	return (NULL);
    392  1.1      cgd }
    393  1.1      cgd 
    394  1.1      cgd char	*
    395  1.1      cgd circle(c)
    396  1.1      cgd {
    397  1.1      cgd 	if (p.altitude == 0)
    398  1.1      cgd 		return ("Planes cannot circle on the ground");
    399  1.1      cgd 	p.new_dir = MAXDIR;
    400  1.1      cgd 	return (NULL);
    401  1.1      cgd }
    402  1.1      cgd 
    403  1.1      cgd char	*
    404  1.1      cgd left(c)
    405  1.1      cgd {
    406  1.1      cgd 	dir = D_LEFT;
    407  1.1      cgd 	p.new_dir = p.dir - 1;
    408  1.1      cgd 	if (p.new_dir < 0)
    409  1.1      cgd 		p.new_dir += MAXDIR;
    410  1.1      cgd 	return (NULL);
    411  1.1      cgd }
    412  1.1      cgd 
    413  1.1      cgd char	*
    414  1.1      cgd right(c)
    415  1.1      cgd {
    416  1.1      cgd 	dir = D_RIGHT;
    417  1.1      cgd 	p.new_dir = p.dir + 1;
    418  1.1      cgd 	if (p.new_dir > MAXDIR)
    419  1.1      cgd 		p.new_dir -= MAXDIR;
    420  1.1      cgd 	return (NULL);
    421  1.1      cgd }
    422  1.1      cgd 
    423  1.1      cgd char	*
    424  1.1      cgd Left(c)
    425  1.1      cgd {
    426  1.1      cgd 	p.new_dir = p.dir - 2;
    427  1.1      cgd 	if (p.new_dir < 0)
    428  1.1      cgd 		p.new_dir += MAXDIR;
    429  1.1      cgd 	return (NULL);
    430  1.1      cgd }
    431  1.1      cgd 
    432  1.1      cgd char	*
    433  1.1      cgd Right(c)
    434  1.1      cgd {
    435  1.1      cgd 	p.new_dir = p.dir + 2;
    436  1.1      cgd 	if (p.new_dir > MAXDIR)
    437  1.1      cgd 		p.new_dir -= MAXDIR;
    438  1.1      cgd 	return (NULL);
    439  1.1      cgd }
    440  1.1      cgd 
    441  1.1      cgd char	*
    442  1.1      cgd delayb(c)
    443  1.1      cgd {
    444  1.1      cgd 	int	xdiff, ydiff;
    445  1.1      cgd 
    446  1.1      cgd 	c -= '0';
    447  1.1      cgd 
    448  1.1      cgd 	if (c >= sp->num_beacons)
    449  1.1      cgd 		return ("Unknown beacon");
    450  1.1      cgd 	xdiff = sp->beacon[c].x - p.xpos;
    451  1.1      cgd 	xdiff = SGN(xdiff);
    452  1.1      cgd 	ydiff = sp->beacon[c].y - p.ypos;
    453  1.1      cgd 	ydiff = SGN(ydiff);
    454  1.1      cgd 	if (xdiff != displacement[p.dir].dx || ydiff != displacement[p.dir].dy)
    455  1.1      cgd 		return ("Beacon is not in flight path");
    456  1.1      cgd 	p.delayd = 1;
    457  1.1      cgd 	p.delayd_no = c;
    458  1.1      cgd 
    459  1.1      cgd 	if (dest_type != T_NODEST) {
    460  1.1      cgd 		switch (dest_type) {
    461  1.1      cgd 		case T_BEACON:
    462  1.1      cgd 			xdiff = sp->beacon[dest_no].x - sp->beacon[c].x;
    463  1.1      cgd 			ydiff = sp->beacon[dest_no].y - sp->beacon[c].y;
    464  1.1      cgd 			break;
    465  1.1      cgd 		case T_EXIT:
    466  1.1      cgd 			xdiff = sp->exit[dest_no].x - sp->beacon[c].x;
    467  1.1      cgd 			ydiff = sp->exit[dest_no].y - sp->beacon[c].y;
    468  1.1      cgd 			break;
    469  1.1      cgd 		case T_AIRPORT:
    470  1.1      cgd 			xdiff = sp->airport[dest_no].x - sp->beacon[c].x;
    471  1.1      cgd 			ydiff = sp->airport[dest_no].y - sp->beacon[c].y;
    472  1.1      cgd 			break;
    473  1.1      cgd 		default:
    474  1.1      cgd 			return ("Bad case in delayb!  Get help!");
    475  1.1      cgd 			break;
    476  1.1      cgd 		}
    477  1.1      cgd 		if (xdiff == 0 && ydiff == 0)
    478  1.1      cgd 			return ("Would already be there");
    479  1.1      cgd 		p.new_dir = DIR_FROM_DXDY(xdiff, ydiff);
    480  1.1      cgd 		if (p.new_dir == p.dir)
    481  1.1      cgd 			return ("Already going in that direction");
    482  1.1      cgd 	}
    483  1.1      cgd 	return (NULL);
    484  1.1      cgd }
    485  1.1      cgd 
    486  1.1      cgd char	*
    487  1.1      cgd beacon(c)
    488  1.1      cgd {
    489  1.1      cgd 	dest_type = T_BEACON;
    490  1.1      cgd 	return (NULL);
    491  1.1      cgd }
    492  1.1      cgd 
    493  1.1      cgd char	*
    494  1.1      cgd ex_it(c)
    495  1.1      cgd {
    496  1.1      cgd 	dest_type = T_EXIT;
    497  1.1      cgd 	return (NULL);
    498  1.1      cgd }
    499  1.1      cgd 
    500  1.1      cgd char	*
    501  1.1      cgd airport(c)
    502  1.1      cgd {
    503  1.1      cgd 	dest_type = T_AIRPORT;
    504  1.1      cgd 	return (NULL);
    505  1.1      cgd }
    506  1.1      cgd 
    507  1.1      cgd char	*
    508  1.1      cgd climb(c)
    509  1.1      cgd {
    510  1.1      cgd 	dir = D_UP;
    511  1.1      cgd 	return (NULL);
    512  1.1      cgd }
    513  1.1      cgd 
    514  1.1      cgd char	*
    515  1.1      cgd descend(c)
    516  1.1      cgd {
    517  1.1      cgd 	dir = D_DOWN;
    518  1.1      cgd 	return (NULL);
    519  1.1      cgd }
    520  1.1      cgd 
    521  1.1      cgd char	*
    522  1.1      cgd setalt(c)
    523  1.1      cgd {
    524  1.1      cgd 	if ((p.altitude == c - '0') && (p.new_altitude == p.altitude))
    525  1.1      cgd 		return ("Already at that altitude");
    526  1.1      cgd 	p.new_altitude = c - '0';
    527  1.1      cgd 	return (NULL);
    528  1.1      cgd }
    529  1.1      cgd 
    530  1.1      cgd char	*
    531  1.1      cgd setrelalt(c)
    532  1.1      cgd {
    533  1.1      cgd 	if (c == 0)
    534  1.1      cgd 		return ("altitude not changed");
    535  1.1      cgd 
    536  1.1      cgd 	switch (dir) {
    537  1.1      cgd 	case D_UP:
    538  1.1      cgd 		p.new_altitude = p.altitude + c - '0';
    539  1.1      cgd 		break;
    540  1.1      cgd 	case D_DOWN:
    541  1.1      cgd 		p.new_altitude = p.altitude - (c - '0');
    542  1.1      cgd 		break;
    543  1.1      cgd 	default:
    544  1.1      cgd 		return ("Unknown case in setrelalt!  Get help!");
    545  1.1      cgd 		break;
    546  1.1      cgd 	}
    547  1.1      cgd 	if (p.new_altitude < 0)
    548  1.1      cgd 		return ("Altitude would be too low");
    549  1.1      cgd 	else if (p.new_altitude > 9)
    550  1.1      cgd 		return ("Altitude would be too high");
    551  1.1      cgd 	return (NULL);
    552  1.1      cgd }
    553  1.1      cgd 
    554  1.1      cgd char	*
    555  1.1      cgd benum(c)
    556  1.1      cgd {
    557  1.1      cgd 	dest_no = c -= '0';
    558  1.1      cgd 
    559  1.1      cgd 	switch (dest_type) {
    560  1.1      cgd 	case T_BEACON:
    561  1.1      cgd 		if (c >= sp->num_beacons)
    562  1.1      cgd 			return ("Unknown beacon");
    563  1.1      cgd 		p.new_dir = DIR_FROM_DXDY(sp->beacon[c].x - p.xpos,
    564  1.1      cgd 			sp->beacon[c].y - p.ypos);
    565  1.1      cgd 		break;
    566  1.1      cgd 	case T_EXIT:
    567  1.1      cgd 		if (c >= sp->num_exits)
    568  1.1      cgd 			return ("Unknown exit");
    569  1.1      cgd 		p.new_dir = DIR_FROM_DXDY(sp->exit[c].x - p.xpos,
    570  1.1      cgd 			sp->exit[c].y - p.ypos);
    571  1.1      cgd 		break;
    572  1.1      cgd 	case T_AIRPORT:
    573  1.1      cgd 		if (c >= sp->num_airports)
    574  1.1      cgd 			return ("Unknown airport");
    575  1.1      cgd 		p.new_dir = DIR_FROM_DXDY(sp->airport[c].x - p.xpos,
    576  1.1      cgd 			sp->airport[c].y - p.ypos);
    577  1.1      cgd 		break;
    578  1.1      cgd 	default:
    579  1.1      cgd 		return ("Unknown case in benum!  Get help!");
    580  1.1      cgd 		break;
    581  1.1      cgd 	}
    582  1.1      cgd 	return (NULL);
    583  1.1      cgd }
    584  1.1      cgd 
    585  1.1      cgd char	*
    586  1.1      cgd to_dir(c)
    587  1.1      cgd {
    588  1.1      cgd 	p.new_dir = dir_no(c);
    589  1.1      cgd 	return (NULL);
    590  1.1      cgd }
    591  1.1      cgd 
    592  1.1      cgd char	*
    593  1.1      cgd rel_dir(c)
    594  1.1      cgd {
    595  1.1      cgd 	int	angle;
    596  1.1      cgd 
    597  1.1      cgd 	angle = dir_no(c);
    598  1.1      cgd 	switch (dir) {
    599  1.1      cgd 	case D_LEFT:
    600  1.1      cgd 		p.new_dir = p.dir - angle;
    601  1.1      cgd 		if (p.new_dir < 0)
    602  1.1      cgd 			p.new_dir += MAXDIR;
    603  1.1      cgd 		break;
    604  1.1      cgd 	case D_RIGHT:
    605  1.1      cgd 		p.new_dir = p.dir + angle;
    606  1.1      cgd 		if (p.new_dir >= MAXDIR)
    607  1.1      cgd 			p.new_dir -= MAXDIR;
    608  1.1      cgd 		break;
    609  1.1      cgd 	default:
    610  1.1      cgd 		return ("Bizarre direction in rel_dir!  Get help!");
    611  1.1      cgd 		break;
    612  1.1      cgd 	}
    613  1.1      cgd 	return (NULL);
    614  1.1      cgd }
    615  1.1      cgd 
    616  1.1      cgd char	*
    617  1.1      cgd mark(c)
    618  1.1      cgd {
    619  1.1      cgd 	if (p.altitude == 0)
    620  1.1      cgd 		return ("Cannot mark planes on the ground");
    621  1.1      cgd 	if (p.status == S_MARKED)
    622  1.1      cgd 		return ("Already marked");
    623  1.1      cgd 	p.status = S_MARKED;
    624  1.1      cgd 	return (NULL);
    625  1.1      cgd }
    626  1.1      cgd 
    627  1.1      cgd char	*
    628  1.1      cgd unmark(c)
    629  1.1      cgd {
    630  1.1      cgd 	if (p.altitude == 0)
    631  1.1      cgd 		return ("Cannot unmark planes on the ground");
    632  1.1      cgd 	if (p.status == S_UNMARKED)
    633  1.1      cgd 		return ("Already unmarked");
    634  1.1      cgd 	p.status = S_UNMARKED;
    635  1.1      cgd 	return (NULL);
    636  1.1      cgd }
    637  1.1      cgd 
    638  1.1      cgd char	*
    639  1.1      cgd ignore(c)
    640  1.1      cgd {
    641  1.1      cgd 	if (p.altitude == 0)
    642  1.1      cgd 		return ("Cannot ignore planes on the ground");
    643  1.1      cgd 	if (p.status == S_IGNORED)
    644  1.1      cgd 		return ("Already ignored");
    645  1.1      cgd 	p.status = S_IGNORED;
    646  1.1      cgd 	return (NULL);
    647  1.1      cgd }
    648  1.1      cgd 
    649  1.1      cgd dir_no(ch)
    650  1.1      cgd 	char	ch;
    651  1.1      cgd {
    652  1.1      cgd 	int	dir;
    653  1.1      cgd 
    654  1.1      cgd 	switch (ch) {
    655  1.1      cgd 	case 'w':	dir = 0;	break;
    656  1.1      cgd 	case 'e':	dir = 1;	break;
    657  1.1      cgd 	case 'd':	dir = 2;	break;
    658  1.1      cgd 	case 'c':	dir = 3;	break;
    659  1.1      cgd 	case 'x':	dir = 4;	break;
    660  1.1      cgd 	case 'z':	dir = 5;	break;
    661  1.1      cgd 	case 'a':	dir = 6;	break;
    662  1.1      cgd 	case 'q':	dir = 7;	break;
    663  1.1      cgd 	default:
    664  1.1      cgd 		fprintf(stderr, "bad character in dir_no\n");
    665  1.1      cgd 		break;
    666  1.1      cgd 	}
    667  1.1      cgd 	return (dir);
    668  1.1      cgd }
    669