snake.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

#ifndef lint
static char sccsid[] = "@(#)snake.c	4.1 (Berkeley) 7/4/83";
#endif

/*
 * snake - crt hack game.
 *
 * You move around the screen with arrow keys trying to pick up money
 * without getting eaten by the snake.  hjkl work as in vi in place of
 * arrow keys.  You can leave at the exit any time.
 *
 * compile as follows:
 *	cc -O snake.c move.c -o snake -lm -ltermlib
 */

#include "snake.h"
#include <pwd.h>

	/*
	 * If CHECKBUSY is defined, the file BUSY must be executable
	 * and must return a value which is used to determine the priority
	 * a which snake runs.  A zero value means no nice.
	 * If BUSY does not exist, snake won't play.
	 */
#ifndef BUSY
#define BUSY	"/usr/games/lib/busy"
#endif

	/*
	 * This is the data file for scorekeeping.
	 */
#ifndef SNAKERAWSCORES
#define SNAKERAWSCORES	"/usr/games/lib/snakerawscores"
#endif

	/*
	 * If it exists, a log is kept here.  Otherwise it isn't.
	 */
#ifndef LOGFILE
#define LOGFILE	"/usr/games/lib/snake.log"
#endif

#define PENALTY  10	/* % penalty for invoking spacewarp	*/

#define EOT	'\004'
#define LF	'\n'
#define DEL	'\177'

#define ME		'I'
#define SNAKEHEAD	'S'
#define SNAKETAIL	's'
#define TREASURE	'$'
#define GOAL		'#'

#define BSIZE	80

struct point you;
struct point money;
struct point finish;
struct point snake[6];

int loot, penalty;
int long tl, tm=0L;
int argcount;
char **argval;
int moves;
static char str[BSIZE];
char stri[BSIZE];
char *p;
char ch, savec;
char *kl, *kr, *ku, *kd;
int fast=1;
int repeat=1;
long tv;
char *tn;

main(argc,argv)
int argc;
char **argv;
{
	int i,k;
	int j;
	long time();
	int stop();
	extern char _sobuf[];

	argcount = argc;
	argval = argv;
	penalty = loot = 0;
	getcap();
	ccnt -= 2; lcnt -= 2;	/* compensate for border */
	busy();
	time(&tv);

	for (i=1; i<argc; i++) {
		switch(argv[i][1]) {
		case 'd':
			sscanf(argv[1], "-d%ld", &tv);
			break;
		case 'w':	/* width */
		case 'c':	/* columns */
			ccnt = atoi(argv[i]+2);
			break;
		case 'l':	/* length */
		case 'h':	/* height */
		case 'r':	/* rows */
			lcnt = atoi(argv[i]+2);
			break;
		default:
			printf("bad option %s\n", argv[1]);
		}
	}

	srand((int)tv);
	setbuf(stdout,_sobuf);
	i = ((lcnt < ccnt) ? lcnt : ccnt);	/* min screen edge */
	if (i < 4) {
		printf("Screen too small for a fair game\n");
		done();
	}
	/*
	 * chunk is the amount of money the user gets for each $.
	 * The formula below tries to be fair for various screen sizes.
	 * We only pay attention to the smaller of the 2 edges, since
	 * that seems to be the bottleneck.
	 * This formula is a hyperbola which includes the following points:
	 *	(24, $25)	(original scoring algorithm)
	 *	(12, $40)	(experimentally derived by the "feel")
	 *	(48, $15)	(a guess)
	 * This will give a 4x4 screen $99/shot.  We don't allow anything
	 * smaller than 4x4 because there is a 3x3 game where you can win
	 * an infinite amount of money.
	 */
	if (i < 12) i = 12;	/* otherwise it isn't fair */
	/*
	 * Compensate for border.  This really changes the game since
	 * the screen is two squares smaller but we want the default
	 * to be $25, and the high scores on small screens were a bit
	 * much anyway.
	 */
	i += 2;
	chunk = (675.0 / (i+6)) + 2.5;	/* min screen edge */

	signal (SIGINT, stop);
	putpad(TI); /*	String to begin programs that use cm */
	putpad(KS); /*	Put terminal in keypad transmit mode */

	random(&finish);
	random(&you);
	random(&money);
	random(&snake[0]);

	if ((orig.sg_ospeed < B9600) ||
	    ((! CM) && (! TA))) fast=0;
	for(i=1;i<6;i++)
		chase (&snake[i], &snake[i-1]);
	setup();
	mainloop();
}

/* Main command loop */
mainloop()
{
	int j, k;

	for (;;) {
		int c,lastc,match;

		move(&you);
		fflush(stdout);
		if (((c = getchar() & 0177) <= '9') && (c >= '0')) {
			ungetc(c,stdin);
			j = scanf("%d",&repeat);
			c = getchar() & 0177;
		} else {
			if (c != '.') repeat = 1;
		}
		if (c == '.') {
			c = lastc;
		}
		if ((Klength > 0) && 
		    (c == *KL || c == *KR || c == *KU || c == *KD)) {
			savec = c;
			match = 0;
			kl = KL;
			kr = KR;
			ku = KU;
			kd = KD;
			for (j=Klength;j>0;j--){
				if (match != 1) {
				match = 0;
					if (*kl++ == c) {
						ch = 'h';
						match++;
					}
					if (*kr++ == c) {
						ch = 'l';
						match++;
					}
					if (*ku++ == c) {
						ch = 'k';
						match++;
					}
					if (*kd++ == c) {
						ch = 'j';
						match++;
					}
					if (match == 0) {
						ungetc(c,stdin);
						ch = savec;
		/* Oops! 
		 * This works if we figure it out on second character.
		 */
						break;
					}
				}
				savec = c;
				if(j != 1) c = getchar() & 0177;
			}
			c = ch;
		}
		if (!fast) flushi();
		lastc = c;
		switch (c){
		case CTRL('z'):
		case CTRL('c'):
			suspend();
			continue;
		case EOT:
		case 'x':
		case 0177:	/* del or end of file */
			ll();
			length(moves);
			logit("quit");
			done();
		case '!':
			cook();
			putchar('\n');
			putchar(c);
			fflush(stdout);
			j = read(0,stri,BSIZE);
			stri[j] = 0;
			if (fork() == 0) {
				setuid(getuid());
				system(stri);
			} else
				wait(0);
			printf("READY?\n");
			fflush(stdout);
			raw();
			c = getchar();
			ungetc(c,stdin);
			putpad(KS);
			putpad(TI);
			point(&cursor,0,lcnt-1);
		case CTRL('l'):
			setup();
			winnings(cashvalue);
			continue;
		case 'p':
		case 'd':
			snap();
			continue;
		case 'w':
			spacewarp(0);
			continue;
		case 'A':
			repeat = you.col;
			c = 'h';
			break;
		case 'H':
		case 'S':
			repeat = you.col - money.col;
			c = 'h';
			break;
		case 'T':
			repeat = you.line;
			c = 'k';
			break;
		case 'K':
		case 'E':
			repeat = you.line - money.line;
			c = 'k';
			break;
		case 'P':
			repeat = ccnt - 1 - you.col;
			c = 'l';
			break;
		case 'L':
		case 'F':
			repeat = money.col - you.col;
			c = 'l';
			break;
		case 'B':
			repeat = lcnt - 1 - you.line;
			c = 'j';
			break;
		case 'J':
		case 'C':
			repeat = money.line - you.line;
			c = 'j';
			break;
		}
		for(k=1;k<=repeat;k++){
			moves++;
			switch(c) {
			case 's':
			case 'h':
			case '\b':
				if (you.col >0) {
					if((fast)||(k == 1))
						pchar(&you,' ');
					you.col--;
					if((fast) || (k == repeat) ||
					   (you.col == 0))
						pchar(&you,ME);
				}
				break;
			case 'f':
			case 'l':
			case ' ':
				if (you.col < ccnt-1) {
					if((fast)||(k == 1))
						pchar(&you,' ');
					you.col++;
					if((fast) || (k == repeat) ||
					   (you.col == ccnt-1))
						pchar(&you,ME);
				}
				break;
			case CTRL('p'):
			case 'e':
			case 'k':
			case 'i':
				if (you.line > 0) {
					if((fast)||(k == 1))
						pchar(&you,' ');
					you.line--;
					if((fast) || (k == repeat) ||
					  (you.line == 0))
						pchar(&you,ME);
				}
				break;
			case CTRL('n'):
			case 'c':
			case 'j':
			case LF:
			case 'm':
				if (you.line+1 < lcnt) {
					if((fast)||(k == 1))
						pchar(&you,' ');
					you.line++;
					if((fast) || (k == repeat) ||
					  (you.line == lcnt-1))
						pchar(&you,ME);
				}
				break;
			}

			if (same(&you,&money))
			{
				char xp[20]; 
				struct point z;
				loot += 25;
				if(k < repeat)
					pchar(&you,' ');
				do {
					random(&money);
				} while (money.col == finish.col && money.line == finish.line ||
					 money.col < 5 && money.line == 0 ||
					 money.col == you.col && money.line == you.line);
				pchar(&money,TREASURE);
				winnings(cashvalue);
				continue;
			}
			if (same(&you,&finish))
			{
				win(&finish);
				ll();
				cook();
				printf("You have won with $%d.\n",cashvalue);
				fflush(stdout);
				logit("won");
				post(cashvalue,0);
				length(moves);
				done(0);
			}
			if (pushsnake())break;
		}
		fflush(stdout);
	}
}

setup(){	/*
		 * setup the board
		 */
	int i;

	clear();
	pchar(&you,ME);
	pchar(&finish,GOAL);
	pchar(&money,TREASURE);
	for(i=1; i<6; i++) {
		pchar(&snake[i],SNAKETAIL);
	}
	pchar(&snake[0], SNAKEHEAD);
	drawbox();
	fflush(stdout);
}

drawbox()
{
	register int i;
	struct point p;

	p.line = -1;
	for (i= 0; i<ccnt; i++) {
		p.col = i;
		pchar(&p, '-');
	}
	p.col = ccnt;
	for (i= -1; i<=lcnt; i++) {
		p.line = i;
		pchar(&p, '|');
	}
	p.col = -1;
	for (i= -1; i<=lcnt; i++) {
		p.line = i;
		pchar(&p, '|');
	}
	p.line = lcnt;
	for (i= 0; i<ccnt; i++) {
		p.col = i;
		pchar(&p, '-');
	}
}


random(sp)
struct point *sp;
{
	register int issame;
	struct point p;
	register int i;

	sp->col = sp->line = -1;	/* impossible */
	do {
		issame = 0;
		p.col = ((rand()>>8) & 0377)% ccnt;
		p.line = ((rand()>>8) & 0377)% lcnt;

		/* make sure it's not on top of something else */