snake.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

		if (p.line == 0 && p.col <5) issame++;
		if(same(&p, &you)) issame++;
		if(same(&p, &money)) issame++;
		if(same(&p, &finish)) issame++;
		for (i=0; i<5; i++)
			if(same(&p, &snake[i])) issame++;

	} while (issame);
	*sp = p;
}

busy()
{
	FILE *pip, *popen();
	char c;
	int b,r;
	float a;

#ifdef CHECKBUSY
	if (! strcmp (argval[0], "test")) return;
	if ((access(BUSY,1) != 0) || (pip = popen(BUSY,"r")) == NULL){
		printf("Sorry, no snake just now.\n");
		done();
	}
	fscanf(pip,"%d",&b);
	pclose(pip);
	if (b > 20) {
		printf("Sorry, the system is too heavily loaded right now.\n");
		done();
	}
	nice(b);
#endif
}

post(score, flag)
int	score, flag;
{
	int	rawscores;
	short	uid = getuid();
	short	oldbest=0;
	short	allbwho=0, allbscore=0;
	struct	passwd *p, *getpwuid();

	/*
	 * Neg uid, 0, and 1 cannot have scores recorded.
	 */
	if ((uid=getuid()) > 1 && (rawscores=open(SNAKERAWSCORES,2))>=0) {
		/* Figure out what happened in the past */
		read(rawscores, &allbscore, sizeof(short));
		read(rawscores, &allbwho, sizeof(short));
		lseek(rawscores, ((long)uid)*sizeof(short), 0);
		read(rawscores, &oldbest, sizeof(short));
		if (flag) return (score > oldbest ? 1 : 0);

		/* Update this jokers best */
		if (score > oldbest) {
			lseek(rawscores, ((long)uid)*sizeof(short), 0);
			write(rawscores, &score, sizeof(short));
			printf("You bettered your previous best of $%d\n", oldbest);
		} else
			printf("Your best to date is $%d\n", oldbest);

		/* See if we have a new champ */
		p = getpwuid(allbwho);
		if (p == NULL || score > allbscore) {
			lseek(rawscores, (long)0, 0);
			write(rawscores, &score, sizeof(short));
			write(rawscores, &uid, sizeof(short));
			if (p != NULL)
				printf("You beat %s's old record of $%d!\n", p->pw_name, allbscore);
			else
				printf("You set a new record!\n");
		} else
			printf("The highest is %s with $%d\n", p->pw_name, allbscore);
		close(rawscores);
	} else
		if (!flag)
			printf("Unable to post score.\n");
	return (1);
}

/*
 * Flush typeahead to keep from buffering a bunch of chars and then
 * overshooting.  This loses horribly at 9600 baud, but works nicely
 * if the terminal gets behind.
 */
flushi()
{
	stty(0, &new);
}
int mx [8] = { 
	0, 1, 1, 1, 0,-1,-1,-1};
int my [8] = {
	-1,-1, 0, 1, 1, 1, 0,-1};
float absv[8]= { 
	1, 1.4, 1, 1.4, 1, 1.4, 1, 1.4
};
int oldw=0;
chase (np, sp)
struct point *sp, *np;
{
	/* this algorithm has bugs; otherwise the
	   snake would get too good */
	struct point d;
	int w, i, wt[8];
	double sqrt(), v1, v2, vp, max;
	point(&d,you.col-sp->col,you.line-sp->line);
	v1 = sqrt( (double) (d.col*d.col + d.line*d.line) );
	w=0; 
	max=0;
	for(i=0; i<8; i++)
	{
		vp = d.col*mx[i] + d.line*my[i];
		v2 = absv[i];
		if (v1>0)
			vp = ((double)vp)/(v1*v2);
		else vp=1.0;
		if (vp>max)
		{
			max=vp;
			w=i;
		}
	}
	for(i=0; i<8; i++)
	{
		point(&d,sp->col+mx[i],sp->line+my[i]);
		wt[i]=0;
		if (d.col<0 || d.col>=ccnt || d.line<0 || d.line>=lcnt)
			continue;
		if (d.line == 0 && d.col < 5) continue;
		if (same(&d,&money)) continue;
		if (same(&d,&finish)) continue;
		wt[i]= i==w ? loot/10 : 1;
		if (i==oldw) wt [i] += loot/20;
	}
	for(w=i=0; i<8; i++)
		w+= wt[i];
	vp = (( rand() >> 6 ) & 01777) %w;
	for(i=0; i<8; i++)
		if (vp <wt[i])
			break;
		else
			vp -= wt[i];
	if (i==8) {
		printf("failure\n"); 
		i=0;
		while (wt[i]==0) i++;
	}
	oldw=w=i;
	point(np,sp->col+mx[w],sp->line+my[w]);
}

spacewarp(w)
int w;{
	struct point p;
	int j;
	
	random(&you);
	point(&p,COLUMNS/2 - 8,LINES/2 - 1);
	if (p.col < 0)
		p.col = 0;
	if (p.line < 0)
		p.line = 0;
	if (w) {
		sprintf(str,"BONUS!!!");
		loot = loot - penalty;
		penalty = 0;
	} else {
		sprintf(str,"SPACE WARP!!!");
		penalty += loot/PENALTY;
	}
	for(j=0;j<3;j++){
		clear();
		delay(5);
		aprintf(&p,str);
		delay(10);
	}
	setup();
	winnings(cashvalue);
}
snap()
{
	struct point p;
	int i;

	if(you.line < 3){
		pchar(point(&p,you.col,0),'-');
	}
	if(you.line > lcnt-4){
		pchar(point(&p,you.col,lcnt-1),'_');
	}
	if(you.col < 10){
		pchar(point(&p,0,you.line),'(');
	}
	if(you.col > ccnt-10){
		pchar(point(&p,ccnt-1,you.line),')');
	}
	if (! stretch(&money)) if (! stretch(&finish)) delay(10);
	if(you.line < 3){
		point(&p,you.col,0);
		remove(&p);
	}
	if(you.line > lcnt-4){
		point(&p,you.col,lcnt-1);
		remove(&p);
	}
	if(you.col < 10){
		point(&p,0,you.line);
		remove(&p);
	}
	if(you.col > ccnt-10){
		point(&p,ccnt-1,you.line);
		remove(&p);
	}
	fflush(stdout);
}
stretch(ps)
struct point *ps;{
	struct point p;
	
	point(&p,you.col,you.line);
	if(abs(ps->col-you.col) < 6){
		if(you.line < ps->line){
			for (p.line = you.line+1;p.line <= ps->line;p.line++)
				pchar(&p,'v');
			delay(10);
			for (;p.line > you.line;p.line--)
				remove(&p);
		} else {
			for (p.line = you.line-1;p.line >= ps->line;p.line--)
				pchar(&p,'^');
			delay(10);
			for (;p.line < you.line;p.line++)
				remove(&p);
		}
		return(1);
	} else if(abs(ps->line-you.line) < 3){
		p.line = you.line;
		if(you.col < ps->col){
			for (p.col = you.col+1;p.col <= ps->col;p.col++)
				pchar(&p,'>');
			delay(10);
			for (;p.col > you.col;p.col--)
				remove(&p);
		} else {
			for (p.col = you.col-1;p.col >= ps->col;p.col--)
				pchar(&p,'<');
			delay(10);
			for (;p.col < you.col;p.col++)
				remove(&p);
		}
		return(1);
	}
	return(0);
}

surround(ps)
struct point *ps;{
	struct point x;
	int i,j;

	if(ps->col == 0)ps->col++;
	if(ps->line == 0)ps->line++;
	if(ps->line == LINES -1)ps->line--;
	if(ps->col == COLUMNS -1)ps->col--;
	aprintf(point(&x,ps->col-1,ps->line-1),"/*\\\r* *\r\\*/");
	for (j=0;j<20;j++){
		pchar(ps,'@');
		delay(1);
		pchar(ps,' ');
		delay(1);
	}
	if (post(cashvalue,1)) {
		aprintf(point(&x,ps->col-1,ps->line-1),"   \ro.o\r\\_/");
		delay(6);
		aprintf(point(&x,ps->col-1,ps->line-1),"   \ro.-\r\\_/");
		delay(6);
	}
	aprintf(point(&x,ps->col-1,ps->line-1),"   \ro.o\r\\_/");
}
win(ps)
struct point *ps;
{
	struct point x;
	int j,k;
	int boxsize;	/* actually diameter of box, not radius */

	boxsize = fast ? 10 : 4;
	point(&x,ps->col,ps->line);
	for(j=1;j<boxsize;j++){
		for(k=0;k<j;k++){
			pchar(&x,'#');
			x.line--;
		}
		for(k=0;k<j;k++){
			pchar(&x,'#');
			x.col++;
		}
		j++;
		for(k=0;k<j;k++){
			pchar(&x,'#');
			x.line++;
		}
		for(k=0;k<j;k++){
			pchar(&x,'#');
			x.col--;
		}
	}
	fflush(stdout);
}

pushsnake()
{
	int i, bonus;
	int issame = 0;

	/*
	 * My manual says times doesn't return a value.  Furthermore, the
	 * snake should get his turn every time no matter if the user is
	 * on a fast terminal with typematic keys or not.
	 * So I have taken the call to times out.
	 */
	for(i=4; i>=0; i--)
		if (same(&snake[i], &snake[5]))
			issame++;
	if (!issame)
		pchar(&snake[5],' ');
	for(i=4; i>=0; i--)
		snake[i+1]= snake[i];
	chase(&snake[0], &snake[1]);
	pchar(&snake[1],SNAKETAIL);
	pchar(&snake[0],SNAKEHEAD);
	for(i=0; i<6; i++)
	{
		if (same(&snake[i],&you))
		{
			surround(&you);
			i = (cashvalue) % 10;
			bonus = ((rand()>>8) & 0377)% 10;
			ll();
			printf("%d\n", bonus);
			delay(30);
			if (bonus == i) {
				spacewarp(1);
				logit("bonus");
				flushi();
				return(1);
			}
			if ( loot >= penalty ){
				printf("You and your $%d have been eaten\n",cashvalue);
			} else {
				printf("The snake ate you.  You owe $%d.\n",-cashvalue);
			}
			logit("eaten");
			length(moves);
			done();
		}
	}
	return(0);
}
	
remove(sp)
struct point *sp;
{
	int j;

	if (same(sp,&money)) {
		pchar(sp,TREASURE);
		return(2);
	}
	if (same(sp,&finish)) {
		pchar(sp,GOAL);
		return(3);
	}
	if (same(sp,&snake[0])) {
		pchar(sp,SNAKEHEAD);
		return(4);
	}
	for(j=1;j<6;j++){
		if(same(sp,&snake[j])){
			pchar(sp,SNAKETAIL);
			return(4);
		}
	}
	if ((sp->col < 4) && (sp->line == 0)){
		winnings(cashvalue);
		if((you.line == 0) && (you.col < 4)) pchar(&you,ME);
		return(5);
	}
	if (same(sp,&you)) {
		pchar(sp,ME);
		return(1);
	}
	pchar(sp,' ');
	return(0);
}
winnings(won)
int won;
{
	struct point p;

	p.line = p.col = 1;
	if(won>0){
		move(&p);
		printf("$%d",won);
	}
}

stop(){
	signal(SIGINT,1);
	ll();
	length(moves);
	done();
}

suspend()
{
	char *sh;

	cook();
#ifdef SIGTSTP
	kill(getpid(), SIGTSTP);
#else
	sh = getenv("SHELL");
	if (sh == NULL)
		sh = "/bin/sh";
	system(sh);
#endif
	raw();
	setup();
	winnings(cashvalue);
}

length(num)
int num;
{
	printf("You made %d moves.\n",num);
}

logit(msg)
char *msg;
{
	FILE *logfile;
	long t;

	if ((logfile=fopen(LOGFILE, "a")) != NULL) {
		time(&t);
		fprintf(logfile, "%s $%d %dx%d %s %s", getlogin(), cashvalue, lcnt, ccnt, msg, ctime(&t));
		fclose(logfile);
	}
}