snake.c -- a slightly enhanced version of the "worm" game

[Mitch Lukaart]

> Happy New Year to Everyone! I was taking a leisure time break when I
> suddenly realized a small enhancement could be made to "worm". 
> Snake has a cute little serpentine head that points in the direction
> you're going, after the snake wakes up and starts stalking his food.
> Apart from flushing buffers at the end so you won't lose your score, 
> this is the only real change. The whole source is here in case you
> didn't already have it. Don't forget to remove the .signature at the end.
> 
> So long, and thanks for all the fish.
> Dave Fiedler
> 
> -------------------- cut here -----------------------
> /*
>  * Snake, from worm Written by Michael Toy
>  * UCSC
>  * modified by a.wiedemann 05.17.82
>  * Siemens AG Munich
>  * ZTI INF 212
>  *
>  * herpetology added by David Fiedler, InfoPro Systems
>  * {astrovax, harpo, whuxcc}!infopro!dave
>  *
>  * compile with "cc -O -s -o snake snake.c -lcurses -ltermcap
>  *
>  */
> 
> #include <ctype.h>
> #include "curses.h"
> #include <signal.h>
> 
> char *getenv();
> 
> #define newlink() (struct body *) malloc(sizeof (struct body));
> #define HEAD '@'
> #define BODY 'o'
> #define	UP	1
> #define	DOWN	2
> #define	LEFT	3
> #define	RIGHT	4
> #define LENGTH 7
> #define RUNLEN 8
> #define when break;case
> #define otherwise break;default
> #define CNTRL(p) ('p'-'A'+1)
> 
> WINDOW *tv;
> WINDOW *stw;
> struct body {
> 	int x;
> 	int y;
> 	struct body *prev;
> 	struct body *next;
> } *head, *tail, goody, *malloc();
> 
> int growing = 0;
> int running = 0;
> int score = 0;
> int start_len = LENGTH;
> char lastch;
> char outbuf[BUFSIZ];
> 
> main(argc, argv)
> char **argv;
> {
> 	int leave(), wake(), suspend();
> 	char ch;
> 
> 	if (argc == 2)
> 		{
> 		start_len = atoi(argv[1]);
> 		score += (start_len - LENGTH);
> 		}
> 	setbuf(stdout, outbuf);
> 	srand(getpid());
> 	signal(SIGALRM, wake);
> 	signal(SIGINT, leave);
> 	signal(SIGQUIT, leave);
> #ifdef SIGTSTP
> 	signal(SIGTSTP, suspend);	/* process control signal */
> #endif
> 	initscr();
> 	crmode();
> 	noecho();
> 	clear();
> 	stw = newwin(1, COLS-1, 0, 0);
> 	tv = newwin(LINES-1, COLS-1, 1, 0);
> 	/* snake cannot be bigger than the inner width of tv window !! */
> 	if ((start_len <= 0) || (start_len > COLS - 6))
> 		start_len = LENGTH;
> 	box(tv, '*', '*');
> 	scrollok(tv, FALSE);
> 	scrollok(stw, FALSE);
> 	wmove(stw, 0, 0);
> 	wprintw(stw, " Snake");
> 	refresh();
> 	wrefresh(stw);
> 	wrefresh(tv);
> 	life();                 /* Create the snake */
> 	prize();                /* Put up a goal */
> 	for (;;)
> 	{
> 		if (running)
> 		{
> 			running--;
> 			process(lastch);
> 		}
> 		else
> 		{
> 		    fflush(stdout);
> 		    if (read(0, &ch, 1) >= 0)
> 			process(ch);
> 		}
> 	}
> }
> 
> life()
> {
> 	register struct body *bp, *np;
> 	register int i;
> 
> 	head = newlink();
> 	head->x = start_len+2;
> 	head->y = 12;
> 	head->next = NULL;
> 	display(head, HEAD);
> 	for (i = 0, bp = head; i < start_len; i++, bp = np) {
> 		np = newlink();
> 		np->next = bp;
> 		bp->prev = np;
> 		np->x = bp->x - 1;
> 		np->y = bp->y;
> 		display(np, BODY);
> 	}
> 	tail = np;
> 	tail->prev = NULL;
> 	wrefresh(tv);
> }
> 
> display(pos, chr)
> struct body *pos;
> char chr;
> {
> 	wmove(tv, pos->y, pos->x);
> 	waddch(tv, chr);
> }
> 
> leave()
> {
> 	move(LINES - 1, 0);
> 	refresh();
> 	endwin();
> 	exit(0);
> }
> 
> wake()
> {
> 	signal(SIGALRM, wake);
> 	fflush(stdout);
> 	process(lastch);
> }
> 
> rnd(range)
> {
> 	return abs((rand()>>5)+(rand()>>5)) % range;
> }
> 
> newpos(bp)
> struct body * bp;
> {
> 	do {
> 		bp->y = rnd(LINES-3)+ 2;
> 		bp->x = rnd(COLS-3) + 1;
> 		wmove(tv, bp->y, bp->x);
> 	} while(winch(tv) != ' ');
> }
> 
> prize()
> {
> 	int value;
> 
> 	value = rnd(9) + 1;
> 	newpos(&goody);
> 	waddch(tv, value+'0');
> 	wrefresh(tv);
> }
> 
> process(ch)
> char ch;
> {
> 	register int x,y;
> 	struct body *nh;
> 	static char headchar, dir;
> 
> 	alarm(0);
> 	x = head->x;
> 	y = head->y;
> 	switch(ch)
> 	{
> 		when 'h': x--; dir=LEFT;
> 		when 'j': y++; dir=DOWN;
> 		when 'k': y--; dir=UP;
> 		when 'l': x++; dir=RIGHT;
> 		when 'H': x--; running = RUNLEN; ch = tolower(ch);dir=LEFT;
> 		when 'J': y++; running = RUNLEN/2; ch = tolower(ch);dir=DOWN;
> 		when 'K': y--; running = RUNLEN/2; ch = tolower(ch);dir=UP;
> 		when 'L': x++; running = RUNLEN; ch = tolower(ch);dir=RIGHT;
> 		when '\f': setup(); return;
> 		when CNTRL(Z): suspend(); return;
> 		when CNTRL(C): crash(); return;
> 		when CNTRL(D): crash(); return;
> 		otherwise: if (! running) alarm(1);
> 			   return;
> 	}
> 	lastch = ch;
> 	if (growing == 0)
> 	{
> 		display(tail, ' ');
> 		tail->next->prev = NULL;
> 		nh = tail->next;
> 		free(tail);
> 		tail = nh;
> 	}
> 	else growing--;
> 	display(head, BODY);
> 	wmove(tv, y, x);
> 	if (isdigit(ch = winch(tv)))
> 	{
> 		growing += ch-'0';
> 		prize();
> 		score += growing;
> 		running = 0;
> 		wmove(stw, 0, 68);
> 		wprintw(stw, "Score: %3d", score);
> 		wrefresh(stw);
> 	}
> 	else if(ch != ' ') crash();
> 	nh = newlink();
> 	nh->next = NULL;
> 	nh->prev = head;
> 	head->next = nh;
> 	nh->y = y;
> 	nh->x = x;
> 	switch (dir) {
> 		case UP:
> 			headchar = '^'; break;
> 		case DOWN:
> 			headchar = 'V'; break;
> 		case LEFT:
> 			headchar = '<' ; break;
> 		case RIGHT:
> 			headchar = '>' ; break;
> 		default:
> 			headchar = HEAD ;
> 		}
> 	display(nh, headchar);
> 	head = nh;
> 	wrefresh(tv);
> 	if (! running) alarm(1);
> }
> 
> crash()
> {
> 	sleep(1);
> 	clear();
> 	move(LINES - 1, 0);
> 	refresh();
> 	endwin();
> 	fflush(stdout);
> 	printf("Well you ran into something and the game is over.\n");
> 	printf("Your final score was %d\n", score);
> 	leave();
> }
> 
> suspend()
> {
> 	char *sh;
> 
> 	move(LINES-1, 0);
> 	refresh();
> 	endwin();
> 	fflush(stdout);
> #ifdef SIGTSTP
> 	kill(getpid(), SIGTSTP);
> 	signal(SIGTSTP, suspend);
> #else
> 	sh = getenv("SHELL");
> 	if (sh == NULL)
> 		sh = "/bin/sh";
> 	system(sh);
> #endif
> 	crmode();
> 	noecho();
> 	setup();
> }
> 
> setup()
> {
> 	clear();
> 	refresh();
> 	touchwin(stw);
> 	wrefresh(stw);
> 	touchwin(tv);
> 	wrefresh(tv);
> 	alarm(1);
> }
> -- 
>           Dave Fiedler
> {harpo,astrovax,whuxcc,clyde}!infopro!dave
> USMail: InfoPro Systems, 3108 Route 10, Denville, NJ 07834
> People Phone: (201) 989-0570

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