From ec82e0f2cd389bfe0fa582244601af9ef70158b2 Mon Sep 17 00:00:00 2001
From: Zihao Yu <yuzihao@ict.ac.cn>
Date: Fri, 21 Jul 2023 10:59:30 +0800
Subject: [PATCH] kernels: import snake from movfuscator

---
 kernels/snake/snake.c | 249 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 249 insertions(+)
 create mode 100644 kernels/snake/snake.c

diff --git a/kernels/snake/snake.c b/kernels/snake/snake.c
new file mode 100644
index 0000000..0462a37
--- /dev/null
+++ b/kernels/snake/snake.c
@@ -0,0 +1,249 @@
+#include <stdlib.h>
+#define _Bool unsigned int /* lcc doesn't define this */
+#include <ncurses.h>
+
+#define MAX_LENGTH 100
+
+typedef enum { NONE, UP, DOWN, LEFT, RIGHT } dir_t;
+
+typedef struct {
+	int x, y;
+} point_t;
+
+typedef struct {
+	int width, height;
+} dim_t;
+
+typedef struct {
+	int top, bottom, left, right;
+} rect_t;
+
+typedef struct {
+	point_t body[MAX_LENGTH];
+	int length;
+	int index;
+	int dead;
+} snake_t;
+
+point_t create_food(dim_t);
+void print_board(rect_t);
+void print_food(point_t, rect_t);
+void print_head(snake_t*, rect_t);
+void clear_tail(snake_t*, rect_t);
+dir_t get_dir(int);
+void move_snake(snake_t*, dir_t);
+int is_dead(snake_t*, dim_t);
+int has_food(snake_t*, point_t);
+
+int main(void)
+{
+	snake_t snake={0};
+	point_t food;
+	rect_t board;
+	dim_t screen;
+	dim_t game_size;
+	dir_t dir=RIGHT;
+	dir_t move_dir=NONE;
+	int c;
+
+	srand(time(0));
+	initscr();
+
+	getmaxyx(stdscr, screen.height, screen.width);
+
+	game_size.width=screen.width/2;
+	game_size.height=screen.height/2;
+
+	food=create_food(game_size);
+
+	snake.body[0].x=game_size.width/2;
+	snake.body[0].y=game_size.height/2;
+	snake.body[1].x=game_size.width/2;
+	snake.body[1].y=game_size.height/2+1;
+	snake.length=2;
+	snake.index=1;
+
+	board.left=screen.width/2-game_size.width/2-1;
+	board.right=board.left+game_size.width+1;
+	board.top=screen.height/2-game_size.height/2-1;
+	board.bottom=board.top+game_size.height+1;
+
+	noecho();
+	cbreak();
+	timeout(0);
+	curs_set(0);
+
+	clear();
+	do {
+		print_board(board);
+		print_food(food,board);
+		print_head(&snake,board);
+		clear_tail(&snake,board);
+		refresh();
+
+		c=getch();
+		move_dir=get_dir(c);
+		if (move_dir!=NONE) {
+			dir=move_dir;
+		}
+
+		move_snake(&snake, dir);
+		snake.dead=is_dead(&snake,game_size);
+
+		if (has_food(&snake, food)) {
+			snake.length++;
+			food=create_food(game_size);
+		}
+
+		usleep (100000-snake.length*5000<5000?5000:100000-snake.length*5000);
+
+	} while (c!=27 && !snake.dead);
+
+	move(
+		screen.height/2,
+		screen.width/2-5
+		);
+	printw("GAME OVER");
+	refresh();
+	nocbreak();
+	timeout(-1);
+	c=getch();
+	endwin();
+
+	return 0;
+}
+
+point_t create_food(dim_t game_size)
+{
+	point_t f;
+	f.x=rand()%game_size.width;
+	f.y=rand()%game_size.height;
+	return f;
+}
+
+void print_board(rect_t board)
+{
+	int i;
+
+	for (i=board.left; i<=board.right; i++) {
+		move(board.top, i);
+		addch(' '|A_REVERSE);
+		move(board.bottom, i);
+		addch(' '|A_REVERSE);
+	}
+
+	for (i=board.top; i<=board.bottom; i++) {
+		move(i, board.left);
+		addch(' '|A_REVERSE);
+		move(i, board.right);
+		addch(' '|A_REVERSE);
+	}
+}
+
+void print_food(point_t food, rect_t board)
+{
+	move(
+		food.y+board.top+1,
+		food.x+board.left+1
+		);
+	printw("@");
+}
+
+void print_head(snake_t* snake, rect_t board)
+{
+	move(
+		snake->body[snake->index].y+board.top+1,
+		snake->body[snake->index].x+board.left+1
+		);
+	printw("o");
+}
+
+void clear_tail(snake_t* snake, rect_t board)
+{
+	int t=snake->index-snake->length;
+	if (t<0) {
+		t+=MAX_LENGTH;
+	}
+	move(
+		snake->body[t].y+board.top+1,
+		snake->body[t].x+board.left+1
+		);
+	printw(" ");
+}
+
+dir_t get_dir(int c)
+{
+	if (c=='a') {
+		return LEFT;
+	}
+	else if (c=='w') {
+		return UP;
+	}
+	else if (c=='d') {
+		return RIGHT;
+	}
+	else if (c=='s') {
+		return DOWN;
+	}
+	else {
+		return NONE;
+	}
+}
+
+void move_snake(snake_t* snake, dir_t dir)
+{
+	point_t p;
+	p=snake->body[snake->index];
+
+	if (dir==LEFT) {
+		p.x--;
+	}
+	else if (dir==DOWN) {
+		p.y++;
+	}
+	else if (dir==RIGHT) {
+		p.x++;
+	}
+	else if (dir==UP) {
+		p.y--;
+	}
+
+	snake->index++;
+	if (snake->index==MAX_LENGTH) {
+		snake->index=0;
+	}
+
+	snake->body[snake->index]=p;
+}
+
+int is_dead(snake_t* snake, dim_t game_size)
+{
+	int i, j;
+	point_t head=snake->body[snake->index];
+
+	if (head.x==-1) return 1;
+	if (head.x==game_size.width) return 1;
+	if (head.y==-1) return 1;
+	if (head.y==game_size.height) return 1;
+
+	i=1;
+	while (i!=snake->length) {
+		j=snake->index-i;
+		if (j<0) {
+			j+=MAX_LENGTH;
+		}
+		if (head.x==snake->body[j].x && head.y==snake->body[j].y) {
+			return 1;
+		}
+		i++;
+	}
+
+	return 0;
+}
+
+int has_food(snake_t* snake, point_t food)
+{
+	return 
+		snake->body[snake->index].x==food.x &&
+		snake->body[snake->index].y==food.y;
+}