forked from len0rd/rockbox
Some improvements to rocklife (FS#10087, but slightly less paranoid). Main improvement is that the file loading will not lead to stack overflow or illegal memory access.
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@20610 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Alexander Levin
parent
64f4b87a72
commit
b549ce9193
1 changed files with 113 additions and 95 deletions
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@ -82,61 +82,82 @@ PLUGIN_HEADER
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const struct button_mapping *plugin_contexts[]
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= {generic_directions, generic_actions};
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unsigned char grid_a[LCD_WIDTH][LCD_HEIGHT];
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unsigned char grid_b[LCD_WIDTH][LCD_HEIGHT];
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#define GRID_W LCD_WIDTH
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#define GRID_H LCD_HEIGHT
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unsigned char grid_a[GRID_W][GRID_H];
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unsigned char grid_b[GRID_W][GRID_H];
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int generation = 0;
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int population = 0;
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int status_line = 0;
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char buf[30];
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static inline void set_cell(int x, int y, char *pgrid){
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pgrid[x+y*LCD_WIDTH]=1;
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static inline bool is_valid_cell(int x, int y) {
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return (x >= 0 && x < GRID_W
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&& y >= 0 && y < GRID_H);
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}
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static inline void set_cell_age(int x, int y, unsigned char age, char *pgrid) {
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pgrid[x+y*GRID_W] = age;
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}
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static inline void set_cell(int x, int y, char *pgrid) {
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set_cell_age(x, y, 1, pgrid);
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}
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static inline unsigned char get_cell(int x, int y, char *pgrid) {
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if (x < 0)
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x += GRID_W;
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else if (x >= GRID_W)
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x -= GRID_W;
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if (y < 0)
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y += GRID_H;
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else if (y >= GRID_H)
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y -= GRID_H;
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return pgrid[x+y*GRID_W];
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}
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/* clear grid */
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void init_grid(char *pgrid){
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int x, y;
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for(y=0; y<LCD_HEIGHT; y++){
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for(x=0; x<LCD_WIDTH; x++){
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pgrid[x+y*LCD_WIDTH] = 0;
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}
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}
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memset(pgrid, 0, GRID_W * GRID_H);
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}
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/*fill grid with pattern from file (viewer mode)*/
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static bool load_cellfile(const char *file, char *pgrid){
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int fd, file_size;
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int fd;
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fd = rb->open(file, O_RDONLY);
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if (fd==-1)
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return false;
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file_size = rb->filesize(fd);
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if (file_size==-1)
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return false;
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init_grid(pgrid);
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char buf1[file_size];
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int i, j, k, xmid, ymid;
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j=0;
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k=0;
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xmid = (LCD_WIDTH>>1) - 2;
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ymid = (LCD_HEIGHT>>1) - 2;
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char c;
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int nc, x, y, xmid, ymid;
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x=0;
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y=0;
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xmid = (GRID_W>>1) - 2;
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ymid = (GRID_H>>1) - 2;
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rb->read(fd, buf1, file_size - 1);
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while (true) {
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nc = read(fd, &c, 1);
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if (nc <= 0)
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break;
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for(i=0; i<file_size; i++){
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switch(buf1[i]){
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switch(c) {
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case '.':
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j++;
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x++;
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break;
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case 'O':
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set_cell(xmid + j, ymid + k, pgrid);
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j++;
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if (is_valid_cell(xmid + x, ymid + y))
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set_cell(xmid + x, ymid + y, pgrid);
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x++;
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break;
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case '\n':
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k++;
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j=0;
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y++;
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x=0;
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break;
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default:
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break;
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@ -151,7 +172,7 @@ static void setup_grid(char *pgrid, int pattern){
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int n, max;
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int xmid, ymid;
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max = LCD_HEIGHT*LCD_WIDTH;
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max = GRID_W * GRID_H;
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switch(pattern){
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case PATTERN_RANDOM:
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@ -174,8 +195,8 @@ static void setup_grid(char *pgrid, int pattern){
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case PATTERN_GROWTH_1:
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rb->splash(HZ, "Growth");
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xmid = (LCD_WIDTH>>1) - 2;
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ymid = (LCD_HEIGHT>>1) - 2;
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xmid = (GRID_W>>1) - 2;
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ymid = (GRID_H>>1) - 2;
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set_cell(xmid + 6, ymid + 0 , pgrid);
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set_cell(xmid + 4, ymid + 1 , pgrid);
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set_cell(xmid + 6, ymid + 1 , pgrid);
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@ -189,8 +210,8 @@ static void setup_grid(char *pgrid, int pattern){
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break;
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case PATTERN_ACORN:
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rb->splash(HZ, "Acorn");
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xmid = (LCD_WIDTH>>1) - 3;
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ymid = (LCD_HEIGHT>>1) - 1;
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xmid = (GRID_W>>1) - 3;
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ymid = (GRID_H>>1) - 1;
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set_cell(xmid + 1, ymid + 0 , pgrid);
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set_cell(xmid + 3, ymid + 1 , pgrid);
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set_cell(xmid + 0, ymid + 2 , pgrid);
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@ -201,8 +222,8 @@ static void setup_grid(char *pgrid, int pattern){
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break;
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case PATTERN_GROWTH_2:
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rb->splash(HZ, "Growth 2");
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xmid = (LCD_WIDTH>>1) - 4;
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ymid = (LCD_HEIGHT>>1) - 1;
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xmid = (GRID_W>>1) - 4;
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ymid = (GRID_H>>1) - 1;
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set_cell(xmid + 0, ymid + 0 , pgrid);
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set_cell(xmid + 1, ymid + 0 , pgrid);
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set_cell(xmid + 2, ymid + 0 , pgrid);
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@ -262,14 +283,12 @@ static void setup_grid(char *pgrid, int pattern){
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/* display grid */
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static void show_grid(char *pgrid){
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int x, y;
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int m;
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unsigned char age;
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rb->lcd_clear_display();
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for(y=0; y<LCD_HEIGHT; y++){
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for(x=0; x<LCD_WIDTH; x++){
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m = y*LCD_WIDTH+x;
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age = pgrid[m];
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for(y=0; y<GRID_H; y++){
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for(x=0; x<GRID_W; x++){
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age = get_cell(x, y, pgrid);
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if(age){
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#if LCD_DEPTH >= 16
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rb->lcd_set_foreground( LCD_RGBPACK( age, age, age ));
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@ -291,11 +310,18 @@ static void show_grid(char *pgrid){
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}
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/* check state of cell depending on the number of neighbours */
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static inline int check_cell(unsigned char *n){
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int sum;
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/* Calculates whether the cell will be alive in the next generation.
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n is the array with 9 elements that represent the cell itself and its
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neighborhood like this (the cell itself is n[4]):
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0 1 2
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3 4 5
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6 7 8
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*/
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static inline bool check_cell(unsigned char *n)
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{
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int empty_cells = 0;
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unsigned char live = 0;
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int alive_cells;
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bool result;
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/* count empty neighbour cells */
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if(n[0]==0) empty_cells++;
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@ -308,38 +334,32 @@ static inline int check_cell(unsigned char *n){
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if(n[8]==0) empty_cells++;
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/* now we build the number of non-zero neighbours :-P */
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sum = 8 - empty_cells;
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alive_cells = 8 - empty_cells;
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/* 1st and 2nd rule*/
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if (n[4] && (sum<2 || sum>3))
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live = false;
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if (n[4]) {
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/* If the cell is alive, it stays alive iff it has 2 or 3 alive neighbours */
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result = (alive_cells==2 || alive_cells==3);
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}
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else {
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/* If the cell is dead, it gets alive iff it has 3 alive neighbours */
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result = (alive_cells==3);
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}
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/* 3rd rule */
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if (n[4] && (sum==2 || sum==3))
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live = true;
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/* 4rd rule */
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if (!n[4] && sum==3)
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live = true;
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return live;
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return result;
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}
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/* Calculate the next generation of cells
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*
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* The borders of the grid are connected to their opposite sides.
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*
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*
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* To avoid multiplications while accessing data in the 2-d grid
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* (pgrid) we try to re-use previously accessed neighbourhood
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* information which is stored in an 3x3 array.
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*
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*/
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static void next_generation(char *pgrid, char *pnext_grid){
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int x, y;
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unsigned char cell;
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int age;
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int m;
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bool cell;
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unsigned char age;
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unsigned char n[9];
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rb->memset(n, 0, sizeof(n));
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@ -357,31 +377,33 @@ static void next_generation(char *pgrid, char *pnext_grid){
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population = 0;
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/* go through the grid */
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for(y=0; y<LCD_HEIGHT; y++){
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for(x=0; x<LCD_WIDTH; x++){
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for(y=0; y<GRID_H; y++){
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for(x=0; x<GRID_W; x++){
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if(y==0 && x==0){
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/* first cell in first row, we have to load all neighbours */
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n[0] = pgrid[((x+LCD_WIDTH-1)%LCD_WIDTH)+((y+LCD_HEIGHT-1)%LCD_HEIGHT)*LCD_WIDTH];
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n[1] = pgrid[((x )%LCD_WIDTH)+((y+LCD_HEIGHT-1)%LCD_HEIGHT)*LCD_WIDTH];
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n[2] = pgrid[((x +1)%LCD_WIDTH)+((y+LCD_HEIGHT-1)%LCD_HEIGHT)*LCD_WIDTH];
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n[3] = pgrid[((x+LCD_WIDTH-1)%LCD_WIDTH)+((y )%LCD_HEIGHT)*LCD_WIDTH];
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n[5] = pgrid[((x +1)%LCD_WIDTH)+((y )%LCD_HEIGHT)*LCD_WIDTH];
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n[6] = pgrid[((x+LCD_WIDTH-1)%LCD_WIDTH)+((y +1)%LCD_HEIGHT)*LCD_WIDTH];
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n[7] = pgrid[((x )%LCD_WIDTH)+((y +1)%LCD_HEIGHT)*LCD_WIDTH];
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n[8] = pgrid[((x +1)%LCD_WIDTH)+((y +1)%LCD_HEIGHT)*LCD_WIDTH];
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n[0] = get_cell(x-1, y-1, pgrid);
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n[1] = get_cell(x, y-1, pgrid);
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n[2] = get_cell(x+1, y-1, pgrid);
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n[3] = get_cell(x-1, y, pgrid);
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n[4] = get_cell(x, y, pgrid);
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n[5] = get_cell(x+1, y, pgrid);
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n[6] = get_cell(x-1, y+1, pgrid);
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n[7] = get_cell(x, y+1, pgrid);
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n[8] = get_cell(x+1, y+1, pgrid);
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} else {
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if(x==0){
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/* beginning of a row, copy what we know about our predecessor,
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0, 1, 3 are known, 2, 5, 6, 7, 8 have to be loaded
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0, 1, 3, 4 are known, 2, 5, 6, 7, 8 have to be loaded
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*/
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n[0] = n[4];
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n[1] = n[5];
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n[2] = pgrid[((x +1)%LCD_WIDTH)+((y+LCD_HEIGHT-1)%LCD_HEIGHT)*LCD_WIDTH];
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n[2] = get_cell(x+1, y-1, pgrid);
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n[3] = n[7];
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n[5] = pgrid[((x +1)%LCD_WIDTH)+((y )%LCD_HEIGHT)*LCD_WIDTH];
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n[6] = pgrid[((x+LCD_WIDTH-1)%LCD_WIDTH)+((y +1)%LCD_HEIGHT)*LCD_WIDTH];
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n[7] = pgrid[((x )%LCD_WIDTH)+((y +1)%LCD_HEIGHT)*LCD_WIDTH];
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n[8] = pgrid[((x +1)%LCD_WIDTH)+((y +1)%LCD_HEIGHT)*LCD_WIDTH];
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n[4] = n[8];
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n[5] = get_cell(x+1, y, pgrid);
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n[6] = get_cell(x-1, y+1, pgrid);
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n[7] = get_cell(x, y+1, pgrid);
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n[8] = get_cell(x+1, y+1, pgrid);
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} else {
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/* we are moving right in a row,
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* copy what we know about the neighbours on our left side,
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@ -389,19 +411,17 @@ static void next_generation(char *pgrid, char *pnext_grid){
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*/
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n[0] = n[1];
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n[1] = n[2];
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n[2] = pgrid[((x +1)%LCD_WIDTH)+((y+LCD_HEIGHT-1)%LCD_HEIGHT)*LCD_WIDTH];
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n[2] = get_cell(x+1, y-1, pgrid);
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n[3] = n[4];
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n[5] = pgrid[((x +1)%LCD_WIDTH)+((y )%LCD_HEIGHT)*LCD_WIDTH];
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n[4] = n[5];
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n[5] = get_cell(x+1, y, pgrid);
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n[6] = n[7];
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n[7] = n[8];
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n[8] = pgrid[((x +1)%LCD_WIDTH)+((y +1)%LCD_HEIGHT)*LCD_WIDTH];
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n[8] = get_cell(x+1, y+1, pgrid);
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}
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}
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m = x+y*LCD_WIDTH;
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/* how old is our cell? */
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n[4] = pgrid[m];
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age = n[4];
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/* calculate the cell based on given neighbour information */
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@ -411,14 +431,12 @@ static void next_generation(char *pgrid, char *pnext_grid){
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if(cell){
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population++;
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/* prevent overflow */
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if(age>252){
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pnext_grid[m] = 252;
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} else {
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pnext_grid[m] = age + 1;
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}
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if(age<252)
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age++;
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set_cell_age(x, y, age, pnext_grid);
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}
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else
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pnext_grid[m] = 0;
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set_cell_age(x, y, 0, pnext_grid);
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#if 0
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DEBUGF("x=%d,y=%d\n", x, y);
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DEBUGF("cell: %d\n", cell);
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