···

       
1
       
1
       
 
       
use std::mem::swap;

     

       
2
       
2
       
 
       


     

       
3
       
3
       
 
       
#[inline]

     

       
4
       
4
       
-
       
fn get_at(world: &Vec<bool>, size: usize, x: isize, y: isize) -> u8 {

     

       
5
       
5
       
-
       
    let isize = size as isize;

     

       
6
       
6
       
-
       
    if x == isize || x == -1 || y == isize || y == -1 {

     

       
4
       
4
       
+
       
fn get_at(world: &Vec<bool>, size: usize, x: usize, y: usize) -> u8 {

     

       
5
       
5
       
+
       
    // benefits from the integer overflow to simplify code

     

       
6
       
6
       
+
       
    if x >= size || y >= size {

     

       
7
       
7
       
 
       
        return 0;

     

       
8
       
8
       
 
       
    };

     

       
9
       
9
       
-
       
    let (x, y) = (x as usize, y as usize);

     

       
10
       
10
       
-
       
    if *world.get(y * size + x).expect("invalid position") {

     

       
11
       
11
       
-
       
        1

     

       
12
       
12
       
-
       
    } else {

     

       
13
       
13
       
-
       
        0

     

       
14
       
14
       
-
       
    }

     

       
9
       
9
       
+
       
    // this is in known bounds

     

       
10
       
10
       
+
       
    unsafe { *world.get_unchecked(y * size + x) as u8 }

     

       
15
       
11
       
 
       
}

     

       
16
       
12
       
 
       


     

       
17
       
13
       
 
       
#[inline]

     

       
18
       
14
       
 
       
fn get_at_bool(world: &Vec<bool>, size: usize, x: usize, y: usize) -> bool {

     

       
19
       
19
       
-
       
    *world.get(y * size + x).expect("invalid position")

     

       
15
       
15
       
+
       
    // this is in known bounds

     

       
16
       
16
       
+
       
    unsafe { *world.get_unchecked(y * size + x) }

     

       
20
       
17
       
 
       
}

     

       
21
       
18
       
 
       


     

       
22
       
19
       
 
       
fn generations(times: u32, mut world: Vec<bool>, size: usize, stuck: bool) -> Vec<bool> {

     
···

       
30
       
27
       
 
       
    }

     

       
31
       
28
       
 
       


     

       
32
       
29
       
 
       
    for _ in 0..times {

     

       
33
       
33
       
-
       
        for y in 0..size {

     

       
34
       
34
       
-
       
            for x in 0..size {

     

       
35
       
35
       
-
       
                let xo = x as isize;

     

       
36
       
36
       
-
       
                let yo = y as isize;

     

       
37
       
37
       
-
       
                let xm = xo - 1;

     

       
38
       
38
       
-
       
                let ym = yo - 1;

     

       
30
       
30
       
+
       
        for yo in 0..size {

     

       
31
       
31
       
+
       
            let ym = yo.wrapping_sub(1);

     

       
32
       
32
       
+
       
            let yp = yo + 1;

     

       
33
       
33
       
+
       
            for xo in 0..size {

     

       
34
       
34
       
+
       
                let xm = xo.wrapping_sub(1);

     

       
39
       
35
       
 
       
                let xp = xo + 1;

     

       
40
       
40
       
-
       
                let yp = yo + 1;

     

       
41
       
36
       
 
       


     

       
42
       
42
       
-
       
                let was = get_at_bool(&world, size, x, y);

     

       
37
       
37
       
+
       
                let was = get_at_bool(&world, size, xo, yo);

     

       
43
       
38
       
 
       
                let neighbours = get_at(&world, size, xm, ym)

     

       
44
       
39
       
 
       
                    + get_at(&world, size, xo, ym)

     

       
45
       
40
       
 
       
                    + get_at(&world, size, xp, ym)

     
···

       
48
       
43
       
 
       
                    + get_at(&world, size, xm, yp)

     

       
49
       
44
       
 
       
                    + get_at(&world, size, xo, yp)

     

       
50
       
45
       
 
       
                    + get_at(&world, size, xp, yp);

     

       
51
       
51
       
-
       
                new_world[y * size + x] = neighbours == 3 || (neighbours == 2 && was);

     

       
46
       
46
       
+
       
                new_world[yo * size + xo] = neighbours == 3 || (neighbours == 2 && was);

     

       
52
       
47
       
 
       
            }

     

       
53
       
48
       
 
       
        }

     

       
54
       
49