woah

src/misc.rs

@@ -1,5 +1,7 @@
 use std::{iter::Rev, ops::RangeInclusive};
 
+use num::CheckedSub;
+
 pub fn split_from<T>(min: T, max: T, x: T) -> Vec<Vec<T>>
 where
     T: num::Integer + Copy,
@@ -22,6 +24,26 @@ where
     output
 }
 
+pub fn offsets(i: usize, j: usize, range: usize) -> Vec<(usize, usize)> {
+    let mut output = Vec::new();
+    for i_o in [-(range as i16), 0, range as i16] {
+        let new_i = i as i16 + i_o;
+        if 0 > new_i {
+            continue;
+        }
+
+        for j_o in [-(range as i16), 0, range as i16] {
+            let new_j = j as i16 + j_o;
+            if 0 > new_j {
+                continue;
+            }
+            output.push((new_i as usize, new_j as usize));
+        }
+    }
+
+    output
+}
+
 #[cfg(test)]
 mod test {
     use super::*;