initial BVM usage (halfs performance :( )

src/repr/board.rs

@@ -26,11 +26,21 @@ type ChainCollection = ArrayVec<Chain, 8>;
 /// Map of all points on the board against some type T
 /// Used to index like so: example[i][j]
 /// with each coordinate
-pub struct PosMap<T>(ArrayVec<T, BOARD_AREA>);
+pub struct PosMap<T: Default>(ArrayVec<T, BOARD_AREA>);
+
+impl<T: Default> PosMap<T> {
+    const fn index(row: usize, col: usize) -> usize {
+        row * BOARD_SIZE + col
+    }
+
+    pub fn new() -> Self {
+        Self(ArrayVec::from_iter(
+            (0..BOARD_AREA).map(|_| Default::default()),
+        ))
+    }
 
-impl<T> PosMap<T> {
     pub fn get(&self, row: usize, col: usize) -> &T {
-        let index = row * BOARD_SIZE + col;
+        let index = Self::index(row, col);
 
         debug_assert!(
             BOARD_AREA + 1 >= index,
@@ -40,6 +50,17 @@ impl<T> PosMap<T> {
 
         unsafe { self.0.get_unchecked(index) }
     }
+
+    pub fn set(&mut self, row: usize, col: usize, value: T) {
+        let index = Self::index(row, col);
+        debug_assert!(
+            BOARD_AREA + 1 >= index,
+            "index out of range, was: {}",
+            index
+        );
+
+        self.0[index] = value;
+    }
 }
 
 /// Creates a lookup map for adjacencies and chains from each position on the board