Add 'MagicMoves'

src/movegen/wizardry/mod.rs

@@ -1,7 +1,7 @@
 pub(crate) mod generation;
 mod mask;
 
-use crate::board::Bitboard;
+use crate::board::{Bitboard, Square};
 
 /// A type representing the magic board indexing a given [crate::board::Square].
 #[derive(Clone, Debug)]
@@ -24,3 +24,36 @@ impl Magic {
         base_index + self.offset
     }
 }
+
+/// A type encapsulating a database of [Magic] bitboard moves.
+#[derive(Clone, Debug)]
+#[allow(unused)] // FIXME: remove when used
+pub(crate) struct MagicMoves {
+    magics: Vec<Magic>,
+    moves: Vec<Bitboard>,
+}
+
+#[allow(unused)] // FIXME: remove when used
+impl MagicMoves {
+    /// Initialize a new [MagicMoves] given a matching list of [Magic] and its corresponding moves
+    /// as a [Bitboard].
+    ///
+    /// # Safety
+    ///
+    /// This should only be called with values generated by [crate::movegen::wizardry::generation].
+    pub unsafe fn new(magics: Vec<Magic>, moves: Vec<Bitboard>) -> Self {
+        Self { magics, moves }
+    }
+
+    /// Get the set of valid moves for a piece standing on a [Square], given a set of blockers.
+    pub fn query(&self, square: Square, blockers: Bitboard) -> Bitboard {
+        // SAFETY: indices are in range by construction
+        unsafe {
+            let index = self
+                .magics
+                .get_unchecked(square.index())
+                .get_index(blockers);
+            *self.moves.get_unchecked(index)
+        }
+    }
+}