From c297e4cbfaa2e08c5f6c17326061e870f0efa76f Mon Sep 17 00:00:00 2001
From: Eryn Wells <eryn@erynwells.me>
Date: Sat, 13 Jul 2024 11:57:57 -0700
Subject: [PATCH] [board] Replace implementation of Board::piece_on_square with
 a simpler one

Now that board has a Mailbox, the implementation of this routine can be greatly
simplified. Instead of needing to iterate through all BitBoards to find the
occupied square, just consult the mailbox.
---
 board/src/board.rs | 15 ++++-----------
 1 file changed, 4 insertions(+), 11 deletions(-)

diff --git a/board/src/board.rs b/board/src/board.rs
index 036d4ee..b602237 100644
--- a/board/src/board.rs
+++ b/board/src/board.rs
@@ -135,17 +135,10 @@ impl Board {
     }
 
     #[must_use]
-    pub fn piece_on_square(&self, sq: Square) -> Option<PlacedPiece> {
-        for color in Color::iter() {
-            for shape in Shape::iter() {
-                let piece = Piece::new(*color, *shape);
-                if self.pieces.bitboard_for_piece(&piece).is_set(sq) {
-                    return Some(PlacedPiece::new(piece, sq));
-                }
-            }
-        }
-
-        None
+    pub fn piece_on_square(&self, square: Square) -> Option<PlacedPiece> {
+        self.pieces
+            .get(square)
+            .map(|piece| PlacedPiece::new(piece, square))
     }
 
     #[must_use]