From 1d694a6fca265229ab4325467c5cf025c2e1a3e5 Mon Sep 17 00:00:00 2001
From: koba-e964 <3303362+koba-e964@users.noreply.github.com>
Date: Mon, 19 Jun 2023 00:18:59 +0900
Subject: [PATCH] Add PositionWrapper::give_piece

---
 mate_solver/src/position_wrapper.rs | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/mate_solver/src/position_wrapper.rs b/mate_solver/src/position_wrapper.rs
index 3e6b85a..b4d96da 100644
--- a/mate_solver/src/position_wrapper.rs
+++ b/mate_solver/src/position_wrapper.rs
@@ -97,6 +97,18 @@ impl PositionWrapper {
         }
     }
 
+    /// 攻め方 (先手) の持ち駒を相手の駒台に移動させる。ハッシュ値も更新する。
+    pub fn give_piece(&mut self, piece_kind: PieceKind) {
+        let s = self.inner.hand_of_a_player_mut(Color::Black);
+        *s = s.removed(piece_kind).unwrap();
+        self.hash ^= TABLE.hands[Color::Black.array_index()][piece_kind.array_index()]
+            [s.count(piece_kind).unwrap() as usize];
+        let s = self.inner.hand_of_a_player_mut(Color::White);
+        self.hash ^= TABLE.hands[Color::White.array_index()][piece_kind.array_index()]
+            [s.count(piece_kind).unwrap() as usize];
+        *s = s.added(piece_kind).unwrap();
+    }
+
     /// 局面のハッシュ値を計算する。
     fn compute_hash(position: &PartialPosition) -> Key {
         let mut x = 0;
@@ -251,4 +263,19 @@ mod tests {
         }
         assert_eq!(hashes[2], hashes[8]);
     }
+
+    #[test]
+    fn give_piece_works() {
+        let piece_kind = PieceKind::Pawn;
+        let mut position = PartialPosition::startpos();
+        position
+            .hand_of_a_player_mut(Color::Black)
+            .Hand_add(piece_kind);
+        let mut position = PositionWrapper::new(position);
+        position.give_piece(piece_kind);
+        assert_eq!(
+            position.hash,
+            PositionWrapper::compute_hash(&position.inner),
+        );
+    }
 }