Better document king safety evaluation

[stockfish] / src / position.h

diff --git a/src/position.h b/src/position.h
index e2365a68f306266bb1ec4ba84c09fab8762c15c2..f6e49687de45c7b7bf2e5cb04ef61c5ff5ee9b5f 100644 (file)
--- a/src/position.h
+++ b/src/position.h
@@ -63,6 +63,18 @@ const int MaxGameLength = 220;
 //// Types
 ////
 
+/// struct checkInfo is initialized at c'tor time and keeps
+/// info used to detect if a move gives check.
+
+struct CheckInfo {
+
+    CheckInfo(const Position&);
+
+    Square ksq;
+    Bitboard dcCandidates;
+    Bitboard checkSq[8];
+};
+
 /// Castle rights, encoded as bit fields
 
 enum CastleRights {
@@ -87,12 +99,13 @@ enum Phase {
 /// must be passed as a parameter.
 
 struct StateInfo {
-  Key key, pawnKey, materialKey;
+  Key pawnKey, materialKey;
   int castleRights, rule50, pliesFromNull;
   Square epSquare;
   Score value;
   Value npMaterial[2];
 
+  Key key;
   PieceType capture;
   Bitboard checkersBB;
   StateInfo* previous;
@@ -205,7 +218,7 @@ public:
   bool pl_move_is_legal(Move m, Bitboard pinned) const;
   bool pl_move_is_evasion(Move m, Bitboard pinned) const;
   bool move_is_check(Move m) const;
-  bool move_is_check(Move m, Bitboard dcCandidates) const;
+  bool move_is_check(Move m, const CheckInfo& ci) const;
   bool move_is_capture(Move m) const;
   bool move_is_capture_or_promotion(Move m) const;
   bool move_is_passed_pawn_push(Move m) const;
@@ -223,7 +236,7 @@ public:
   // Doing and undoing moves
   void saveState();
   void do_move(Move m, StateInfo& st);
-  void do_move(Move m, StateInfo& st, Bitboard dcCandidates);
+  void do_move(Move m, StateInfo& st, const CheckInfo& ci, bool moveIsCheck);
   void undo_move(Move m);
   void do_null_move(StateInfo& st);
   void undo_null_move();
@@ -283,9 +296,6 @@ private:
   void undo_castle_move(Move m);
   void find_checkers();
 
-  template<PieceType Piece>
-  void update_checkers(Bitboard* pCheckersBB, Square ksq, Square from, Square to, Bitboard dcCandidates);
-
   template<bool FindPinned>
   Bitboard hidden_checkers(Color c) const;