Wrap state variables in a named struct

[stockfish] / src / position.h

diff --git a/src/position.h b/src/position.h
index 02e3a2452fd6382c05e1b0a714c69aa775056ff3..a7d951c3c6ec72af1abf684e2101359b5ca6d026 100644 (file)
--- a/src/position.h
+++ b/src/position.h
@@ -87,6 +87,7 @@ struct UndoInfo {
   Move lastMove;
   Value mgValue, egValue;
   PieceType capture;
+  UndoInfo* previous;
 };
 
 
@@ -240,12 +241,10 @@ public:
   bool square_is_weak(Square s, Color c) const;
 
   // Doing and undoing moves
-  void backup(UndoInfo &u) const;
-  void restore(const UndoInfo &u);
   void do_move(Move m, UndoInfo &u);
-  void undo_move(Move m, const UndoInfo &u);
+  void undo_move(Move m);
   void do_null_move(UndoInfo &u);
-  void undo_null_move(const UndoInfo &u);
+  void undo_null_move();
 
   // Static exchange evaluation
   int see(Square from, Square to) const;
@@ -298,10 +297,10 @@ private:
   // Helper functions for doing and undoing moves
   void do_capture_move(Move m, PieceType capture, Color them, Square to);
   void do_castle_move(Move m);
-  void do_promotion_move(Move m, UndoInfo &u);
+  void do_promotion_move(Move m);
   void do_ep_move(Move m);
   void undo_castle_move(Move m);
-  void undo_promotion_move(Move m, const UndoInfo &u);
+  void undo_promotion_move(Move m);
   void undo_ep_move(Move m);
   void find_checkers();
 
@@ -317,10 +316,12 @@ private:
   Key compute_material_key() const;
 
   // Computing incremental evaluation scores and material counts
-  Value mg_pst(Color c, PieceType pt, Square s) const;
-  Value eg_pst(Color c, PieceType pt, Square s) const;
-  Value compute_mg_value() const;
-  Value compute_eg_value() const;
+  enum GamePhase {
+      MidGame,
+      EndGame
+  };
+  template<GamePhase> Value pst(Color c, PieceType pt, Square s) const;
+  template<GamePhase> Value compute_value() const;
   Value compute_non_pawn_material(Color c) const;
 
   // Bitboards
@@ -345,13 +346,20 @@ private:
   File initialKFile, initialKRFile, initialQRFile;
 
   // Info backed up in do_move()
-  mutable Bitboard pinners[2], pinned[2], dcCandidates[2];
-  Bitboard checkersBB;
-  Key key, pawnKey, materialKey;
-  int castleRights, rule50;
-  Square epSquare;
-  Move lastMove;
-  Value mgValue, egValue;
+  union {
+      UndoInfo undoInfoUnion;
+      struct { // Must have the same layout of UndoInfo
+          mutable Bitboard pinners[2], pinned[2], dcCandidates[2];
+          Bitboard checkersBB;
+          Key key, pawnKey, materialKey;
+          int castleRights, rule50;
+          Square epSquare;
+          Move lastMove;
+          Value mgValue, egValue;
+          PieceType capture;
+          UndoInfo* previous;
+      } st;
+  };
 
   // Static variables
   static int castleRightsMask[64];
@@ -502,7 +510,7 @@ inline Square Position::piece_list(Color c, PieceType pt, int index) const {
 }
 
 inline Square Position::ep_square() const {
-  return epSquare;
+  return st.epSquare;
 }
 
 inline Square Position::king_square(Color c) const {
@@ -510,11 +518,11 @@ inline Square Position::king_square(Color c) const {
 }
 
 inline bool Position::can_castle_kingside(Color side) const {
-  return castleRights & (1+int(side));
+  return st.castleRights & (1+int(side));
 }
 
 inline bool Position::can_castle_queenside(Color side) const {
-  return castleRights & (4+4*int(side));
+  return st.castleRights & (4+4*int(side));
 }
 
 inline bool Position::can_castle(Color side) const {
@@ -564,11 +572,11 @@ inline Bitboard Position::piece_attacks<KING>(Square s) const {
 }
 
 inline Bitboard Position::checkers() const {
-  return checkersBB;
+  return st.checkersBB;
 }
 
 inline bool Position::is_check() const {
-  return checkersBB != EmptyBoardBB;
+  return st.checkersBB != EmptyBoardBB;
 }
 
 inline bool Position::pawn_attacks_square(Color c, Square f, Square t) const {
@@ -615,19 +623,21 @@ inline bool Position::square_is_weak(Square s, Color c) const {
 }
 
 inline Key Position::get_key() const {
-  return key;
+  return st.key;
 }
 
 inline Key Position::get_pawn_key() const {
-  return pawnKey;
+  return st.pawnKey;
 }
 
 inline Key Position::get_material_key() const {
-  return materialKey;
+  return st.materialKey;
 }
 
-inline Value Position::mg_pst(Color c, PieceType pt, Square s) const {
-  return MgPieceSquareTable[piece_of_color_and_type(c, pt)][s];
+template<Position::GamePhase Phase>
+inline Value Position::pst(Color c, PieceType pt, Square s) const {
+  return (Phase == MidGame ? MgPieceSquareTable[piece_of_color_and_type(c, pt)][s]
+                           : EgPieceSquareTable[piece_of_color_and_type(c, pt)][s]);
 }
 
 inline Value Position::mg_pst_delta(Move m) const {
@@ -635,16 +645,12 @@ inline Value Position::mg_pst_delta(Move m) const {
         -MgPieceSquareTable[piece_on(move_from(m))][move_from(m)];
 }
 
-inline Value Position::eg_pst(Color c, PieceType pt, Square s) const {
-  return EgPieceSquareTable[piece_of_color_and_type(c, pt)][s];
-}
-
 inline Value Position::mg_value() const {
-  return mgValue;
+  return st.mgValue;
 }
 
 inline Value Position::eg_value() const {
-  return egValue;
+  return st.egValue;
 }
 
 inline Value Position::non_pawn_material(Color c) const {
@@ -703,7 +709,7 @@ inline bool Position::move_was_passed_pawn_push(Move m) const {
 
 inline int Position::rule_50_counter() const {
 
-  return rule50;
+  return st.rule50;
 }
 
 inline bool Position::opposite_colored_bishops() const {