Make key_after() more consistent with key()

[stockfish] / src / position.h

diff --git a/src/position.h b/src/position.h
index a7654aa1a547f9f4646157bf3a9cba1e4c5c6c72..078ff5b79f23e9e2d85b943734f2c4713bbbb3bd 100644 (file)
--- a/src/position.h
+++ b/src/position.h
@@ -1,6 +1,6 @@
 /*
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
-  Copyright (C) 2004-2021 The Stockfish developers (see AUTHORS file)
+  Copyright (C) 2004-2022 The Stockfish developers (see AUTHORS file)
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -51,11 +51,11 @@ struct StateInfo {
   // Not copied when making a move (will be recomputed anyhow)
   Key        key;
   Bitboard   checkersBB;
-  Piece      capturedPiece;
   StateInfo* previous;
   Bitboard   blockersForKing[COLOR_NB];
   Bitboard   pinners[COLOR_NB];
   Bitboard   checkSquares[PIECE_TYPE_NB];
+  Piece      capturedPiece;
   int        repetition;
 
   // Used by NNUE
@@ -115,20 +115,18 @@ public:
   Bitboard blockers_for_king(Color c) const;
   Bitboard check_squares(PieceType pt) const;
   Bitboard pinners(Color c) const;
-  bool is_discovered_check_on_king(Color c, Move m) const;
 
   // Attacks to/from a given square
   Bitboard attackers_to(Square s) const;
   Bitboard attackers_to(Square s, Bitboard occupied) const;
   Bitboard slider_blockers(Bitboard sliders, Square s, Bitboard& pinners) const;
+  template<PieceType Pt> Bitboard attacks_by(Color c) const;
 
   // Properties of moves
   bool legal(Move m) const;
   bool pseudo_legal(const Move m) const;
   bool capture(Move m) const;
-  bool capture_or_promotion(Move m) const;
   bool gives_check(Move m) const;
-  bool advanced_pawn_push(Move m) const;
   Piece moved_piece(Move m) const;
   Piece captured_piece() const;
 
@@ -163,6 +161,7 @@ public:
   bool has_repeated() const;
   int rule50_count() const;
   Score psq_score() const;
+  Value psq_eg_stm() const;
   Value non_pawn_material(Color c) const;
   Value non_pawn_material() const;
 
@@ -173,6 +172,9 @@ public:
   // Used by NNUE
   StateInfo* state() const;
 
+  void put_piece(Piece pc, Square s);
+  void remove_piece(Square s);
+
 private:
   // Initialization helpers (used while setting up a position)
   void set_castling_right(Color c, Square rfrom);
@@ -180,11 +182,11 @@ private:
   void set_check_info(StateInfo* si) const;
 
   // Other helpers
-  void put_piece(Piece pc, Square s);
-  void remove_piece(Square s);
   void move_piece(Square from, Square to);
   template<bool Do>
   void do_castling(Color us, Square from, Square& to, Square& rfrom, Square& rto);
+  template<bool AfterMove>
+  Key adjust_key50(Key k) const;
 
   // Data members
   Piece board[SQUARE_NB];
@@ -194,11 +196,11 @@ private:
   int castlingRightsMask[SQUARE_NB];
   Square castlingRookSquare[CASTLING_RIGHT_NB];
   Bitboard castlingPath[CASTLING_RIGHT_NB];
+  Thread* thisThread;
+  StateInfo* st;
   int gamePly;
   Color sideToMove;
   Score psq;
-  Thread* thisThread;
-  StateInfo* st;
   bool chess960;
 };
 
@@ -286,6 +288,22 @@ inline Bitboard Position::attackers_to(Square s) const {
   return attackers_to(s, pieces());
 }
 
+template<PieceType Pt>
+inline Bitboard Position::attacks_by(Color c) const {
+
+  if constexpr (Pt == PAWN)
+      return c == WHITE ? pawn_attacks_bb<WHITE>(pieces(WHITE, PAWN))
+                        : pawn_attacks_bb<BLACK>(pieces(BLACK, PAWN));
+  else
+  {
+      Bitboard threats = 0;
+      Bitboard attackers = pieces(c, Pt);
+      while (attackers)
+          threats |= attacks_bb<Pt>(pop_lsb(attackers), pieces());
+      return threats;
+  }
+}
+
 inline Bitboard Position::checkers() const {
   return st->checkersBB;
 }
@@ -302,26 +320,23 @@ inline Bitboard Position::check_squares(PieceType pt) const {
   return st->checkSquares[pt];
 }
 
-inline bool Position::is_discovered_check_on_king(Color c, Move m) const {
-  return st->blockersForKing[c] & from_sq(m);
-}
-
 inline bool Position::pawn_passed(Color c, Square s) const {
   return !(pieces(~c, PAWN) & passed_pawn_span(c, s));
 }
 
-inline bool Position::advanced_pawn_push(Move m) const {
-  return   type_of(moved_piece(m)) == PAWN
-        && relative_rank(sideToMove, to_sq(m)) > RANK_6;
-}
-
 inline int Position::pawns_on_same_color_squares(Color c, Square s) const {
   return popcount(pieces(c, PAWN) & ((DarkSquares & s) ? DarkSquares : ~DarkSquares));
 }
 
 inline Key Position::key() const {
-  return st->rule50 < 14 ? st->key
-                         : st->key ^ make_key((st->rule50 - 14) / 8);
+  return adjust_key50<false>(st->key);
+}
+
+template<bool AfterMove>
+inline Key Position::adjust_key50(Key k) const
+{
+  return st->rule50 < 14 - AfterMove
+      ? k : k ^ make_key((st->rule50 - (14 - AfterMove)) / 8);
 }
 
 inline Key Position::pawn_key() const {
@@ -336,6 +351,10 @@ inline Score Position::psq_score() const {
   return psq;
 }
 
+inline Value Position::psq_eg_stm() const {
+  return (sideToMove == WHITE ? 1 : -1) * eg_value(psq);
+}
+
 inline Value Position::non_pawn_material(Color c) const {
   return st->nonPawnMaterial[c];
 }
@@ -362,11 +381,6 @@ inline bool Position::is_chess960() const {
   return chess960;
 }
 
-inline bool Position::capture_or_promotion(Move m) const {
-  assert(is_ok(m));
-  return type_of(m) != NORMAL ? type_of(m) != CASTLING : !empty(to_sq(m));
-}
-
 inline bool Position::capture(Move m) const {
   assert(is_ok(m));
   // Castling is encoded as "king captures rook"
@@ -397,7 +411,7 @@ inline void Position::remove_piece(Square s) {
   byTypeBB[ALL_PIECES] ^= s;
   byTypeBB[type_of(pc)] ^= s;
   byColorBB[color_of(pc)] ^= s;
-  /* board[s] = NO_PIECE;  Not needed, overwritten by the capturing one */
+  board[s] = NO_PIECE;
   pieceCount[pc]--;
   pieceCount[make_piece(color_of(pc), ALL_PIECES)]--;
   psq -= PSQT::psq[pc][s];