Refactor pawns shelter and storm

[stockfish] / src / pawns.h

diff --git a/src/pawns.h b/src/pawns.h
index 86708488cb276f6c13ce40d768d7bda7991d3485..1e49a307f64d3748ea742a618869585b0cc46fdb 100644 (file)
--- a/src/pawns.h
+++ b/src/pawns.h
@@ -1,7 +1,7 @@
 /*
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
-  Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
+  Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -17,30 +17,22 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-
 #if !defined(PAWNS_H_INCLUDED)
 #define PAWNS_H_INCLUDED
 
-////
-//// Includes
-////
-
-#include "bitboard.h"
 #include "position.h"
-#include "value.h"
-
-////
-//// Types
-////
+#include "tt.h"
+#include "types.h"
 
 const int PawnTableSize = 16384;
 
 /// PawnInfo is a class which contains various information about a pawn
 /// structure. Currently, it only includes a middle game and an end game
 /// pawn structure evaluation, and a bitboard of passed pawns. We may want
-/// to add further information in the future. A lookup to the pawn hash table
-/// (performed by calling the get_pawn_info method in a PawnInfoTable object)
-/// returns a pointer to a PawnInfo object.
+/// to add further information in the future. A lookup to the pawn hash
+/// table (performed by calling the pawn_info method in a PawnInfoTable
+/// object) returns a pointer to a PawnInfo object.
+
 class PawnInfo {
 
   friend class PawnInfoTable;
@@ -54,11 +46,14 @@ public:
   int has_open_file_to_right(Color c, File f) const;
 
   template<Color Us>
-  Score king_shelter(const Position& pos, Square ksq);
+  Score king_safety(const Position& pos, Square ksq);
 
 private:
   template<Color Us>
-  Score updateShelter(const Position& pos, Square ksq);
+  Score update_safety(const Position& pos, Square ksq);
+
+  template<Color Us>
+  int shelter_storm(const Position& pos, Square ksq);
 
   Key key;
   Bitboard passedPawns[2];
@@ -69,43 +64,20 @@ private:
   Score kingShelters[2];
 };
 
-/// The PawnInfoTable class represents a pawn hash table.  It is basically
-/// just an array of PawnInfo objects and a few methods for accessing these
-/// objects.  The most important method is get_pawn_info, which looks up a
-/// position in the table and returns a pointer to a PawnInfo object.
-
-class PawnInfoTable {
-
-  enum SideType { KingSide, QueenSide };
 
-  PawnInfoTable(const PawnInfoTable&);
-  PawnInfoTable& operator=(const PawnInfoTable&);
+/// The PawnInfoTable class represents a pawn hash table. The most important
+/// method is pawn_info, which returns a pointer to a PawnInfo object.
 
+class PawnInfoTable : public SimpleHash<PawnInfo, PawnTableSize> {
 public:
-  PawnInfoTable();
-  ~PawnInfoTable();
-  PawnInfo* get_pawn_info(const Position& pos) const;
-  void prefetch(Key key) const;
+  PawnInfo* pawn_info(const Position& pos) const;
 
 private:
   template<Color Us>
-  Score evaluate_pawns(const Position& pos, Bitboard ourPawns, Bitboard theirPawns, PawnInfo* pi) const;
-
-  PawnInfo* entries;
+  static Score evaluate_pawns(const Position& pos, Bitboard ourPawns, Bitboard theirPawns, PawnInfo* pi);
 };
 
 
-////
-//// Inline functions
-////
-
-inline void PawnInfoTable::prefetch(Key key) const {
-
-    unsigned index = unsigned(key & (PawnTableSize - 1));
-    PawnInfo* pi = entries + index;
-    ::prefetch((char*) pi);
-}
-
 inline Score PawnInfo::pawns_value() const {
   return value;
 }
@@ -119,7 +91,7 @@ inline Bitboard PawnInfo::passed_pawns(Color c) const {
 }
 
 inline int PawnInfo::file_is_half_open(Color c, File f) const {
-  return (halfOpenFiles[c] & (1 << int(f)));
+  return halfOpenFiles[c] & (1 << int(f));
 }
 
 inline int PawnInfo::has_open_file_to_left(Color c, File f) const {
@@ -130,34 +102,9 @@ inline int PawnInfo::has_open_file_to_right(Color c, File f) const {
   return halfOpenFiles[c] & ~((1 << int(f+1)) - 1);
 }
 
-/// PawnInfo::updateShelter() calculates and caches king shelter. It is called
-/// only when king square changes, about 20% of total king_shelter() calls.
-template<Color Us>
-Score PawnInfo::updateShelter(const Position& pos, Square ksq) {
-
-  const int Shift = (Us == WHITE ? 8 : -8);
-
-  Bitboard pawns;
-  int r, shelter = 0;
-
-  if (relative_rank(Us, ksq) <= RANK_4)
-  {
-      pawns = pos.pieces(PAWN, Us) & this_and_neighboring_files_bb(ksq);
-      r = square_rank(ksq) * 8;
-      for (int i = 1; i < 4; i++)
-      {
-          r += Shift;
-          shelter += BitCount8Bit[(pawns >> r) & 0xFF] * (128 >> i);
-      }
-  }
-  kingSquares[Us] = ksq;
-  kingShelters[Us] = make_score(shelter, 0);
-  return kingShelters[Us];
-}
-
 template<Color Us>
-inline Score PawnInfo::king_shelter(const Position& pos, Square ksq) {
-  return kingSquares[Us] == ksq ? kingShelters[Us] : updateShelter<Us>(pos, ksq);
+inline Score PawnInfo::king_safety(const Position& pos, Square ksq) {
+  return kingSquares[Us] == ksq ? kingShelters[Us] : update_safety<Us>(pos, ksq);
 }
 
 #endif // !defined(PAWNS_H_INCLUDED)