src/pawns.h

   1 /*
   2   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   3   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   4   Copyright (C) 2008 Marco Costalba
   5
   6   Stockfish is free software: you can redistribute it and/or modify
   7   it under the terms of the GNU General Public License as published by
   8   the Free Software Foundation, either version 3 of the License, or
   9   (at your option) any later version.
  10
  11   Stockfish is distributed in the hope that it will be useful,
  12   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14   GNU General Public License for more details.
  15
  16   You should have received a copy of the GNU General Public License
  17   along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20
  21 #if !defined(PAWNS_H_INCLUDED)
  22 #define PAWNS_H_INCLUDED
  23
  24 ////
  25 //// Includes
  26 ////
  27
  28 #include "position.h"
  29
  30
  31 ////
  32 //// Types
  33 ////
  34
  35 /// PawnInfo is a class which contains various information about a pawn
  36 /// structure.  Currently, it only includes a middle game and an end game
  37 /// pawn structure evaluation, and a bitboard of passed pawns.  We may want
  38 /// to add further information in the future.  A lookup to the pawn hash table
  39 /// (performed by calling the get_pawn_info method in a PawnInfoTable object)
  40 /// returns a pointer to a PawnInfo object.
  41
  42 class PawnInfo {
  43
  44   friend class PawnInfoTable;
  45
  46 public:
  47   Value mg_value() const;
  48   Value eg_value() const;
  49   Value kingside_storm_value(Color c) const;
  50   Value queenside_storm_value(Color c) const;
  51   Bitboard passed_pawns() const;
  52   bool file_is_half_open(Color c, File f) const;
  53   bool has_open_file_to_left(Color c, File f) const;
  54   bool has_open_file_to_right(Color c, File f) const;
  55
  56 private:
  57   void clear();
  58
  59   Key key;
  60   Bitboard passedPawns;
  61   int mgValue, egValue;
  62   int ksStormValue[2], qsStormValue[2];
  63   int halfOpenFiles[2];
  64 };
  65
  66
  67 /// The PawnInfoTable class represents a pawn hash table.  It is basically
  68 /// just an array of PawnInfo objects and a few methods for accessing these
  69 /// objects.  The most important method is get_pawn_info, which looks up a
  70 /// position in the table and returns a pointer to a PawnInfo object.
  71
  72 class PawnInfoTable {
  73
  74 public:
  75   PawnInfoTable(unsigned numOfEntries);
  76   ~PawnInfoTable();
  77   void clear();
  78   PawnInfo *get_pawn_info(const Position &pos);
  79
  80 private:
  81   unsigned size;
  82   PawnInfo *entries;
  83 };
  84
  85
  86 ////
  87 //// Inline functions
  88 ////
  89
  90 inline Value PawnInfo::mg_value() const {
  91   return Value(mgValue);
  92 }
  93
  94 inline Value PawnInfo::eg_value() const {
  95   return Value(egValue);
  96 }
  97
  98 inline Bitboard PawnInfo::passed_pawns() const {
  99   return passedPawns;
 100 }
 101
 102 inline Value PawnInfo::kingside_storm_value(Color c) const {
 103   return Value(ksStormValue[c]);
 104 }
 105
 106 inline Value PawnInfo::queenside_storm_value(Color c) const {
 107   return Value(qsStormValue[c]);
 108 }
 109
 110 inline bool PawnInfo::file_is_half_open(Color c, File f) const {
 111   return (halfOpenFiles[c] & (1 << int(f)));
 112 }
 113
 114 inline bool PawnInfo::has_open_file_to_left(Color c, File f) const {
 115   return halfOpenFiles[c] & ((1 << int(f)) - 1);
 116 }
 117
 118 inline bool PawnInfo::has_open_file_to_right(Color c, File f) const {
 119   return halfOpenFiles[c] & ~((1 << int(f+1)) - 1);
 120 }
 121
 122 inline void PawnInfo::clear() {
 123
 124   passedPawns = EmptyBoardBB;
 125   mgValue = egValue = 0;
 126   ksStormValue[WHITE] = ksStormValue[BLACK] = 0;
 127   qsStormValue[WHITE] = qsStormValue[BLACK] = 0;
 128   halfOpenFiles[WHITE] = halfOpenFiles[BLACK] = 0xFF;
 129 }
 130
 131
 132 #endif // !defined(PAWNS_H_INCLUDED)