src/move.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(MOVE_H_INCLUDED)
  22 #define MOVE_H_INCLUDED
  23
  24 ////
  25 //// Includes
  26 ////
  27
  28 #include <iostream>
  29
  30 #include "misc.h"
  31 #include "piece.h"
  32 #include "square.h"
  33
  34
  35 ////
  36 //// Types
  37 ////
  38
  39 class Position;
  40
  41 /// A move needs 17 bits to be stored
  42 ///
  43 /// bit  0- 5: destination square (from 0 to 63)
  44 /// bit  6-11: origin square (from 0 to 63)
  45 /// bit 12-14: promotion piece type
  46 /// bit    15: en passant flag
  47 /// bit    16: castle flag
  48 ///
  49 /// Special cases are MOVE_NONE and MOVE_NULL. We can sneak these in
  50 /// because in any normal move destination square is always different
  51 /// from origin square while MOVE_NONE and MOVE_NULL have the same
  52 /// origin and destination square, 0 and 1 respectively.
  53
  54 enum Move {
  55   MOVE_NONE = 0,
  56   MOVE_NULL = 65
  57 };
  58
  59
  60 struct MoveStack {
  61   Move move;
  62   int score;
  63 };
  64
  65 // Note that operator< is set up such that std::sort() will sort in descending order
  66 inline bool operator<(const MoveStack& f, const MoveStack& s) { return s.score < f.score; }
  67
  68
  69 ////
  70 //// Inline functions
  71 ////
  72
  73 inline Square move_from(Move m) {
  74   return Square((int(m) >> 6) & 0x3F);
  75 }
  76
  77 inline Square move_to(Move m) {
  78   return Square(m & 0x3F);
  79 }
  80
  81 inline PieceType move_promotion(Move m) {
  82   return PieceType((int(m) >> 12) & 7);
  83 }
  84
  85 inline bool move_is_ep(Move m) {
  86   return bool((int(m) >> 15) & 1);
  87 }
  88
  89 inline bool move_is_castle(Move m) {
  90   return bool((int(m) >> 16) & 1);
  91 }
  92
  93 inline bool move_is_short_castle(Move m) {
  94   return move_is_castle(m) && (move_to(m) > move_from(m));
  95 }
  96
  97 inline bool move_is_long_castle(Move m) {
  98   return move_is_castle(m) && (move_to(m) < move_from(m));
  99 }
 100
 101 inline Move make_promotion_move(Square from, Square to, PieceType promotion) {
 102   return Move(int(to) | (int(from) << 6) | (int(promotion) << 12));
 103 }
 104
 105 inline Move make_move(Square from, Square to) {
 106   return Move(int(to) | (int(from) << 6));
 107 }
 108
 109 inline Move make_castle_move(Square from, Square to) {
 110   return Move(int(to) | (int(from) << 6) | (1 << 16));
 111 }
 112
 113 inline Move make_ep_move(Square from, Square to) {
 114   return Move(int(to) | (int(from) << 6) | (1 << 15));
 115 }
 116
 117
 118 ////
 119 //// Prototypes
 120 ////
 121
 122 extern std::ostream &operator << (std::ostream &os, Move m);
 123 extern Move move_from_string(const Position &pos, const std::string &str);
 124 extern const std::string move_to_string(Move m);
 125 extern bool move_is_ok(Move m);
 126
 127
 128 #endif // !defined(MOVE_H_INCLUDED)