Position::Position(const Position& pos, int th) {
memcpy(this, &pos, sizeof(Position));
- detach(); // Always detach() in copy c'tor to avoid surprises
threadID = th;
nodes = 0;
}
-/// Position::detach() copies the content of the current state and castling
-/// masks inside the position itself. This is needed when the st pointee could
-/// become stale, as example because the caller is about to going out of scope.
-
-void Position::detach() {
-
- startState = *st;
- st = &startState;
- st->previous = NULL; // As a safe guard
-}
-
-
/// Position::from_fen() initializes the position object with the given FEN
/// string. This function is not very robust - make sure that input FENs are
/// correct (this is assumed to be the responsibility of the GUI).
}
// 5-6. Halfmove clock and fullmove number
- fen >> std::skipws >> st->rule50 >> fullMoves;
+ fen >> std::skipws >> st->rule50 >> startPosPly;
+
+ // Convert from fullmove starting from 1 to ply starting from 0,
+ // handle also common incorrect FEN with fullmove = 0.
+ startPosPly = Max(2 * (startPosPly - 1), 0) + int(sideToMove == BLACK);
// Various initialisations
chess960 = isChess960;
fen << '-';
fen << (ep_square() == SQ_NONE ? " -" : " " + square_to_string(ep_square()))
- << " " << st->rule50 << " " << fullMoves;
+ << " " << st->rule50 << " " << 1 + (startPosPly - int(sideToMove == BLACK)) / 2;
return fen.str();
}
}
-/// Position::do_setup_move() makes a permanent move on the board. It should
-/// be used when setting up a position on board. You can't undo the move.
-
-void Position::do_setup_move(Move m) {
-
- StateInfo newSt;
-
- // Update the number of full moves after black's move
- if (sideToMove == BLACK)
- fullMoves++;
-
- do_move(m, newSt);
-
- // Reset "game ply" in case we made a non-reversible move.
- // "game ply" is used for repetition detection.
- if (st->rule50 == 0)
- st->gamePly = 0;
-
- // Our StateInfo newSt is about going out of scope so copy
- // its content before it disappears.
- detach();
-
- assert(is_ok());
-}
-
-
/// Position::do_move() makes a move, and saves all information necessary
/// to a StateInfo object. The move is assumed to be legal. Pseudo-legal
/// moves should be filtered out before this function is called.
// pointer to point to the new, ready to be updated, state.
struct ReducedStateInfo {
Key pawnKey, materialKey;
- int castleRights, rule50, gamePly, pliesFromNull;
- Square epSquare;
- Score value;
Value npMaterial[2];
+ int castleRights, rule50, pliesFromNull;
+ Score value;
+ Square epSquare;
};
memcpy(&newSt, st, sizeof(ReducedStateInfo));
newSt.previous = st;
st = &newSt;
- // Save the current key to the history[] array, in order to be able to
- // detect repetition draws.
- history[st->gamePly++] = key;
-
// Update side to move
key ^= zobSideToMove;
backupSt.pliesFromNull = st->pliesFromNull;
st->previous = &backupSt;
- // Save the current key to the history[] array, in order to be able to
- // detect repetition draws.
- history[st->gamePly++] = st->key;
-
// Update the necessary information
if (st->epSquare != SQ_NONE)
st->key ^= zobEp[st->epSquare];
// Update the necessary information
sideToMove = opposite_color(sideToMove);
st->rule50--;
- st->gamePly--;
assert(is_ok());
}
castleRightsMask[sq] = ALL_CASTLES;
}
sideToMove = WHITE;
- fullMoves = 1;
nodes = 0;
}
// Draw by repetition?
if (!SkipRepetition)
- for (int i = 4, e = Min(Min(st->gamePly, st->rule50), st->pliesFromNull); i <= e; i += 2)
- if (history[st->gamePly - i] == st->key)
- return true;
+ {
+ int i = 4, e = Min(st->rule50, st->pliesFromNull);
+
+ if (i <= e)
+ {
+ StateInfo* stp = st->previous->previous;
+
+ do {
+ stp = stp->previous->previous;
+
+ if (stp->key == st->key)
+ return true;
+
+ i +=2;
+
+ } while (i <= e);
+ }
+ }
return false;
}