/// <summary>
/// Clears the piece from the board on the parameter square.
/// </summary>
/// <param name="sq"> The position of the piece </param>
/// <param name="board"> The board to remove from </param>
public static void ClearPiece(int sq, Board.Board board)
{
Debug.Assert(Validators.IsSq(sq), String.Format("Invalid Square {0}", Io.SqToString(sq)));
int pce = board[sq];
int colour = (int)Data.PIECE_COLOURS[pce];
int t_pceNum = -1;
Debug.Assert(Validators.PieceValid(pce), String.Format("Invalid Piece {0} at square {1}", (Piece)pce, Io.SqToString(sq)));
MakeMove.HashPiece(board, pce, sq);
board[sq] = (int)Piece.EMPTY;
// Subtract the value of the piece from the material total.
board.Material[colour] -= Data.PIECE_VAL[pce];
if (Data.IS_PIECE_BIG[pce])
{
board.BigPieces[colour]--;
if (Data.IS_PIECE_MAJ[pce])
{
board.MajPieces[colour]--;
}
else // else piece is minor piece
{
board.MinPieces[colour]--;
}
}
else // else piece is pawn.
{
int sq64 = Conversion.getSq120ToSq64(sq);
BitBoard.ClearBit(ref board.Pawns[colour], sq64);
BitBoard.ClearBit(ref board.Pawns[(int)Colour.BOTH], sq64);
}
for (int i = 0; i < board.PceNum[pce]; ++i)
{
// Find the correct piece by comparing squares.
if (board.PList[pce, i] == sq)
{
t_pceNum = i;
break;
}
}
// Ensure that the piece has been located in the PList.
Debug.Assert(t_pceNum != -1, String.Format("Piece {0} at square {1} wasn't found in the Board's PList", (Piece)pce, Io.SqToString(sq)));
// Decrement the value of the PList.
board.PceNum[pce]--;
board.PList[pce, t_pceNum] = board.PList[pce, board.PceNum[pce]];
}
/// <summary>
/// Moves the piece at the from square to the to square
/// </summary>
/// <param name="from"> The starting square for the piece </param>
/// <param name="to"> The new square for the piece </param>
/// <param name="board"> The board to operate on </param>
/// <exception cref="Exception"> Throws an exception if the from or to Square is invalid </exception>
public static void MovePiece(int from, int to, Board.Board board)
{
Debug.Assert(Validators.IsSq(from), String.Format("Invalid From Square {0}", Io.SqToString(from)));
Debug.Assert(Validators.IsSq(to), String.Format("Invalid To Square {0}", Io.SqToString(from)));
int pce = board[from];
Debug.Assert(Validators.PieceValid(pce), String.Format(
"Invalid Pce represented by integer {0} On Sq {0}", pce, Io.SqToString(from)));
int colour = (int)Data.PIECE_COLOURS[pce];
int t_pceNum = -1;
MakeMove.HashPiece(board, pce, from);
// Removes the piece from the from square.
board[from] = (int)Piece.EMPTY;
MakeMove.HashPiece(board, pce, to);
// Adds the piece to the to square.
board[to] = pce;
if (!Data.IS_PIECE_BIG[pce]) // If piece is pawn.
{
int sq64From = Conversion.getSq120ToSq64(from);
int sq64To = Conversion.getSq120ToSq64(to);
// Clear from sq
BitBoard.ClearBit(ref board.Pawns[colour], sq64From);
BitBoard.ClearBit(ref board.Pawns[(int)Colour.BOTH], sq64From);
// Sets to sq
BitBoard.SetBit(ref board.Pawns[colour], sq64To);
BitBoard.SetBit(ref board.Pawns[(int)Colour.BOTH], sq64To);
}
// Now we move the piece in the piece list:
for (int i = 0; i < board.PceNum[pce]; ++i)
{
// Find the correct piece by comparing squares.
if (board.PList[pce, i] == from)
{
board.PList[pce, i] = to;
t_pceNum = i;
break;
}
}
// If t_pceNum is unchanged.
Debug.Assert(t_pceNum != -1, String.Format("Piece {0} at square {1} wasn't found in the Board's PList", (Piece)pce, Io.SqToString(from)));
}
/// <summary>
/// Adds the piece to the board on the parameter square.
/// </summary>
/// <param name="sq"> The position of the piece </param>
/// <param name="pce"> The piece to add to the board </param>
/// <param name="board"> The board to add to </param>
public static void AddPiece(int sq, Board.Board board, int pce)
{
Debug.Assert(Validators.PieceValid(pce), String.Format("Invalid Piece integer value {0}", pce));
Debug.Assert(Validators.IsSq(sq), String.Format("Invalid Square {0}", Io.SqToString(sq)));
int colour = (int)Data.PIECE_COLOURS[pce];
// Hash in the piece
MakeMove.HashPiece(board, pce, sq);
// Add the piece to the board
board[sq] = pce;
// Add the value of the piece to the material total.
board.Material[colour] += Data.PIECE_VAL[pce];
if (Data.IS_PIECE_BIG[pce])
{
board.BigPieces[colour]++;
if (Data.IS_PIECE_MAJ[pce])
{
board.MajPieces[colour]++;
}
else // else piece is minor piece
{
board.MinPieces[colour]++;
}
}
else // else piece is pawn.
{
int sq64 = Conversion.getSq120ToSq64(sq);
BitBoard.SetBit(ref board.Pawns[colour], sq64);
BitBoard.SetBit(ref board.Pawns[(int)Colour.BOTH], sq64);
}
// holds the position of every piece on the board.
// pList[(int) wN][0] = E1;
// pList[(int) wN][1] = D4; ... ...
// emptySquares initialized to NO_SQ.
board.PList[pce, board.PceNum[pce]++] = sq;
}
// Possibly not static
// Returns true if legal move, or false otherwise
/// <summary>
/// Makes the input move on the board, if the move is legal.
/// If illegal, nothing happens and the method returns false.
/// </summary>
/// <param name="board"> The board to make the move on </param>
/// <param name="move"> The move to perform </param>
public static bool Make_Move(Board.Board board, int move)
{
Debug.Assert(BoardOperations.CheckBoard(board), "The CheckBoard method returned false.");
int from = MoveOperations.FromSq(move);
int to = MoveOperations.ToSq(move);
int side = board.Side;
Debug.Assert(Validators.SqOnBoard(from), String.Format("Invalid From Square {0}", Io.SqToString(from)));
Debug.Assert(Validators.SqOnBoard(to), String.Format("Invalid To Square {0}", Io.SqToString(to)));
Debug.Assert(Validators.SideValid(side), String.Format("Invalid Side with integer value {0}", side));
Debug.Assert(Validators.PieceValid(board[from]), String.Format("Invalid From Square {0}", Io.SqToString(from)));
board.History[board.HistoryPly].PosKey = board.PosKey;
// Now we check for special moves.
if ((move & MoveOperations.MoveFlagEnPas) != 0)
{
if (side == (int)Colour.WHITE) // If EnPas move we need to kill the pawn
{
ClearPiece(to - 10, board);
}
else // Else black
{
ClearPiece(to + 10, board);
}
}
else if ((move & MoveOperations.MoveFlagCastle) != 0)
{
// If castle we need to move the rook.
switch (to)
{
case (int)Square.C1:
MovePiece((int)Square.A1, (int)Square.D1, board); break;
case (int)Square.C8:
MovePiece((int)Square.A8, (int)Square.D8, board); break;
case (int)Square.G1:
MovePiece((int)Square.H1, (int)Square.F1, board); break;
case (int)Square.G8:
MovePiece((int)Square.H8, (int)Square.F8, board); break;
default:
throw new Exception(
"The move is a castling move, but the to square doesn't match any eligible moves");
}
}
if (board.EnPas != (int)Square.NO_SQ)
{
MakeMove.HashEnPas(board);
}
MakeMove.HashCastle(board); // POSSIBLE ERROR, MAYBE IT SHOULD BE IN IF STATEMENT ABOVE.
// Store information in history array.
board.History[board.HistoryPly].Move = move;
board.History[board.HistoryPly].EnPas = board.EnPas;
board.History[board.HistoryPly].CastlePerm = board.CastlePerm;
board.History[board.HistoryPly].FiftyMoves = board.FiftyMoves;
// Adjust castle permissions if rook or king has moved.
board.CastlePerm &= MakeMove.castlePerm[from];
board.CastlePerm &= MakeMove.castlePerm[to];
board.EnPas = (int)Square.NO_SQ;
HashCastle(board);
int captured = MoveOperations.Captured(move);
board.FiftyMoves++;
// If there is a piece captured
if (captured != (int)Piece.EMPTY)
{
// Test if the piece is valid.
Debug.Assert(Validators.PieceValid(captured), String.Format("Invalid piece ID integer {0}", captured));
ClearPiece(to, board);
board.FiftyMoves = 0; // reset 50moves, cuz a piece has been captured.
}
board.HistoryPly++;
board.Ply++;
if (Data.IsPiecePawn(board[from]))
{
board.FiftyMoves = 0; // Reset 50moves, cuz a pawn has moved.
if ((move & MoveOperations.MoveFlagPawnStart) != 0)
{
if (side == (int)Colour.WHITE)
{
board.EnPas = from + 10;
Debug.Assert(Conversion.getRanksBrd(board.EnPas) == (int)Rank.RANK_3, String.Format("Invalid board state: the enPas square {0} is wrong", Io.SqToString(board.EnPas)));
}
else
{
board.EnPas = from - 10;
Debug.Assert(Conversion.getRanksBrd(board.EnPas) == (int)Rank.RANK_6, String.Format("Invalid board state: the enPas square {0} is wrong", Io.SqToString(board.EnPas)));
}
HashEnPas(board);
}
}
MovePiece(from, to, board);
int promotedPce = MoveOperations.Promoted(move);
if (promotedPce != (int)Piece.EMPTY) // If there is a promoted piece
// A piece cannot be promoted to a pawn.
{
Debug.Assert(Validators.PieceValid(promotedPce) && !Data.IsPiecePawn(promotedPce), String.Format("Promoted piece {0} is invalid", (Piece)promotedPce));
ClearPiece(to, board);
AddPiece(to, board, promotedPce);
}
if (Data.IsPieceKing(board[to]))
{
// If piece is king set the KingSQ
board.KingSq[side] = to;
}
// Exclusive or, changes the side from white to black or black to white.
board.Side ^= 1;
HashSide(board);
Debug.Assert(BoardOperations.CheckBoard(board));
// Make sure that the new king square isn't attacked.
if (Attack.IsSqAttacked(board.KingSq[side], board.Side, board))
{
TakeMove(board);
return(false);
}
return(true);
}