/// <summary>
/// Generates the move.
/// </summary>
/// <param name="board">The board</param>
/// <param name="from">The starting square</param>
/// <param name="to">The ending square</param>
/// <returns></returns>
internal override Move GenerateMove(Board board, int from, int to)
{
Move move;
// if it's an en passant capture
if (IsEnPassantCaptureMove(board, from, to))
{
move = new EnPassantCaptureMove(board.Status, from, to);
move.ChangeSideToMove(); // change the side to move
move.SetEnPassantTarget(null); // reset the en passant target
move.ResetPly(); // reset the ply
// we need to verify for check
move.Make(board);
bool result = !board.WhiteKingInCheck();
move.TakeBack(board);
return(result ? move : null);
}
move = base.GenerateMove(board, from, to);
if (move != null)
{
move.ResetPly();// reset the ply
// if it's the two-squares move
if (IsTwoSquaresMove(board, from, to))
{
move.SetEnPassantTarget(to + Board.SideSquareNo);// set the en passant target
}
// if it's a promotion
if (Board.Rank(to) == 0)
{
// we don't need to verify for check again
// so the promotion delegate will not be triggered
// later we will change the promotion type as needed
move = new PromotionMove(board.Status, from, to);
move.ChangeSideToMove(); // change the side to move
move.SetEnPassantTarget(null); // reset the en passant target
move.ResetPly(); // reset the ply
(move as PromotionMove).SetCapture(board[to]); // the capture information is set
}
return(move);
}
else
{
return(null);
}
}
/// <summary>
/// Generates the move.
/// Adds check verification to move generation,
/// returns null if its own king will be in check.
/// </summary>
/// <param name="board">The board</param>
/// <param name="from">The starting square</param>
/// <param name="to">The ending square</param>
/// <returns></returns>
internal override Move GenerateMove(Board board, int from, int to)
{
Move move = base.GenerateMove(board, from, to);
if (move != null)
{
// verify for king in check
move.Make(board);
bool result = !board.WhiteKingInCheck();
move.TakeBack(board);
return(result ? move : null);
}
else
{
return(null);
}
}
/// <summary>
/// Generates the move.
/// Adds check verification to move generation,
/// returns null if its own king will be in check.
/// </summary>
/// <param name="board">The board</param>
/// <param name="from">The starting square</param>
/// <param name="to">The ending square</param>
/// <returns></returns>
internal override Move GenerateMove(Board board, int from, int to)
{
Move move = base.GenerateMove(board, from, to);
if (move != null)
{
// verify for king in check
move.Make(board);
bool result = !board.WhiteKingInCheck();
move.TakeBack(board);
return result ? move : null;
}
else
{
return null;
}
}
/// <summary>
/// Verifies the current board for check.
/// </summary>
/// <returns></returns>
private bool IsCheck()
{
return(currentBoard.Status.WhiteTurn ? currentBoard.WhiteKingInCheck() : currentBoard.BlackKingInCheck());
}
/// <summary>
/// Verifies if the board is in a valid state, throws ArgumentException if it's not.
/// </summary>
/// <param name="board">The board</param>
public static void VerifyState(Board board)
{
// the board must not be null
if (board == null)
{
throw new ArgumentNullException("board", Resources.NullBoardMsg);
}
// hastable to remember the number of each piece type
// a pair consists in a piece type and the number of pieces on this board
Dictionary <Type, int> pieceNo = new Dictionary <Type, int>(Piece.TypesNo);
// initialize the values with 0
foreach (Type type in pieceZobristIndexTable.Keys)
{
pieceNo[type] = 0;
}
// loop through the squares
for (int sqIndex = 0; sqIndex < Board.SquareNo; sqIndex++)
{
if (board[sqIndex] != null)
{
// increment the number of this piece type
Type type = board[sqIndex].GetType();
pieceNo[type] = pieceNo[type] + 1;
// check if the White Pawn has rank 1
if (type == typeof(WhitePawn) && Utils.GetRankNotation(sqIndex) == '1')
{
throw new ArgumentException(Resources.WhitePawnRank1Msg, "board");
}
// check if the Black Pawn has rank 8
if (type == typeof(BlackPawn) && Utils.GetRankNotation(sqIndex) == '8')
{
throw new ArgumentException(Resources.BlackPawnRank8Msg, "board");
}
}
}
// if there are too many White pieces
// check if the number of Pawns
// plus the number of extra Queens, Rooks, Bishops, Knights
// (which can result only by promotion) exceeds 8
if ((pieceNo[typeof(WhitePawn)] + Math.Max(pieceNo[typeof(WhiteQueen)] - 1, 0) + Math.Max(pieceNo[typeof(WhiteRook)] - 2, 0) + Math.Max(pieceNo[typeof(WhiteBishop)] - 2, 0) + Math.Max(pieceNo[typeof(WhiteKnight)] - 2, 0)) > 8)
{
throw new ArgumentException(Resources.TooManyWhitePiecesMsg, "board");
}
// if there are too many Black pieces
// check if the number of Pawns
// plus the number of extra Queens, Rooks, Bishops, Knights
// (which can result only by promotion) exceeds 8
if ((pieceNo[typeof(BlackPawn)] + Math.Max(pieceNo[typeof(BlackQueen)] - 1, 0) + Math.Max(pieceNo[typeof(BlackRook)] - 2, 0) + Math.Max(pieceNo[typeof(BlackBishop)] - 2, 0) + Math.Max(pieceNo[typeof(BlackKnight)] - 2, 0)) > 8)
{
throw new ArgumentException(Resources.TooManyBlackPiecesMsg, "board");
}
// check for White King
if (pieceNo[typeof(WhiteKing)] > 1)
{
throw new ArgumentException(Resources.MoreThanOneWhiteKingMsg, "board");
}
if (pieceNo[typeof(WhiteKing)] < 1)
{
throw new ArgumentException(Resources.NoWhiteKingMsg, "board");
}
// check for Black King
if (pieceNo[typeof(BlackKing)] > 1)
{
throw new ArgumentException(Resources.MoreThanOneBlackKingMsg, "board");
}
if (pieceNo[typeof(BlackKing)] < 1)
{
throw new ArgumentException(Resources.NoBlackKingMsg, "board");
}
// check if the King and the Rook are in place for castling availability
if (board.Status.WhiteCouldCastleShort && !(board[Board.E1] is WhiteKing && board[Board.H1] is WhiteRook))
{
throw new ArgumentException(Resources.IllegalWhiteKingShortCastlingMsg, "board");
}
// check if the King and the Rook are in place for castling availability
if (board.Status.WhiteCouldCastleLong && !(board[Board.E1] is WhiteKing && board[Board.A1] is WhiteRook))
{
throw new ArgumentException(Resources.IllegalWhiteKingLongCastlingMsg, "board");
}
// check if the King and the Rook are in place for castling availability
if (board.Status.BlackCouldCastleShort && !(board[Board.E8] is BlackKing && board[Board.H8] is BlackRook))
{
throw new ArgumentException(Resources.IllegalBlackKingShortCastlingMsg, "board");
}
// check if the King and the Rook are in place for castling availability
if (board.Status.BlackCouldCastleLong && !(board[Board.E8] is BlackKing && board[Board.A8] is BlackRook))
{
throw new ArgumentException(Resources.IllegalBlackKingLongCastlingMsg, "board");
}
// check the en passant target
if (
board.Status.EnPassantTarget != null &&
!(
(
Board.Rank(board.Status.EnPassantTarget.Value) == 5 && board.Status.BlackTurn && // the rank of en passant target is correct
board[board.Status.EnPassantTarget.Value - Board.SideSquareNo] is WhitePawn && // there is a pawn in front of the target
board[board.Status.EnPassantTarget.Value] == null && board[board.Status.EnPassantTarget.Value + Board.SideSquareNo] == null // the en passant target square and the one behind are empty
) ||
(
Board.Rank(board.Status.EnPassantTarget.Value) == 2 && board.Status.WhiteTurn && // the rank of en passant target is correct
board[board.Status.EnPassantTarget.Value + Board.SideSquareNo] is BlackPawn && // there is a pawn in front of the target
board[board.Status.EnPassantTarget.Value] == null && board[board.Status.EnPassantTarget.Value - Board.SideSquareNo] == null // the en passant target square and the one behind are empty
)
)
)
{
throw new ArgumentException(Resources.IllegalEPTargetMsg, "board");
}
// check if ply >= 0
if (board.Status.Ply < 0)
{
throw new ArgumentException(Resources.NonNegativePlyMsg, "board");
}
// check if move number >= 1
if (board.Status.Moves < 1)
{
throw new ArgumentException(Resources.PositiveMoveNoMsg, "board");
}
// check if the side which is not to move is in check
if ((board.Status.WhiteTurn && board.BlackKingInCheck()) || (board.Status.BlackTurn && board.WhiteKingInCheck()))
{
throw new ArgumentException(Resources.NoSideNotToMoveCheckMsg, "board");
}
}
/// <summary>
/// Verifies if the board is in a valid state, throws ArgumentException if it's not.
/// </summary>
/// <param name="board">The board</param>
public static void VerifyState(Board board)
{
// the board must not be null
if (board == null) { throw new ArgumentNullException("board", "Resources.NullBoardMsg"); }
// hastable to remember the number of each piece type
// a pair consists in a piece type and the number of pieces on this board
Dictionary<Type, int> pieceNo = new Dictionary<Type, int>(Piece.TypesNo);
// initialize the values with 0
foreach (Type type in pieceZobristIndexTable.Keys) { pieceNo[type] = 0; }
// loop through the squares
for (int sqIndex = 0; sqIndex < Board.SquareNo; sqIndex++)
{
if (board[sqIndex] != null)
{
// increment the number of this piece type
Type type = board[sqIndex].GetType();
pieceNo[type] = pieceNo[type] + 1;
// check if the White Pawn has rank 1
if (type == typeof(WhitePawn) && Utils.GetRankNotation(sqIndex) == '1')
{
throw new ArgumentException("Resources.WhitePawnRank1Msg", "board");
}
// check if the Black Pawn has rank 8
if (type == typeof(BlackPawn) && Utils.GetRankNotation(sqIndex) == '8')
{
throw new ArgumentException("Resources.BlackPawnRank8Msg", "board");
}
}
}
// if there are too many White pieces
// check if the number of Pawns
// plus the number of extra Queens, Rooks, Bishops, Knights
// (which can result only by promotion) exceeds 8
if ((pieceNo[typeof(WhitePawn)] + Math.Max(pieceNo[typeof(WhiteQueen)] - 1, 0) + Math.Max(pieceNo[typeof(WhiteRook)] - 2, 0) + Math.Max(pieceNo[typeof(WhiteBishop)] - 2, 0) + Math.Max(pieceNo[typeof(WhiteKnight)] - 2, 0)) > 8)
{
throw new ArgumentException("Resources.TooManyWhitePiecesMsg", "board");
}
// if there are too many Black pieces
// check if the number of Pawns
// plus the number of extra Queens, Rooks, Bishops, Knights
// (which can result only by promotion) exceeds 8
if ((pieceNo[typeof(BlackPawn)] + Math.Max(pieceNo[typeof(BlackQueen)] - 1, 0) + Math.Max(pieceNo[typeof(BlackRook)] - 2, 0) + Math.Max(pieceNo[typeof(BlackBishop)] - 2, 0) + Math.Max(pieceNo[typeof(BlackKnight)] - 2, 0)) > 8)
{
throw new ArgumentException("Resources.TooManyBlackPiecesMsg", "board");
}
// check for White King
if (pieceNo[typeof(WhiteKing)] > 1)
{
throw new ArgumentException("Resources.MoreThanOneWhiteKingMsg", "board");
}
if (pieceNo[typeof(WhiteKing)] < 1)
{
throw new ArgumentException("Resources.NoWhiteKingMsg", "board");
}
// check for Black King
if (pieceNo[typeof(BlackKing)] > 1)
{
throw new ArgumentException("Resources.MoreThanOneBlackKingMsg", "board");
}
if (pieceNo[typeof(BlackKing)] < 1)
{
throw new ArgumentException("Resources.NoBlackKingMsg", "board");
}
// check if the King and the Rook are in place for castling availability
if (board.Status.WhiteCouldCastleShort && !(board[Board.E1] is WhiteKing && board[Board.H1] is WhiteRook))
{
throw new ArgumentException("Resources.IllegalWhiteKingShortCastlingMsg", "board");
}
// check if the King and the Rook are in place for castling availability
if (board.Status.WhiteCouldCastleLong && !(board[Board.E1] is WhiteKing && board[Board.A1] is WhiteRook))
{
throw new ArgumentException("Resources.IllegalWhiteKingLongCastlingMsg", "board");
}
// check if the King and the Rook are in place for castling availability
if (board.Status.BlackCouldCastleShort && !(board[Board.E8] is BlackKing && board[Board.H8] is BlackRook))
{
throw new ArgumentException("Resources.IllegalBlackKingShortCastlingMsg", "board");
}
// check if the King and the Rook are in place for castling availability
if (board.Status.BlackCouldCastleLong && !(board[Board.E8] is BlackKing && board[Board.A8] is BlackRook))
{
throw new ArgumentException("Resources.IllegalBlackKingLongCastlingMsg", "board");
}
// check the en passant target
if (
board.Status.EnPassantTarget != null &&
!(
(
Board.Rank(board.Status.EnPassantTarget.Value) == 5 && board.Status.BlackTurn &&// the rank of en passant target is correct
board[board.Status.EnPassantTarget.Value - Board.SideSquareNo] is WhitePawn &&// there is a pawn in front of the target
board[board.Status.EnPassantTarget.Value] == null && board[board.Status.EnPassantTarget.Value + Board.SideSquareNo] == null// the en passant target square and the one behind are empty
) ||
(
Board.Rank(board.Status.EnPassantTarget.Value) == 2 && board.Status.WhiteTurn &&// the rank of en passant target is correct
board[board.Status.EnPassantTarget.Value + Board.SideSquareNo] is BlackPawn &&// there is a pawn in front of the target
board[board.Status.EnPassantTarget.Value] == null && board[board.Status.EnPassantTarget.Value - Board.SideSquareNo] == null// the en passant target square and the one behind are empty
)
)
)
{
throw new ArgumentException("Resources.IllegalEPTargetMsg", "board");
}
// check if ply >= 0
if (board.Status.Ply < 0)
{
throw new ArgumentException("Resources.NonNegativePlyMsg", "board");
}
// check if move number >= 1
if (board.Status.Moves < 1)
{
throw new ArgumentException("Resources.PositiveMoveNoMsg", "board");
}
// check if the side which is not to move is in check
if ((board.Status.WhiteTurn && board.BlackKingInCheck()) || (board.Status.BlackTurn && board.WhiteKingInCheck()))
{
throw new ArgumentException("Resources.NoSideNotToMoveCheckMsg", "board");
}
}
/// <summary>
/// Generates the move.
/// </summary>
/// <param name="board">The board</param>
/// <param name="from">The starting square</param>
/// <param name="to">The ending square</param>
/// <returns></returns>
internal override Move GenerateMove(Board board, int from, int to)
{
Move move;
// if it's an en passant capture
if (IsEnPassantCaptureMove(board, from, to))
{
move = new EnPassantCaptureMove(board.Status, from, to);
move.ChangeSideToMove();// change the side to move
move.SetEnPassantTarget(null);// reset the en passant target
move.ResetPly();// reset the ply
// we need to verify for check
move.Make(board);
bool result = !board.WhiteKingInCheck();
move.TakeBack(board);
return result ? move : null;
}
move = base.GenerateMove(board, from, to);
if (move != null)
{
move.ResetPly();// reset the ply
// if it's the two-squares move
if (IsTwoSquaresMove(board, from, to))
{
move.SetEnPassantTarget(to + Board.SideSquareNo);// set the en passant target
}
// if it's a promotion
if (Board.Rank(to) == 0)
{
// we don't need to verify for check again
// so the promotion delegate will not be triggered
// later we will change the promotion type as needed
move = new PromotionMove(board.Status, from, to);
move.ChangeSideToMove();// change the side to move
move.SetEnPassantTarget(null);// reset the en passant target
move.ResetPly();// reset the ply
(move as PromotionMove).SetCapture(board[to]);// the capture information is set
}
return move;
}
else
{
return null;
}
}
