public static PlayerPieceSet MovePiece(PlayerPieceSet base_obj,
Exports.Pieces piece, int remove_at_cell, int new_cell)
{
Debug.Assert(base_obj != null);
Debug.Assert(piece != Exports.Pieces.NoPiece);
Debug.Assert(remove_at_cell >= 0 && remove_at_cell < 64);
Debug.Assert(new_cell >= 0 && new_cell < 64);
Debug.Assert(remove_at_cell != new_cell);
Debug.Assert(base_obj.IsOccupiedCell(remove_at_cell));
Debug.Assert(!base_obj.IsOccupiedCell(new_cell));
var result = (PlayerPieceSet)base_obj.MemberwiseClone();
result.m_bitboard.UnsetBit(remove_at_cell);
result.m_bitboard.SetBit(new_cell);
// Insert new_cell first. Easier to do it now, because we know
// the sorted ranges
uint range_begin = 0;
uint range_length = 0;
switch (piece)
{
case Exports.Pieces.Pawn:
range_begin = result.PawnsStartIndex;
range_length = result.PawnsCount;
break;
case Exports.Pieces.Knight:
range_begin = result.KnightsStartIndex;
range_length = result.KnightsCount;
break;
case Exports.Pieces.Bishop:
range_begin = result.BishopsStartIndex;
range_length = result.BishopsCount;
break;
case Exports.Pieces.Rook:
range_begin = result.RooksStartIndex;
range_length = result.RooksCount;
break;
case Exports.Pieces.Queen:
range_begin = result.QueensStartIndex;
range_length = result.QueensCount;
break;
case Exports.Pieces.King:
range_begin = 0;
range_length = 1;
break;
}
bool is_inserted = false;
for (uint i = range_begin, e = range_begin + range_length; i < e; ++i)
{
if (new_cell < result.m_pieces_cells.GetCell(i))
{
result.m_pieces_cells.InsertAt(i, new_cell);
is_inserted = true;
break;
}
}
if (!is_inserted)
{
result.m_pieces_cells.InsertAt(range_begin + range_length, new_cell);
}
result.m_pieces_cells.EraseAt(
(uint)result.m_pieces_cells.FindIndex(remove_at_cell));
return result;
}
public static PlayerPieceSet RemovePiece(PlayerPieceSet base_obj,
Exports.Pieces piece_to_remove, int remove_at_cell)
{
Debug.Assert(base_obj != null);
Debug.Assert(piece_to_remove != Exports.Pieces.NoPiece
&& piece_to_remove != Exports.Pieces.King);
Debug.Assert(remove_at_cell >= 0 && remove_at_cell < 64);
Debug.Assert(base_obj.IsOccupiedCell(remove_at_cell));
var result = (PlayerPieceSet)base_obj.MemberwiseClone();
result.m_bitboard.UnsetBit(remove_at_cell);
uint start_index = 0;
switch (piece_to_remove)
{
case Exports.Pieces.Pawn:
start_index = result.PawnsStartIndex;
Debug.Assert(result.PawnsCount > 0);
--result.PawnsCount;
break;
case Exports.Pieces.Knight:
start_index = result.KnightsStartIndex;
Debug.Assert(result.KnightsCount > 0);
// Decrement result.KnightsCount
--result.PawnsStartIndex;
break;
case Exports.Pieces.Bishop:
start_index = result.BishopsStartIndex;
Debug.Assert(result.BishopsCount > 0);
// Decrement result.BishopsCount
--result.PawnsStartIndex;
--result.KnightsStartIndex;
break;
case Exports.Pieces.Rook:
start_index = result.RooksStartIndex;
Debug.Assert(result.RooksCount > 0);
// Decrement result.RooksCount
--result.PawnsStartIndex;
--result.KnightsStartIndex;
--result.BishopsStartIndex;
break;
case Exports.Pieces.Queen:
start_index = result.QueensStartIndex;
Debug.Assert(result.QueensCount > 0);
// Decrement result.QueensCount
--result.PawnsStartIndex;
--result.KnightsStartIndex;
--result.BishopsStartIndex;
--result.RooksStartIndex;
break;
}
result.m_pieces_cells.EraseAt((uint)result.m_pieces_cells
.FindNextIndex(start_index, remove_at_cell));
return result;
}
private Castle CalcNewCastlingOptions(Players player, PlayerPieceSet pieces,
int base_row)
{
// We could deduce base_row value here, but let us pass it is as a
// parameter for better(?) performance
// Nevertheless, it is worth to check for typos
Debug.Assert((player == Players.White && base_row == Chessboard.ROW_MIN)
|| (player == Players.Black && base_row == Chessboard.ROW_MAX));
var result = Castle.None;
if (pieces.KingsCell == ChessboardCell.CalculateValue(base_row,
Chessboard.COLUMN_E))
{
var cell = ChessboardCell.CalculateValue(base_row, Chessboard.COLUMN_H);
if (IsCanCastleShort(player) && pieces.IsOccupiedCell(cell)
&& pieces.IsRookAtCell(cell))
{
result |= Castle.Short;
}
cell = ChessboardCell.CalculateValue(base_row, Chessboard.COLUMN_A);
if (IsCanCastleLong(player) && pieces.IsOccupiedCell(cell)
&& pieces.IsRookAtCell(cell))
{
result |= Castle.Long;
}
}
return result;
}
public static PlayerPieceSet InsertPiece(PlayerPieceSet base_obj,
Exports.Pieces piece_to_insert, int insert_at_cell)
{
Debug.Assert(base_obj != null);
Debug.Assert(piece_to_insert != Exports.Pieces.NoPiece
&& piece_to_insert != Exports.Pieces.King);
Debug.Assert(insert_at_cell >= 0 && insert_at_cell < 64);
Debug.Assert(!base_obj.IsOccupiedCell(insert_at_cell));
var result = (PlayerPieceSet)base_obj.MemberwiseClone();
result.m_bitboard.SetBit(insert_at_cell);
uint start_index = 0;
uint cur_piece_count = 0;
switch (piece_to_insert)
{
// TODO - add checks like PawnsCount < MAX_PAWN_COUNT
case Exports.Pieces.Pawn:
start_index = result.PawnsStartIndex;
cur_piece_count = result.PawnsCount;
++result.PawnsCount;
break;
case Exports.Pieces.Knight:
start_index = result.KnightsStartIndex;
cur_piece_count = result.KnightsCount;
// Increment result.KnightsCount
++result.PawnsStartIndex;
break;
case Exports.Pieces.Bishop:
start_index = result.BishopsStartIndex;
cur_piece_count = result.BishopsCount;
// Increment result.BishopsCount
++result.PawnsStartIndex;
++result.KnightsStartIndex;
break;
case Exports.Pieces.Rook:
start_index = result.RooksStartIndex;
cur_piece_count = result.RooksCount;
// Increment result.RooksCount
++result.PawnsStartIndex;
++result.KnightsStartIndex;
++result.BishopsStartIndex;
break;
case Exports.Pieces.Queen:
start_index = result.QueensStartIndex;
cur_piece_count = result.QueensCount;
// Increment result.QueensCount
++result.PawnsStartIndex;
++result.KnightsStartIndex;
++result.BishopsStartIndex;
++result.RooksStartIndex;
break;
}
result.m_pieces_cells.InsertAt(result.m_pieces_cells
.GetInsertionIndex(start_index, cur_piece_count, insert_at_cell),
insert_at_cell);
return result;
}
public static bool IsCellAttackedFromDir(ChessboardCell attacked_cell,
ChessboardCell attack_origin, PlayerPieceSet attacker_pieces,
PlayerPieceSet defender_pieces)
{
Debug.Assert(!attacked_cell.IsSame(attack_origin));
int delta_row = attack_origin.Row - attacked_cell.Row;
int delta_column = attack_origin.Column - attacked_cell.Column;
// Fast check if the two cells are on the same vertical or horizontal line
// or one the same diagonal
if (delta_row != 0 && delta_column != 0 && delta_row != delta_column
&& delta_row != -delta_column)
{
return false;
}
// Check the ray from attacked_cell towards attack_origin and possibly behind
// attack_origin until we reach the edge of the chessboard
bool result = false;
int row_inc = 0;
int column_inc = 0;
int iter_count = int.MaxValue;
if (delta_row < 0)
{
row_inc = -1;
iter_count = attacked_cell.Row - Chessboard.ROW_MIN;
}
else if (delta_row > 0)
{
row_inc = 1;
iter_count = Chessboard.ROW_MAX - attacked_cell.Row;
}
if (delta_column < 0)
{
column_inc = -1;
iter_count = Math.Min(iter_count,
attacked_cell.Column - Chessboard.COLUMN_MIN);
}
else if (delta_column > 0)
{
column_inc = 1;
iter_count = Math.Min(iter_count,
Chessboard.COLUMN_MAX - attacked_cell.Column);
}
int cur_row = attacked_cell.Row;
int cur_column = attacked_cell.Column;
for (int i = 0; i < iter_count; ++i)
{
cur_row += row_inc;
cur_column += column_inc;
Debug.Assert(cur_row >= Chessboard.ROW_MIN
&& cur_row <= Chessboard.ROW_MAX
&& cur_column >= Chessboard.COLUMN_MIN
&& cur_column <= Chessboard.COLUMN_MAX);
int cur_cell = ChessboardCell.CalculateValue(cur_row, cur_column);
if (defender_pieces.IsOccupiedCell(cur_cell))
{
result = false;
break;
}
if (attacker_pieces.IsOccupiedCell(cur_cell))
{
if (attacker_pieces.IsQueenAtCell(cur_cell))
{
result = true;
}
else if (row_inc == 0 || column_inc == 0)
{
result = attacker_pieces.IsRookAtCell(cur_cell);
}
else
{
result = attacker_pieces.IsBishopAtCell(cur_cell);
}
break;
}
}
return result;
}
private static void MakePawnMoves(PlayerPieceSet my_pieces, PlayerPieceSet other_pieces,
bool is_white_to_move, int? en_passant_capture_column, List<Move> moves)
{
int move_row_diff = is_white_to_move ? 1 : -1;
for (uint i = 0, e = my_pieces.PawnsCount; i < e; ++i)
{
uint cell_index;
var pawn_cell = new ChessboardCell(my_pieces.GetPawnCell(i,
out cell_index));
var new_cell_value = ChessboardCell.CalculateValue(
pawn_cell.Row + move_row_diff, pawn_cell.Column);
// Moves without captures
if (!my_pieces.IsOccupiedCell(new_cell_value)
&& !other_pieces.IsOccupiedCell(new_cell_value))
{
WritePawnMove(pawn_cell.Value, new_cell_value, cell_index, 0,
moves);
// Two-rows move from the initial rank
int initial_row = is_white_to_move ? Chessboard.ROW_MIN + 1
: Chessboard.ROW_MAX - 1;
if (pawn_cell.Row == initial_row)
{
new_cell_value = ChessboardCell.CalculateValue(
pawn_cell.Row + 2 * move_row_diff, pawn_cell.Column);
if (!my_pieces.IsOccupiedCell(new_cell_value)
&& !other_pieces.IsOccupiedCell(new_cell_value))
{
WritePawnMove(pawn_cell.Value, new_cell_value, cell_index,
0, moves);
}
}
}
// Captures except en passant captures
// delta_column can be -1 or 1
for (int delta_column = -1; delta_column <= 1; delta_column += 2)
{
int new_column = pawn_cell.Column + delta_column;
if (new_column >= Chessboard.COLUMN_MIN
&& new_column <= Chessboard.COLUMN_MAX)
{
new_cell_value = ChessboardCell.CalculateValue(pawn_cell.Row
+ move_row_diff, new_column);
if (other_pieces.IsOccupiedCell(new_cell_value))
{
WritePawnMove(pawn_cell.Value, new_cell_value, cell_index,
Move.Flags.Capture, moves);
}
}
}
// En passant capture
if (en_passant_capture_column.HasValue
&& ((is_white_to_move && pawn_cell.Row == 4)
|| (!is_white_to_move && pawn_cell.Row == 3))
&& Math.Abs(pawn_cell.Column - en_passant_capture_column.Value) == 1)
{
new_cell_value = ChessboardCell.CalculateValue(pawn_cell.Row
+ move_row_diff, en_passant_capture_column.Value);
// Since en passant capture is allowed, we know that the destination
// cell is not occupied
WritePawnMove(pawn_cell.Value, new_cell_value, cell_index,
Move.Flags.Capture | Move.Flags.EnPassantCapture, moves);
}
// TODO - add en passant captures
// TODO - uncomment
//throw new NotImplementedException();
}
}
private static void MakeMovesAlongLine(Exports.Pieces piece, PlayerPieceSet my_pieces,
PlayerPieceSet other_pieces, int from_cell, int delta_row, int delta_column,
int count, List<Move> moves)
{
var from_cell_obj = new ChessboardCell(from_cell);
// count must be such that we hit the border of the chessboard at the end
// of the loop
Debug.Assert(
from_cell_obj.Row + count * delta_row == Chessboard.ROW_MIN
|| from_cell_obj.Row + count * delta_row == Chessboard.ROW_MAX
|| from_cell_obj.Column + count * delta_column == Chessboard.COLUMN_MIN
|| from_cell_obj.Column + count * delta_column == Chessboard.COLUMN_MAX);
int cur_row = from_cell_obj.Row;
int cur_column = from_cell_obj.Column;
for (int i = 0; i < count; ++i)
{
cur_row += delta_row;
cur_column += delta_column;
Debug.Assert(cur_row >= Chessboard.ROW_MIN
&& cur_row <= Chessboard.ROW_MAX
&& cur_column >= Chessboard.COLUMN_MIN
&& cur_column <= Chessboard.COLUMN_MAX);
var cur_cell = ChessboardCell.CalculateValue(cur_row, cur_column);
if (my_pieces.IsOccupiedCell(cur_cell))
{
break;
}
bool is_capture = other_pieces.IsOccupiedCell(cur_cell);
moves.Add(new Move(piece, from_cell, cur_cell,
0 /* TODO - FIXME */, is_capture ? Move.Flags.Capture : 0));
if (is_capture)
{
break;
}
}
}
private static void MakeKnightMoves(PlayerPieceSet my_pieces,
PlayerPieceSet other_pieces, List<Move> moves)
{
for (uint i = 0, e = my_pieces.KnightsCount; i < e; ++i)
{
uint cell_index;
var knight_cell = new ChessboardCell(my_pieces.GetKnightCell(i,
out cell_index));
if (knight_cell.Row - 2 >= Chessboard.ROW_MIN &&
knight_cell.Row + 2 <= Chessboard.ROW_MAX &&
knight_cell.Column - 2 >= Chessboard.COLUMN_MIN &&
knight_cell.Column + 2 <= Chessboard.COLUMN_MAX)
{
// In this case we do not need to check that new cells are within
// the chessboard
foreach (var move_delta in m_knight_moves)
{
var new_cell = ChessboardCell.CalculateValue(
knight_cell.Row + move_delta.m_delta_row,
knight_cell.Column + move_delta.m_delta_column);
if (!my_pieces.IsOccupiedCell(new_cell))
{
bool is_capture = other_pieces.IsOccupiedCell(new_cell);
moves.Add(new Move(Exports.Pieces.Knight, knight_cell.Value,
new_cell, cell_index,
is_capture ? Move.Flags.Capture : 0));
}
}
}
else
{
// Do range check for every new cell
foreach (var move_delta in m_knight_moves)
{
int new_row = knight_cell.Row + move_delta.m_delta_row;
if (new_row < Chessboard.ROW_MIN || new_row > Chessboard.ROW_MAX)
{
continue;
}
int new_column = knight_cell.Column + move_delta.m_delta_column;
if (new_column < Chessboard.COLUMN_MIN
|| new_column > Chessboard.COLUMN_MAX)
{
continue;
}
var new_cell = ChessboardCell.CalculateValue(new_row, new_column);
if (!my_pieces.IsOccupiedCell(new_cell))
{
bool is_capture = other_pieces.IsOccupiedCell(new_cell);
moves.Add(new Move(Exports.Pieces.Knight, knight_cell.Value,
new_cell, cell_index,
is_capture ? Move.Flags.Capture : 0));
}
}
}
}
}
private static void MakeKingMoves(PlayerPieceSet my_pieces,
PlayerPieceSet other_pieces, List<Move> moves)
{
var king_cell = new ChessboardCell(my_pieces.KingsCell);
int row_min = Math.Max(Chessboard.ROW_MIN, king_cell.Row - 1);
int row_max = Math.Min(Chessboard.ROW_MAX, king_cell.Row + 1);
int column_min = Math.Max(Chessboard.COLUMN_MIN, king_cell.Column - 1);
int column_max = Math.Min(Chessboard.COLUMN_MAX, king_cell.Column + 1);
for (int row = row_min; row <= row_max; ++row)
{
for (int column = column_min; column <= column_max; ++column)
{
int new_cell = ChessboardCell.CalculateValue(row, column);
if (!my_pieces.IsOccupiedCell(new_cell))
{
bool is_capture = other_pieces.IsOccupiedCell(new_cell);
moves.Add(new Move(Exports.Pieces.King, king_cell.Value,
new_cell, 0, is_capture ? Move.Flags.Capture : 0));
}
}
}
}