// Returns the short algebraic chess notation and the new board of a castling
// type move. Assume that the castling move is legal. Equivalent of
// Game#apply_move but for a castling move.
char*
castling (Board *board, int castling_type, Board *new_board)
{
char *move;
switch (castling_type)
{
case WHITE_SHORT_CASTLING:
memcpy (new_board, board, sizeof (Board));
new_board->king[WHITE] ^= 0x50;
new_board->rooks[WHITE] ^= 0xa0;
new_board->placement[E1] = '\0';
new_board->placement[F1] = 'R';
new_board->placement[G1] = 'K';
new_board->placement[H1] = '\0';
new_board->castling ^= new_board->castling & 0x1100;
move = (char *) malloc (5);
strcpy (move, "O-O");
break;
case WHITE_LONG_CASTLING:
memcpy (new_board, board, sizeof (Board));
new_board->king[WHITE] ^= 0x14;
new_board->rooks[WHITE] ^= 0x09;
new_board->placement[E1] = '\0';
new_board->placement[D1] = 'R';
new_board->placement[C1] = 'K';
new_board->placement[A1] = '\0';
new_board->castling ^= new_board->castling & 0x1100;
move = (char *) malloc (7);
strcpy (move, "O-O-O");
break;
case BLACK_SHORT_CASTLING:
memcpy (new_board, board, sizeof (Board));
new_board->king[BLACK] ^= 0x5000000000000000;
new_board->rooks[BLACK] ^= 0xa000000000000000;
new_board->placement[E8] = '\0';
new_board->placement[F8] = 'r';
new_board->placement[G8] = 'k';
new_board->placement[H8] = '\0';
new_board->castling ^= new_board->castling & 0x0011;
move = (char *) malloc (5);
strcpy (move, "O-O");
break;
case BLACK_LONG_CASTLING:
memcpy (new_board, board, sizeof (Board));
new_board->king[BLACK] ^= 0x1400000000000000;
new_board->rooks[BLACK] ^= 0x0900000000000000;
new_board->placement[E8] = '\0';
new_board->placement[D8] = 'r';
new_board->placement[C8] = 'k';
new_board->placement[A8] = '\0';
new_board->castling ^= new_board->castling & 0x0011;
move = (char *) malloc (7);
strcpy (move, "O-O-O");
break;
default:
return NULL;
}
set_occupied (new_board);
return move;
}
/*
A FEN string is composed of 6 parts separated by " " (space).
1. Piece placement (from white's perspective).
2. Active color. "w" means white moves next, "b" means black.
3. Castling availability. If neither side can castle, this is "-".
4. En passant target square in algebraic notation. If there's no en passant target square, this is "-".
5. Halfmove clock: this is the number of halfmoves since the last pawn advance or capture.
6. Fullmove number: the number of the full move. It starts at 1, and is incremented after black's move.
*/
void
set_fen (Game *g, const char *fen)
{
Board *board = NEW_BOARD;
int i = 0, j, k, square;
char *pch;
char *s = (char *) malloc (sizeof (char) * (strlen (fen) + 1));
strcpy (s, fen);
// Init board
memset (board->placement, '\0', 64);
board->pawns[WHITE] = 0x0;
board->pawns[BLACK] = 0x0;
board->rooks[WHITE] = 0x0;
board->rooks[BLACK] = 0x0;
board->knights[WHITE] = 0x0;
board->knights[BLACK] = 0x0;
board->bishops[WHITE] = 0x0;
board->bishops[BLACK] = 0x0;
board->queens[WHITE] = 0x0;
board->queens[BLACK] = 0x0;
board->king[WHITE] = 0x0;
board->king[BLACK] = 0x0;
pch = strtok (s, " /");
while (pch != NULL)
{
if (i < 8)
{
for (j = 0, k = 0; j < (int) strlen (pch); j++)
{
if (pch[j] - 48 > 8)
{
square = (abs (i - 7) * 8) + k;
switch (pch[j])
{
case 'P':
board->placement[square] = pch[j];
board->pawns[WHITE] ^= 1ULL << square;
break;
case 'p':
board->placement[square] = pch[j];
board->pawns[BLACK] ^= 1ULL << square;
break;
case 'R':
board->placement[square] = pch[j];
board->rooks[WHITE] ^= 1ULL << square;
break;
case 'r':
board->placement[square] = pch[j];
board->rooks[BLACK] ^= 1ULL << square;
break;
case 'N':
board->placement[square] = pch[j];
board->knights[WHITE] ^= 1ULL << square;
break;
case 'n':
board->placement[square] = pch[j];
board->knights[BLACK] ^= 1ULL << square;
break;
case 'B':
board->placement[square] = pch[j];
board->bishops[WHITE] ^= 1ULL << square;
break;
case 'b':
board->placement[square] = pch[j];
board->bishops[BLACK] ^= 1ULL << square;
break;
case 'Q':
board->placement[square] = pch[j];
board->queens[WHITE] ^= 1ULL << square;
break;
case 'q':
board->placement[square] = pch[j];
board->queens[BLACK] ^= 1ULL << square;
break;
case 'K':
board->placement[square] = pch[j];
board->king[WHITE] ^= 1ULL << square;
break;
case 'k':
board->placement[square] = pch[j];
board->king[BLACK] ^= 1ULL << square;
break;
}
k++;
}
else
k += pch[j] - 48;
}
}
else if (i == 8)
{
board->active_color = pch[0] == 'b';
}
else if (i == 9)
{
board->castling = 0x0000;
for (j = 0; j < (int) strlen (pch); j++)
{
switch (pch[j])
{
case 'K':
board->castling |= 0x1000;
break;
case 'Q':
board->castling |= 0x0100;
break;
case 'k':
board->castling |= 0x0010;
break;
case 'q':
board->castling |= 0x0001;
break;
}
}
}
else if (i == 10)
{
board->en_passant = coord_to_square (pch);
}
else if (i == 11)
{
board->halfmove_clock = atoi (pch);
}
else if (i == 12)
{
board->fullmove_number = atoi (pch);
}
i++;
pch = strtok (NULL, " /");
}
set_occupied (board);
g->boards[g->current] = board;
g->moves[g->current] = (char *) malloc (11);
g->coord_moves[g->current] = (char *) malloc (11);
strcpy (g->moves[g->current], "SET BY FEN");
strcpy (g->coord_moves[g->current], "SET BY FEN");
g->current++;
// check result
if (king_in_checkmate (board, board->active_color))
g->result = !board->active_color;
else
if (stalemate (board, board->active_color) || insufficient_material (board))
g->result = DRAW;
free (s);
}
