bool piece_is_ok(Piece pc) {
return
piece_type_is_ok(type_of_piece(pc)) &&
color_is_ok(color_of_piece(pc));
}
const std::string move_to_san(Position &pos, Move m) {
std::string str;
assert(pos.is_ok());
assert(move_is_ok(m));
Square from, to;
Piece pc;
from = move_from(m);
to = move_to(m);
pc = pos.piece_on(move_from(m));
if(m == MOVE_NONE) {
str = "(none)";
return str;
}
else if(m == MOVE_NULL) {
str = "(null)";
return str;
}
else if(move_is_long_castle(m)
|| (int(to - from) == -2 && type_of_piece(pc) == KING))
str = "O-O-O";
else if(move_is_short_castle(m)
|| (int(to - from) == 2 && type_of_piece(pc) == KING))
str = "O-O";
else {
str = "";
if(type_of_piece(pc) == PAWN) {
if(pos.move_is_capture(m))
str += file_to_char(square_file(move_from(m)));
}
else {
str += piece_type_to_char(type_of_piece(pc), true);
Ambiguity amb = move_ambiguity(pos, m);
switch(amb) {
case AMBIGUITY_NONE:
break;
case AMBIGUITY_FILE:
str += file_to_char(square_file(from));
break;
case AMBIGUITY_RANK:
str += rank_to_char(square_rank(from));
break;
case AMBIGUITY_BOTH:
str += square_to_string(from);
break;
default:
assert(false);
}
}
if(pos.move_is_capture(m))
str += "x";
str += square_to_string(move_to(m));
if(move_promotion(m)) {
str += "=";
str += piece_type_to_char(move_promotion(m), true);
}
}
// Is the move check? We don't use pos.move_is_check(m) here, because
// Position::move_is_check doesn't detect all checks (not castling moves,
// promotions and en passant captures).
UndoInfo u;
pos.do_move(m, u);
if(pos.is_check())
str += pos.is_mate()? "#" : "+";
pos.undo_move(m, u);
return str;
}
bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) {
assert(pos.is_ok());
assert(move_is_ok(m));
assert(pinned == pos.pinned_pieces(pos.side_to_move()));
Color us = pos.side_to_move();
Color them = opposite_color(us);
Square from = move_from(m);
Square to = move_to(m);
Piece pc = pos.piece_on(from);
// Use a slower but simpler function for uncommon cases
if (move_is_ep(m) || move_is_castle(m))
return move_is_legal(pos, m);
// If the from square is not occupied by a piece belonging to the side to
// move, the move is obviously not legal.
if (color_of_piece(pc) != us)
return false;
// The destination square cannot be occupied by a friendly piece
if (pos.color_of_piece_on(to) == us)
return false;
// Handle the special case of a pawn move
if (type_of_piece(pc) == PAWN)
{
// Move direction must be compatible with pawn color
int direction = to - from;
if ((us == WHITE) != (direction > 0))
return false;
// A pawn move is a promotion iff the destination square is
// on the 8/1th rank.
if (( (square_rank(to) == RANK_8 && us == WHITE)
||(square_rank(to) == RANK_1 && us != WHITE)) != bool(move_is_promotion(m)))
return false;
// Proceed according to the square delta between the origin and
// destination squares.
switch (direction)
{
case DELTA_NW:
case DELTA_NE:
case DELTA_SW:
case DELTA_SE:
// Capture. The destination square must be occupied by an enemy
// piece (en passant captures was handled earlier).
if (pos.color_of_piece_on(to) != them)
return false;
break;
case DELTA_N:
case DELTA_S:
// Pawn push. The destination square must be empty.
if (!pos.square_is_empty(to))
return false;
break;
case DELTA_NN:
// Double white pawn push. The destination square must be on the fourth
// rank, and both the destination square and the square between the
// source and destination squares must be empty.
if ( square_rank(to) != RANK_4
|| !pos.square_is_empty(to)
|| !pos.square_is_empty(from + DELTA_N))
return false;
break;
case DELTA_SS:
// Double black pawn push. The destination square must be on the fifth
// rank, and both the destination square and the square between the
// source and destination squares must be empty.
if ( square_rank(to) != RANK_5
|| !pos.square_is_empty(to)
|| !pos.square_is_empty(from + DELTA_S))
return false;
break;
default:
return false;
}
// The move is pseudo-legal, check if it is also legal
return pos.is_check() ? pos.pl_move_is_evasion(m, pinned) : pos.pl_move_is_legal(m, pinned);
}
// Luckly we can handle all the other pieces in one go
return bit_is_set(pos.attacks_from(pc, from), to)
&& (pos.is_check() ? pos.pl_move_is_evasion(m, pinned) : pos.pl_move_is_legal(m, pinned))
&& !move_is_promotion(m);
}
