chessfriend/position/src/move_generator/move_set.rs

98 lines
2.7 KiB
Rust

// Eryn Wells <eryn@erynwells.me>
use chessfriend_bitboard::BitBoard;
use chessfriend_core::{PlacedPiece, Square};
use chessfriend_moves::{Builder as MoveBuilder, Castle, Move};
/// A set of bitboards defining the moves for a single piece on the board.
#[derive(Clone, Debug, Default, Eq, PartialEq)]
struct BitBoardSet {
quiet: BitBoard,
captures: BitBoard,
}
/// A set of moves for a single piece on the board.
#[derive(Clone, Debug, Eq, PartialEq)]
pub(crate) struct MoveSet {
piece: PlacedPiece,
bitboards: BitBoardSet,
special: u8,
}
impl MoveSet {
pub(super) fn new(piece: PlacedPiece) -> MoveSet {
MoveSet {
piece,
bitboards: BitBoardSet::default(),
special: 0,
}
}
pub(crate) fn can_move_to_square(&self, to: Square) -> bool {
self.bitboard().is_set(to)
}
pub(crate) fn can_castle(&self, castle: Castle) -> bool {
match castle {
Castle::KingSide => (self.special & 0b1) != 0,
Castle::QueenSide => (self.special & 0b10) != 0,
}
}
pub(super) fn quiet_moves(mut self, bitboard: BitBoard) -> MoveSet {
self.bitboards.quiet = bitboard;
self
}
pub(super) fn capture_moves(mut self, bitboard: BitBoard) -> MoveSet {
self.bitboards.captures = bitboard;
self
}
pub(super) fn kingside_castle(&mut self) -> &mut MoveSet {
self.special |= 0b1;
self
}
pub(super) fn queenside_castle(&mut self) -> &mut MoveSet {
self.special |= 0b10;
self
}
/// Return a BitBoard representing all possible moves.
pub(super) fn bitboard(&self) -> BitBoard {
self.bitboards.captures | self.bitboards.quiet
}
pub(crate) fn moves(&self) -> impl Iterator<Item = Move> + '_ {
let piece = &self.piece;
self.bitboards
.quiet
.occupied_squares()
.filter_map(|to_square| MoveBuilder::push(&self.piece).to(to_square).build().ok())
.chain(
self.bitboards
.captures
.occupied_squares()
.filter_map(|to_square| MoveBuilder::push(piece).to(to_square).build().ok()),
)
.chain(
if (self.special & 0b1) != 0 {
let mv = MoveBuilder::castling(Castle::KingSide).build();
Some(mv)
} else {
None
}
.into_iter(),
)
.chain(
if (self.special & 0b10) != 0 {
Some(MoveBuilder::castling(Castle::QueenSide).build())
} else {
None
}
.into_iter(),
)
}
}