134 lines
3.9 KiB
Rust
134 lines
3.9 KiB
Rust
use crate::board::{Bitboard, Color, Direction, Rank, Square};
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pub fn pawn_moves(color: Color, square: Square, blockers: Bitboard) -> Bitboard {
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if (square.rank() == Rank::First) || (square.rank() == Rank::Eighth) {
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return Bitboard::EMPTY;
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}
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let dir = color.forward_direction();
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let first_push = dir.move_board(square.into_bitboard());
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let second_push = if square.rank() == color.second_rank() {
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Square::new(square.file(), color.fourth_rank()).into_bitboard()
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} else {
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Bitboard::EMPTY
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};
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if (first_push & blockers).is_empty() {
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first_push | second_push
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} else {
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Bitboard::EMPTY
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}
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}
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pub fn pawn_captures(color: Color, square: Square) -> Bitboard {
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if (square.rank() == Rank::First) || (square.rank() == Rank::Eighth) {
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return Bitboard::EMPTY;
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}
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let dir = color.forward_direction();
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let advanced = dir.move_board(square.into_bitboard());
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let attack_west = Direction::West.move_board(advanced);
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let attack_east = Direction::East.move_board(advanced);
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attack_west | attack_east
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}
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pub fn en_passant_origins(square: Square) -> Bitboard {
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let board = square.into_bitboard();
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let origin_west = Direction::West.move_board(board);
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let origin_east = Direction::East.move_board(board);
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origin_west | origin_east
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}
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#[cfg(test)]
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mod test {
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use super::*;
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#[test]
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fn moves() {
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assert_eq!(
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pawn_moves(Color::White, Square::A2, Bitboard::EMPTY),
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Square::A3 | Square::A4
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);
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assert_eq!(
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pawn_moves(Color::Black, Square::A7, Bitboard::EMPTY),
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Square::A5 | Square::A6
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);
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assert_eq!(
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pawn_moves(Color::Black, Square::A2, Bitboard::EMPTY),
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Square::A1.into_bitboard()
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);
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assert_eq!(
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pawn_moves(Color::White, Square::A7, Bitboard::EMPTY),
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Square::A8.into_bitboard()
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);
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}
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#[test]
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fn captures() {
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assert_eq!(
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pawn_captures(Color::White, Square::A2),
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Square::B3.into_bitboard()
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);
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assert_eq!(
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pawn_captures(Color::White, Square::B2),
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Square::A3 | Square::C3
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);
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assert_eq!(
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pawn_captures(Color::White, Square::H2),
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Square::G3.into_bitboard()
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);
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assert_eq!(
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pawn_captures(Color::Black, Square::A2),
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Square::B1.into_bitboard()
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);
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assert_eq!(
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pawn_captures(Color::Black, Square::B2),
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Square::A1 | Square::C1
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);
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assert_eq!(
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pawn_captures(Color::Black, Square::H2),
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Square::G1.into_bitboard()
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);
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assert_eq!(
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pawn_captures(Color::White, Square::A7),
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Square::B8.into_bitboard()
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);
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assert_eq!(
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pawn_captures(Color::White, Square::B7),
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Square::A8 | Square::C8
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);
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assert_eq!(
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pawn_captures(Color::Black, Square::H7),
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Square::G6.into_bitboard()
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);
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assert_eq!(
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pawn_captures(Color::Black, Square::A7),
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Square::B6.into_bitboard()
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);
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assert_eq!(
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pawn_captures(Color::Black, Square::B7),
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Square::A6 | Square::C6
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);
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assert_eq!(
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pawn_captures(Color::Black, Square::H7),
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Square::G6.into_bitboard()
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);
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}
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#[test]
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fn en_passant() {
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assert_eq!(en_passant_origins(Square::A4), Square::B4.into_bitboard());
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assert_eq!(en_passant_origins(Square::A5), Square::B5.into_bitboard());
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assert_eq!(en_passant_origins(Square::B4), Square::A4 | Square::C4);
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assert_eq!(en_passant_origins(Square::B5), Square::A5 | Square::C5);
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assert_eq!(en_passant_origins(Square::H4), Square::G4.into_bitboard());
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assert_eq!(en_passant_origins(Square::H5), Square::G5.into_bitboard());
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}
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}
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