Move State struct impl to its own file

src/board.rs

@@ -5,12 +5,13 @@ use crate::attack::{
     get_rook_attacks,
 };
 use crate::bitboard::{have_common_bit, lsb, square_to_bitboard};
-use crate::game::{Castle, State};
 use crate::movegen::{
     bishop_pseudo_moves, king_pseudo_moves, knight_pseudo_moves, pawn_pseudo_moves,
     queen_pseudo_moves, rook_pseudo_moves,
 };
 use crate::r#move::{Move, MoveType, Promote};
+use crate::square::Square;
+use crate::state::{Castle, State};
 
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub struct Board {
@@ -242,14 +243,14 @@ impl Board {
         }
     }
 
-    fn move_rook_castle(square: usize, pieces: &mut [Piece; 6]) {
-        let (rook_source, rook_target) = match square {
-            2 | 58 => (square - 2, square + 1),
-            6 | 62 => (square + 1, square - 1),
+    fn move_rook_castle(king_dst: usize, pieces: &mut [Piece; 6]) {
+        let (rook_src, rook_dst) = match king_dst {
+            Square::C1 | Square::C8 => (king_dst - 2, king_dst + 1),
+            Square::G1 | Square::G8 => (king_dst + 1, king_dst - 1),
             _ => return,
         };
 
-        Self::move_piece(rook_source, rook_target, pieces);
+        Self::move_piece(rook_src, rook_dst, pieces);
     }
 
     fn promote_piece(square: usize, pieces: &mut [Piece; 6], promote: Promote) {

src/fen.rs

@@ -1,5 +1,6 @@
 use crate::board::{Board, Color, Kind, Piece};
-use crate::game::{Castle, Game, State};
+use crate::game::Game;
+use crate::state::{Castle, State};
 use String as FenError;
 
 pub fn from_fen(fen: &str) -> Result<Game, FenError> {

src/game.rs

@@ -1,7 +1,4 @@
-use crate::{
-    board::{Board, Color},
-    fen::from_fen,
-};
+use crate::{board::Board, fen::from_fen};
 use String as FenError;
 
 #[derive(Debug, PartialEq, Eq)]
@@ -30,120 +27,3 @@ impl Default for Game {
         Self::new()
     }
 }
-
-#[derive(Debug, PartialEq, Eq, Clone, Copy)]
-pub struct State {
-    side_to_move: Color,
-    castling_ability: [Castle; 2],
-    en_passant_target_square: Option<usize>,
-    halfmove_clock: u8,
-    fullmove_counter: u8,
-}
-
-impl State {
-    pub const fn new() -> Self {
-        Self {
-            side_to_move: Color::White,
-            castling_ability: [Castle::Both, Castle::Both],
-            en_passant_target_square: None,
-            halfmove_clock: 0,
-            fullmove_counter: 1,
-        }
-    }
-
-    pub const fn load_state(
-        side_to_move: Color,
-        castling_ability: [Castle; 2],
-        en_passant_target_square: Option<usize>,
-        halfmove_clock: u8,
-        fullmove_counter: u8,
-    ) -> Self {
-        Self {
-            side_to_move,
-            castling_ability,
-            en_passant_target_square,
-            halfmove_clock,
-            fullmove_counter,
-        }
-    }
-
-    pub const fn get_en_passant_target_square(&self) -> Option<usize> {
-        self.en_passant_target_square
-    }
-
-    pub fn set_castling_ability(&mut self, color: Color, castle: Castle) {
-        match color {
-            Color::White => self.castling_ability[0] = castle,
-            Color::Black => self.castling_ability[1] = castle,
-        }
-    }
-
-    pub fn update_castling_state_quiet(&mut self, source: usize, color: Color) {
-        self.update_castling_state_capture(source, color);
-
-        match (source, color) {
-            (4, Color::White) => self.set_castling_ability(color, Castle::None),
-            (60, Color::Black) => self.set_castling_ability(color, Castle::None),
-            _ => (),
-        }
-    }
-
-    pub fn update_castling_state_capture(&mut self, target: usize, color: Color) {
-        let (short_square, long_square) = match color {
-            Color::White => (7, 0),
-            Color::Black => (63, 56),
-        };
-
-        if target == short_square {
-            match self.get_castling_ability(color) {
-                Castle::Both => self.set_castling_ability(color, Castle::Long),
-                Castle::Short => self.set_castling_ability(color, Castle::None),
-                _ => (),
-            }
-        }
-
-        if target == long_square {
-            match self.get_castling_ability(color) {
-                Castle::Both => self.set_castling_ability(color, Castle::Short),
-                Castle::Long => self.set_castling_ability(color, Castle::None),
-                _ => (),
-            }
-        }
-    }
-
-    pub fn change_side(&mut self) {
-        self.side_to_move = match self.side_to_move {
-            Color::White => Color::Black,
-            Color::Black => Color::White,
-        }
-    }
-
-    pub const fn next_turn(&self) -> Color {
-        self.side_to_move
-    }
-
-    pub fn set_en_passant_target_square(&mut self, sq: Option<usize>) {
-        self.en_passant_target_square = sq;
-    }
-
-    pub const fn get_castling_ability(&self, color: Color) -> Castle {
-        match color {
-            Color::White => self.castling_ability[0],
-            Color::Black => self.castling_ability[1],
-        }
-    }
-}
-
-impl Default for State {
-    fn default() -> Self {
-        Self::new()
-    }
-}
-
-#[derive(Debug, PartialEq, Eq, Clone, Copy)]
-pub enum Castle {
-    Short,
-    Long,
-    Both,
-    None,
-}

src/main.rs

@@ -8,6 +8,7 @@ pub mod r#move;
 pub mod movegen;
 pub mod perft;
 pub mod square;
+pub mod state;
 
 fn main() {
     attack::init_attacks();

src/movegen.rs

@@ -7,8 +7,8 @@ use crate::bitboard::{
     RANK_5, RANK_7, RANK_8,
 };
 use crate::board::{Board, Color};
-use crate::game::Castle;
 use crate::r#move::{Move, MoveType, Promote};
+use crate::state::Castle;
 use u64 as Bitboard;
 
 pub fn pawn_pseudo_moves(

src/state.rs

@@ -0,0 +1,118 @@
+use crate::board::Color;
+
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
+pub struct State {
+    side_to_move: Color,
+    castling_ability: [Castle; 2],
+    en_passant_target_square: Option<usize>,
+    halfmove_clock: u8,
+    fullmove_counter: u8,
+}
+
+impl State {
+    pub const fn new() -> Self {
+        Self {
+            side_to_move: Color::White,
+            castling_ability: [Castle::Both, Castle::Both],
+            en_passant_target_square: None,
+            halfmove_clock: 0,
+            fullmove_counter: 1,
+        }
+    }
+
+    pub const fn load_state(
+        side_to_move: Color,
+        castling_ability: [Castle; 2],
+        en_passant_target_square: Option<usize>,
+        halfmove_clock: u8,
+        fullmove_counter: u8,
+    ) -> Self {
+        Self {
+            side_to_move,
+            castling_ability,
+            en_passant_target_square,
+            halfmove_clock,
+            fullmove_counter,
+        }
+    }
+
+    pub const fn get_en_passant_target_square(&self) -> Option<usize> {
+        self.en_passant_target_square
+    }
+
+    pub fn set_castling_ability(&mut self, color: Color, castle: Castle) {
+        match color {
+            Color::White => self.castling_ability[0] = castle,
+            Color::Black => self.castling_ability[1] = castle,
+        }
+    }
+
+    pub fn update_castling_state_quiet(&mut self, source: usize, color: Color) {
+        self.update_castling_state_capture(source, color);
+
+        match (source, color) {
+            (4, Color::White) => self.set_castling_ability(color, Castle::None),
+            (60, Color::Black) => self.set_castling_ability(color, Castle::None),
+            _ => (),
+        }
+    }
+
+    pub fn update_castling_state_capture(&mut self, target: usize, color: Color) {
+        let (short_square, long_square) = match color {
+            Color::White => (7, 0),
+            Color::Black => (63, 56),
+        };
+
+        if target == short_square {
+            match self.get_castling_ability(color) {
+                Castle::Both => self.set_castling_ability(color, Castle::Long),
+                Castle::Short => self.set_castling_ability(color, Castle::None),
+                _ => (),
+            }
+        }
+
+        if target == long_square {
+            match self.get_castling_ability(color) {
+                Castle::Both => self.set_castling_ability(color, Castle::Short),
+                Castle::Long => self.set_castling_ability(color, Castle::None),
+                _ => (),
+            }
+        }
+    }
+
+    pub fn change_side(&mut self) {
+        self.side_to_move = match self.side_to_move {
+            Color::White => Color::Black,
+            Color::Black => Color::White,
+        }
+    }
+
+    pub const fn next_turn(&self) -> Color {
+        self.side_to_move
+    }
+
+    pub fn set_en_passant_target_square(&mut self, sq: Option<usize>) {
+        self.en_passant_target_square = sq;
+    }
+
+    pub const fn get_castling_ability(&self, color: Color) -> Castle {
+        match color {
+            Color::White => self.castling_ability[0],
+            Color::Black => self.castling_ability[1],
+        }
+    }
+}
+
+impl Default for State {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
+pub enum Castle {
+    Short,
+    Long,
+    Both,
+    None,
+}