From 3239f288d773047d6b18b7b787e39fe858b757cc Mon Sep 17 00:00:00 2001
From: Eryn Wells <eryn@erynwells.me>
Date: Mon, 29 Jan 2024 15:00:53 -0800
Subject: [PATCH] [bitboard] Bitboards for kingside and queenside per color

Add two small BitBoard slices that represent kingside and queenside squares per
color.

Add doc comments to DARK_SQUARES and LIGHT_SQUARES.
Add getters on BitBoard for getting a boardside bitboard.
Clean up imports. Import the whole library module and refer to library things in
BitBoard by path.
---
 bitboard/src/bitboard.rs | 22 +++++++++++++++-------
 bitboard/src/library.rs  | 15 +++++++++++++--
 2 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/bitboard/src/bitboard.rs b/bitboard/src/bitboard.rs
index 10620e5..b2e1a4c 100644
--- a/bitboard/src/bitboard.rs
+++ b/bitboard/src/bitboard.rs
@@ -1,6 +1,6 @@
 // Eryn Wells <eryn@erynwells.me>
 
-use crate::library::{library, FILES, RANKS};
+use crate::library;
 use crate::LeadingBitScanner;
 use chessfriend_core::{Color, Direction, Square};
 use std::fmt;
@@ -12,7 +12,7 @@ pub struct BitBoard(pub(crate) u64);
 macro_rules! moves_getter {
     ($getter_name:ident) => {
         pub fn $getter_name(sq: Square) -> BitBoard {
-            library().$getter_name(sq)
+            library::library().$getter_name(sq)
         }
     };
 }
@@ -28,24 +28,24 @@ impl BitBoard {
 
     pub fn rank(rank: &u8) -> BitBoard {
         debug_assert!(*rank < 8);
-        RANKS[*rank as usize]
+        library::RANKS[*rank as usize]
     }
 
     pub fn file(file: &u8) -> BitBoard {
         debug_assert!(*file < 8);
-        FILES[*file as usize]
+        library::FILES[*file as usize]
     }
 
     pub fn ray(sq: Square, dir: Direction) -> BitBoard {
-        library().ray(sq, dir)
+        library::library().ray(sq, dir)
     }
 
     pub fn pawn_attacks(sq: Square, color: Color) -> BitBoard {
-        library().pawn_attacks(sq, color)
+        library::library().pawn_attacks(sq, color)
     }
 
     pub fn pawn_pushes(sq: Square, color: Color) -> BitBoard {
-        library().pawn_pushes(sq, color)
+        library::library().pawn_pushes(sq, color)
     }
 
     moves_getter!(knight_moves);
@@ -53,6 +53,14 @@ impl BitBoard {
     moves_getter!(rook_moves);
     moves_getter!(queen_moves);
     moves_getter!(king_moves);
+
+    pub const fn kingside(color: Color) -> &'static BitBoard {
+        &library::KINGSIDES[color as usize]
+    }
+
+    pub const fn queenside(color: Color) -> &'static BitBoard {
+        &library::QUEENSIDES[color as usize]
+    }
 }
 
 impl BitBoard {
diff --git a/bitboard/src/library.rs b/bitboard/src/library.rs
index 6e51f24..41951c7 100644
--- a/bitboard/src/library.rs
+++ b/bitboard/src/library.rs
@@ -26,9 +26,20 @@ pub(super) const FILES: [BitBoard; 8] = [
     BitBoard(0x0101010101010101 << 7),
 ];
 
-pub(super) const LIGHT_SQUARES: BitBoard =
+/// Bitboards representing the kingside of the board, per color.
+pub(crate) const KINGSIDES: [BitBoard; 2] =
+    [BitBoard(0xF0F0F0F0F0F0F0F0), BitBoard(0x0F0F0F0F0F0F0F0F)];
+
+/// Bitboards representing the queenside of the board, per color.
+pub(crate) const QUEENSIDES: [BitBoard; 2] =
+    [BitBoard(0x0F0F0F0F0F0F0F0F), BitBoard(0xF0F0F0F0F0F0F0F0)];
+
+/// A bitboard representing the light squares.
+pub(crate) const LIGHT_SQUARES: BitBoard =
     BitBoard(0x5555 | 0x5555 << 16 | 0x5555 << 32 | 0x5555 << 48);
-pub(super) const DARK_SQUARES: BitBoard = BitBoard(!LIGHT_SQUARES.0);
+
+/// A bitboad representing the dark squares
+pub(crate) const DARK_SQUARES: BitBoard = BitBoard(!LIGHT_SQUARES.0);
 
 pub(super) fn library() -> &'static MoveLibrary {
     static MOVE_LIBRARY_INIT: Once = Once::new();