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[board] Move all the BitBoard shift code to a new bitboard::shifts module

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This commit is contained in:
Eryn Wells 2023-12-28 12:14:30 -07:00
parent 5a08a4477e
commit 4c9e6a51fc
3 changed files with 115 additions and 105 deletions
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106
board/src/bitboard/bitboard.rs
View file

@ -6,7 +6,7 @@ use std::fmt;
use std::ops::{BitAnd, BitOr, Not};
#[derive(Clone, Copy, Eq, Hash, PartialEq)]
pub(crate) struct BitBoard(u64);
pub(crate) struct BitBoard(pub(super) u64);
impl BitBoard {
pub fn empty() -> BitBoard {
@ -38,61 +38,6 @@ impl BitBoard {
}
}
impl BitBoard {
const NOT_A_FILE: u64 = 0xfefefefefefefefe;
const NOT_H_FILE: u64 = 0x7f7f7f7f7f7f7f7f;
#[inline]
pub fn shift_north(&self, n: u8) -> BitBoard {
BitBoard(self.0 << (8 * n))
}
#[inline]
pub fn shift_north_one(&self) -> BitBoard {
BitBoard(self.0 << 8)
}
#[inline]
pub fn shift_north_east_one(&self) -> BitBoard {
BitBoard(self.0 << 9 & BitBoard::NOT_A_FILE)
}
#[inline]
pub fn shift_east_one(&self) -> BitBoard {
BitBoard(self.0 << 1 & BitBoard::NOT_A_FILE)
}
#[inline]
pub fn shift_south_east_one(&self) -> BitBoard {
BitBoard(self.0 >> 7 & BitBoard::NOT_A_FILE)
}
#[inline]
pub fn shift_south(&self, n: u8) -> BitBoard {
BitBoard(self.0 >> (8 * n))
}
#[inline]
pub fn shift_south_one(&self) -> BitBoard {
BitBoard(self.0 >> 8)
}
#[inline]
pub fn shift_south_west_one(&self) -> BitBoard {
BitBoard(self.0 >> 9 & BitBoard::NOT_H_FILE)
}
#[inline]
pub fn shift_west_one(&self) -> BitBoard {
BitBoard(self.0 >> 1 & BitBoard::NOT_H_FILE)
}
#[inline]
pub fn shift_north_west_one(&self) -> BitBoard {
BitBoard(self.0 << 7 & BitBoard::NOT_H_FILE)
}
}
impl BitBoard {
pub(crate) fn occupied_squares(&self) -> impl Iterator<Item = Square> {
BitScanner::new(self.0)
@ -200,55 +145,6 @@ mod tests {
assert!(!bb.has_piece_at(&sq));
}
#[test]
fn cardinal_direction_shifts() {
let bb = BitBoard(0x1000_0000); // e4
assert_eq!(bb.shift_north_one(), BitBoard(0x0010_0000_0000), "North");
assert_eq!(bb.shift_east_one(), BitBoard(0x2000_0000), "East");
assert_eq!(bb.shift_south_one(), BitBoard(0x0010_0000), "South");
assert_eq!(bb.shift_west_one(), BitBoard(0x0800_0000), "West");
}
#[test]
fn intercardinal_direction_shifts() {
let bb = BitBoard(0x1000_0000); // e4
assert_eq!(
bb.shift_north_east_one(),
BitBoard(0x0020_0000_0000),
"North East"
);
assert_eq!(
bb.shift_south_east_one(),
BitBoard(0x0020_0000),
"South East"
);
assert_eq!(
bb.shift_south_west_one(),
BitBoard(0x0008_0000),
"South West"
);
assert_eq!(
bb.shift_north_west_one(),
BitBoard(0x0008_0000_0000),
"North West"
);
}
#[test]
fn shift_n() {
assert_eq!(
BitBoard(0x0008_0000_0000).shift_north(2),
BitBoard(0x0008_0000_0000_0000)
);
assert_eq!(
BitBoard(0x0008_0000_0000).shift_south(2),
BitBoard(0x0008_0000)
);
}
#[test]
fn pieces() {
let bb = BitBoard(0x1001_1010); // e4

1
board/src/bitboard/mod.rs
View file

@ -1,5 +1,6 @@
mod bit_scanner;
mod bitboard;
mod shifts;
pub(crate) use self::bit_scanner::BitScanner;
pub(crate) use self::bitboard::BitBoard;

113
board/src/bitboard/shifts.rs Normal file
View file

@ -0,0 +1,113 @@
// Eryn Wells <eryn@erynwells.me>
use super::BitBoard;
impl BitBoard {
const NOT_A_FILE: u64 = 0xfefefefefefefefe;
const NOT_H_FILE: u64 = 0x7f7f7f7f7f7f7f7f;
#[inline]
pub fn shift_north(&self, n: u8) -> BitBoard {
BitBoard(self.0 << (8 * n))
}
#[inline]
pub fn shift_north_one(&self) -> BitBoard {
BitBoard(self.0 << 8)
}
#[inline]
pub fn shift_north_east_one(&self) -> BitBoard {
BitBoard(self.0 << 9 & BitBoard::NOT_A_FILE)
}
#[inline]
pub fn shift_east_one(&self) -> BitBoard {
BitBoard(self.0 << 1 & BitBoard::NOT_A_FILE)
}
#[inline]
pub fn shift_south_east_one(&self) -> BitBoard {
BitBoard(self.0 >> 7 & BitBoard::NOT_A_FILE)
}
#[inline]
pub fn shift_south(&self, n: u8) -> BitBoard {
BitBoard(self.0 >> (8 * n))
}
#[inline]
pub fn shift_south_one(&self) -> BitBoard {
BitBoard(self.0 >> 8)
}
#[inline]
pub fn shift_south_west_one(&self) -> BitBoard {
BitBoard(self.0 >> 9 & BitBoard::NOT_H_FILE)
}
#[inline]
pub fn shift_west_one(&self) -> BitBoard {
BitBoard(self.0 >> 1 & BitBoard::NOT_H_FILE)
}
#[inline]
pub fn shift_north_west_one(&self) -> BitBoard {
BitBoard(self.0 << 7 & BitBoard::NOT_H_FILE)
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::Square;
#[test]
fn cardinal_direction_shifts() {
let bb = BitBoard(0x1000_0000); // e4
assert_eq!(bb.shift_north_one(), BitBoard(0x0010_0000_0000), "North");
assert_eq!(bb.shift_east_one(), BitBoard(0x2000_0000), "East");
assert_eq!(bb.shift_south_one(), BitBoard(0x0010_0000), "South");
assert_eq!(bb.shift_west_one(), BitBoard(0x0800_0000), "West");
}
#[test]
fn intercardinal_direction_shifts() {
let bb = BitBoard(0x1000_0000); // e4
assert_eq!(
bb.shift_north_east_one(),
BitBoard(0x0020_0000_0000),
"North East"
);
assert_eq!(
bb.shift_south_east_one(),
BitBoard(0x0020_0000),
"South East"
);
assert_eq!(
bb.shift_south_west_one(),
BitBoard(0x0008_0000),
"South West"
);
assert_eq!(
bb.shift_north_west_one(),
BitBoard(0x0008_0000_0000),
"North West"
);
}
#[test]
fn shift_n() {
assert_eq!(
BitBoard(0x0008_0000_0000).shift_north(2),
BitBoard(0x0008_0000_0000_0000)
);
assert_eq!(
BitBoard(0x0008_0000_0000).shift_south(2),
BitBoard(0x0008_0000)
);
}
}