Files
Knightly/engine/src/bitboard/utils.rs
2025-11-18 17:38:48 +01:00

125 lines
2.9 KiB
Rust

#[inline(always)]
pub fn pop_lsb(value: &mut u64) -> usize {
let idx = value.trailing_zeros() as usize;
*value &= !(1 << idx);
return idx;
}
#[inline(always)]
pub fn pop_msb(value: &mut u64) -> usize {
let idx = 63 - value.leading_zeros() as usize;
*value &= !(1 << idx);
return idx;
}
const RANK_NUMBERS: [char; 8] = ['1', '2', '3', '4', '5', '6', '7', '8'];
const FILE_LETTERS: [char; 8] = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'];
pub fn notation_from_square_number(sq: u8) -> String {
let row = sq / 8;
let col = sq % 8;
let mut notation = String::new();
let row_not = RANK_NUMBERS[row as usize];
let col_not = FILE_LETTERS[col as usize];
notation.push(col_not);
notation.push(row_not);
return notation;
}
pub fn try_get_square_number_from_notation(notation: &str) -> Result<u8, ()> {
let file = match notation.chars().nth(0).unwrap() {
'a' => 0,
'b' => 1,
'c' => 2,
'd' => 3,
'e' => 4,
'f' => 5,
'g' => 6,
'h' => 7,
_ => { return Result::Err(()); }
};
if let Some(rank) = notation.chars().nth(1) {
return Result::Ok(file + 8 * (rank.to_digit(10).unwrap() as u8) - 8);
}
else {
return Result::Err(());
}
}
const PIECE_CHARACTERS: [char; 12] = ['P', 'N', 'B', 'R', 'Q', 'K', 'p', 'n', 'b', 'r', 'q', 'k'];
pub fn get_character_by_piece_id(id: u8) -> char {
return PIECE_CHARACTERS[id as usize];
}
// <----- TESTS ----->
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn pop_lsb_test() {
// test setup
let test_values: [u64; 6] = [
0x8000_0000_0000_0000,
0x4E91_CF05_713E_451B,
0xD588_2D58_6962_34B0,
0x9581_3335_DCAB_1DD4,
0xBEAC_DBE0_903A_AC00,
0x01E8_C895_A6F0_0000
];
let expected_values: [usize; 6] = [63, 0, 4, 2, 10, 20];
// tests
for index in 0..6 {
let mut test_value = test_values[index];
assert_eq!(pop_lsb(&mut test_value), expected_values[index])
}
}
#[test]
fn pop_msb_test() {
// test setup
let test_values: [u64; 6] = [
0x86D6_8EB0_96A8_8D1C,
0x0000_0000_0000_0001,
0x3809_24AF_A7AE_8129,
0x0277_DA36_3B31_86D9,
0x0000_C1C3_201C_0DB1,
0x0000_0203_0DE4_E944
];
let expected_values: [usize; 6] = [63, 0, 61, 57, 47, 41];
// tests
for index in 0..6 {
let mut test_value = test_values[index];
assert_eq!(pop_msb(&mut test_value), expected_values[index])
}
}
#[test]
fn notation_from_square_number_test() {
// test setup
let square_indices: [u8; 8] = [1, 12, 22, 27, 32, 47, 53, 58];
let notations: [String; 8] = [
String::from("b1"),
String::from("e2"),
String::from("g3"),
String::from("d4"),
String::from("a5"),
String::from("h6"),
String::from("f7"),
String::from("c8")
];
// tests
for index in 0..8 {
let notation = notation_from_square_number(square_indices[index].clone());
assert_eq!(notation, notations[index]);
}
}
}