seer/src/board/file.rs

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Rust
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2022-07-16 14:05:56 +02:00
use super::Bitboard;
/// An enum representing a singular file on a chess board (i.e: the columns).
#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub enum File {
A,
B,
C,
D,
E,
F,
G,
H,
}
impl File {
const ALL: [File; 8] = [
File::A,
File::B,
File::C,
File::D,
File::E,
File::F,
File::G,
File::H,
];
/// Iterate over all files in order.
pub fn iter() -> impl Iterator<Item = File> {
Self::ALL.iter().cloned()
}
/// Convert from a file index into a [File] type.
#[inline(always)]
pub fn from_index(index: usize) -> Self {
assert!(index < 8);
// SAFETY: we know the value is in-bounds
unsafe { Self::from_index_unchecked(index) }
}
/// Convert from a file index into a [File] type, no bounds checking.
///
/// # Safety
///
/// Should only be called with values that can be output by [File::index()].
#[inline(always)]
pub unsafe fn from_index_unchecked(index: usize) -> Self {
std::mem::transmute(index as u8)
}
/// Return the index of a given [File].
#[inline(always)]
pub fn index(self) -> usize {
self as usize
}
/// Turn a [File] into a [Bitboard] of all squares in that file.
#[inline(always)]
pub fn into_bitboard(self) -> Bitboard {
// SAFETY: we know the value is in-bounds
unsafe { *Bitboard::FILES.get_unchecked(self.index()) }
}
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn from_index() {
assert_eq!(File::from_index(0), File::A);
assert_eq!(File::from_index(1), File::B);
assert_eq!(File::from_index(7), File::H);
}
#[test]
fn index() {
assert_eq!(File::A.index(), 0);
assert_eq!(File::B.index(), 1);
assert_eq!(File::H.index(), 7);
}
#[test]
fn into_bitboard() {
assert_eq!(File::A.into_bitboard(), Bitboard::FILES[0]);
assert_eq!(File::B.into_bitboard(), Bitboard::FILES[1]);
assert_eq!(File::H.into_bitboard(), Bitboard::FILES[7]);
}
}