90 lines
2.2 KiB
Rust
90 lines
2.2 KiB
Rust
|
use super::Bitboard;
|
||
|
|
||
|
/// An enum representing a singular rank on a chess board (i.e: the rows).
|
||
|
#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
|
||
|
pub enum Rank {
|
||
|
First,
|
||
|
Second,
|
||
|
Third,
|
||
|
Fourth,
|
||
|
Fifth,
|
||
|
Sixth,
|
||
|
Seventh,
|
||
|
Eighth,
|
||
|
}
|
||
|
|
||
|
impl Rank {
|
||
|
const ALL: [Rank; 8] = [
|
||
|
Rank::First,
|
||
|
Rank::Second,
|
||
|
Rank::Third,
|
||
|
Rank::Fourth,
|
||
|
Rank::Fifth,
|
||
|
Rank::Sixth,
|
||
|
Rank::Seventh,
|
||
|
Rank::Eighth,
|
||
|
];
|
||
|
|
||
|
/// Iterate over all ranks in order.
|
||
|
pub fn iter() -> impl Iterator<Item = Rank> {
|
||
|
Self::ALL.iter().cloned()
|
||
|
}
|
||
|
|
||
|
/// Convert from a rank index into a [Rank] 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 rank index into a [Rank] type, no bounds checking.
|
||
|
///
|
||
|
/// # Safety
|
||
|
///
|
||
|
/// Should only be called with values that can be output by [Rank::index()].
|
||
|
#[inline(always)]
|
||
|
pub unsafe fn from_index_unchecked(index: usize) -> Self {
|
||
|
std::mem::transmute(index as u8)
|
||
|
}
|
||
|
|
||
|
/// Return the index of a given [Rank].
|
||
|
#[inline(always)]
|
||
|
pub fn index(self) -> usize {
|
||
|
self as usize
|
||
|
}
|
||
|
|
||
|
/// Turn a [Rank] into a [Bitboard] of all squares in that rank.
|
||
|
#[inline(always)]
|
||
|
pub fn into_bitboard(self) -> Bitboard {
|
||
|
// SAFETY: we know the value is in-bounds
|
||
|
unsafe { *Bitboard::RANKS.get_unchecked(self.index()) }
|
||
|
}
|
||
|
}
|
||
|
|
||
|
#[cfg(test)]
|
||
|
mod test {
|
||
|
use super::*;
|
||
|
|
||
|
#[test]
|
||
|
fn from_index() {
|
||
|
assert_eq!(Rank::from_index(0), Rank::First);
|
||
|
assert_eq!(Rank::from_index(1), Rank::Second);
|
||
|
assert_eq!(Rank::from_index(7), Rank::Eighth);
|
||
|
}
|
||
|
|
||
|
#[test]
|
||
|
fn index() {
|
||
|
assert_eq!(Rank::First.index(), 0);
|
||
|
assert_eq!(Rank::Second.index(), 1);
|
||
|
assert_eq!(Rank::Eighth.index(), 7);
|
||
|
}
|
||
|
|
||
|
#[test]
|
||
|
fn into_bitboard() {
|
||
|
assert_eq!(Rank::First.into_bitboard(), Bitboard::RANKS[0]);
|
||
|
assert_eq!(Rank::Second.into_bitboard(), Bitboard::RANKS[1]);
|
||
|
assert_eq!(Rank::Eighth.into_bitboard(), Bitboard::RANKS[7]);
|
||
|
}
|
||
|
}
|