othello/src/repr/coords.rs

69 lines
1.7 KiB
Rust

use super::Board;
use num::Integer;
use static_assertions::const_assert;
/// PERF! having `Coord` be of type `u8` (instead of usize) increases
/// performance by about 1-2% overall
pub type CoordAxis = u8;
/// using u8 for this results in a ~3-6% perf increase
pub type CoordPairInner = u8;
const_assert!(CoordPairInner::MAX as usize >= Board::AREA.0 as usize);
#[derive(PartialEq, Eq, Copy, Clone, Hash)]
pub struct CoordPair(pub CoordPairInner);
impl CoordPair {
/// Convert a row and column to an index in the board
pub const fn from_axes(row: CoordAxis, col: CoordAxis) -> Self {
Self(row * Board::SIZE + col)
}
#[allow(clippy::wrong_self_convention)]
fn into_indexes(&self) -> (CoordAxis, CoordAxis) {
self.0.div_mod_floor(&Board::SIZE)
}
pub const fn area(pos: CoordAxis) -> Self {
Self(pos.pow(2) as CoordPairInner)
}
}
impl std::fmt::Display for CoordPair {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
let (i, j) = (*self).into();
write!(f, "({}, {})", i, j)
}
}
impl std::fmt::Debug for CoordPair {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
write!(f, "{}", self)
}
}
impl From<CoordPair> for (CoordAxis, CoordAxis) {
fn from(val: CoordPair) -> Self {
val.into_indexes()
}
}
impl From<(CoordAxis, CoordAxis)> for CoordPair {
fn from(value: (CoordAxis, CoordAxis)) -> Self {
Self::from_axes(value.0, value.1)
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn into_out_of() {
let a: CoordPair = (1, 3).into();
let back: (CoordAxis, CoordAxis) = a.into();
assert_eq!(back, (1, 3));
}
}