advent-of-code/common/rust/src/lib.rs

79 lines
1.7 KiB
Rust

#![warn(clippy::pedantic)]
mod section_range;
use std::{mem, path::Path};
pub use section_range::{EmptyRange, InvalidSectionString, SectionRange};
pub enum UpToTwo<T> {
Zero,
One(T),
Two(T, T),
}
impl<T> UpToTwo<T> {
pub fn is_empty(&self) -> bool {
matches!(self, UpToTwo::Zero)
}
pub fn first(&self) -> Option<&T> {
match self {
UpToTwo::Zero => None,
UpToTwo::One(x) | UpToTwo::Two(x, _) => Some(x),
}
}
pub fn second(&self) -> Option<&T> {
match self {
UpToTwo::Zero | UpToTwo::One(_) => None,
UpToTwo::Two(_, x) => Some(x),
}
}
}
impl<T> IntoIterator for UpToTwo<T> {
type Item = T;
type IntoIter = UpToTwoIter<T>;
fn into_iter(self) -> Self::IntoIter {
UpToTwoIter(self)
}
}
pub struct UpToTwoIter<T>(UpToTwo<T>);
impl<T> Iterator for UpToTwoIter<T> {
type Item = T;
fn next(&mut self) -> Option<Self::Item> {
let mut content = UpToTwo::Zero;
mem::swap(&mut self.0, &mut content);
let (ret, mut content) = match content {
UpToTwo::Zero => (None, UpToTwo::Zero),
UpToTwo::One(x) => (Some(x), UpToTwo::Zero),
UpToTwo::Two(x, y) => (Some(x), UpToTwo::One(y)),
};
mem::swap(&mut self.0, &mut content);
ret
}
}
pub trait PathExt {
type Iter<'a>: Iterator<Item = &'a Path>
where
Self: 'a;
fn parents(&self) -> Self::Iter<'_>;
}
impl PathExt for Path {
type Iter<'a> = std::iter::Successors<&'a Path, for<'p> fn(&&'p Path) -> Option<&'p Path>>;
fn parents(&self) -> Self::Iter<'_> {
std::iter::successors(Some(self), |dir| dir.parent())
}
}