rust/crates/stdx/src/non_empty_vec.rs
2022-01-02 19:05:37 +03:00

40 lines
768 B
Rust

//! See [`NonEmptyVec`].
/// A [`Vec`] that is guaranteed to at least contain one element.
pub struct NonEmptyVec<T> {
first: T,
rest: Vec<T>,
}
impl<T> NonEmptyVec<T> {
#[inline]
pub fn new(first: T) -> Self {
NonEmptyVec { first, rest: Vec::new() }
}
#[inline]
pub fn last_mut(&mut self) -> &mut T {
self.rest.last_mut().unwrap_or(&mut self.first)
}
#[inline]
pub fn pop(&mut self) -> Option<T> {
self.rest.pop()
}
#[inline]
pub fn push(&mut self, value: T) {
self.rest.push(value)
}
#[inline]
pub fn len(&self) -> usize {
1 + self.rest.len()
}
#[inline]
pub fn into_last(mut self) -> T {
self.rest.pop().unwrap_or(self.first)
}
}