use std::fmt;
use std::ops::{Deref, Range};
use rustc_data_structures::sync::Lrc;
use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
HashStable};
#[derive(Clone)]
pub struct RcSlice<T> {
data: Lrc<Box<[T]>>,
offset: u32,
len: u32,
}
impl<T> RcSlice<T> {
pub fn new(vec: Vec<T>) -> Self {
RcSlice {
offset: 0,
len: vec.len() as u32,
data: Lrc::new(vec.into_boxed_slice()),
}
}
pub fn sub_slice(&self, range: Range<usize>) -> Self {
RcSlice {
data: self.data.clone(),
offset: self.offset + range.start as u32,
len: (range.end - range.start) as u32,
}
}
}
impl<T> Deref for RcSlice<T> {
type Target = [T];
fn deref(&self) -> &[T] {
&self.data[self.offset as usize .. (self.offset + self.len) as usize]
}
}
impl<T: fmt::Debug> fmt::Debug for RcSlice<T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
fmt::Debug::fmt(self.deref(), f)
}
}
impl<CTX, T> HashStable<CTX> for RcSlice<T>
where T: HashStable<CTX>
{
fn hash_stable<W: StableHasherResult>(&self,
hcx: &mut CTX,
hasher: &mut StableHasher<W>) {
(**self).hash_stable(hcx, hasher);
}
}