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use std::io::IoSlice;
use std::ops::Deref;
use std::slice;
pub struct IoBufs<'a, 'b>(&'b mut [IoSlice<'a>]);
impl<'a, 'b> IoBufs<'a, 'b> {
pub fn new(slices: &'b mut [IoSlice<'a>]) -> Self {
IoBufs(slices)
}
pub fn is_empty(&self) -> bool {
self.0.is_empty()
}
pub fn advance(mut self, n: usize) -> IoBufs<'a, 'b> {
let mut to_remove = 0;
let mut remaining_len = n;
for slice in self.0.iter() {
if remaining_len < slice.len() {
break;
} else {
remaining_len -= slice.len();
to_remove += 1;
}
}
self.0 = self.0.split_at_mut(to_remove).1;
if let Some(slice) = self.0.first_mut() {
let tail = &slice[remaining_len..];
// Safety: recasts slice to the original lifetime
let tail = unsafe { slice::from_raw_parts(tail.as_ptr(), tail.len()) };
*slice = IoSlice::new(tail);
} else if remaining_len != 0 {
panic!("advance past the end of the slice vector");
}
self
}
}
impl<'a, 'b> Deref for IoBufs<'a, 'b> {
type Target = [IoSlice<'a>];
fn deref(&self) -> &[IoSlice<'a>] {
self.0
}
}