use crate::api::ManagedTypeApi;
use super::{ManagedVec, ManagedVecItem};
pub struct ManagedVecRefIterator<'a, M, T>
where
M: ManagedTypeApi,
T: ManagedVecItem,
{
managed_vec: &'a ManagedVec<M, T>,
byte_start: usize,
byte_end: usize,
}
impl<'a, M, T> ManagedVecRefIterator<'a, M, T>
where
M: ManagedTypeApi,
T: ManagedVecItem,
{
pub(crate) fn new(managed_vec: &'a ManagedVec<M, T>) -> Self {
ManagedVecRefIterator {
managed_vec,
byte_start: 0,
byte_end: managed_vec.byte_len(),
}
}
}
impl<'a, M, T> Iterator for ManagedVecRefIterator<'a, M, T>
where
M: ManagedTypeApi,
T: ManagedVecItem,
{
type Item = T::Ref<'a>;
fn next(&mut self) -> Option<Self::Item> {
let next_byte_start = self.byte_start + T::PAYLOAD_SIZE;
if next_byte_start > self.byte_end {
return None;
}
let result = unsafe {
T::from_byte_reader_as_borrow(|dest_slice| {
let _ = self
.managed_vec
.buffer
.load_slice(self.byte_start, dest_slice);
})
};
self.byte_start = next_byte_start;
Some(result)
}
fn size_hint(&self) -> (usize, Option<usize>) {
let remaining = (self.byte_end - self.byte_start) / T::PAYLOAD_SIZE;
(remaining, Some(remaining))
}
}
impl<'a, M, T> ExactSizeIterator for ManagedVecRefIterator<'a, M, T>
where
M: ManagedTypeApi,
T: ManagedVecItem,
{
}
impl<'a, M, T> DoubleEndedIterator for ManagedVecRefIterator<'a, M, T>
where
M: ManagedTypeApi,
T: ManagedVecItem,
{
fn next_back(&mut self) -> Option<Self::Item> {
if self.byte_start + T::PAYLOAD_SIZE > self.byte_end {
return None;
}
self.byte_end -= T::PAYLOAD_SIZE;
let result = unsafe {
T::from_byte_reader_as_borrow(|dest_slice| {
let _ = self
.managed_vec
.buffer
.load_slice(self.byte_end, dest_slice);
})
};
Some(result)
}
}
impl<'a, M, T> Clone for ManagedVecRefIterator<'a, M, T>
where
M: ManagedTypeApi,
T: ManagedVecItem,
{
#[allow(clippy::clone_double_ref)]
fn clone(&self) -> Self {
Self {
managed_vec: self.managed_vec,
byte_start: self.byte_start,
byte_end: self.byte_end,
}
}
}