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Attempt for cleaner implementation #1

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Attempt for cleaner implementation #1

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33 changes: 20 additions & 13 deletions src/distributing_iterator.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -37,15 +37,15 @@ pub struct DistributingIterator<T, ID> {
pos: usize,
original_size: usize,
spread: usize,
queue_per_id: Option<FnvHashMap<ID, VecDeque<T>>>,
queue_per_id: FnvHashMap<ID, VecDeque<T>>,
last_pos: IndexMap<ID, usize>,
iterator_reached_end: bool,
id_func: Box<dyn Fn(&T) -> ID + Send>,
}

impl<T, ID> DistributingIterator<T, ID>
where
ID: Eq + std::hash::Hash,
ID: Eq + std::hash::Hash + Clone,
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Let's not please

{
pub fn new(
data: VecDeque<T>,
Expand All @@ -59,7 +59,7 @@ where
spread,
pos: 0,
id_func: Box::new(id_func),
queue_per_id: Some(FnvHashMap::default()),
queue_per_id: FnvHashMap::default(),
last_pos: IndexMap::default(),
iterator_reached_end: false,
}
Expand All @@ -80,17 +80,17 @@ where
}

fn get_next_item(&mut self) -> Option<T> {
let mut queue_per_id = self.queue_per_id.take().unwrap();
let mut adjust_spread = false;

let result = loop {
let mut result = None;
for id in self.sorted_spreadable_ids() {
match queue_per_id.get_mut(id) {
let ids: Vec<ID> = self.sorted_spreadable_ids().map(|id| id.clone()).collect();
for id in ids.iter() {
match self.queue_per_id.get_mut(id) {
Some(queue) => {
if let Some(item) = queue.pop_front() {
if self.iterator_reached_end && queue.is_empty() {
queue_per_id.remove(id);
self.queue_per_id.remove(id);
adjust_spread = true
}
result = Some(item);
Expand All @@ -105,7 +105,7 @@ where
}

if self.iterator_reached_end {
if queue_per_id.values().flatten().any(|_| true) {
if self.queue_per_id.values().flatten().any(|_| true) {
panic!(
"Nothing can be returned even though the queue is not empty. This is a bug"
);
Expand All @@ -121,22 +121,21 @@ where
break Some(item);
} else {
// queue_per_id.entry(id).or_default().push_back(item);
queue_per_id
self.queue_per_id
.entry(id)
.or_insert_with(|| VecDeque::with_capacity(100))
.push_back(item);
}
}
None => {
self.spread = Self::calculate_spread(&queue_per_id);
self.spread = Self::calculate_spread(&self.queue_per_id);
self.iterator_reached_end = true;
}
}
};
if adjust_spread {
self.spread = Self::calculate_spread(&queue_per_id);
self.spread = Self::calculate_spread(&self.queue_per_id);
}
self.queue_per_id = Some(queue_per_id);
result
}

Expand All @@ -158,7 +157,7 @@ where
impl<T, ID> Iterator for DistributingIterator<T, ID>
where
T: std::fmt::Debug,
ID: Eq + std::hash::Hash + std::fmt::Debug,
ID: Eq + std::hash::Hash + std::fmt::Debug + Clone,
{
type Item = T;

Expand Down Expand Up @@ -223,4 +222,12 @@ mod tests {
]
);
}

#[test]
fn test_empty_array() {
let data: Vec<Item> = vec![];
let iterator = DistributingIterator::new(data.into(), 3, |item| item.id);
let data: Vec<_> = iterator.collect();
assert_eq!(data, vec![]);
}
}
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