pub const MAX_THREADS: usize = 16;
pub struct FixedQueue<T: Sized> {
data: [Option<T>; MAX_THREADS],
size: usize,
start: usize,
}
impl<T: Sized> Default for FixedQueue<T> {
fn default() -> Self {
Self::new()
}
}
impl<T: Sized> FixedQueue<T> {
pub fn new() -> Self {
FixedQueue {
data: [
None, None, None, None, None, None, None, None, None, None, None, None, None, None,
None, None,
],
size: 0,
start: 0,
}
}
pub fn can_push(&self) -> bool {
self.size < self.data.len()
}
pub fn size(&self) -> usize {
self.size
}
pub fn push(&mut self, item: T) -> Result<(), ()> {
if self.size == self.data.len() {
return Err(());
}
let index = (self.start + self.size) % self.data.len();
self.data[index] = Some(item);
self.size += 1;
Ok(())
}
pub fn pop(&mut self) -> Option<T> {
if self.size == 0 {
return None;
}
let index = self.start % self.data.len();
let ret = self.data[index].take();
self.start += 1;
self.size -= 1;
ret
}
pub fn how_much_free_space(&self) -> usize {
self.data.len() - self.size
}
pub fn remove<F: Fn(&Option<T>) -> bool>(&mut self, f: F) -> Option<T> {
if self.size == 0 {
return None;
}
for index in 0..self.size {
if f(&self.data[(self.start + index) % self.data.len()]) {
let start_index = self.start % self.data.len();
let target_index = (self.start + index) % self.data.len();
let ret = self.data[target_index].take();
let replace = self.data[start_index].take();
let is_none = core::mem::replace(&mut self.data[target_index], replace);
assert!(is_none.is_none());
self.start += 1;
self.size -= 1;
return ret;
}
}
None
}
}