65 lines
1.7 KiB
Rust
65 lines
1.7 KiB
Rust
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//! Pooled list data structure.
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use std::convert::TryFrom;
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use std::default::Default;
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use std::fmt::Debug;
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use std::marker::PhantomData;
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use std::ops::{Index, IndexMut};
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#[derive(Clone, Debug)]
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pub struct ListPool<T: Clone + Debug> {
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storage: Vec<T>,
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}
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impl<T: Clone + Debug> Default for ListPool<T> {
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fn default() -> Self {
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ListPool { storage: vec![] }
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}
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}
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#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
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pub struct ListRef<T>(u32, u32, PhantomData<T>);
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impl<T> Default for ListRef<T> {
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fn default() -> Self {
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ListRef(0, 0, PhantomData)
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}
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}
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impl<T: Clone + Debug> ListPool<T> {
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pub fn from_iter<I: Iterator<Item = T>>(&mut self, iter: I) -> ListRef<T> {
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let start = u32::try_from(self.storage.len()).unwrap();
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self.storage.extend(iter);
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let end = u32::try_from(self.storage.len()).unwrap();
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ListRef(start, end, PhantomData)
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}
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pub fn single(&mut self, value: T) -> ListRef<T> {
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self.from_iter(std::iter::once(value))
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}
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pub fn allocate(&mut self, size: usize, initial: T) -> ListRef<T> {
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self.from_iter(std::iter::repeat(initial).take(size))
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}
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}
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impl<T: Clone + Debug> Index<ListRef<T>> for ListPool<T> {
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type Output = [T];
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fn index(&self, index: ListRef<T>) -> &[T] {
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&self.storage[index.0 as usize..index.1 as usize]
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}
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}
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impl<T: Clone + Debug> IndexMut<ListRef<T>> for ListPool<T> {
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fn index_mut(&mut self, index: ListRef<T>) -> &mut [T] {
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&mut self.storage[index.0 as usize..index.1 as usize]
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}
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}
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impl<T> ListRef<T> {
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pub fn len(&self) -> usize {
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(self.1 - self.0) as usize
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}
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pub fn is_empty(&self) -> bool {
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self.len() == 0
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}
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}
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