veloren/common/src/store.rs
2022-03-21 23:35:08 +01:00

107 lines
2.9 KiB
Rust

use rayon::prelude::*;
use std::{
cmp::{Eq, Ord, Ordering, PartialEq, PartialOrd},
fmt, hash,
marker::PhantomData,
ops::{Index, IndexMut},
};
// NOTE: We use u64 to make sure we are consistent across all machines. We
// assume that usize fits into 8 bytes.
pub struct Id<T>(u64, PhantomData<T>);
impl<T> Id<T> {
pub fn id(&self) -> u64 { self.0 }
}
impl<T> Copy for Id<T> {}
impl<T> Clone for Id<T> {
fn clone(&self) -> Self { Self(self.0, PhantomData) }
}
impl<T> Eq for Id<T> {}
impl<T> PartialEq for Id<T> {
fn eq(&self, other: &Self) -> bool { self.0 == other.0 }
}
impl<T> Ord for Id<T> {
fn cmp(&self, other: &Self) -> Ordering { self.0.cmp(&(other.0)) }
}
impl<T> PartialOrd for Id<T> {
fn partial_cmp(&self, other: &Self) -> Option<Ordering> { Some(self.cmp(other)) }
}
impl<T> fmt::Debug for Id<T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "Id<{}>({})", std::any::type_name::<T>(), self.0)
}
}
impl<T> hash::Hash for Id<T> {
fn hash<H: hash::Hasher>(&self, h: &mut H) { self.0.hash(h); }
}
pub struct Store<T> {
items: Vec<T>,
}
impl<T> Default for Store<T> {
fn default() -> Self { Self { items: Vec::new() } }
}
impl<T> Store<T> {
pub fn get(&self, id: Id<T>) -> &T {
// NOTE: Safe conversion, because it came from usize.
self.items.get(id.0 as usize).unwrap()
}
pub fn get_mut(&mut self, id: Id<T>) -> &mut T {
// NOTE: Safe conversion, because it came from usize.
self.items.get_mut(id.0 as usize).unwrap()
}
pub fn ids(&self) -> impl Iterator<Item = Id<T>> {
(0..self.items.len()).map(|i| Id(i as u64, PhantomData))
}
pub fn values(&self) -> impl ExactSizeIterator<Item = &T> { self.items.iter() }
pub fn values_mut(&mut self) -> impl ExactSizeIterator<Item = &mut T> { self.items.iter_mut() }
pub fn iter(&self) -> impl Iterator<Item = (Id<T>, &T)> { self.ids().zip(self.values()) }
pub fn iter_mut(&mut self) -> impl Iterator<Item = (Id<T>, &mut T)> {
self.ids().zip(self.values_mut())
}
pub fn insert(&mut self, item: T) -> Id<T> {
// NOTE: Assumes usize fits into 8 bytes.
let id = Id(self.items.len() as u64, PhantomData);
self.items.push(item);
id
}
pub fn recreate_id(&self, i: u64) -> Option<Id<T>> {
if i as usize >= self.items.len() {
None
} else {
Some(Id::<T>(i, PhantomData))
}
}
}
impl<T: Send + Sync> Store<T> {
pub fn par_iter_mut(&mut self) -> impl ParallelIterator<Item = (Id<T>, &mut T)> {
self.items
.par_iter_mut()
.enumerate()
.map(|(idx, obj)| (Id(idx as u64, PhantomData), obj))
}
}
impl<T> Index<Id<T>> for Store<T> {
type Output = T;
fn index(&self, id: Id<T>) -> &Self::Output { self.get(id) }
}
impl<T> IndexMut<Id<T>> for Store<T> {
fn index_mut(&mut self, id: Id<T>) -> &mut Self::Output { self.get_mut(id) }
}