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use crate::{Error, ErrorExt};
use std::any::Any;
use std::collections::HashMap;
pub struct Table {
map: HashMap<u32, Box<dyn Any + Send + Sync>>,
next_key: u32,
}
impl Table {
pub fn new() -> Self {
Table {
map: HashMap::new(),
next_key: 3,
}
}
pub fn insert_at(&mut self, key: u32, a: Box<dyn Any + Send + Sync>) {
self.map.insert(key, a);
}
pub fn push(&mut self, a: Box<dyn Any + Send + Sync>) -> Result<u32, Error> {
if self.map.len() == u32::MAX as usize {
return Err(Error::trap("table has no free keys"));
}
loop {
let key = self.next_key;
self.next_key = self.next_key.wrapping_add(1);
if self.map.contains_key(&key) {
continue;
}
self.map.insert(key, a);
return Ok(key);
}
}
pub fn contains_key(&self, key: u32) -> bool {
self.map.contains_key(&key)
}
pub fn is<T: Any + Sized>(&self, key: u32) -> bool {
if let Some(r) = self.map.get(&key) {
r.is::<T>()
} else {
false
}
}
pub fn get<T: Any + Sized>(&self, key: u32) -> Result<&T, Error> {
if let Some(r) = self.map.get(&key) {
r.downcast_ref::<T>()
.ok_or_else(|| Error::badf().context("element is a different type"))
} else {
Err(Error::badf().context("key not in table"))
}
}
pub fn get_mut<T: Any + Sized>(&mut self, key: u32) -> Result<&mut T, Error> {
if let Some(r) = self.map.get_mut(&key) {
r.downcast_mut::<T>()
.ok_or_else(|| Error::badf().context("element is a different type"))
} else {
Err(Error::badf().context("key not in table"))
}
}
pub fn delete(&mut self, key: u32) -> Option<Box<dyn Any + Send + Sync>> {
self.map.remove(&key)
}
}