89 lines
2.6 KiB
Rust
89 lines
2.6 KiB
Rust
use crate::Error;
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use std::any::Any;
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use std::cell::{Ref, RefCell, RefMut};
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use std::collections::HashMap;
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pub struct Table {
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map: HashMap<u32, RefCell<Box<dyn Any>>>,
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next_key: u32,
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}
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impl Table {
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pub fn new() -> Self {
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Table {
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map: HashMap::new(),
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next_key: 3, // 0, 1 and 2 are reserved for stdio
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}
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}
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pub fn insert_at(&mut self, key: u32, a: Box<dyn Any>) {
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self.map.insert(key, RefCell::new(a));
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}
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pub fn push(&mut self, a: Box<dyn Any>) -> Result<u32, Error> {
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loop {
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let key = self.next_key;
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// XXX this is not correct. The table may still have empty entries, but our
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// linear search strategy is quite bad
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self.next_key = self.next_key.checked_add(1).ok_or(Error::TableOverflow)?;
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if self.map.contains_key(&key) {
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continue;
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}
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self.map.insert(key, RefCell::new(a));
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return Ok(key);
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}
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}
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pub fn contains_key(&self, key: u32) -> bool {
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self.map.contains_key(&key)
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}
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pub fn is<T: Any + Sized>(&self, key: u32) -> bool {
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if let Some(refcell) = self.map.get(&key) {
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if let Ok(refmut) = refcell.try_borrow_mut() {
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refmut.is::<T>()
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} else {
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false
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}
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} else {
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false
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}
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}
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pub fn get<T: Any + Sized>(&self, key: u32) -> Result<Ref<T>, Error> {
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if let Some(refcell) = self.map.get(&key) {
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if let Ok(r) = refcell.try_borrow() {
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if r.is::<T>() {
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Ok(Ref::map(r, |r| r.downcast_ref::<T>().unwrap()))
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} else {
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Err(Error::Exist) // Exists at another type
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}
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} else {
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Err(Error::Exist) // Does exist, but borrowed
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}
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} else {
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Err(Error::Exist) // Does not exist
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}
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}
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pub fn get_mut<T: Any + Sized>(&self, key: u32) -> Result<RefMut<T>, Error> {
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if let Some(refcell) = self.map.get(&key) {
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if let Ok(r) = refcell.try_borrow_mut() {
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if r.is::<T>() {
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Ok(RefMut::map(r, |r| r.downcast_mut::<T>().unwrap()))
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} else {
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Err(Error::Exist) // Exists at another type
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}
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} else {
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Err(Error::Exist) // Does exist, but borrowed
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}
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} else {
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Err(Error::Exist) // Does not exist
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}
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}
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pub fn delete(&mut self, key: u32) -> Option<Box<dyn Any>> {
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self.map.remove(&key).map(|rc| RefCell::into_inner(rc))
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}
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}
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