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use std::error::Error;
use astro_format::IntoBytes;
use super::{RadixTree, RadixNode};
impl<K, V> RadixTree<K, V>
where
K: Eq + std::hash::Hash + Clone + std::cmp::Ord + IntoBytes + std::fmt::Display,
V: Clone + IntoBytes,
{
pub fn remove<I>(&mut self, key: I) -> Result<(), Box<dyn Error>> where I: IntoIterator<Item = K>, {
let mut node_hash = self.root;
let mut key_iter = key.into_iter().peekable();
while let Some(k) = key_iter.next() {
match self.nodes.get(&node_hash) {
Some(node) => {
if node.key.is_empty() {
if key_iter.peek().is_none() {
if let Some(mut_node) = self.nodes.get_mut(&node_hash) {
mut_node.value = None;
self.rehash(&node_hash);
return Ok(());
}
} else {
match node.children.get(&k) {
Some(next_node_hash) => {
node_hash = *next_node_hash;
},
None => return Ok(()),
}
}
} else {
let mut key_matched = true;
let mut node_key_iter = node.key.iter().peekable();
if Some(&k) != node_key_iter.next() {
key_matched = false;
}
while let Some(nk) = node_key_iter.next() {
if Some(nk) != key_iter.peek() {
key_matched = false;
break;
} else {
key_iter.next();
}
}
if key_matched && key_iter.peek().is_none() {
if let Some(mut_node) = self.nodes.get_mut(&node_hash) {
if mut_node.children.is_empty() {
if let Some(parent_hash) = self.parents.remove(&node_hash) {
let parent_node_opt = match self.nodes.get(&parent_hash) {
Some(parent_node) => Some(parent_node.clone()),
None => None,
};
if let Some(mut parent_node) = parent_node_opt {
let remove_key = parent_node.children.iter().find_map(|(k, &v)| {
if v == node_hash {
Some(k.clone())
} else {
None
}
});
if let Some(rk) = &remove_key {
parent_node.children.remove(rk);
}
if parent_node.children.len() == 0 {
self.nodes.remove(&parent_hash);
if self.root == parent_hash {
self.root = [0;32];
break;
}
} else if parent_node.children.len() == 1 && parent_node.value.is_none() {
self.nodes.remove(&node_hash);
if let Some((child_key, child_hash)) = parent_node.children.first_key_value() {
if let Some(child_node) = self.nodes.get(child_hash) {
let mut new_key = parent_node.key.clone();
new_key.push(child_key.clone());
new_key.extend(child_node.key.clone());
let join_node = RadixNode {
children: child_node.children.clone(),
key: new_key,
value: child_node.value.clone(),
};
self.nodes.insert(parent_hash, join_node);
self.rehash(&parent_hash);
}
self.parents.remove(child_hash);
self.nodes.remove(child_hash);
};
return Ok(());
} else {
break;
}
self.nodes.insert(parent_hash, parent_node.clone());
self.rehash(&parent_hash);
} else {
return Ok(())
}
}
self.nodes.remove(&node_hash);
} else {
}
}
} else if key_matched {
if let Some(k_next) = key_iter.next() {
if let Some(next_node_hash) = node.children.get(&k_next) {
node_hash = *next_node_hash;
} else {
return Err("Invalid Child!")?;
}
}
} else {
return Ok(())
}
}
},
None => Err("Invalid node!")?,
}
}
Ok(())
}
}