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use std::cmp::Ordering::{Equal, Greater, Less};
use crate::{IndexTreeMap, Item, Key, Node, Value, ARRAY_SIZE};
impl<K: Key, V: Value> IndexTreeMap<K, V> {
/// Removes an item from the map from it's corresponding key, returning the key-value pair was previously in the map.
///
/// # Example
///
/// Basic usage:
/// ```rust
/// use indextreemap::IndexTreeMap;
///
/// let mut tree = IndexTreeMap::new();
/// tree.insert(1, "a".to_string());
/// assert_eq!(tree.remove(&1), (Some(1), Some("a".to_string())));
/// assert_eq!(tree.remove(&2), (None, None));
/// ```
pub fn remove(&mut self, key: &K) -> (Option<K>, Option<V>) {
match self.root.remove(key) {
None => (None, None),
Some(item) => {
self.size -= 1;
(Some(*item.key), item.value.map(|value: Box<V>| *value))
}
}
}
/// Removes an item from the map from it's corresponding index, returning the key-value pair was previously in the map.
///
/// # Example
///
/// Basic usage:
/// ```rust
/// use indextreemap::IndexTreeMap;
///
/// let mut tree = IndexTreeMap::new();
/// tree.insert(1, "a".to_string());
/// assert_eq!(tree.remove_from_index(0), (Some(1), Some("a".to_string())));
/// assert_eq!(tree.remove_from_index(1), (None, None));
/// ```
pub fn remove_from_index(&mut self, index: usize) -> (Option<K>, Option<V>) {
match self.root.remove_index(index) {
None => (None, None),
Some(item) => {
self.size -= 1;
(Some(*item.key), item.value.map(|value: Box<V>| *value))
}
}
}
}
impl<K: Key, V: Value> Node<K, V> {
pub fn remove(&mut self, key: &K) -> Option<Item<K, V>> {
let mut removed_item = None;
'items: for (index, item) in self.items.clone().iter().enumerate() {
match item {
None => return None,
Some(item) => match key.compare_keys(item.key.as_ref()) {
Less => {
if index == 0 {
match self.children[0].as_deref_mut() {
None => return None,
Some(child) => {
removed_item = child.remove(key);
if removed_item.is_some() && child.is_empty() {
self.children[0] = None;
self.children_size[0] = 0;
} else if removed_item.is_some() {
self.children_size[0] -= 1;
}
}
}
} else {
return None;
}
}
Equal => match self.items[index].take() {
None => return None,
Some(item) => {
removed_item = Some(item.as_ref().to_owned());
self.replace_item();
break 'items;
}
},
Greater => {
if index == ARRAY_SIZE - 1 {
match self.children[1].as_deref_mut() {
None => return None,
Some(child) => {
removed_item = child.remove(key);
if removed_item.is_some() && child.is_empty() {
self.children[1] = None;
self.children_size[1] = 0;
} else if removed_item.is_some() {
self.children_size[1] -= 1;
}
}
}
} else {
continue 'items;
}
}
},
}
}
if removed_item.is_some() {
self.balance();
}
removed_item
}
pub fn remove_index(&mut self, mut id: usize) -> Option<Item<K, V>> {
if id < self.children_size[0] {
match self.children[0].as_deref_mut() {
Some(child) => {
let removed_item = child.remove_index(id);
if removed_item.is_some() && child.is_empty() {
self.children[0] = None;
self.children_size[0] = 0;
} else if removed_item.is_some() {
self.children_size[0] -= 1;
}
if removed_item.is_some() {
self.balance();
}
return removed_item;
}
None => return None,
}
} else {
id -= self.children_size[0];
}
if id < ARRAY_SIZE {
match self.items[id].take() {
None => return None,
Some(item) => {
let removed_item = Some(*item);
self.replace_item();
if removed_item.is_some() {
self.balance();
}
return removed_item;
}
}
} else {
id -= ARRAY_SIZE;
}
if id < self.children_size[1] {
match self.children[1].as_deref_mut() {
None => return None,
Some(child) => {
if id < self.children_size[1] {
let removed_item = child.remove_index(id);
if removed_item.is_some() && child.is_empty() {
self.children[1] = None;
self.children_size[1] = 0;
} else if removed_item.is_some() {
self.children_size[1] -= 1;
}
if removed_item.is_some() {
self.balance();
}
return removed_item;
}
}
}
}
None
}
pub fn replace_item(&mut self) {
self.bias_right();
match self.children[0].as_deref_mut() {
Some(child) => {
let removed_item = child.take_largest_item();
if removed_item.is_some() && child.is_empty() {
self.children[0] = None;
self.children_size[0] = 0;
self.balance();
} else if removed_item.is_some() {
self.children_size[0] -= 1;
self.balance();
}
self.items[0] = removed_item;
}
None => {
self.bias_left();
match self.children[1].as_deref_mut() {
None => {}
Some(child) => {
let removed_item = child.take_smallest_item();
if removed_item.is_some() && child.is_empty() {
self.children[1] = None;
self.children_size[1] = 0;
self.balance();
} else if removed_item.is_some() {
self.children_size[1] -= 1;
self.balance();
}
self.items[ARRAY_SIZE - 1] = removed_item;
}
}
}
}
self.bias_left();
}
pub fn take_largest_item(&mut self) -> Option<Box<Item<K, V>>> {
match self.children[1].as_deref_mut() {
Some(child) => {
let removed_item = child.take_largest_item();
if removed_item.is_some() && child.is_empty() {
self.children[1] = None;
self.children_size[1] = 0;
self.balance();
} else if removed_item.is_some() {
self.children_size[1] -= 1;
self.balance();
}
removed_item
}
None => {
for index in (0..self.items.len()).rev() {
let removed_item = self.items[index].take();
if removed_item.is_some() {
self.replace_item();
return removed_item;
}
}
None
}
}
}
pub fn take_smallest_item(&mut self) -> Option<Box<Item<K, V>>> {
match self.children[0].as_deref_mut() {
Some(child) => {
let removed_item = child.take_smallest_item();
if removed_item.is_some() && child.is_empty() {
self.children[0] = None;
self.children_size[0] = 0;
self.balance();
} else if removed_item.is_some() {
self.children_size[0] -= 1;
self.balance();
}
removed_item
}
None => {
let removed_item = self.items[0].take();
if removed_item.is_some() {
self.replace_item();
return removed_item;
}
None
}
}
}
pub fn is_empty(&self) -> bool {
for item in &self.items {
match item {
None => continue,
Some(_) => return false,
}
}
true
}
pub fn bias_right(&mut self) {
'index: for index in (0..ARRAY_SIZE).rev() {
if index == 0 {
break 'index;
}
if self.items[index].is_some() {
continue 'index;
}
self.items[index] = self.items[index - 1].to_owned();
self.items[index - 1] = None;
}
}
pub fn bias_left(&mut self) {
'index: for index in 0..ARRAY_SIZE {
if index == ARRAY_SIZE - 1 {
break 'index;
}
if self.items[index].is_some() {
continue 'index;
}
self.items[index] = self.items[index + 1].to_owned();
self.items[index + 1] = None;
}
}
}