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use crate::{
stc::{
Item, Node,
Output::{self, KeyExists, KeyIsNew, NewKeyPointer, Null},
Pointer,
},
KEY_ARRAY,
};
use std::cmp::Ordering::{Equal, Greater, Less};
impl<K: Ord, V> Node<K, V> {
pub fn insert(&mut self, key: K, value: V) -> Output<K, V> {
// if node is a leaf then the node has no pointers
match self.leaf {
true => {
// match self.binary_search(&key) {
// Ok(index) => {
// if let Some(k) = self.keys[index].as_mut() {
// k.value = Box::new(value);
// return KeyExists;
// }
// }
// Err(index) => match &self.keys[index] {
// Some(_) => self.insert_to_keys(index, key, value),
// None => {
// self.keys[index] = Some(Item::new(key, value));
// self.n += 1;
// }
// },
// }
'search: for index in 0..self.keys.len() {
if let Some(k) = self.keys[index].as_mut() {
match &key.cmp(&k.key) {
Less => {
self.insert_to_keys(index, key, value);
break;
}
Equal => {
k.value = value;
return KeyExists;
}
Greater => continue 'search,
}
} else {
self.keys[index] = Some(Item::new(key, value));
self.n += 1;
break;
}
}
if self.n == KEY_ARRAY {
return self.split_leaf();
} else {
return Null;
}
}
false => {
'search: for index in 0..self.keys.len() {
if let Some(k) = self.keys[index].as_mut() {
match key.cmp(&k.key) {
Less => {
let output = if let Some(pointer) = self.pointers[index].as_mut() {
pointer.child.insert(key, value)
} else {
let mut pointer = Pointer::new();
pointer.child.insert(key, value);
self.pointers[index] = Some(pointer);
KeyIsNew
};
match output {
KeyExists => return output,
NewKeyPointer(new_key, new_pointer) => {
self.pointers[index].as_mut().unwrap().counter =
self.pointers[index].as_ref().unwrap().child.size();
return self.insert_key_pointer(
index,
new_key,
new_pointer,
);
}
_ => {
self.pointers[index].as_mut().unwrap().counter += 1;
return Null;
}
}
}
Equal => {
k.value = value;
return KeyExists;
}
Greater => {
continue 'search;
}
}
} else {
let output = if let Some(pointer) = self.pointers[index].as_mut() {
pointer.child.insert(key, value)
} else {
let mut pointer = Pointer::new();
pointer.child.insert(key, value);
self.pointers[index] = Some(pointer);
KeyIsNew
};
match output {
KeyExists => return output,
NewKeyPointer(new_key, new_pointer) => {
self.pointers[index].as_mut().unwrap().counter =
self.pointers[index].as_ref().unwrap().child.size();
return self.insert_key_pointer(index, new_key, new_pointer);
}
_ => {
self.pointers[index].as_mut().unwrap().counter += 1;
return Null;
}
}
// key does not exist, insert to pointer at [index]
}
}
}
}
Null
}
pub fn insert_key_pointer(
&mut self,
index: usize,
key: Option<Item<K, V>>,
pointer: Option<Pointer<K, V>>,
) -> Output<K, V> {
let (_, key_right) = self.keys.split_at_mut(index);
let (_, pointer_right) = self.pointers.split_at_mut(index + 1);
key_right.rotate_right(1);
pointer_right.rotate_right(1);
key_right[0] = key;
pointer_right[0] = pointer;
self.n += 1;
if self.is_full() {
self.split_parent()
} else {
Null
}
}
pub fn insert_to_keys(&mut self, index: usize, key: K, value: V) {
let (_, right) = self.keys.split_at_mut(index);
right.rotate_right(1);
right[0] = Some(Item::new(key, value));
self.n += 1;
}
pub fn update_root(&mut self, new_key: Option<Item<K, V>>, new_pointer: Option<Pointer<K, V>>) {
let mut new_child = Node {
keys: Default::default(),
pointers: Default::default(),
n: 0,
leaf: self.leaf,
};
new_child.keys = self.take_keys();
new_child.pointers = self.take_pointers();
new_child.n = new_child.keys.iter().filter(|k| k.is_some()).count();
let size = new_child.size();
let pointer = Pointer {
child: Box::new(new_child),
counter: size,
};
self.pointers[0] = Some(pointer);
self.keys[0] = new_key;
self.pointers[1] = new_pointer;
self.n = 1;
self.leaf = false;
}
}