record
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bronku
parent
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6 changed files with 397 additions and 153 deletions
63
src/btree.rs
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63
src/btree.rs
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@ -0,0 +1,63 @@
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use crate::node::Node;
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use crate::record::Record;
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#[derive(Debug)]
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pub struct BTree {
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root: Option<Box<Node>>,
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}
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impl BTree {
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pub fn new() -> Self {
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BTree { root: None }
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}
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pub fn insert(&mut self, rec: Record) {
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match &mut self.root {
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None => {
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let mut root = Box::new(Node::new(true));
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root.keys.push(rec);
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self.root = Some(root);
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}
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Some(root) => {
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if root.is_full() {
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let mut new_root = Box::new(Node::new(false));
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let old_root = self.root.take().unwrap();
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new_root.children.push(old_root);
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new_root.split_child(0);
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new_root.insert_non_full(rec);
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self.root = Some(new_root);
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} else {
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root.insert_non_full(rec);
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}
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}
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}
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}
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pub fn search(&self, key: i32) -> Option<Record> {
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match &self.root {
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None => None,
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Some(root) => root.search(key),
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}
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}
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pub fn print_tree(&self) {
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if let Some(root) = &self.root {
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Self::print_node(root, 0);
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} else {
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println!("Empty tree");
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}
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}
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fn print_node(node: &Node, level: usize) {
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print!("{}", " ".repeat(level));
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let key_values: Vec<i32> = node.keys.iter().map(|r| r.key).collect();
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println!("Keys: {:?}", key_values);
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if !node.is_leaf {
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for child in &node.children {
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Self::print_node(child, level + 1);
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}
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}
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}
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}
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167
src/main.rs
167
src/main.rs
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@ -1,166 +1,27 @@
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const MIN_DEGREE: usize = 3; // Minimum degree (minimum children per node)
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mod btree;
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mod node;
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mod record;
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#[derive(Debug)]
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pub struct BTree<K: Ord> {
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root: Option<Box<Node<K>>>,
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}
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#[derive(Debug)]
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struct Node<K: Ord> {
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keys: Vec<K>,
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children: Vec<Box<Node<K>>>,
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is_leaf: bool,
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}
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impl<K: Ord> Node<K> {
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fn new(is_leaf: bool) -> Self {
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Node {
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keys: Vec::new(),
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children: Vec::new(),
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is_leaf,
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}
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}
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fn is_full(&self) -> bool {
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self.keys.len() >= 2 * MIN_DEGREE - 1
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}
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fn search(&self, key: &K) -> bool {
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let mut i = 0;
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while i < self.keys.len() && key > &self.keys[i] {
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i += 1;
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}
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if i < self.keys.len() && key == &self.keys[i] {
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return true;
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}
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if self.is_leaf {
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return false;
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}
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self.children[i].search(key)
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}
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fn insert_non_full(&mut self, key: K) {
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let mut i = self.keys.len();
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if self.is_leaf {
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self.keys.push(key);
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i = self.keys.len() - 1;
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while i > 0 && self.keys[i] < self.keys[i - 1] {
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self.keys.swap(i, i - 1);
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i -= 1;
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}
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} else {
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while i > 0 && key < self.keys[i - 1] {
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i -= 1;
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}
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if self.children[i].is_full() {
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self.split_child(i);
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if key > self.keys[i] {
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i += 1;
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}
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}
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self.children[i].insert_non_full(key);
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}
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}
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fn split_child(&mut self, i: usize) {
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let t = MIN_DEGREE;
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let full_child = &mut self.children[i];
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let mut new_child = Box::new(Node::new(full_child.is_leaf));
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// Move the second half of keys to new child
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new_child.keys = full_child.keys.split_off(t);
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let median = full_child.keys.pop().unwrap();
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// Move the second half of children if not a leaf
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if !full_child.is_leaf {
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new_child.children = full_child.children.split_off(t);
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}
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// Insert median key and new child into parent
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self.keys.insert(i, median);
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self.children.insert(i + 1, new_child);
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}
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}
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impl<K: Ord + std::fmt::Debug> BTree<K> {
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pub fn new() -> Self {
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BTree { root: None }
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}
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pub fn insert(&mut self, key: K) {
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match &mut self.root {
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None => {
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let mut root = Box::new(Node::new(true));
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root.keys.push(key);
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self.root = Some(root);
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}
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Some(root) => {
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if root.is_full() {
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let mut new_root = Box::new(Node::new(false));
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let old_root = self.root.take().unwrap();
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new_root.children.push(old_root);
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new_root.split_child(0);
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new_root.insert_non_full(key);
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self.root = Some(new_root);
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} else {
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root.insert_non_full(key);
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}
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}
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}
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}
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pub fn search(&self, key: &K) -> bool {
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match &self.root {
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None => false,
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Some(root) => root.search(key),
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}
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}
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pub fn print_tree(&self) {
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if let Some(root) = &self.root {
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Self::print_node(root, 0);
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} else {
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println!("Empty tree");
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}
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}
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fn print_node(node: &Node<K>, level: usize)
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where
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K: std::fmt::Debug,
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{
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print!("{}", " ".repeat(level));
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println!("Keys: {:?}", node.keys);
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if !node.is_leaf {
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for child in &node.children {
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Self::print_node(child, level + 1);
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}
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}
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}
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}
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use btree::BTree;
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use record::Record;
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fn main() {
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let mut btree = BTree::new();
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// Insert some values
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let values = vec![10, 20, 5, 6, 12, 30, 7, 17, 3, 16, 21, 22, 23, 24];
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let mut values: Vec<i32> = vec![];
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println!("Inserting values: {:?}", values);
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for val in values {
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btree.insert(val);
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println!("Inserting values");
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for _ in 0..10 {
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let rec = Record::random();
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values.push(rec.key);
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btree.insert(rec);
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}
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println!("\nB-Tree structure:");
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btree.print_tree();
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// Search for some values
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println!("\nSearch results:");
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println!("Search for 6: {}", btree.search(&6));
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println!("Search for 15: {}", btree.search(&15));
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println!("Search for 21: {}", btree.search(&21));
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println!("Search for 6: {:?}", btree.search(values[0]));
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println!("Search for 15: {:?}", btree.search(values[4]));
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println!("Search for 21: {:?}", btree.search(100));
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}
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85
src/node.rs
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85
src/node.rs
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use crate::record::Record;
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const MIN_DEGREE: usize = 3; // Minimum degree (minimum children per node)
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#[derive(Debug)]
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pub struct Node {
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pub keys: Vec<Record>,
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pub children: Vec<Box<Node>>,
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pub is_leaf: bool,
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}
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impl Node {
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pub fn new(is_leaf: bool) -> Self {
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Node {
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keys: Vec::new(),
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children: Vec::new(),
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is_leaf,
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}
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}
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pub fn is_full(&self) -> bool {
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self.keys.len() >= 2 * MIN_DEGREE - 1
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}
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pub fn search(&self, key: i32) -> Option<Record> {
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let mut i = 0;
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while i < self.keys.len() && key > self.keys[i].key {
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i += 1;
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}
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if i < self.keys.len() && key == self.keys[i].key {
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return Some(self.keys[i]);
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}
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if self.is_leaf {
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return None;
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}
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self.children[i].search(key)
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}
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pub fn insert_non_full(&mut self, rec: Record) {
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let mut i = self.keys.len();
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if self.is_leaf {
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self.keys.push(rec);
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i = self.keys.len() - 1;
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while i > 0 && self.keys[i] < self.keys[i - 1] {
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self.keys.swap(i, i - 1);
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i -= 1;
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}
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} else {
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while i > 0 && rec < self.keys[i - 1] {
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i -= 1;
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}
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if self.children[i].is_full() {
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self.split_child(i);
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if rec > self.keys[i] {
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i += 1;
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}
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}
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self.children[i].insert_non_full(rec);
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}
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}
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pub fn split_child(&mut self, i: usize) {
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let t = MIN_DEGREE;
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let full_child = &mut self.children[i];
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let mut new_child = Box::new(Node::new(full_child.is_leaf));
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// Move the second half of keys to new child
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new_child.keys = full_child.keys.split_off(t);
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let median = full_child.keys.pop().unwrap();
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// Move the second half of children if not a leaf
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if !full_child.is_leaf {
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new_child.children = full_child.children.split_off(t);
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}
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// Insert median key and new child into parent
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self.keys.insert(i, median);
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self.children.insert(i + 1, new_child);
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}
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}
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30
src/record.rs
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30
src/record.rs
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use bincode::{Decode, Encode};
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use rand::Rng;
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#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Encode, Decode)]
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pub struct Record {
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pub key: i32,
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pub a: [i32; 5],
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pub x: i32,
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}
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impl Record {
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pub fn new(a: [i32; 5], x: i32) -> Self {
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let mut key: i32 = 0;
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let mut x_n: i32 = 1;
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for i in 0..5 {
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// rust is annyoing like that, and panics on overflow in arithmetic operations
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key = key.wrapping_add(a[i].wrapping_mul(x_n));
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x_n = x_n.wrapping_mul(x);
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}
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Self { key, a, x }
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}
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pub fn random() -> Self {
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let mut rng = rand::rng();
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let a = rng.random::<[i32; 5]>();
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let x = rng.random::<i32>();
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Self::new(a, x)
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}
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}
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