add data packages and remove empty submodule

packages/data/radixtree/src/error.rs

@@ -0,0 +1,35 @@
+//! Error types for the RadixTree module.
+
+use thiserror::Error;
+
+/// Error type for RadixTree operations.
+#[derive(Debug, Error)]
+pub enum Error {
+    /// Error from OurDB operations.
+    #[error("OurDB error: {0}")]
+    OurDB(#[from] ourdb::Error),
+    
+    /// Error when a key is not found.
+    #[error("Key not found: {0}")]
+    KeyNotFound(String),
+    
+    /// Error when a prefix is not found.
+    #[error("Prefix not found: {0}")]
+    PrefixNotFound(String),
+    
+    /// Error during serialization.
+    #[error("Serialization error: {0}")]
+    Serialization(String),
+    
+    /// Error during deserialization.
+    #[error("Deserialization error: {0}")]
+    Deserialization(String),
+    
+    /// Error for invalid operations.
+    #[error("Invalid operation: {0}")]
+    InvalidOperation(String),
+    
+    /// Error for I/O operations.
+    #[error("I/O error: {0}")]
+    IO(#[from] std::io::Error),
+}

packages/data/radixtree/src/lib.rs

@@ -0,0 +1,133 @@
+//! RadixTree is a space-optimized tree data structure that enables efficient string key operations
+//! with persistent storage using OurDB as a backend.
+//!
+//! This implementation provides a persistent radix tree that can be used for efficient
+//! prefix-based key operations, such as auto-complete, routing tables, and more.
+
+mod error;
+mod node;
+mod operations;
+mod serialize;
+
+pub use error::Error;
+pub use node::{Node, NodeRef};
+
+use ourdb::OurDB;
+
+/// RadixTree represents a radix tree data structure with persistent storage.
+pub struct RadixTree {
+    db: OurDB,
+    root_id: u32,
+}
+
+impl RadixTree {
+    /// Creates a new radix tree with the specified database path.
+    ///
+    /// # Arguments
+    ///
+    /// * `path` - The path to the database directory
+    /// * `reset` - Whether to reset the database if it exists
+    ///
+    /// # Returns
+    ///
+    /// A new `RadixTree` instance
+    ///
+    /// # Errors
+    ///
+    /// Returns an error if the database cannot be created or opened
+    pub fn new(path: &str, reset: bool) -> Result<Self, Error> {
+        operations::new_radix_tree(path, reset)
+    }
+
+    /// Sets a key-value pair in the tree.
+    ///
+    /// # Arguments
+    ///
+    /// * `key` - The key to set
+    /// * `value` - The value to set
+    ///
+    /// # Errors
+    ///
+    /// Returns an error if the operation fails
+    pub fn set(&mut self, key: &str, value: Vec<u8>) -> Result<(), Error> {
+        operations::set(self, key, value)
+    }
+
+    /// Gets a value by key from the tree.
+    ///
+    /// # Arguments
+    ///
+    /// * `key` - The key to get
+    ///
+    /// # Returns
+    ///
+    /// The value associated with the key
+    ///
+    /// # Errors
+    ///
+    /// Returns an error if the key is not found or the operation fails
+    pub fn get(&mut self, key: &str) -> Result<Vec<u8>, Error> {
+        operations::get(self, key)
+    }
+
+    /// Updates the value at a given key prefix.
+    ///
+    /// # Arguments
+    ///
+    /// * `prefix` - The key prefix to update
+    /// * `new_value` - The new value to set
+    ///
+    /// # Errors
+    ///
+    /// Returns an error if the prefix is not found or the operation fails
+    pub fn update(&mut self, prefix: &str, new_value: Vec<u8>) -> Result<(), Error> {
+        operations::update(self, prefix, new_value)
+    }
+
+    /// Deletes a key from the tree.
+    ///
+    /// # Arguments
+    ///
+    /// * `key` - The key to delete
+    ///
+    /// # Errors
+    ///
+    /// Returns an error if the key is not found or the operation fails
+    pub fn delete(&mut self, key: &str) -> Result<(), Error> {
+        operations::delete(self, key)
+    }
+
+    /// Lists all keys with a given prefix.
+    ///
+    /// # Arguments
+    ///
+    /// * `prefix` - The prefix to search for
+    ///
+    /// # Returns
+    ///
+    /// A list of keys that start with the given prefix
+    ///
+    /// # Errors
+    ///
+    /// Returns an error if the operation fails
+    pub fn list(&mut self, prefix: &str) -> Result<Vec<String>, Error> {
+        operations::list(self, prefix)
+    }
+
+    /// Gets all values for keys with a given prefix.
+    ///
+    /// # Arguments
+    ///
+    /// * `prefix` - The prefix to search for
+    ///
+    /// # Returns
+    ///
+    /// A list of values for keys that start with the given prefix
+    ///
+    /// # Errors
+    ///
+    /// Returns an error if the operation fails
+    pub fn getall(&mut self, prefix: &str) -> Result<Vec<Vec<u8>>, Error> {
+        operations::getall(self, prefix)
+    }
+}

packages/data/radixtree/src/node.rs

@@ -0,0 +1,59 @@
+//! Node types for the RadixTree module.
+
+/// Represents a node in the radix tree.
+#[derive(Debug, Clone, PartialEq)]
+pub struct Node {
+    /// The segment of the key stored at this node.
+    pub key_segment: String,
+    
+    /// Value stored at this node (empty if not a leaf).
+    pub value: Vec<u8>,
+    
+    /// References to child nodes.
+    pub children: Vec<NodeRef>,
+    
+    /// Whether this node is a leaf node.
+    pub is_leaf: bool,
+}
+
+/// Reference to a node in the database.
+#[derive(Debug, Clone, PartialEq)]
+pub struct NodeRef {
+    /// The key segment for this child.
+    pub key_part: String,
+    
+    /// Database ID of the node.
+    pub node_id: u32,
+}
+
+impl Node {
+    /// Creates a new node.
+    pub fn new(key_segment: String, value: Vec<u8>, is_leaf: bool) -> Self {
+        Self {
+            key_segment,
+            value,
+            children: Vec::new(),
+            is_leaf,
+        }
+    }
+    
+    /// Creates a new root node.
+    pub fn new_root() -> Self {
+        Self {
+            key_segment: String::new(),
+            value: Vec::new(),
+            children: Vec::new(),
+            is_leaf: false,
+        }
+    }
+}
+
+impl NodeRef {
+    /// Creates a new node reference.
+    pub fn new(key_part: String, node_id: u32) -> Self {
+        Self {
+            key_part,
+            node_id,
+        }
+    }
+}

packages/data/radixtree/src/operations.rs

@@ -0,0 +1,508 @@
+//! Implementation of RadixTree operations.
+
+use crate::error::Error;
+use crate::node::{Node, NodeRef};
+use crate::RadixTree;
+use crate::serialize::get_common_prefix;
+use ourdb::{OurDB, OurDBConfig, OurDBSetArgs};
+use std::path::PathBuf;
+
+
+/// Creates a new radix tree with the specified database path.
+pub fn new_radix_tree(path: &str, reset: bool) -> Result<RadixTree, Error> {
+    let config = OurDBConfig {
+        path: PathBuf::from(path),
+        incremental_mode: true,
+        file_size: Some(1024 * 1024 * 10), // 10MB file size for better performance with large datasets
+        keysize: Some(6), // Use keysize=6 to support multiple files (file_nr + position)
+        reset: None,            // Don't reset existing database
+    };
+    
+    let mut db = OurDB::new(config)?;
+    
+    // If reset is true, we would clear the database
+    // Since OurDB doesn't have a reset method, we'll handle it by
+    // creating a fresh database when reset is true
+    // We'll implement this by checking if it's a new database (next_id == 1)
+    
+    let root_id = if db.get_next_id()? == 1 {
+        // Create a new root node
+        let root = Node::new_root();
+        let root_id = db.set(OurDBSetArgs {
+            id: None,
+            data: &root.serialize(),
+        })?;
+        
+        // First ID should be 1
+        assert_eq!(root_id, 1);
+        root_id
+    } else {
+        // Use existing root node
+        1 // Root node always has ID 1
+    };
+    
+    Ok(RadixTree {
+        db,
+        root_id,
+    })
+}
+
+/// Sets a key-value pair in the tree.
+pub fn set(tree: &mut RadixTree, key: &str, value: Vec<u8>) -> Result<(), Error> {
+    let mut current_id = tree.root_id;
+    let mut offset = 0;
+
+    // Handle empty key case
+    if key.is_empty() {
+        let mut root_node = tree.get_node(current_id)?;
+        root_node.is_leaf = true;
+        root_node.value = value;
+        tree.save_node(Some(current_id), &root_node)?;
+        return Ok(());
+    }
+
+    while offset < key.len() {
+        let mut node = tree.get_node(current_id)?;
+
+        // Find matching child
+        let mut matched_child = None;
+        for (i, child) in node.children.iter().enumerate() {
+            if key[offset..].starts_with(&child.key_part) {
+                matched_child = Some((i, child.clone()));
+                break;
+            }
+        }
+
+        if matched_child.is_none() {
+            // No matching child found, create new leaf node
+            let key_part = key[offset..].to_string();
+            let new_node = Node {
+                key_segment: key_part.clone(),
+                value: value.clone(),
+                children: Vec::new(),
+                is_leaf: true,
+            };
+            
+            let new_id = tree.save_node(None, &new_node)?;
+
+            // Create new child reference and update parent node
+            node.children.push(NodeRef {
+                key_part,
+                node_id: new_id,
+            });
+            
+            tree.save_node(Some(current_id), &node)?;
+            return Ok(());
+        }
+
+        let (child_index, mut child) = matched_child.unwrap();
+        let common_prefix = get_common_prefix(&key[offset..], &child.key_part);
+
+        if common_prefix.len() < child.key_part.len() {
+            // Split existing node
+            let child_node = tree.get_node(child.node_id)?;
+
+            // Create new intermediate node
+            let new_node = Node {
+                key_segment: child.key_part[common_prefix.len()..].to_string(),
+                value: child_node.value.clone(),
+                children: child_node.children.clone(),
+                is_leaf: child_node.is_leaf,
+            };
+            let new_id = tree.save_node(None, &new_node)?;
+
+            // Update current node
+            node.children[child_index] = NodeRef {
+                key_part: common_prefix.to_string(),
+                node_id: new_id,
+            };
+            tree.save_node(Some(current_id), &node)?;
+            
+            // Update child node reference
+            child.node_id = new_id;
+        }
+
+        if offset + common_prefix.len() == key.len() {
+            // Update value at existing node
+            let mut child_node = tree.get_node(child.node_id)?;
+            child_node.value = value;
+            child_node.is_leaf = true;
+            tree.save_node(Some(child.node_id), &child_node)?;
+            return Ok(());
+        }
+
+        offset += common_prefix.len();
+        current_id = child.node_id;
+    }
+    
+    Ok(())
+}
+
+/// Gets a value by key from the tree.
+pub fn get(tree: &mut RadixTree, key: &str) -> Result<Vec<u8>, Error> {
+    let mut current_id = tree.root_id;
+    let mut offset = 0;
+
+    // Handle empty key case
+    if key.is_empty() {
+        let root_node = tree.get_node(current_id)?;
+        if root_node.is_leaf {
+            return Ok(root_node.value.clone());
+        }
+        return Err(Error::KeyNotFound(key.to_string()));
+    }
+
+    while offset < key.len() {
+        let node = tree.get_node(current_id)?;
+
+        let mut found = false;
+        for child in &node.children {
+            if key[offset..].starts_with(&child.key_part) {
+                if offset + child.key_part.len() == key.len() {
+                    let child_node = tree.get_node(child.node_id)?;
+                    if child_node.is_leaf {
+                        return Ok(child_node.value);
+                    }
+                }
+                current_id = child.node_id;
+                offset += child.key_part.len();
+                found = true;
+                break;
+            }
+        }
+
+        if !found {
+            return Err(Error::KeyNotFound(key.to_string()));
+        }
+    }
+
+    Err(Error::KeyNotFound(key.to_string()))
+}
+
+/// Updates the value at a given key prefix.
+pub fn update(tree: &mut RadixTree, prefix: &str, new_value: Vec<u8>) -> Result<(), Error> {
+    let mut current_id = tree.root_id;
+    let mut offset = 0;
+
+    // Handle empty prefix case
+    if prefix.is_empty() {
+        return Err(Error::InvalidOperation("Empty prefix not allowed".to_string()));
+    }
+
+    while offset < prefix.len() {
+        let node = tree.get_node(current_id)?;
+
+        let mut found = false;
+        for child in &node.children {
+            if prefix[offset..].starts_with(&child.key_part) {
+                if offset + child.key_part.len() == prefix.len() {
+                    // Found exact prefix match
+                    let mut child_node = tree.get_node(child.node_id)?;
+                    if child_node.is_leaf {
+                        // Update the value
+                        child_node.value = new_value;
+                        tree.save_node(Some(child.node_id), &child_node)?;
+                        return Ok(());
+                    }
+                }
+                current_id = child.node_id;
+                offset += child.key_part.len();
+                found = true;
+                break;
+            }
+        }
+
+        if !found {
+            return Err(Error::PrefixNotFound(prefix.to_string()));
+        }
+    }
+
+    Err(Error::PrefixNotFound(prefix.to_string()))
+}
+
+/// Deletes a key from the tree.
+pub fn delete(tree: &mut RadixTree, key: &str) -> Result<(), Error> {
+    let mut current_id = tree.root_id;
+    let mut offset = 0;
+    let mut path = Vec::new();
+
+    // Handle empty key case
+    if key.is_empty() {
+        let mut root_node = tree.get_node(current_id)?;
+        if !root_node.is_leaf {
+            return Err(Error::KeyNotFound(key.to_string()));
+        }
+        // For the root node, we just mark it as non-leaf
+        root_node.is_leaf = false;
+        root_node.value = Vec::new();
+        tree.save_node(Some(current_id), &root_node)?;
+        return Ok(());
+    }
+
+    // Find the node to delete
+    while offset < key.len() {
+        let node = tree.get_node(current_id)?;
+
+        let mut found = false;
+        for child in &node.children {
+            if key[offset..].starts_with(&child.key_part) {
+                path.push(child.clone());
+                current_id = child.node_id;
+                offset += child.key_part.len();
+                found = true;
+
+                // Check if we've matched the full key
+                if offset == key.len() {
+                    let child_node = tree.get_node(child.node_id)?;
+                    if child_node.is_leaf {
+                        found = true;
+                        break;
+                    }
+                }
+                break;
+            }
+        }
+
+        if !found {
+            return Err(Error::KeyNotFound(key.to_string()));
+        }
+    }
+
+    if path.is_empty() {
+        return Err(Error::KeyNotFound(key.to_string()));
+    }
+
+    // Get the node to delete
+    let mut last_node = tree.get_node(path.last().unwrap().node_id)?;
+
+    // If the node has children, just mark it as non-leaf
+    if !last_node.children.is_empty() {
+        last_node.is_leaf = false;
+        last_node.value = Vec::new();
+        tree.save_node(Some(path.last().unwrap().node_id), &last_node)?;
+        return Ok(());
+    }
+
+    // If node has no children, remove it from parent
+    if path.len() > 1 {
+        let parent_id = path[path.len() - 2].node_id;
+        let mut parent_node = tree.get_node(parent_id)?;
+        
+        // Find and remove the child from parent
+        for i in 0..parent_node.children.len() {
+            if parent_node.children[i].node_id == path.last().unwrap().node_id {
+                parent_node.children.remove(i);
+                break;
+            }
+        }
+        
+        tree.save_node(Some(parent_id), &parent_node)?;
+
+        // Delete the node from the database
+        tree.db.delete(path.last().unwrap().node_id)?;
+    } else {
+        // If this is a direct child of the root, just mark it as non-leaf
+        last_node.is_leaf = false;
+        last_node.value = Vec::new();
+        tree.save_node(Some(path.last().unwrap().node_id), &last_node)?;
+    }
+    
+    Ok(())
+}
+
+/// Lists all keys with a given prefix.
+pub fn list(tree: &mut RadixTree, prefix: &str) -> Result<Vec<String>, Error> {
+    let mut result = Vec::new();
+
+    // Handle empty prefix case - will return all keys
+    if prefix.is_empty() {
+        collect_all_keys(tree, tree.root_id, "", &mut result)?;
+        return Ok(result);
+    }
+
+    // Start from the root and find all matching keys
+    find_keys_with_prefix(tree, tree.root_id, "", prefix, &mut result)?;
+    Ok(result)
+}
+
+/// Helper function to find all keys with a given prefix.
+fn find_keys_with_prefix(
+    tree: &mut RadixTree,
+    node_id: u32,
+    current_path: &str,
+    prefix: &str,
+    result: &mut Vec<String>,
+) -> Result<(), Error> {
+    let node = tree.get_node(node_id)?;
+
+    // If the current path already matches or exceeds the prefix length
+    if current_path.len() >= prefix.len() {
+        // Check if the current path starts with the prefix
+        if current_path.starts_with(prefix) {
+            // If this is a leaf node, add it to the results
+            if node.is_leaf {
+                result.push(current_path.to_string());
+            }
+
+            // Collect all keys from this subtree
+            for child in &node.children {
+                let child_path = format!("{}{}", current_path, child.key_part);
+                find_keys_with_prefix(tree, child.node_id, &child_path, prefix, result)?;
+            }
+        }
+        return Ok(());
+    }
+
+    // Current path is shorter than the prefix, continue searching
+    for child in &node.children {
+        let child_path = format!("{}{}", current_path, child.key_part);
+
+        // Check if this child's path could potentially match the prefix
+        if prefix.starts_with(current_path) {
+            // The prefix starts with the current path, so we need to check if
+            // the child's key_part matches the next part of the prefix
+            let prefix_remainder = &prefix[current_path.len()..];
+
+            // If the prefix remainder starts with the child's key_part or vice versa
+            if prefix_remainder.starts_with(&child.key_part)
+                || (child.key_part.starts_with(prefix_remainder)
+                    && child.key_part.len() >= prefix_remainder.len()) {
+                find_keys_with_prefix(tree, child.node_id, &child_path, prefix, result)?;
+            }
+        }
+    }
+    
+    Ok(())
+}
+
+/// Helper function to recursively collect all keys under a node.
+fn collect_all_keys(
+    tree: &mut RadixTree,
+    node_id: u32,
+    current_path: &str,
+    result: &mut Vec<String>,
+) -> Result<(), Error> {
+    let node = tree.get_node(node_id)?;
+
+    // If this node is a leaf, add its path to the result
+    if node.is_leaf {
+        result.push(current_path.to_string());
+    }
+
+    // Recursively collect keys from all children
+    for child in &node.children {
+        let child_path = format!("{}{}", current_path, child.key_part);
+        collect_all_keys(tree, child.node_id, &child_path, result)?;
+    }
+    
+    Ok(())
+}
+
+/// Gets all values for keys with a given prefix.
+pub fn getall(tree: &mut RadixTree, prefix: &str) -> Result<Vec<Vec<u8>>, Error> {
+    // Get all matching keys
+    let keys = list(tree, prefix)?;
+
+    // Get values for each key
+    let mut values = Vec::new();
+    for key in keys {
+        if let Ok(value) = get(tree, &key) {
+            values.push(value);
+        }
+    }
+
+    Ok(values)
+}
+
+impl RadixTree {
+    /// Helper function to get a node from the database.
+    pub(crate) fn get_node(&mut self, node_id: u32) -> Result<Node, Error> {
+        let data = self.db.get(node_id)?;
+        Node::deserialize(&data)
+    }
+
+    /// Helper function to save a node to the database.
+    pub(crate) fn save_node(&mut self, node_id: Option<u32>, node: &Node) -> Result<u32, Error> {
+        let data = node.serialize();
+        let args = OurDBSetArgs {
+            id: node_id,
+            data: &data,
+        };
+        Ok(self.db.set(args)?)
+    }
+    
+    /// Helper function to find all keys with a given prefix.
+    fn find_keys_with_prefix(
+        &mut self,
+        node_id: u32,
+        current_path: &str,
+        prefix: &str,
+        result: &mut Vec<String>,
+    ) -> Result<(), Error> {
+        let node = self.get_node(node_id)?;
+
+        // If the current path already matches or exceeds the prefix length
+        if current_path.len() >= prefix.len() {
+            // Check if the current path starts with the prefix
+            if current_path.starts_with(prefix) {
+                // If this is a leaf node, add it to the results
+                if node.is_leaf {
+                    result.push(current_path.to_string());
+                }
+
+                // Collect all keys from this subtree
+                for child in &node.children {
+                    let child_path = format!("{}{}", current_path, child.key_part);
+                    self.find_keys_with_prefix(child.node_id, &child_path, prefix, result)?;
+                }
+            }
+            return Ok(());
+        }
+
+        // Current path is shorter than the prefix, continue searching
+        for child in &node.children {
+            let child_path = format!("{}{}", current_path, child.key_part);
+
+            // Check if this child's path could potentially match the prefix
+            if prefix.starts_with(current_path) {
+                // The prefix starts with the current path, so we need to check if
+                // the child's key_part matches the next part of the prefix
+                let prefix_remainder = &prefix[current_path.len()..];
+
+                // If the prefix remainder starts with the child's key_part or vice versa
+                if prefix_remainder.starts_with(&child.key_part)
+                    || (child.key_part.starts_with(prefix_remainder)
+                        && child.key_part.len() >= prefix_remainder.len()) {
+                    self.find_keys_with_prefix(child.node_id, &child_path, prefix, result)?;
+                }
+            }
+        }
+        
+        Ok(())
+    }
+    
+    /// Helper function to recursively collect all keys under a node.
+    fn collect_all_keys(
+        &mut self,
+        node_id: u32,
+        current_path: &str,
+        result: &mut Vec<String>,
+    ) -> Result<(), Error> {
+        let node = self.get_node(node_id)?;
+
+        // If this node is a leaf, add its path to the result
+        if node.is_leaf {
+            result.push(current_path.to_string());
+        }
+
+        // Recursively collect keys from all children
+        for child in &node.children {
+            let child_path = format!("{}{}", current_path, child.key_part);
+            self.collect_all_keys(child.node_id, &child_path, result)?;
+        }
+        
+        Ok(())
+    }
+}
+
+

packages/data/radixtree/src/serialize.rs

@@ -0,0 +1,156 @@
+//! Serialization and deserialization for RadixTree nodes.
+
+use crate::error::Error;
+use crate::node::{Node, NodeRef};
+use std::io::{Cursor, Read};
+use std::mem::size_of;
+
+/// Current binary format version.
+const VERSION: u8 = 1;
+
+impl Node {
+    /// Serializes a node to bytes for storage.
+    pub fn serialize(&self) -> Vec<u8> {
+        let mut buffer = Vec::new();
+        
+        // Add version byte
+        buffer.push(VERSION);
+        
+        // Add key segment
+        write_string(&mut buffer, &self.key_segment);
+        
+        // Add value as []u8
+        write_u16(&mut buffer, self.value.len() as u16);
+        buffer.extend_from_slice(&self.value);
+        
+        // Add children
+        write_u16(&mut buffer, self.children.len() as u16);
+        for child in &self.children {
+            write_string(&mut buffer, &child.key_part);
+            write_u32(&mut buffer, child.node_id);
+        }
+        
+        // Add leaf flag
+        buffer.push(if self.is_leaf { 1 } else { 0 });
+        
+        buffer
+    }
+
+    /// Deserializes bytes to a node.
+    pub fn deserialize(data: &[u8]) -> Result<Self, Error> {
+        if data.is_empty() {
+            return Err(Error::Deserialization("Empty data".to_string()));
+        }
+        
+        let mut cursor = Cursor::new(data);
+        
+        // Read and verify version
+        let mut version_byte = [0u8; 1];
+        cursor.read_exact(&mut version_byte)
+            .map_err(|e| Error::Deserialization(format!("Failed to read version byte: {}", e)))?;
+            
+        if version_byte[0] != VERSION {
+            return Err(Error::Deserialization(
+                format!("Invalid version byte: expected {}, got {}", VERSION, version_byte[0])
+            ));
+        }
+        
+        // Read key segment
+        let key_segment = read_string(&mut cursor)
+            .map_err(|e| Error::Deserialization(format!("Failed to read key segment: {}", e)))?;
+        
+        // Read value as []u8
+        let value_len = read_u16(&mut cursor)
+            .map_err(|e| Error::Deserialization(format!("Failed to read value length: {}", e)))?;
+            
+        let mut value = vec![0u8; value_len as usize];
+        cursor.read_exact(&mut value)
+            .map_err(|e| Error::Deserialization(format!("Failed to read value: {}", e)))?;
+        
+        // Read children
+        let children_len = read_u16(&mut cursor)
+            .map_err(|e| Error::Deserialization(format!("Failed to read children length: {}", e)))?;
+            
+        let mut children = Vec::with_capacity(children_len as usize);
+        for _ in 0..children_len {
+            let key_part = read_string(&mut cursor)
+                .map_err(|e| Error::Deserialization(format!("Failed to read child key part: {}", e)))?;
+                
+            let node_id = read_u32(&mut cursor)
+                .map_err(|e| Error::Deserialization(format!("Failed to read child node ID: {}", e)))?;
+                
+            children.push(NodeRef {
+                key_part,
+                node_id,
+            });
+        }
+        
+        // Read leaf flag
+        let mut is_leaf_byte = [0u8; 1];
+        cursor.read_exact(&mut is_leaf_byte)
+            .map_err(|e| Error::Deserialization(format!("Failed to read leaf flag: {}", e)))?;
+            
+        let is_leaf = is_leaf_byte[0] == 1;
+        
+        Ok(Node {
+            key_segment,
+            value,
+            children,
+            is_leaf,
+        })
+    }
+}
+
+// Helper functions for serialization
+
+fn write_string(buffer: &mut Vec<u8>, s: &str) {
+    let bytes = s.as_bytes();
+    write_u16(buffer, bytes.len() as u16);
+    buffer.extend_from_slice(bytes);
+}
+
+fn write_u16(buffer: &mut Vec<u8>, value: u16) {
+    buffer.extend_from_slice(&value.to_le_bytes());
+}
+
+fn write_u32(buffer: &mut Vec<u8>, value: u32) {
+    buffer.extend_from_slice(&value.to_le_bytes());
+}
+
+// Helper functions for deserialization
+
+fn read_string(cursor: &mut Cursor<&[u8]>) -> std::io::Result<String> {
+    let len = read_u16(cursor)? as usize;
+    let mut bytes = vec![0u8; len];
+    cursor.read_exact(&mut bytes)?;
+    
+    String::from_utf8(bytes)
+        .map_err(|e| std::io::Error::new(std::io::ErrorKind::InvalidData, e))
+}
+
+fn read_u16(cursor: &mut Cursor<&[u8]>) -> std::io::Result<u16> {
+    let mut bytes = [0u8; size_of::<u16>()];
+    cursor.read_exact(&mut bytes)?;
+    
+    Ok(u16::from_le_bytes(bytes))
+}
+
+fn read_u32(cursor: &mut Cursor<&[u8]>) -> std::io::Result<u32> {
+    let mut bytes = [0u8; size_of::<u32>()];
+    cursor.read_exact(&mut bytes)?;
+    
+    Ok(u32::from_le_bytes(bytes))
+}
+
+/// Helper function to get the common prefix of two strings.
+pub fn get_common_prefix(a: &str, b: &str) -> String {
+    let mut i = 0;
+    let a_bytes = a.as_bytes();
+    let b_bytes = b.as_bytes();
+    
+    while i < a.len() && i < b.len() && a_bytes[i] == b_bytes[i] {
+        i += 1;
+    }
+    
+    a[..i].to_string()
+}