From 325c491691117f65b2ddb2189f9efa327647d90a Mon Sep 17 00:00:00 2001
From: cscherr <Christoph.Scherr@newtec.de>
Date: Wed, 4 Jun 2025 18:06:01 +0200
Subject: [PATCH] btree

---
 crates/datastructures/src/btree.rs | 111 ++++++++++++++---------------
 crates/datastructures/src/lib.rs   |   1 +
 2 files changed, 55 insertions(+), 57 deletions(-)

diff --git a/crates/datastructures/src/btree.rs b/crates/datastructures/src/btree.rs
index 7d64f34..1a50e88 100644
--- a/crates/datastructures/src/btree.rs
+++ b/crates/datastructures/src/btree.rs
@@ -1,66 +1,61 @@
-#[derive(Clone, Debug, Default)]
-pub struct BTree<K: Ord, V> {
-    root: Option<Node<K, V>>,
-    len: usize,
+use crate::vec::Vec;
+
+#[derive(Clone, Debug)]
+pub struct BTree<T> {
+    root: Node<T>,
+    degree: usize,
 }
 
 #[derive(Clone, Debug)]
-pub struct Node<K, V> {
-    key: K,
-    value: V,
+struct Node<T> {
+    keys: Vec<T>,
+    children: Vec<Node<T>>,
 }
 
-impl<K, V> Node<K, V> {
-    pub fn new_root(key: K, value: V) -> Self {
-        Node { key, value }
-    }
-}
-
-impl<K: Ord, V> BTree<K, V> {
-    pub fn new() -> Self {
-        Self { root: None, len: 0 }
-    }
-
-    pub fn clear(&mut self) {
-        self.root = None;
-        self.len = 0;
-    }
-
-    pub fn rebalance() {
-        todo!()
-    }
-
-    pub fn insert(&mut self, key: K, value: V) -> Option<V> {
-        if let Some(root) = &self.root {
-            todo!()
-        } else {
-            let new_node = Node::new_root(key, value);
-            self.root = Some(new_node);
-            None
+impl<T> Node<T>
+where
+    T: Ord,
+{
+    fn new(degree: usize, keys: Option<Vec<T>>, children: Option<Vec<Node<T>>>) -> Self {
+        Node {
+            keys: match keys {
+                Some(keys) => keys,
+                None => Vec::with_capacity(degree - 1),
+            },
+            children: match children {
+                Some(children) => children,
+                None => Vec::with_capacity(degree),
+            },
         }
     }
 
-    pub fn remove(&mut self, key: K) -> Option<V> {
+    fn is_leaf(&self) -> bool {
+        self.children.is_empty()
+    }
+}
+
+impl<T: Ord> BTree<T> {
+    pub fn new(branch_factor: usize) -> Self {
+        let degree = 2 * branch_factor;
+        Self {
+            root: Node::new(degree, None, None),
+            degree,
+        }
+    }
+
+    pub fn clear(&mut self) {
+        self.root = Node::new(self.degree, None, None);
+    }
+
+    fn rebalance() {
         todo!()
     }
 
-    pub fn has_key(&self, key: K) -> bool {
+    pub fn insert(&mut self, value: T) -> Option<T> {
         todo!()
     }
 
-    pub fn get(&self, key: K) -> Option<&V> {
-        todo!()
-    }
-
-    pub fn get_mut(&mut self, key: K) -> Option<&mut V> {
-        todo!()
-    }
-
-    pub fn get_node(&self, key: K) -> Option<&Node<K, V>> {
-        todo!()
-    }
-
-    pub fn get_node_mut(&mut self, key: K) -> Option<&mut Node<K, V>> {
+    pub fn has(&self, value: T) -> bool {
         todo!()
     }
 }
@@ -70,18 +65,20 @@ mod test {
     use super::*;
     #[test]
     fn test_create() {
-        let _tree = BTree::<u32, u32>::default();
+        let _tree = BTree::<u32>::new();
     }
 
     #[test]
     fn test_insert() {
-        let mut tree = BTree::<u32, &str>::default();
-        tree.insert(19, "19");
-        tree.insert(9, "09");
-        tree.insert(14, "14");
+        let mut tree = BTree::<u32>::new();
+        let data = &[19, 125, 25, 16, 2, 73, 384, 435, 12924, 42, 125251, 2548];
 
-        assert!(tree.get(19).is_some_and(|s| *s == "19"));
-        assert!(tree.get(9).is_some_and(|s| *s == "09"));
-        assert!(tree.get(14).is_some_and(|s| *s == "14"));
+        for d in data {
+            assert!(tree.insert(*d).is_none())
+        }
+
+        for d in data {
+            assert!(tree.has(*d))
+        }
     }
 }
diff --git a/crates/datastructures/src/lib.rs b/crates/datastructures/src/lib.rs
index 9ff8ce3..b895c26 100644
--- a/crates/datastructures/src/lib.rs
+++ b/crates/datastructures/src/lib.rs
@@ -1,2 +1,3 @@
+pub mod btree;
 pub mod raw_vec;
 pub mod vec;