#tree #arena #index #indextree #trie


Arena based tree structure by using indices instead of reference counted pointers. Fork of indextree by Sascha Grunert which allows to remove nodes

6 stable releases

Uses old Rust 2015

1.0.5 Jan 2, 2018
1.0.4 Dec 15, 2017
1.0.3 Dec 13, 2017
1.0.2 Dec 12, 2017

#981 in Data structures

48 downloads per month
Used in 2 crates (via rustupolis)

MIT license

440 lines


Build Status

Arena based tree structure with multithreading support

This is a fork of the indextree crate which allows to remove nodes. The original version was not capable of removing nodes as the initial idea was to drop all nodes at the same time if the lifetime of the underlying memory arena has ended.

The arena tree structure is using a single Vec, a HashMap and numerical identifiers. Every node holds an id which is mapped to an index of the vector via the HashMap. This allows to drop single nodes before the lifetime of the arena hash ended.

There is no RefCell and mutability is handled in a way much more idiomatic to Rust through unique (&mut) access to the arena.

Example usage

use indextree_ng::Arena;

// Create a new arena
let arena = &mut Arena::new();

// Add some new nodes to the arena
let a = arena.new_node(1);
let b = arena.new_node(2);

// Append b to a
a.append(b, arena);
assert_eq!(b.ancestors(arena).into_iter().count(), 2);

//Access a node
assert_eq!(arena[b], 2);

// Remove a node
assert_eq!(b.ancestors(arena).into_iter().count(), 1);

No runtime deps