slotmap

A Rust library providing two containers with persistent unique keys to access stored values, SlotMap and DenseSlotMap. Upon insertion a key is returned that can be used to later access or remove the values. Insertion, deletion and access all take O(1) time with low overhead. Great for storing collections of objects that need stable, safe references but have no clear ownership otherwise, such as game entities or graph nodes. Please refer to the the documentation for more information.

To start using slotmap add the following to your Cargo.toml:

[dependencies]
slotmap = "0.2"

Example

A short example:

use slotmap::SlotMap;

let mut sm = SlotMap::new();
let foo = sm.insert("foo");  // Key generated on insert.
let bar = sm.insert("bar");
assert_eq!(sm[foo], "foo");
assert_eq!(sm[bar], "bar");

sm.remove(bar);
let reused = sm.insert("reuse");  // Space from bar reused.
assert_eq!(sm.contains_key(bar), false);  // After deletion a key stays invalid.

License

slotmap is released under the Zlib license, a permissive license. It is OSI and FSF approved and GPL compatible.