https://github.com/gossiperloturot/densemap
A collection data structure that is permanently accessible by unique keys and fast iterable
https://github.com/gossiperloturot/densemap
data-structures rust
Last synced: 6 months ago
JSON representation
A collection data structure that is permanently accessible by unique keys and fast iterable
- Host: GitHub
- URL: https://github.com/gossiperloturot/densemap
- Owner: GossiperLoturot
- License: mit
- Created: 2023-09-09T14:23:07.000Z (over 2 years ago)
- Default Branch: main
- Last Pushed: 2024-07-22T13:42:46.000Z (over 1 year ago)
- Last Synced: 2025-06-01T13:43:57.229Z (7 months ago)
- Topics: data-structures, rust
- Language: Rust
- Homepage:
- Size: 45.9 KB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# densemap
[**Documentation**](https://docs.rs/densemap)
This library provides a collection `DenseMap` that are permanently accessible by unique keys and fast
iterable. A key is generated upon insertion and can be used to access any element. Inserts,
removes, and gets run in constant time, and iteration has the same performance as `Vec`. Also
`DenseMap` reduces memory usage by reusing removed areas.
# Examples
```rust
use densemap::{DenseMap, Key};
// Creates a new dense map and inserts some elements.
let mut densemap = DenseMap::new();
let key_of_alice = densemap.insert("alice");
let key_of_bob = densemap.insert("bob");
// Gets an element.
assert_eq!(densemap.get(key_of_alice), Some(&"alice"));
// Removes an element.
assert_eq!(densemap.remove(key_of_alice), Some("alice"));
let key_of_charlie = densemap.insert("charlie");
// Keys are unique and permanently accessible.
assert_eq!(densemap.get(key_of_alice), None);
// Iterates all elements.
for value in densemap.values() {
println!("{value}");
}
```
# Differences from other libraries
This library is similar to `slotmap::DenseSlotMap`, but it has some differences.
`DenseMap` has a performance advantage due to reduced overhead. Also this library simply provides
only a collection `DenseMap`.
# Benchmarks
The performance measurement results for inserts, removes, reinserts, and iterates on the
collections of `std-1.72.1`. `slab-0.4.9`, `slotmap-1.0.6`, and `densemap-0.1.0` are shown
below table. The results are measured by using `criterion` on WSL.
| collection | insertion | removal | reinsertion | iteration |
|:----------:|:---------:|:-------:|:-----------:|:---------:|
| std::vec::Vec | 16.367 | 7.0338μs | 10.438μs | 3.6754μs |
| std::collections::HashMap | 351.25μs | 187.99μs | 174.97μs | 14.617μs |
| slab::Slab | 17.728μs | 17.952μs | 26.207μs | 4.9409μs |
| slotmap::SlotMap | 49.043μs | 29.594μs | 48.153μs | 22.566μs |
| slotmap::HopSlotMap | 46.897μs | 126.29μs | 67.884μs | 24.349μs |
| slotmap::DenseSlotMap | 63.195μs | 62.308μs | 67.072μs | 5.2833μs |
| densemap::DenseMap | 40.357μs | 24.969μs | 47.280μs | 3.6269μs |
# License
This library is licensed under the [MIT license](LICENSE).