https://github.com/softdevteam/packedvec

Store vectors of integers efficiently
https://github.com/softdevteam/packedvec

rust

Last synced: 10 months ago
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Store vectors of integers efficiently

• Host: GitHub
• URL: https://github.com/softdevteam/packedvec
• Owner: softdevteam
• License: other
• Created: 2017-10-03T15:17:33.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2025-03-17T17:49:35.000Z (11 months ago)
• Last Synced: 2025-03-17T18:04:31.243Z (11 months ago)
• Topics: rust
• Language: Rust
• Homepage:
• Size: 90.8 KB
• Stars: 5
• Watchers: 3
• Forks: 4
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGES.md
  • License: LICENSE-APACHE

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README

          
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# PackedVec

A [`PackedVec`](https://docs.rs/packedvec/) stores vectors of integers

efficiently while providing an API similar to `Vec`. The basic idea is to store

each element using the minimum number of bits needed to represent every element

in the `Vec`. For example, if we have a `Vec` with elements [20, 30, 140],

every element wastes most of its 64 bits: 7 bits is sufficient to represent the

range of elements in the vector. Given this input vector, `PackedVec` stores

each elements using exactly 7 bits, saving substantial memory. For vectors which

often contain small ranges of numbers, and which are created rarely, but read

from frequently, this can be a significant memory and performance win.

# Examples

`PackedVec` has two main API differences from `Vec`: a `PackedVec` is created

from a `Vec`; and a `PackedVec` returns values rather than references. Both

points can be seen in this example:

```rust

use packedvec::PackedVec;

let v = vec![-1, 30, 120];

let pv = PackedVec::new(v.clone());

assert_eq!(pv.get(0), Some(-1));

assert_eq!(pv.get(2), Some(120));

assert_eq!(pv.get(3), None);

assert_eq!(v.iter().cloned().collect::>(), pv.iter().collect::>());

```