#huffman-coding #huffman #probability-distribution

huffman-compress

Huffman compression given a probability distribution over arbitrary symbols

10 releases (5 breaking)

Uses old Rust 2015

0.6.1 Apr 25, 2021
0.6.0 Jun 2, 2019
0.5.0 May 10, 2018
0.4.0 Mar 5, 2018
0.1.1 Jan 29, 2018

#228 in Compression

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78 downloads per month
Used in 6 crates (4 directly)

MIT/Apache

22KB
391 lines

huffman-compress

Huffman compression given a probability distribution over arbitrary symbols.

Build Status crates.io docs.rs No Maintenance Intended

Examples

use std::iter::FromIterator;
use std::collections::HashMap;
use bit_vec::BitVec;
use huffman_compress::{CodeBuilder, Book, Tree};

let mut weights = HashMap::new();
weights.insert("CG", 293);
weights.insert("AG", 34);
weights.insert("AT", 4);
weights.insert("CT", 4);
weights.insert("TG", 1);

// Construct a Huffman code based on the weights (e.g. counts or relative
// frequencies).
let (book, tree) = CodeBuilder::from_iter(weights).finish();

// More frequent symbols will be encoded with fewer bits.
assert!(book.get("CG").map_or(0, |cg| cg.len()) <
        book.get("AG").map_or(0, |ag| ag.len()));

// Encode some symbols using the book.
let mut buffer = BitVec::new();
let example = vec!["AT", "CG", "AT", "TG", "AG", "CT", "CT", "AG", "CG"];
for symbol in &example {
    book.encode(&mut buffer, symbol);
}

// Decode the symbols using the tree.
let decoded: Vec<&str> = tree.decoder(&buffer).collect();
assert_eq!(decoded, example);

Documentation

Read the documentation

Changelog

  • 0.6.1
    • Fix deprecation warning and remove #[deny(warnings)] (a future compatibility hazard in libraries).
  • 0.6.0
    • Update to bit-vec 0.6.
  • 0.5.0
    • Update to bit-vec 0.5.
  • 0.4.0
    • Renamed Tree::decoder() to Tree::unbounded_decoder() to avoid surprises. A new Tree::decoder() takes the maximum number of symbols to decode.
    • No longer reexporting Saturating from num-traits.
  • 0.3.2
    • Preallocate arena space for Huffman tree.
  • 0.3.1
    • Update num-traits to 0.2 (semver compatible).
  • 0.3.0
    • Introduce CodeBuilder.
    • Changes tie breaking order.
  • 0.2.0
    • Allow initialization from iterators without creating a HashMap. Thanks @mernen.
    • Require K: Ord instead of K: Hash + Eq for symbols and switch Book internals from HashMap to BTreeMap.
    • Specify stability guarantees.
  • 0.1.1
    • Expose more methods on Book.
  • 0.1.0
    • Initial release.

License

huffman-compress is dual licensed under the Apache 2.0 and MIT license, at your option.

Dependencies

~250KB