Crate huffman_compress

source ·
Expand description

Huffman compression given a probability distribution over arbitrary symbols.

Examples

extern crate bit_vec;
extern crate huffman_compress;

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, example.len()).collect();
assert_eq!(decoded, example);

Structs

  • Book
    A codebook used for encoding.
  • CodeBuilder
    Collects information about symbols and their weights used to construct a Huffman code.
  • EncodeError
    Tried to encode an unknown symbol.
  • Tree
    A trie used for decoding.
  • UnboundedDecoder
    Decodes symbols from a source of bits.

Functions

Type Aliases