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
- A codebook used for encoding.
- Collects information about symbols and their weights used to construct a Huffman code.
- Tried to encode an unknown symbol.
- A trie used for decoding.
- Decodes symbols from a source of bits.
Functions
- Shortcut for
CodeBuilder::from_iter(weights).finish()
.
Type Aliases
- A bounded decoder, decoding symbols from a source of bits.