yada 0.1.0

Yada is a yet another double-array trie library aiming for fast search and compact data representation.
Documentation

Yada: Yet Another Double-Array

Yada is a yet another double-array trie library aiming for fast search and compact data representation.

Features

  • Build static double-array tries
    • Yada adopts the compact binary representation of double-array nodes like Darts-clone.
  • Common prefix search
    • The method returns an Iterator that is an effective way to find multiple values without heap allocation.
  • Exact match search
    • The method finds a value associated with an exact match key as a Option.

Usage

See also example code for more details.

Build a double-array trie

use yada::builder::DoubleArrayBuilder;

// make a keyset which have key-value pairs
let keyset = &[
    ("a\0".as_bytes(), 0),
    ("ab\0".as_bytes(), 1),
    ("abc\0".as_bytes(), 2),
    ("b\0".as_bytes(), 3),
    ("bc\0".as_bytes(), 4),
    ("c\0".as_bytes(), 5),
];

// build a double-array trie binary
let da_bytes: Option<Vec<u8>> = DoubleArrayBuilder::build(keyset);

Search entries by keys

use yada::DoubleArray;

// create a double-array trie instance
let da = DoubleArray::new(da_bytes.unwrap());

// exact match search
for (key, value) in keyset {
    assert_eq!(da.exact_match_search(key), Some(*value as u32));
}
assert_eq!(da.exact_match_search("abc\0".as_bytes()), Some(2));
assert_eq!(da.exact_match_search("abcd\0".as_bytes()), None);

// common prefix search
assert_eq!(
    da.common_prefix_search("abcd".as_bytes()).collect::<Vec<_>>(),
    vec![0, 1, 2] // match "a", "ab", "abc"
);
assert_eq!(
    da.common_prefix_search("d".as_bytes()).collect::<Vec<_>>(),
    vec![] // don't match
);

Limitations

  • The offset of an double-array node is 23 bit wide, so it can only represent up to ~8.3M nodes.
    • It means this limitation results in the size upper bound ~33 MB of double-arrays.

License

Licensed under either of

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

References