Crate bcmp [] [src]

bcmp is a simple crate which offers data comparison mechanisms which go beyond the simple equality. It only operates on byte slices, hence its name, and relies on efficiently finding common substrings between two blob of data. The implementation relies on two different linear time algorithms: a HashMap based algorithm called HashMatch and a suffix tree built using Ukkonen algorithm called TreeMatch.


Iterate over the matches between two strings using HashMatch with a minimum match length of 2 bytes:

use bcmp::{AlgoSpec, MatchIterator};

let a = "abcdefg";
let b = "012abc34cdef56efg78abcdefg";
let match_iter = MatchIterator::new(a.as_bytes(), b.as_bytes(), AlgoSpec::HashMatch(2));
for m in match_iter {
    println!("Match: {:}", &a[m.first_pos..m.first_end()]);

Construct a patch set to build the file b from the file a using TreeMatch with a minimum match length of 4 bytes:

use std::fs::File;
use std::io::Read;
use bcmp::{AlgoSpec, patch_set};
let mut a = Vec::<u8>::new();
let mut b = Vec::<u8>::new();
File::open("a").unwrap().read_to_end(&mut a);
File::open("b").unwrap().read_to_end(&mut b);

let ps = patch_set(&a, &b, AlgoSpec::TreeMatch(4));
for patch in ps {
    println!("b[0x{:x}..0x{:x}] == a[0x{:x}..0x{:x}]", patch.second_pos, patch.second_end(), patch.first_pos, patch.first_end());



HashMatch is a binary matching algorithm based on a HashMap to retrieve the begining of matching strings.


TreeMatch is a binary matching algorithm based on a suffix tree to retrieve matching strings.



A structure representing a matching substring between two pieces of data.


A generic wrapper for HashMatchIterator and TreeMatchIterator.



An enumeration describing the algorithm specification: either HashMatch or TreeMatch with the minimal matching length parameter.



Return the longest common substring between two byte slices.


Return the N longest common substrings between two byte slices. The vector is sorted in decreasing order of Match length.


Identify the smallest set of patches needed the build the second byte slice from the first.


Find the list of unique strings from the second byte slice which can't be found in the first.