Chocobo1 / kmps

Knuth–Morris–Pratt algorithm that works with JS Array & TypedArray

Knuth–Morris–Pratt Search

An naive implementation of Knuth–Morris–Pratt algorithm that works with Array & TypedArray

Installation

npm install git+https://github.com/Chocobo1/kmps.git

Usage example

const Kmp = require('kmps');  // import this module, CommonJS style
//import * as Kmp from 'kmps';  // import this module, ES module style

// working with TypedArray
{
    const pattern = Uint32Array.from([0xFFFF, 0x3000]);
    const corpus = Uint32Array.from([0xFFFF, 0xFFFF, 0x3000, 0x1000]);

    // setup `kmp` for later reuse
    const kmp = Kmp.KnuthMorrisPratt(pattern);
    // returns the first index of the exact match in `corpus`; -1 if not found
    const idx = kmp.match(corpus);
    if (idx !== 1)
        throw (new Error('Please file an issue'));
}

// also working with String
{
    const pattern = "pattern";
    const corpus = "some pattern !@#$%";

    const kmp = Kmp.KnuthMorrisPratt(pattern);
    const idx = kmp.match(corpus);
    if (idx !== corpus.indexOf(pattern))
        throw (new Error('Please file an issue'));
}

// you can specify offset!
{
    const pattern = "123";
    const corpus = "123abc123";
    const corpusOffset = 1;

    const idx = Kmp.KnuthMorrisPratt(pattern).match(corpus, corpusOffset);
    if (idx !== corpus.indexOf(pattern, corpusOffset))
        throw (new Error('Please file an issue'));
}

Run tests

npm install -D  # install dev dependencies
npm test        # run tests

References

• https://www.inf.hs-flensburg.de/lang/algorithmen/pattern/kmpen.htm
• https://people.ok.ubc.ca/ylucet/DS/KnuthMorrisPratt.html

See also

You might be interested to Boyer–Moore–Horspool algorithm

License

See LICENSE file