rolling-string-hash

rolling-string-hash is a node library that lets you use a rolling hash on strings. Using a rolling hash allows you to do things such as string search in O(n) time.

Installation

If you are using node, you can install it with npm

npm install rolling-string-hash

Then include it in your project

var RollingStringHash = require('rolling-string-hash');

Usage

Rolling String Hashes are best utilized when keeping the number of characters hashed constant, and moving the hash block forwards or backwards on the string.

Constructor

To create a new Rolling String Hash, you can initialize it with no parameters or a string parameter which will represent the hash's initial contents.

var rsh = new RollingStringHash('hello');

Methods

addRight(string)

Adds a string to the right side of the hash.

addLeft(string)

Adds a string to the left side of the hash.

removeRight(number = 1)

Removes a number of characters from the right side of the hash. If no number is specified, it removes one character. Returns the characters that were removed.

removeLeft(number = 1)

Removes a number of characters from the left side of the hash. If no number is specified, it removes one character. Returns the characters that were removed.

getHash()

Returns the JavaScript number representation of the hash value.

getLength()

Returns the length of the string being hashed.

getString()

Returns the string being hashed. Runs in O(string.length) time.

equals(object)

Used to see if two Rolling String Hashes are equal.