fnv1a.js

/* jslint node: true */
'use strict';

let _		= require('lodash');

//	FNV-1a based on work here: https://github.com/wiedi/node-fnv
module.exports = class FNV1a {
	constructor(data) {
		this.hash = 0x811c9dc5;
		
		if(!_.isUndefined(data)) {
			this.update(data);
		}
	}

	update(data) {
		if(_.isNumber(data)) {
			data = data.toString();
		}
		
		if(_.isString(data)) {
			data = new Buffer(data);
		}

		if(!Buffer.isBuffer(data)) {
			throw new Error('data must be String or Buffer!');
		}

		for(let b of data) {
			this.hash = this.hash ^ b;
			this.hash += 
				(this.hash << 24) + (this.hash << 8) + (this.hash << 7) + 
				(this.hash << 4) + (this.hash << 1);
		}

		return this;
	}

	digest(encoding) {
		encoding = encoding || 'binary';
		let buf = new Buffer(4);
		buf.writeInt32BE(this.hash & 0xffffffff, 0);
		return buf.toString(encoding);
	}

	get value() {
		return this.hash & 0xffffffff;
	}
}