https://github.com/rootslab/hazz
Hazz, a pseudo-random-data-filled-table, to generate k indipendent and uniform, very fast hash functions.
https://github.com/rootslab/hazz
bloom-filter hash hash-functions hashing nodejs random universal-hashing
Last synced: 15 days ago
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Hazz, a pseudo-random-data-filled-table, to generate k indipendent and uniform, very fast hash functions.
- Host: GitHub
- URL: https://github.com/rootslab/hazz
- Owner: rootslab
- License: mit
- Created: 2017-11-08T20:31:07.000Z (over 8 years ago)
- Default Branch: master
- Last Pushed: 2018-02-17T17:33:18.000Z (over 8 years ago)
- Last Synced: 2025-07-01T13:05:45.215Z (11 months ago)
- Topics: bloom-filter, hash, hash-functions, hashing, nodejs, random, universal-hashing
- Language: JavaScript
- Homepage:
- Size: 33.2 KB
- Stars: 2
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: Readme.md
- License: LICENSE
Awesome Lists containing this project
README
### Hazz
[](https://www.npmjs.org/package/hazz)
[](https://www.codacy.com/public/44gatti/hazz)
[](https://codeclimate.com/github/rootslab/hazz)
[](https://github.com/rootslab/hazz#mit-license)
[](http://travis-ci.org/rootslab/hazz)
[](https://david-dm.org/rootslab/hazz)
[](https://david-dm.org/rootslab/hazz#info=devDependencies)
[](http://npm-stat.com/charts.html?package=hazz)
[](http://npm-stat.com/charts.html?package=hazz)
[](https://nodei.co/npm/hazz/)
> __Hazz__, a __pseudo-random-data-filled-table__ to generate __k indipendent__ and __uniform__, __very fast__ (non-cryptographic) hash functions.
> If you need to hash __arbitrary long length__ inputs, without using a fixed (big) size pseudo-random table, a fast way is to __simulate__ a set of indipendent hash functions using a single crpyto-digest (with a sha-512 digest we can simulate up to 16 functions). Take a look to __[Mazz](https://github.com/rootslab/mazz)__ (the fast way of the __tonto__).
### Install
```bash
$ npm install hazz [-g]
```
> __require__:
```javascript
var Hazz = require( 'hazz' );
```
### Run Tests
> __to run all test files, install devDependencies:__
```bash
$ cd hazz/
# install or update devDependencies
$ npm install
# run tests
$ npm test
```
> __to execute a single test file simply do__:
```bash
$ node test/file-name.js
```
### Constructor
> Specify how many bytes to parse (at max), from every
> input key to hash, then the number of functions to use.
> NOTE:
> - default value for input length is 16 byte.
> - default and minimum value for hfn is 2
> Arguments between [] are optional.
```javascript
Hazz( [ Number max_input_length [, Number hfn ] ] )
// or
new Hazz( [ Number max_input_length [, Number hfn ] ] )
```
### Properties
```javascript
/*
* the table containing pseudo-random data for generating hash numbers.
* NOTE: the size of the table is: (max_input_length * hfn) kilobytes,
* it doesn't depends on the expected population.
*/
Hazz.table
/*
* max input key length
*/
Hazz.ilength
/*
* total number of hash functions
*/
Hazz.hfn
```
### Methods
> Arguments between [] are optional.
```javascript
/*
* re-fill table with fresh pseudo-random numbers
*/
Hazz#refill() : Hazz
/*
* Specify a positive integer (from 0 to k-1) to use the k-th
* hash function. If specified it returns a number within a
* range.
*
* NOTE:
* - the input should be a Buffer (no Strings or Arrays).
* - the minimum range is obviously 2 (0, 1).
* - the integers produced are at min 4 byte long (>= 2^24),
* longer the input parsed, bigger the numbers produced.
*/
Hazz#do( Number hfn, Buffer data [, Number range ] ) : Number
/*
* hash with all functions in parallel,
* it returns an array of results
*/
Hazz#all( Buffer data [, Number range ] ) : Array
```
> See [examples](example/).
### MIT License
> Copyright (c) 2017-present < Guglielmo Ferri : 44gatti@gmail.com >
> Permission is hereby granted, free of charge, to any person obtaining
> a copy of this software and associated documentation files (the
> 'Software'), to deal in the Software without restriction, including
> without limitation the rights to use, copy, modify, merge, publish,
> distribute, sublicense, and/or sell copies of the Software, and to
> permit persons to whom the Software is furnished to do so, subject to
> the following conditions:
> __The above copyright notice and this permission notice shall be
> included in all copies or substantial portions of the Software.__
> THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
> EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
> MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
> IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
> CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
> TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
> SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
[](https://github.com/igrigorik/ga-beacon)