https://github.com/rootslab/asino
Asino a stubborn, simple and fast Bloom filter for the rest of us.
https://github.com/rootslab/asino
bloom-filter hashing nodejs-modules pseudo-random universal-hashing
Last synced: about 1 year ago
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Asino a stubborn, simple and fast Bloom filter for the rest of us.
- Host: GitHub
- URL: https://github.com/rootslab/asino
- Owner: rootslab
- License: mit
- Created: 2017-11-15T00:20:42.000Z (over 8 years ago)
- Default Branch: master
- Last Pushed: 2018-01-09T20:11:00.000Z (over 8 years ago)
- Last Synced: 2025-03-09T03:34:28.894Z (about 1 year ago)
- Topics: bloom-filter, hashing, nodejs-modules, pseudo-random, universal-hashing
- Language: JavaScript
- Homepage:
- Size: 36.1 KB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: Readme.md
- License: LICENSE
Awesome Lists containing this project
README
### Asino
[](https://www.npmjs.org/package/asino)
[](https://www.codacy.com/public/44gatti/asino)
[](https://codeclimate.com/github/rootslab/asino)
[](https://github.com/rootslab/asino#mit-license)
[](http://travis-ci.org/rootslab/asino)
[](https://david-dm.org/rootslab/asino)
[](https://david-dm.org/rootslab/asino#info=devDependencies)
[](http://npm-stat.com/charts.html?package=asino)
[](http://npm-stat.com/charts.html?package=asino)
[](https://nodei.co/npm/asino/)
> __Asino__, a stubborn, simple and fast __Bloom filter__ for the rest of us.
### Install
```bash
$ npm install asino [-g]
```
> __require__:
```javascript
var Asino = require( 'asino' );
```
### Run Tests
> __to run all test files, install devDependencies:__
```bash
$ cd asino/
# install or update devDependencies
$ npm install
# run tests
$ npm test
```
### Constructor
```javascript
Asino( [ Object opt ] )
// or
new Asino( [ Object opt ] )
```
### Options
> Default options are listed.
```javascript
opt = {
/*
* expected population of elements
*/
epop : 10000
/*
* The max number of bytes to parse from every
* input element, using the pseudo-random table.
* In normal mode you should specify this property
* generally sizing it on the expected input length.
*
* When dunce mode is on, this property is ignored,
* because no pseduo-random table will be generated.
*/
, ilen : 32
/*
* The number of hash functions to use.
* The greater the number, lesser is the probability
* of collisions.
*
* - the false positive probability:
*
* fpp ~= - 1 / ( 10 ^ hfn )
*
* In dunce mode this number is limited to 16.
*/
, hfn : 6
/*
* Dunce mode, it is off for default.
*
* It is a fast way for testing collisions/duplicates on
* long inputs ( > ~ 64 bytes ), without the construction
* and the use of pseudo-random table, because it uses a
* crypto digest to simulate 16 different hash functions.
*
* However, no randomness is involved for producing values,
* then, for every distinct function (0-15):
*
* Same input -> Same hash result. Every time.
*
* In dunce mode the integer produced by hash functions
* are limited to the range [2^24, 2^32 -1].
*/
, dunce: false
}
```
### Properties
```javascript
/*
* the internal bitmap.
*/
Asino.vector
/*
* the internal pseudo-random table used to generate k
* indipendent hash functions.
*/
Asino.hash
/*
* the total number of bits used for the bitmap vector.
*/
Asino.bits
/*
* the total number of hash functions
*/
Asino.hfn
/*
* the max bytes to parse from input
*/
Asino.ilen
/*
* the current false positive probability
*/
Asino.fpp
```
### Methods
> Arguments between [] are optional.
```javascript
/*
* Check if an element exists.
* When it returns false, we are sure that the element
* does not exist in the filter.
* When it returns true, there is a probability of a
* false positive, equal to the current fpp.
*/
Asino#key( Buffer data ) : Boolean
/*
* try to add the element if it doesn't exist.
* It returns the same result of Asino#key
*/
Asino#try( Buffer data ) : Boolean
/*
* Reset/regenerate the filter
*/
Asino#yoke() : Asino
/*
* Re-build Bloom filter, via a config object.
*/
Asino#grow( [ Object opt ] ) : Asino
opt : { [ hfn: Number ] [, epop: Number] [, ilen : Number] [, dunce: Boolean] }
```
> 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.