A fast algorithm to hash string or binary file inspired by the JSW hash.
npm install jhashA fast algorithm to hash string or binary file inspired by the JSW hash.
Not likes md5 or sha1, the hash sum it creates is only about 6 chars (if you use base 70).
I used it in one of my company's node project.
It helps me peacefully distribute different versions of files to the CDN service.
Useful when using it in the URL hash or table lookup.
 
* Easy to control the length of the result hash value.
* Lite and fast.
I have implemented the core algorithm into 7 commonly used languages:
* c
* coffeescript
* go
* lua
* php
* python
* ruby
Only the coffeescript one has full API. If you only want the minimal function, go for the src/jhash.core.js file,
Or require('jhash/lib/jhash.core.js')
* Install
``shell`
npm install jhash
* Usage
`javascript
var jhash = require('jhash');
jhash.hash('test'); // output => '349o'
var fs = require('fs');
jhash.hash(fs.readFileSync('a.jpg'));
// Control the hash char set.
jhash.setSymbols('abcdef');
jhash.hash('test'); // output => 'decfddfe'
// Control the max length of the result hash value. Unit is bit.
jhash.setMaskLen(10);
jhash.hash('test'); // output => 'ede'
// New jhash instance.
myJhash = new jhash.constructor
`
Install it via [Bower][2]: bower install jhash.
Or download the js file from the release page: [Release][1].
`html`
* Install
To use it as a command line tool, install it globally.
npm install -g jhash
* Usage
Here are some examples.
Print help information:
jhash -h
Hash string abc, it outputs 2csX:
jhash abc
Hash a jpg image file (it will automatically detect whether the passed in argument is a file or not):
jhash a.jpg
#### Unit test
You must have installed coffeescript and mocha globally.
cake test
#### Collision test for 10 seconds random data
cake collision
#### Compare to some other hash algorithms
This is just a random test, you may need to test some real data before using it in project.
`
jhash *
sample: ["jg0ayq","nz9fb0","oa9iz1","4w5egf","dt7dsv","9wkm25","duu2j2","solh6y","z6rnbl","aa8ebp","g568a2"]
time: 6.836s
collisions: 0.000999999999995449%
rotating_hash *
sample: ["ahuz3","2hxrf3","k68zy","3cdf61","2857v2","fgua","3216o4","2i69dz","1ehpfn","1y46pv","3m1r0h"]
time: 7.154s
collisions: 48.626000000000005%
bjb2_hash *
sample: ["sdflvy","-g2j5ix","-1dsjyy","sezbl2","-wye5kw","-bdfy0t","-mudsaj","-4f3shn","-z1mxsl","-165mmr","q5oh58"]
time: 16.718s
collisions: 0.002000000000002%
fnv_hash *
sample: ["4ct07k","-pdrz0h","me11fv","t9px7i","-y120s","251qw7","h83axv","tob69f","eonk6","-6dkeny","elxam6"]
time: 16.787s
collisions: 0.000999999999995449%
oat_hash *
sample: ["-fg1gqa","-2k0tg","a391j2","1jd98xw","2dw8oj","-uldzx3","-t9m4me","-5z57og","6m0uqx","-17q8t0j","u8m0lo"]
time: 19.028s
collisions: 0.000999999999995449%
jsw_hash *
sample: ["-hm4rfv","vehfuu","jwf2v0","5c2oq3","-9xs2xt","p1ho2c","-ri84uf","op47br","-13wvwp","ek12tv","hrc6ki"]
time: 15.702s
collisions: 0.002999999999997449%
`
Run cake benchmark`.
Intel Core i7 2.3GHz SSD
87174 ops/s.
Avr. file size 6716B.
* Add more test cases.
Apr 2014 jhash
[1]: https://github.com/ysmood/jhash/releases
[2]: https://github.com/bower/bower