xxhashjs

Synopsis

xxHash is a very fast hashing algorithm (see the details here). xxhashjs is a Javascript implementation of it, written in 100% Javascript. Although not as fast as the C version, it does perform pretty well given the current Javascript limitations in handling unsigned 32 bits integers.

Installation

In nodejs:

npm install xxhashjs

In the browser, include the following, and access the constructor with XXH:

<script src="/your/path/to/xxhash.js"></script>

Examples

• In one step:

var h = XXH.h32( 'abcd', 0xABCD ).toString(16)	// seed = 0xABCD

0xCDA8FAE4

• In several steps (useful in conjunction of NodeJS streams):

var H = XXH.h32( 0xABCD )	// seed = 0xABCD
var h = H.update( 'abcd' ).digest().toString(16)

0xCDA8FAE4

• More examples in the examples directory:

* Compute xxHash from a file data
* Use xxHashjs in the browser

Usage

• XXH makes 2 functions available for 32 bits XXH and 64 bits XXH respectively, with the same signature:

* XXH.h32
* XXH.h64

• In one step:

XXH.h32(<data>, <seed>) The data can either be a string, an ArrayBuffer or a NodeJS Buffer object. The seed can either be a number or a UINT32 object.

• In several steps:

* instantiate a new XXH object H:

XXH.h32(<seed>) or XXH.h32() The seed can be set later on with the init method

* add data to the hash calculation:

H.update(<data>)

* finish the calculations:

H.digest()
The object returned can be converted to a string with toString(<radix>) or a number toNumber(). Once digest() has been called, the object can be reused. The same seed will be used or it can be changed with init(<seed>).

Methods

• XXH.h32()

* `.init(<seed>)`
Initialize the XXH object with the given seed. The seed can either be a number or a UINT32 object.
* `.update(<data>)`
Add data for hashing. The data can either be a string, an ArrayBuffer or a NodeJS Buffer object.

• digest() (UINT32)

Finalize the hash calculations and returns an UINT32 object. The hash value can be retrieved with toString(<radix>).

• XXH.h64()

* `.init(<seed>)`
Initialize the XXH object with the given seed. The seed can either be a number or a UINT64 object.
* `.update(<data>)`
Add data for hashing. The data can either be a string, an ArrayBuffer or a NodeJS Buffer object.
* `.digest()` (_UINT64_)
Finalize the hash calculations and returns an UINT64 object. The hash value can be retrieved with toString(<radix>).

License

MIT