Javascript implementation of xxHash

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

  0xCDA8FAE4

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

• 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().

License

MIT