murmur

Murmur3

A NodeJS module for sub-millisecond, non-cryptographic hashes using the Murmur3 algorithm.

Note: As of v0.0.1, only the 128 bit hash is supported.

Bonus

Javascript does not contain 64 bit operations....

Instead, the standard complies to a 64 bit floating point representation that gives 58 bits of precision in integers.

To overcome this, I had to fill in these gaps. As such, I have allowed these operations to be accessed from the murmur object.

The functions include:

• add64(a, b) :: Addition
• mult64(a, b) :: Multiplication
• shiftr(a, bits) :: Shift right
• shiftl(a, bits) :: Shift left
• rotl(a, bits) :: Rotate left
• where (a) or (b) are a 64 bit integer of format [nHigh, nLow]

Hash Usage

• .hash128(string) :: Hash the given string. Returns the murmur object.
• .raw() :: Return the array of four "32 bit unsigned integers"
• .hex() :: Return a 16 character/byte, string, hex representation

Alternatively, the raw array may be accessed with murmur.hash_raw.

var murmur = require('murmur3');

// NOTE: currently only 128 bit length is implemented

// array of 4 "32 bit unsigned integers"
var hash = murmur.hash128('string of text or data').raw();

// or with a seed (limited to 32 bit address space)
var seeded = murmur.hash128('string of text or data', 0xFFFFFFFF);

// returns 16 character hex representation as a string
var string_hex = murmur.hash128('will be 16byte hex').hex();

Testing

Install mocha and should using

npm install --dev

Note: npm 1.2.18 contains a bug that tries to install the development version of all devDependencies. Omit the --dev option and it should work correctly.

Once everything is installed:

make test