farmhash

What is farmhash?

The farmhash npm package provides fast, non-cryptographic hash functions for strings and binary data. It is based on Google's FarmHash family of hash functions, which are designed for high performance and reliability.

What are farmhash's main functionalities?

Hashing a string

This feature allows you to generate a 32-bit hash from a given string. The hash function is optimized for speed and can be used for tasks like data partitioning or quick lookups.

const farmhash = require('farmhash');
const hash = farmhash.hash32('Hello, world!');
console.log(hash);

Hashing a buffer

This feature allows you to generate a 32-bit hash from a buffer. This is useful for hashing binary data or files.

const farmhash = require('farmhash');
const buffer = Buffer.from('Hello, world!');
const hash = farmhash.hash32(buffer);
console.log(hash);

Hashing a string to 64-bit

This feature allows you to generate a 64-bit hash from a given string. The 64-bit hash provides a larger hash space, reducing the likelihood of collisions.

const farmhash = require('farmhash');
const hash = farmhash.hash64('Hello, world!');
console.log(hash);

Hashing a buffer to 64-bit

This feature allows you to generate a 64-bit hash from a buffer. This is useful for applications requiring a larger hash space for binary data.

const farmhash = require('farmhash');
const buffer = Buffer.from('Hello, world!');
const hash = farmhash.hash64(buffer);
console.log(hash);

Other packages similar to farmhash

murmurhash

MurmurHash is a non-cryptographic hash function suitable for general hash-based lookup. It is known for its good distribution and performance. Compared to farmhash, MurmurHash is also very fast but may not be as optimized for certain hardware architectures.

xxhash

xxHash is an extremely fast non-cryptographic hash algorithm, working at speeds close to RAM limits. It is designed for speed and is often faster than farmhash, but farmhash may offer better distribution properties in some cases.

cityhash

CityHash, like FarmHash, is developed by Google and provides fast hashing for strings. It is similar to FarmHash but is an older version. FarmHash is designed to be more portable and faster on newer hardware.

README

farmhash

Node.js implementation of Google's FarmHash family of very fast hash functions.

FarmHash is the successor to CityHash. Functions in the FarmHash family are not suitable for cryptography. A fast, cryptographically-secure alternative is HighwayHash.

As the V8 JavaScript engine only natively supports 32-bit unsigned integers, the 64-bit methods return strings instead of Numbers and the 128-bit methods are not implemented.

This module uses FarmHash v1.1.0 (2015-03-01). It has been tested with Node.js v0.10, v0.12, v4, v6 on Linux, OS X and Windows.

Installation

npm install farmhash

Usage

var farmhash = require('farmhash');

var hash = farmhash.hash32('test');
console.log(typeof hash); // 'number'

var hash = farmhash.hash64(new Buffer('test'));
console.log(typeof hash); // 'string'

var hash = farmhash.hash64WithSeed('test', 123);
console.log(typeof hash); // 'string'

var hash = farmhash.fingerprint32(new Buffer('test'));
console.log(typeof hash); // 'number'

var hash = farmhash.fingerprint64('test');
console.log(typeof hash); // 'string'

API

Hash

The hash methods are platform dependent. Different CPU architectures, for example 32-bit vs 64-bit, Intel vs ARM, SSE4.2 vs AVX might produce different results for a given input.

hash32(input)

• input is the Buffer or String to hash.

Returns a Number containing the 32-bit unsigned integer hash value of input.

hash32WithSeed(input, seed)

• input is the Buffer or String to hash.
• seed is an integer Number to use as a seed.

Returns a Number containing the 32-bit unsigned integer hash value of input.

hash64(input)

• input is the Buffer or String to hash.

Returns a String representing the 64-bit unsigned integer hash value of input.

hash64WithSeed(input, seed)

• input is the Buffer or String to hash.
• seed is an integer Number to use as a seed.

Returns a String representing the 64-bit unsigned integer hash value of input.

hash64WithSeeds(input, seed1, seed2)

• input is the Buffer or String to hash.
• seed1 and seed2 are integer Numbers to use as seeds.

Returns a String representing the 64-bit unsigned integer hash value of input.

hash32v1(input)

Legacy function to access v1 of the FarmHash implementation.

• input is the Buffer or String to hash.

Returns a Number containing the 32-bit unsigned integer v1 hash value of input.

Fingerprint

The fingerprint methods are platform independent, producing the same results for a given input on any machine.

fingerprint32(input)

• input is the Buffer or String to fingerprint.

Returns a Number containing the 32-bit unsigned integer fingerprint value of input.

fingerprint64(input)

• input is the Buffer or String to fingerprint.

Returns a String representing the 64-bit unsigned integer fingerprint value of input.

Testing

npm test

Licence

Copyright 2014, 2015, 2016 Lovell Fuller and contributors.

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

 http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Copyright 2014, 2015 Google, Inc.

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.