fnv-plus
!NPM versionnpm-imagenpm-url
!Build statustravis-imagetravis-urlJavascript FNV-1a Hashing Algorithm up to 1024 bits, with highly optimized 32bit and 52bit implementations.
Concept
The FNV-1a hash algorithm, often simply called "fnv", disperses hashes throughout the n-bit hash space with very good dispersion and is very fast.Use this module to generate unique hash/checksum values for Javascript strings or objects. Note: The FNV-1a algorithm is not even remotely suitable as a cryptographic pseudo-random generator, and should not be used to secure any thing for any reason. It is designed for uniqueness, not randomness.
Why fnv-plus?
- It is the fastest FNV implementation available for Node.js (thanks desudesutalk). See Benchmarks.
- It is the only npm module that is capable of generating fnv hashes for keyspaces larger than 32 bits.
fnv-plus
is well-tested. Many other fnv implementations offer no unit tests to prove they work and are performant.fnv-plus
implements a 52bit version of FNV-1a which provides a larger hash space while still making use of Javascript's 53-bit integer space.
New in 1.3.x
- No dependencies!
- Fast Variants that optimize for speed.
New in 1.2.x
- You can easily define custom seeds.
- the
hash()
function can now take arbitrary Javascript objects as input. - changed default bitlength to 52
Install
$ npm install fnv-plus --save
Usage
var fnv = require('fnv-plus'),
astring = 'hello world',
ahash52 = fnv.hash(astring), // 52-bit hash by default
ahash64 = fnv.hash(astring, 64); // 64-bit hash specified
console.log(ahash52.hex() == 'a65e7023cd59e'); //true
console.log(ahash52.str() == 'stglysbf6m'); //true
console.log(ahash52.dec() == '2926792616498590'); //true
console.log(ahash64.hex() == '779a65e7023cd2e7'); //true
console.log(ahash64.str() == '1th7cxzlyc0dj'); //true
console.log(ahash64.dec() == '8618312879776256743'); //true
// fast variants
console.log(fnv.fast1a32hex(astring) == 'd58b3fa7'); //true
console.log(fnv.fast1a52hex(astring) == 'a65e7023cd59e'); //true
fnv.seed('foobar testseed');
console.log(fnv.hash(astring, 64).hex() == ahash64.hex()); // false
// ^^ because the default seed is not 'foobar testseed'
API
fnv.hash(string, bitlength)
- Hash a string using the given bit length (52 is default)
- returns a FnvHash
objectfnv.seed(string)
- Seed the algorithm to produce different values. Hashing the same value withdifferent seeds will very likely result in different results. To the extent
your seed can be random, it can serve as a source of randomness, but
nonetheless is *not* a replacement for a crypgographic PRG (pseudo-random
generator).
- default seed is chongo <Landon Curt Noll> /\>./\\
fnv.useUTF8(bool)
- Controls UTF-8 awareness of hash functions
- default is false
FnvHash.str()
Returns the hashed value as an ascii stringFnvHash.hex()
Returns the hashed value as a hexadecimal stringFnvHash.dec()
Returns the hashed value as a decimal stringFast variants
This functions runs faster because they have no lib-overhead (see benchmarks for more info). They always compute 1a version of hashes and always use default seed. Directly returns hash values (notFnvHash
object).