Module fasthash::spooky
[−]
[src]
SpookyHash
: a 128-bit noncryptographic hash function
by Bob Jenkins
http://www.burtleburtle.net/bob/hash/spooky.html
- Oct 31 2010: alpha, framework +
SpookyHash
::Mix appears right - Oct 31 2011: alpha again, Mix only good to 269 but rest appears right
- Dec 31 2011: beta, improved Mix, tested it for 2-bit deltas
- Feb 2 2012: production, same bits as beta
- Feb 5 2012: adjusted definitions of uint* to be more portable
Up to 4 bytes/cycle for long messages. Reasonably fast for short messages. All 1 or 2 bit deltas achieve avalanche within 1% bias per output bit.
This was developed for and tested on 64-bit x86-compatible processors. It assumes the processor is little-endian. There is a macro controlling whether unaligned reads are allowed (by default they are). This should be an equally good hash on big-endian machines, but it will compute different results on them than on little-endian machines.
Google's CityHash
has similar specs to SpookyHash
, and CityHash
is faster
on some platforms. MD4 and MD5 also have similar specs, but they are orders
of magnitude slower. CRCs are two or more times slower, but unlike
SpookyHash
, they have nice math for combining the CRCs of pieces to form
the CRCs of wholes. There are also cryptographic hashes, but those are even
slower than MD5.
Examples
use std::hash::{Hash, Hasher}; use fasthash::{spooky, SpookyHasher}; fn hash<T: Hash>(t: &T) -> u64 { let mut s: SpookyHasher = Default::default(); t.hash(&mut s); s.finish() } let h = spooky::hash128(b"hello world\xff"); assert_eq!(h.low64(), hash(&"hello world"));
Structs
SpookyHash128 |
|
SpookyHash32 |
|
SpookyHash64 |
|
SpookyHasher128 |
An implementation of |
Functions
hash128 |
|
hash128_with_seed |
|
hash32 |
|
hash32_with_seed |
|
hash64 |
|
hash64_with_seed |
|