Hashing Algorithm for Hash Table Implementation

Question

I'm looking for a high-speed hashing function with good (i.e near uniform) distribution for use in a hash table implementation.

The hash table will be used exclusively for storing values with an integer key.

Can i just use the lower few bits of the integer as the hash?

e.g int key = n & 15; and create an array with 16 slots to store them.

Any recommendations?

Answer 1

Well, last night I made a versatile hash test (in C) which covers several top-gun hashers and 38 different keys.

You all are welcome to benchmark it at: http://www.overclock.net/t/1319572/benchmarking-the-fastest-hash-function/0_20#post_18495990

I would be glad for revealing how Intel vs AMD and Intel 12.1 compiler vs Microsoft 16 (VS2010) compiler combinations behave with your help.

Answer 2

You can see here xxhash

Your mentioned hash function is very fast, but it is very bad too. If you want a "stupid" hash function maybe you can consider the modulus.

Example:

int key = item % size_of_hash_table