Jakse wrote: > It would also be interesting to have ideas for the general > case
Yes, ideas might be interesting. :-) A root of "good" hashing is incorporated in algorithm2 of your posting: spread the values produced by the hash function uniformly over the interval size_t.min .. size_t.max. Therefore: Compute the hash value for a given key by multiplying each byte of the key with a factor, which increases from the byte with lowest significance to the byte with highest significance; of course add the results. Remarks: a) Because of the general case: assume that the original key contains much redundance. Therefore do not use the bytes of the original key but compute a ( at least close to) lossless compression of the original key. b) The factors in the factor list should be primes for spreading the hash value uniformly over the intended range c) The quotint of two consecutives primes in the factor list should be greater than 256, because the used key might not contain any reduundancy. -manfred
