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I'm looking for an efficient hash algorithm with which I can have 64-bit values represent strings in a databse.

Following Mark Adler's answer+comments here it seems that using a cryptographical hash function is an overkill. Mark has recommended to try Java's hashCode, but I need a C++ library. I thought about using boost::hash_range.

My question is: Does anyone know how is the distribution of this function vs. Java's hashCode? It would be nice if someone has something to say about about boost::hash_range's performance as well :)

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Why not run them both for your actual data set, or a sample of it? Then you know how they'll actually perform on your data, rather than some theoretical inputs. You could time them while you're at it :-) – Useless Apr 2 at 14:28
@Useless - +1; distribution and speed depend on the details of the hash function; if distribution and speed are critical, then assessment requires measuring with expected data. – Pete Becker Apr 2 at 14:34
I have no idea about Java's hashCode, but hash_range combines the range values using the following algorithm: seed ^= hash(value) + 0x9e3779b9 + (seed<<6) + (seed>>2); - where seed is accumulating the hash result (initially zero). – Igor R. Apr 2 at 14:35
@Useless - I don't have the data yet, nor I have a sample of it. It's an infrastructure I'm preparing. All I know is that the elements will be strings in different lengths. – Subway Apr 2 at 14:46
I'd still suggest measuring yourself tbh, even if it's on artificial inputs. Any answer you get will just be an anecdote about how it performed on some other set of data. Let us know if you're not sure how to measure boost::hash_range's performance or distribution. – Useless Apr 2 at 15:02
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