From: Joel VanderWerf <vjoel@...>
Date: 2005-05-11T06:32:33+09:00
Subject: Re: String Hashing Algorithms

Phrogz wrote:
> Joel VanderWerf wrote:
> 
>>Phrogz wrote:
>>
>>>A brief analysis of Ruby versions of a few string hashing
> 
> algorithms,
> 
>>>and my conclusions about their efficacy at preventing collisions.
>>
>>Is ruby's own String#hash one of the ones you tested? If not, how
> 
> does
> 
>>it compare?
> 
> 
> Because I was interested in C algorithms, I didn't consider it. But, I
> just ran it again, and ruby came out with the best of them:
> 
> ruby :: 100.0000 percent coverage (0 collisions out of 42884)
> 

It is coded in C, and looking at rb_str_hash() in string.h, I see that 
it is one of HASH_ELFHASH, HASH_PERL, or a third (very simple) one.