Re: Hashing strings

Jason Barnett wrote:

Gerard Samuel wrote: ...

Im trying to determine if md5() would be the fastest, *cheapest* solution.

...

What Im looking for is something where the generated hashes can be reproduced. For example, md5('foo') today, will be equal to md5('foo') tomorrow. Thanks

AFAIK crc32() is the fastest hashing function in PHP. I don't have actual results on hand still, but I created a filesystem plugin that auto-generates hashes for each file in a directory. crc32() was faster than md5() and sha1(). FYI the benchmarking that I did was for a Windows XP system... YMMV

I normally profile with apd, but it only measures in the hundredth of a second. So I used getrusage() & memory_get_usage() functions to *unscientifically* profile md5()/sha1()/crc32() on FreeBSD 5.3. I ran a for loop 75 times, hashing the constant __FILE__ These are an average of 5 runs -> ---- md5: Usertime -> 784.2 µsec Systemtime -> 72.2 µsec

Memory     -> 120.0 bytes

sha1: Usertime -> 846.8 µsec Systemtime -> 150.2 µsec

Memory     ->  80.0 bytes
      crc32:

Usertime -> 194.8 µsec Systemtime -> 54.2 µsec

Memory     ->  80.0 bytes

Can you shed some light on that code, that you're using for the filesystem plugin? Thanks