I've just checked in a proof-of-concept implementation to use Bloom filters to handle arbitrary option string values with popt.
The problem that I am trying to solve in popt (and for RPM and for option processing in general) is to devise a means to handle arbitrary (as in unknown when code is compiled) string options and values and argument lists. Bloom filters, because they partition the space, not the data, are the best means to that end that I'm aware of. (aside) All that the above means is that a Bloom filter bit set with all 1's: 11111111111.... will match *everything* that is fed to it. Consider the alternative, an explicit table of "known" values, which will fail if/when a Newer! Better! Bestest! string is added but someone fergits to add it to the "known" value table. The cost (as in no. of bytes required) is quite modest: Assuming a population of an option attribute set of ~1024 arbitrary strings (>2 orders of magnitude more than the number of fingers that I have ;-), uisng 16 linearly combined hashes (to reduce the probability of false positives to < 0.01%), popt will lazily alloc a bit set of approx. (3 * 1024) / 2 which is 1536 bits (or 192 bytes). *shrug* (aside) All of the above parameters are tunable, the only hard question is What should the default pramaters in popt be? I won't know whether I like the popt implementation (Bloom filters are not at all bloaty) until I try using it at an application level. todo++ Other opinions welcomed, particularly on the API. There's still some polishing that remains. Enjoy! 73 de Jeff ______________________________________________________________________ POPT Library http://rpm5.org Developer Communication List firstname.lastname@example.org