On Tue, Jun 9, 2009 at 11:40 PM, Dean Michael Berris<mikhailberis@gmail.com> wrote:
On Tue, Jun 9, 2009 at 8:10 PM, Sebastian Redl<sebastian.redl@getdesigned.at> wrote:
The request was for a bloom filter whose size is set at construction time. This is useful e.g. because it allows the user of some filtering tool to trade memory for reliability via a configuration file instead of having to recompile.
Agreed. Then I'll implement a dynamically sized bloom filter, maybe call it dynamic_bloom_filter that uses a Boost.Dynamic_bitset internally.
Thanks for pointing out my oversight.
And as of revision 53785 of the Boost Sandbox, boost::bloom_filter<> now has the following template parameters: template <class Input, class Sequence, class Block, class Allocator> struct bloom_filter; Sequence is a Fusion-compliant sequence of hash functions. The default parameter is a set of three pre-seeded hash functions which are an improved version of the earlier boost::detail::default_hash<Size> type. Block is the type used by the underlying Boost.Dynamic_bitset allocated by Allocator. Now a bloom_filter can just be defined as: bloom_filter<int> bf(2048); // 2048 is the number of bits to store, a runtime value The default bloom_filter has three functions, all specializations of the boost::detail::default_hash<Size> type (namely default_hash<0>, default_hash<1>, default_hash<2>). HTH -- Dean Michael Berris | Software Engineer, Friendster, Inc. blog.cplusplus-soup.com | twitter.com/mikhailberis | linkedin.com/in/mikhailberis | profiles.friendster.com/mikhailberis | deanberris.com