Crate flowerbloom

Structs

• BloomBuilder
  Provides a way to build a bloom filter with optional fields, such as customizing the Hasher used or the number of hash functions used in its representation. Will use a DefaultHasher if no other hasher is specified, and will use the optimal number of hash functions depending on the number of items by default.
• BloomFilter
  Defines a bloom filter for items of a given type provided a capacity and a desired false positive rate.
• DefaultHasher
  The default hasher for the bloom filter simply takes the first 8 bytes from a sha256 hash of an item and reads that as a big-endian, u64 number. It implements the Hasher trait.

Traits

• Hasher
  Hasher defines a struct that can produce a u64 from an item that can be referenced as a byte slice. Our bloom filter implementation maps the output number from this hash function to indices in its internal representation.

Functions

• optimal_bits_needed
  Computes the optimal bits needed to store n items with an expected false positive rate in the range [0, 1.0]. The formula is derived analytically as a well-known result for bloom filters, computed as follows:
• optimal_num_hash_fns
  Computes the optimal number of hash functions needed a bloom filter with an expected n num_items, and a desired false positive rate. Rounds up to the nearest integer.

Type Definitions

• HashFn
  HashFn defines a function that can produce a u64 from an input value and is thread-safe.