BloomFilter class final

Bloom filter used to skip segments that cannot contain a key.

Ten bits per key with seven probes gives roughly a 1% false-positive rate. The serialized form is [u32 bitCount][u8 hashCount][bits], little-endian.

Probes use double hashing over CRC-32C: h1 + i * h2. Both are 32-bit, and the intermediate i * h2 stays below 2^35, so this is exact on dart2js.

Constructors

BloomFilter.build(Iterable<Uint8List> keys, {int bitsPerKey = 10, int minBits = 64, int hashCount = 7})

Builds a filter over keys.

factory

Properties

bitCount → int

Total number of bits.

final

bits → Uint8List

Backing bits.

final

byteLength → int

Serialized size in bytes.

no setter

hashCode → int

The hash code for this object.

no setter, inherited

hashCount → int

Number of probes per key.

final

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

add(Uint8List key) → void

Adds key to the filter.

mightContain(Uint8List key) → bool

Whether key may be present. False positives are possible; false negatives are not.

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

toBytes() → Uint8List

Serializes the filter to a new buffer.

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited

Static Methods

parse(Uint8List source, [int offset = 0]) → ({BloomFilter filter, int next})

Parses a filter starting at offset; next reports the end offset.