bloom

Documentation

Index

• func K(bitsPerKey int) uint8
• func LegacyEstimateBloomK(itemCount int) int
• type Filter
  • func (f *Filter) Contains(key []byte) bool
• type Generator
  • func (g *Generator) Add(key []byte)
  • func (g *Generator) Generate(bitsPerKey int, k uint8) *Filter
• type LegacyBloom
  • func NewLegacyBloom(k int) *LegacyBloom
  • func (b *LegacyBloom) Add(item []byte)
  • func (b *LegacyBloom) Test(item []byte) bool

Functions

func K

func K(bitsPerKey int) uint8

K calculate the best K value.

func LegacyEstimateBloomK

func LegacyEstimateBloomK(itemCount int) int

LegacyEstimateBloomK estimate k(num of hash funcs) according to item count.

Types

type Filter

type Filter struct {
	Bits []byte
	K    uint8
}

Filter the bloom filter.

func (*Filter) Contains

func (f *Filter) Contains(key []byte) bool

Contains to test if the given key is contained (false positive).

type Generator

type Generator struct {
	// contains filtered or unexported fields
}

Generator to generate variable-length bloom filter.

func (*Generator) Add

func (g *Generator) Add(key []byte)

Add add the key into bloom.

func (*Generator) Generate

func (g *Generator) Generate(bitsPerKey int, k uint8) *Filter

Generate generate variable-length bloom filter according to bits per key and count of key. The generator will be reset right after Generate.

type LegacyBloom

type LegacyBloom struct {
	Bits [legacyBitsLength / 8]byte
	K    int
}

LegacyBloom a simple bloom filter in 2048 bit length.

func NewLegacyBloom

func NewLegacyBloom(k int) *LegacyBloom

NewLegacyBloom new bloom.

func (*LegacyBloom) Add

func (b *LegacyBloom) Add(item []byte)

Add add item into bloom.

func (*LegacyBloom) Test

func (b *LegacyBloom) Test(item []byte) bool

Test test if item contained. (false positive)