Documentation
¶
Overview ¶
Package bloom provides a counting Bloom filter for probabilistic membership testing with element removal support.
NOT safe for concurrent use. Callers must synchronize access externally.
Index ¶
- Variables
- type CountingFilter
- func (f *CountingFilter) Add(data []byte)
- func (f *CountingFilter) Clear()
- func (f *CountingFilter) Copy() *CountingFilter
- func (f *CountingFilter) MarshalBinary() ([]byte, error)
- func (f *CountingFilter) Remove(data []byte)
- func (f *CountingFilter) Test(data []byte) bool
- func (f *CountingFilter) ToBytes() ([]byte, error)
- func (f *CountingFilter) UnmarshalBinary(data []byte) error
Examples ¶
Constants ¶
This section is empty.
Variables ¶
var ( ErrEmptyDump = errors.New("empty dump") ErrBitsetTooBig = errors.New("bitset overflow: parameters require more than 2^32 bits") )
Bloom filter errors.
Functions ¶
This section is empty.
Types ¶
type CountingFilter ¶
type CountingFilter struct {
// contains filtered or unexported fields
}
CountingFilter is a probabilistic data structure that supports both membership testing and element removal.
func NewCounting ¶
func NewCounting(n int, p float64) (*CountingFilter, error)
NewCounting creates an optimized counting bloom filter. It returns ErrBitsetTooBig when n and p require more bits than a 32-bit filter supports.
Example ¶
package main
import (
"fmt"
"github.com/FrogoAI/memory/bloom"
)
func main() {
bf, err := bloom.NewCounting(1000, 0.01)
if err != nil {
panic(err)
}
bf.Add([]byte("hello"))
fmt.Println(bf.Test([]byte("hello")))
}
Output: true
func NewCountingFromBytes ¶
func NewCountingFromBytes(data []byte) (*CountingFilter, error)
NewCountingFromBytes deserializes a byte slice into a CountingFilter.
func (*CountingFilter) Add ¶
func (f *CountingFilter) Add(data []byte)
Add inserts data into the filter by incrementing its counters. It protects against counter overflow (stopping at 255).
Example ¶
package main
import (
"fmt"
"github.com/FrogoAI/memory/bloom"
)
func main() {
bf, _ := bloom.NewCounting(1000, 0.01)
bf.Add([]byte("apple"))
bf.Add([]byte("banana"))
bf.Add([]byte("cherry"))
fmt.Println(bf.Test([]byte("apple")))
fmt.Println(bf.Test([]byte("banana")))
fmt.Println(bf.Test([]byte("cherry")))
}
Output: true true true
func (*CountingFilter) Clear ¶
func (f *CountingFilter) Clear()
Clear resets all counters in the filter.
Example ¶
package main
import (
"fmt"
"github.com/FrogoAI/memory/bloom"
)
func main() {
bf, _ := bloom.NewCounting(1000, 0.01)
bf.Add([]byte("apple"))
bf.Add([]byte("banana"))
fmt.Println(bf.Test([]byte("apple")))
bf.Clear()
fmt.Println(bf.Test([]byte("apple")))
}
Output: true false
func (*CountingFilter) Copy ¶
func (f *CountingFilter) Copy() *CountingFilter
Copy returns a deep copy of the CountingFilter.
func (*CountingFilter) MarshalBinary ¶
func (f *CountingFilter) MarshalBinary() ([]byte, error)
MarshalBinary implements the encoding.BinaryMarshaler interface.
func (*CountingFilter) Remove ¶
func (f *CountingFilter) Remove(data []byte)
Remove deletes data from the filter by decrementing its counters. It protects against counter underflow (stopping at 0).
Example ¶
package main
import (
"fmt"
"github.com/FrogoAI/memory/bloom"
)
func main() {
bf, _ := bloom.NewCounting(1000, 0.01)
bf.Add([]byte("apple"))
fmt.Println(bf.Test([]byte("apple")))
bf.Remove([]byte("apple"))
fmt.Println(bf.Test([]byte("apple")))
}
Output: true false
func (*CountingFilter) Test ¶
func (f *CountingFilter) Test(data []byte) bool
Test checks if an item is likely in the set. It returns true if the item might be in the filter, false if it is definitely not.
Example ¶
package main
import (
"fmt"
"github.com/FrogoAI/memory/bloom"
)
func main() {
bf, _ := bloom.NewCounting(1000, 0.01)
bf.Add([]byte("apple"))
fmt.Println(bf.Test([]byte("apple")))
fmt.Println(bf.Test([]byte("banana")))
}
Output: true false
func (*CountingFilter) ToBytes ¶
func (f *CountingFilter) ToBytes() ([]byte, error)
ToBytes serializes the CountingFilter to a byte slice.
func (*CountingFilter) UnmarshalBinary ¶
func (f *CountingFilter) UnmarshalBinary(data []byte) error
UnmarshalBinary implements the encoding.BinaryUnmarshaler interface.
Source Files