### Create Cuckoo Filter (Go)

Source: https://context7.com/seiflotfy/cuckoofilter/llms.txt

Initializes a standard cuckoo filter with a specified capacity. The capacity determines the maximum number of elements the filter can hold. This example demonstrates creating a filter capable of holding approximately 1 million elements.

```go
package main

import (
    "fmt"
    cuckoo "github.com/seiflotfy/cuckoofilter"
)

func main() {
    // Create a filter with capacity for ~1,000,000 elements
    // This allocates approximately 1MB on 64-bit systems
    cf := cuckoo.NewFilter(1000000)

    fmt.Printf("Filter created with capacity for 1M items\n")
    fmt.Printf("Current count: %d\n", cf.Count())
    // Output: Current count: 0
}
```

--------------------------------

### Cuckoo Filter Basic Operations in Go

Source: https://github.com/seiflotfy/cuckoofilter/blob/master/README.md

Demonstrates the fundamental operations of the Cuckoo Filter including creation, insertion, lookup, deletion, and counting elements. It shows how to initialize a filter, add unique items, check for existence, remove items, and get the current count. The filter is then reset.

```go
package main

import "fmt"
import cuckoo "github.com/seiflotfy/cuckoofilter"

func main() {
  cf := cuckoo.NewFilter(1000)
  cf.InsertUnique([]byte("geeky ogre"))

  // Lookup a string (and it a miss) if it exists in the cuckoofilter
  cf.Lookup([]byte("hello"))

  count := cf.Count()
  fmt.Println(count) // count == 1

  // Delete a string (and it a miss)
  cf.Delete([]byte("hello"))

  count = cf.Count()
  fmt.Println(count) // count == 1

  // Delete a string (a hit)
  cf.Delete([]byte("geeky ogre"))

  count = cf.Count()
  fmt.Println(count) // count == 0
  
  cf.Reset()    // reset
}
```

--------------------------------

### Insert Element into Cuckoo Filter (Go)

Source: https://context7.com/seiflotfy/cuckoofilter/llms.txt

Inserts an element (as a byte slice) into the cuckoo filter. This operation allows duplicate entries. It returns true if the insertion was successful and false if the filter is full. The example shows inserting unique and duplicate elements.

```go
package main

import (
    "fmt"
    cuckoo "github.com/seiflotfy/cuckoofilter"
)

func main() {
    cf := cuckoo.NewFilter(1000)

    // Insert elements (duplicates allowed)
    data1 := []byte("user@example.com")
    data2 := []byte("user@example.com") // duplicate
    data3 := []byte("another@example.com")

    success1 := cf.Insert(data1)
    success2 := cf.Insert(data2) // duplicate insertion succeeds
    success3 := cf.Insert(data3)

    fmt.Printf("Insert results: %v, %v, %v\n", success1, success2, success3)
    fmt.Printf("Total count: %d\n", cf.Count())
    // Output: Insert results: true, true, true
    // Output: Total count: 3
}
```

--------------------------------

### Lookup Element in Cuckoo Filter (Go)

Source: https://context7.com/seiflotfy/cuckoofilter/llms.txt

Checks for the presence of an element within the cuckoo filter. This operation has an approximate 3% false positive rate, meaning it might return true even if the element was not inserted. The example demonstrates looking up existing and non-existing elements.

```go
package main

import (
    "fmt"
    cuckoo "github.com/seiflotfy/cuckoofilter"
)

func main() {
    cf := cuckoo.NewFilter(1000)

    // Insert some test data
    users := [][]byte{
        []byte("alice@example.com"),
        []byte("bob@example.com"),
        []byte("charlie@example.com"),
    }

    for _, user := range users {
        cf.InsertUnique(user)
    }

    // Lookup existing elements (should return true)
    fmt.Printf("alice exists: %v\n", cf.Lookup([]byte("alice@example.com")))
    fmt.Printf("bob exists: %v\n", cf.Lookup([]byte("bob@example.com")))

    // Lookup non-existing element (should return false, ~3% false positive rate)
    fmt.Printf("dave exists: %v\n", cf.Lookup([]byte("dave@example.com")))

    // Output: alice exists: true
    // Output: bob exists: true
    // Output: dave exists: false
}
```

--------------------------------

### Delete Element from Cuckoo Filter (Go)

Source: https://context7.com/seiflotfy/cuckoofilter/llms.txt

Deletes an element from the cuckoo filter. This operation returns true if the element was found and deleted, and false otherwise. The example shows deleting an existing element and attempting to delete a non-existent one.

```go
package main

import (
    "fmt"
    cuckoo "github.com/seiflotfy/cuckoofilter"
)

func main() {
    cf := cuckoo.NewFilter(1000)

    // Insert an element
    item := []byte("test@example.com")
    cf.InsertUnique(item)
    fmt.Printf("Count after insert: %d\n", cf.Count())

    // Delete the element
    deleted := cf.Delete(item)
    fmt.Printf("Deletion result: %v\n", deleted)
    fmt.Printf("Count after delete: %d\n", cf.Count())

    // Attempt to delete a non-existent element
    deletedNonExistent := cf.Delete([]byte("nonexistent@example.com"))
    fmt.Printf("Deletion result (non-existent): %v\n", deletedNonExistent)

    // Output: Count after insert: 1
    // Output: Deletion result: true
    // Output: Count after delete: 0
    // Output: Deletion result (non-existent): false
}
```

--------------------------------

### Insert Unique Element into Cuckoo Filter (Go)

Source: https://context7.com/seiflotfy/cuckoofilter/llms.txt

Inserts an element into the cuckoo filter only if it does not already exist. This operation prevents duplicate entries. The function returns true if the unique element was successfully inserted and false if it was already present. The example demonstrates the behavior with existing and new elements.

```go
package main

import (
    "fmt"
    cuckoo "github.com/seiflotfy/cuckoofilter"
)

func main() {
    cf := cuckoo.NewFilter(1000)

    email := []byte("user@example.com")

    // First insertion succeeds
    result1 := cf.InsertUnique(email)
    fmt.Printf("First insert: %v, count: %d\n", result1, cf.Count())

    // Second insertion fails (duplicate)
    result2 := cf.InsertUnique(email)
    fmt.Printf("Duplicate insert: %v, count: %d\n", result2, cf.Count())

    // Different data succeeds
    result3 := cf.InsertUnique([]byte("another@example.com"))
    fmt.Printf("New insert: %v, count: %d\n", result3, cf.Count())

    // Output: First insert: true, count: 1
    // Output: Duplicate insert: false, count: 1
    // Output: New insert: true, count: 2
}
```

--------------------------------

### Create a Scalable Cuckoo Filter in Go

Source: https://context7.com/seiflotfy/cuckoofilter/llms.txt

Initializes a Cuckoo filter that automatically adjusts its capacity as more elements are added. This is achieved using `NewScalableCuckooFilter()`, which defaults to an initial capacity and load factor, allowing for dynamic resizing. It simplifies managing filters that may experience unpredictable growth.

```go
package main

import (
    "fmt"
    cuckoo "github.com/seiflotfy/cuckoofilter"
)

func main() {
    // Create scalable filter with default settings
    // Initial capacity: 10,000, load factor: 0.9
    scf := cuckoo.NewScalableCuckooFilter()

    fmt.Printf("Initial count: %d\n", scf.Count())

    // Insert many elements - filter auto-scales
    for i := 0; i < 50000; i++ {
        scf.Insert([]byte(fmt.Sprintf("user-%d", i)))
    }

    fmt.Printf("After 50k inserts - Count: %d\n", scf.Count())

    // Verify lookups still work
    fmt.Printf("user-1000 exists: %v\n", scf.Lookup([]byte("user-1000")))
    fmt.Printf("user-49999 exists: %v\n", scf.Lookup([]byte("user-49999")))
    fmt.Printf("user-99999 exists: %v\n", scf.Lookup([]byte("user-99999")))

    // Output: Initial count: 0
    // Output: After 50k inserts - Count: 50000
    // Output: user-1000 exists: true
    // Output: user-49999 exists: true
    // Output: user-99999 exists: false
}

```

--------------------------------

### Scalable Filter Serialization in Go

Source: https://context7.com/seiflotfy/cuckoofilter/llms.txt

Illustrates how to encode and decode a scalable Cuckoo filter to preserve its state. It demonstrates creating a filter, populating it with data, encoding it to bytes, decoding it back, and verifying the integrity of the data. This uses the cuckoofilter Go library.

```Go
package main

import (
    "fmt"
    "log"
    cuckoo "github.com/seiflotfy/cuckoofilter"
)

func main() {
    // Create and populate scalable filter
    scf := cuckoo.NewScalableCuckooFilter()

    // Add enough data to trigger scaling
    for i := 0; i < 25000; i++ {
        scf.Insert([]byte(fmt.Sprintf("record-%d", i)))
    }

    originalCount := scf.Count()
    fmt.Printf("Original count: %d\n", originalCount)

    // Encode to bytes
    encoded := scf.Encode()
    fmt.Printf("Encoded to %d bytes\n", len(encoded))

    // Decode back
    decoded, err := cuckoo.DecodeScalableFilter(encoded)
    if err != nil {
        log.Fatalf("Decode failed: %v", err)
    }

    // Verify data integrity
    fmt.Printf("Decoded count: %d\n", decoded.Count())
    fmt.Printf("record-100 exists: %v\n", decoded.Lookup([]byte("record-100")))
    fmt.Printf("record-24999 exists: %v\n", decoded.Lookup([]byte("record-24999")))
    fmt.Printf("record-99999 exists: %v\n", decoded.Lookup([]byte("record-99999")))

    // Output: Original count: 25000
    // Output: Encoded to ~X bytes (varies by scaling)
    // Output: Decoded count: 25000
    // Output: record-100 exists: true
    // Output: record-24999 exists: true
    // Output: record-99999 exists: false
}
```

--------------------------------

### Scalable Filter Operations in Go

Source: https://context7.com/seiflotfy/cuckoofilter/llms.txt

Demonstrates common operations (InsertUnique, Lookup, Delete, Count, Reset) on a scalable Cuckoo filter. It highlights duplicate prevention, data presence checks, and filter clearing. The code uses the cuckoofilter Go library and manages automatic capacity scaling.

```Go
package main

import (
    "fmt"
    cuckoo "github.com/seiflotfy/cuckoofilter"
)

func main() {
    scf := cuckoo.NewScalableCuckooFilter()

    // InsertUnique prevents duplicates
    scf.InsertUnique([]byte("session-abc123"))
    scf.InsertUnique([]byte("session-def456"))
    duplicate := scf.InsertUnique([]byte("session-abc123"))

    fmt.Printf("Duplicate insert result: %v\n", duplicate)
    fmt.Printf("Count after inserts: %d\n", scf.Count())

    // Lookup
    exists := scf.Lookup([]byte("session-abc123"))
    fmt.Printf("session-abc123 exists: %v\n", exists)

    // Delete
    deleted := scf.Delete([]byte("session-def456"))
    fmt.Printf("Deleted session-def456: %v\n", deleted)
    fmt.Printf("Count after delete: %d\n", scf.Count())

    // Reset clears all internal filters
    scf.Reset()
    fmt.Printf("Count after reset: %d\n", scf.Count())

    // Output: Duplicate insert result: false
    // Output: Count after inserts: 2
    // Output: session-abc123 exists: true
    // Output: Deleted session-def456: true
    // Output: Count after delete: 1
    // Output: Count after reset: 0
}
```

--------------------------------

### Custom Hash Function in Go

Source: https://context7.com/seiflotfy/cuckoofilter/llms.txt

Shows how to replace the default hash function (MetroHash) in a Cuckoo filter with a custom implementation (SHA256). This enables specialized fingerprint generation and bucket index calculations. The code demonstrates setting the default hasher and inserting data using the custom hash function.

```Go
package main

import (
    "crypto/sha256"
    "encoding/binary"
    "fmt"
    cuckoo "github.com/seiflotfy/cuckoofilter"
)

// Custom hasher using SHA256
type SHA256Hasher struct{}

func (h *SHA256Hasher) Hash64(data []byte) uint64 {
    hash := sha256.Sum256(data)
    // Use first 8 bytes as uint64
    return binary.BigEndian.Uint64(hash[:8])
}

func main() {
    // Set custom hasher globally
    cuckoo.SetDefaultHasher(&SHA256Hasher{}

    // All new filters will use SHA256
    cf := cuckoo.NewFilter(1000)

    cf.Insert([]byte("secure-data"))
    cf.Insert([]byte("another-secure-data"))

    fmt.Printf("Count: %d\n", cf.Count())
    fmt.Printf("secure-data exists: %v\n", cf.Lookup([]byte("secure-data")))

    // Note: Custom hashers affect fingerprint generation
    // and bucket index calculation

    // Output: Count: 2
    // Output: secure-data exists: true
}
```

--------------------------------

### Serialize and Deserialize Cuckoo Filter in Go

Source: https://context7.com/seiflotfy/cuckoofilter/llms.txt

Converts a Cuckoo filter into a byte slice for storage or transmission, and reconstructs it from a byte slice. This is useful for persistence and inter-process communication. The `Encode` method returns the serialized data, and `Decode` reconstructs the filter.

```go
package main

import (
    "fmt"
    "log"
    cuckoo "github.com/seiflotfy/cuckoofilter"
)

func main() {
    // Create and populate a filter
    cf := cuckoo.NewFilter(1000)
    cf.InsertUnique([]byte("important-data-1"))
    cf.InsertUnique([]byte("important-data-2"))
    cf.InsertUnique([]byte("important-data-3"))

    originalCount := cf.Count()
    fmt.Printf("Original count: %d\n", originalCount)

    // Serialize to bytes
    encoded := cf.Encode()
    fmt.Printf("Encoded to %d bytes\n", len(encoded))

    // Deserialize from bytes
    decoded, err := cuckoo.Decode(encoded)
    if err != nil {
        log.Fatalf("Decode failed: %v", err)
    }

    // Verify data integrity
    fmt.Printf("Decoded count: %d\n", decoded.Count())
    fmt.Printf("Data-1 exists: %v\n", decoded.Lookup([]byte("important-data-1")))
    fmt.Printf("Data-2 exists: %v\n", decoded.Lookup([]byte("important-data-2")))
    fmt.Printf("Data-3 exists: %v\n", decoded.Lookup([]byte("important-data-3")))

    // Output: Original count: 3
    // Output: Encoded to 1024 bytes
    // Output: Decoded count: 3
    // Output: Data-1 exists: true
    // Output: Data-2 exists: true
    // Output: Data-3 exists: true
}

```

--------------------------------

### Reset Cuckoo Filter to Empty State in Go

Source: https://context7.com/seiflotfy/cuckoofilter/llms.txt

Clears all elements from the Cuckoo filter, returning it to an empty state while preserving its configured capacity. The `Reset` method is suitable for reusing a filter without reallocating memory. Elements inserted after a reset are treated as new additions.

```go
package main

import (
    "fmt"
    cuckoo "github.com/seiflotfy/cuckoofilter"
)

func main() {
    cf := cuckoo.NewFilter(1000)

    // Add multiple elements
    for i := 0; i < 100; i++ {
        cf.Insert([]byte(fmt.Sprintf("item-%d", i)))
    }

    fmt.Printf("Before reset - Count: %d\n", cf.Count())
    fmt.Printf("item-50 exists: %v\n", cf.Lookup([]byte("item-50")))

    // Reset the filter
    cf.Reset()

    fmt.Printf("After reset - Count: %d\n", cf.Count())
    fmt.Printf("item-50 exists: %v\n", cf.Lookup([]byte("item-50")))

    // Filter can be reused
    cf.Insert([]byte("new-item"))
    fmt.Printf("After new insert - Count: %d\n", cf.Count())

    // Output: Before reset - Count: 100
    // Output: item-50 exists: true
    // Output: After reset - Count: 0
    // Output: item-50 exists: false
    // Output: After new insert - Count: 1
}

```

--------------------------------

### Delete Element from Cuckoo Filter in Go

Source: https://context7.com/seiflotfy/cuckoofilter/llms.txt

Removes an element from the Cuckoo filter. It returns true if the element was found and successfully deleted, otherwise false. This operation modifies the filter in-place and affects the element count.

```go
package main

import (
    "fmt"
    cuckoo "github.com/seiflotfy/cuckoofilter"
)

func main() {
    cf := cuckoo.NewFilter(1000)

    // Setup: insert elements
    cf.InsertUnique([]byte("temp@example.com"))
    cf.InsertUnique([]byte("keep@example.com"))
    fmt.Printf("Initial count: %d\n", cf.Count())

    // Delete existing element
    deleted1 := cf.Delete([]byte("temp@example.com"))
    fmt.Printf("Deleted temp: %v, count: %d\n", deleted1, cf.Count())

    // Try to delete non-existing element
    deleted2 := cf.Delete([]byte("nonexistent@example.com"))
    fmt.Printf("Deleted nonexistent: %v, count: %d\n", deleted2, cf.Count())

    // Verify deletion
    fmt.Printf("temp exists: %v\n", cf.Lookup([]byte("temp@example.com")))
    fmt.Printf("keep exists: %v\n", cf.Lookup([]byte("keep@example.com")))

    // Output: Initial count: 2
    // Output: Deleted temp: true, count: 1
    // Output: Deleted nonexistent: false, count: 1
    // Output: temp exists: false
    // Output: keep exists: true
}

```

=== COMPLETE CONTENT === This response contains all available snippets from this library. No additional content exists. Do not make further requests.