Struct FibonacciHash

pub struct FibonacciHash;

A hash function implementation using the Fibonacci hashing technique.

Fibonacci hashing is a multiplication-based hashing method that uses the golden ratio to achieve a good distribution of hash values. It works particularly well for integer keys and provides good performance characteristics due to its simplicity.

Examples

Basic usage:

use toolbox_rs::fibonacci_hash::FibonacciHash;
use toolbox_rs::fast_hash_trait::FastHash;

let hasher = FibonacciHash::new();
let hash = hasher.hash(42);
assert!(hash <= u16::MAX);

Different inputs produce different hashes:

use toolbox_rs::fibonacci_hash::FibonacciHash;
use toolbox_rs::fast_hash_trait::FastHash;

let hasher = FibonacciHash::new();
let hash1 = hasher.hash(1);
let hash2 = hasher.hash(2);
assert_ne!(hash1, hash2);

Implementations

impl FibonacciHash

pub fn new() -> Self

Creates a new FibonacciHash instance with the specified shift amount.

The shift amount determines how many bits to shift during the hashing process. A typical value is 16, which produces good distribution for most use cases.

Examples

use toolbox_rs::fibonacci_hash::FibonacciHash;

let hasher = FibonacciHash::new();

Trait Implementations

impl Default for FibonacciHash

fn default() -> FibonacciHash

Returns the “default value” for a type.

impl FastHash for FibonacciHash

fn hash(&self, key: u32) -> u16

Computes a 16-bit hash value for a 32-bit input using Fibonacci hashing.

Algorithm

1. XORs the input with a shifted version of itself
2. Multiplies by the golden ratio constant (≈ (√5-1)/2 * 2⁶⁴)
3. Shifts the result right to get the final hash

Arguments

• key - 32-bit unsigned integer to hash

Returns

A 16-bit hash value

Examples

use toolbox_rs::fibonacci_hash::FibonacciHash;
use toolbox_rs::fast_hash_trait::FastHash;

let hasher = FibonacciHash::new();

// Same input produces same hash
assert_eq!(hasher.hash(42), hasher.hash(42));

// Values are within u16 range
for i in 0..10 {
    assert!(hasher.hash(i) <= u16::MAX);
}