Struct RollingHashWindow 

pub struct RollingHashWindow { /* private fields */ }

Rolling hash window for fast substring detection.

Maintains rolling hash values over accumulated content using the Rabin-Karp algorithm. Provides O(1) hash computation for sliding windows.

Algorithm

Uses polynomial rolling hash with base 256 (byte values) and modulus from a large prime to minimize collisions.

Hash computation:

hash(s[0..n]) = (s[0] * b^(n-1) + s[1] * b^(n-2) + ... + s[n-1]) mod m

Rolling update:

hash(s[i+1..i+n+1]) = ((hash(s[i..i+n]) - s[i] * b^(n-1)) * b + s[i+n]) mod m

Example

let mut window = RollingHashWindow::new();
window.add_content("Hello World");

// Check if "World" exists in the accumulated content
let hashes = window.get_window_hashes(5); // 5 = length of "World"
let world_hash = RollingHashWindow::compute_hash("World");

if hashes.contains(&world_hash) {
    // Potential match - verify with KMP
}

Implementations

impl RollingHashWindow

pub fn compute_hash(text: &str) -> u64

Compute rolling hash of a string slice.

Uses polynomial rolling hash with base 256 and a large prime modulus.

Arguments

• text - The text to hash

Returns

The hash value as a u64

Example

let hash = RollingHashWindow::compute_hash("Hello");

pub fn clear(&mut self)

Clear all content and cached hashes.

Trait Implementations

impl Clone for RollingHashWindow

fn clone(&self) -> RollingHashWindow

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for RollingHashWindow

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for RollingHashWindow

fn default() -> RollingHashWindow

Returns the “default value” for a type.