Struct ssdeep::internal_hashes::RollingHash

pub struct RollingHash { /* private fields */ }

Hasher which computes a variant of 32-bit rolling hash as used in ssdeep.

In ssdeep, this is the most important hash function to decide whether to trigger a context update based on the last 7 bytes it met.

To be specific, RollingHash implements the rolling hash implemented in ssdeep version 2.13 or later. This is the first version which officially supported inputs larger than (or as large as) 4GiB and implemented a true rolling hash function.

Implementations

impl RollingHash

pub const WINDOW_SIZE: usize = 7usize

The window size of the rolling hash.

This is 7 bytes in ssdeep.

pub fn new() -> Self

Creates a new RollingHash with the initial value.

pub fn update_by_byte(&mut self, ch: u8) -> &mut Self

Updates the hash value by processing a byte.

pub fn update_by_iter(&mut self, iter: impl Iterator<Item = u8>) -> &mut Self

Updates the hash value by processing an iterator of u8.

pub fn update(&mut self, buf: &[u8]) -> &mut Self

Updates the hash value by processing a slice of u8.

pub fn value(&self) -> u32

Returns the current hash value.

Note that there’s no “finalization” on this rolling hash. You can even continue updating after reading the hash value.

This is the sum of its three internal states (h1, h2 and h3). See the source code and the private documentation for its mathematical details.

Trait Implementations

impl Debug for RollingHash

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

Formats the value using the given formatter.

impl Default for RollingHash

fn default() -> Self

Returns the “default value” for a type.