Trait core::hash::Hasher

1.0.0· source · [−]
pub trait Hasher {

Show 14 methods    fn finish(&self) -> u64;

    fn write(&mut self, bytes: &[u8]);

    fn write_u8(&mut self, i: u8) { ... }

    fn write_u16(&mut self, i: u16) { ... }

    fn write_u32(&mut self, i: u32) { ... }

    fn write_u64(&mut self, i: u64) { ... }

    fn write_u128(&mut self, i: u128) { ... }

    fn write_usize(&mut self, i: usize) { ... }

    fn write_i8(&mut self, i: i8) { ... }

    fn write_i16(&mut self, i: i16) { ... }

    fn write_i32(&mut self, i: i32) { ... }

    fn write_i64(&mut self, i: i64) { ... }

    fn write_i128(&mut self, i: i128) { ... }

    fn write_isize(&mut self, i: isize) { ... }

}
Expand description

A trait for hashing an arbitrary stream of bytes.

Instances of Hasher usually represent state that is changed while hashing data.

Hasher provides a fairly basic interface for retrieving the generated hash (with finish), and writing integers as well as slices of bytes into an instance (with write and write_u8 etc.). Most of the time, Hasher instances are used in conjunction with the Hash trait.

This trait makes no assumptions about how the various write_* methods are defined and implementations of Hash should not assume that they work one way or another. You cannot assume, for example, that a write_u32 call is equivalent to four calls of write_u8.

Examples

use std::collections::hash_map::DefaultHasher;
use std::hash::Hasher;

let mut hasher = DefaultHasher::new();

hasher.write_u32(1989);
hasher.write_u8(11);
hasher.write_u8(9);
hasher.write(b"Huh?");

println!("Hash is {:x}!", hasher.finish());
Run

Required methods

Returns the hash value for the values written so far.

Despite its name, the method does not reset the hasher’s internal state. Additional writes will continue from the current value. If you need to start a fresh hash value, you will have to create a new hasher.

Examples
use std::collections::hash_map::DefaultHasher;
use std::hash::Hasher;

let mut hasher = DefaultHasher::new();
hasher.write(b"Cool!");

println!("Hash is {:x}!", hasher.finish());
Run

Writes some data into this Hasher.

Examples
use std::collections::hash_map::DefaultHasher;
use std::hash::Hasher;

let mut hasher = DefaultHasher::new();
let data = [0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef];

hasher.write(&data);

println!("Hash is {:x}!", hasher.finish());
Run

Provided methods

Writes a single u8 into this hasher.

Writes a single u16 into this hasher.

Writes a single u32 into this hasher.

Writes a single u64 into this hasher.

Writes a single u128 into this hasher.

Writes a single usize into this hasher.

Writes a single i8 into this hasher.

Writes a single i16 into this hasher.

Writes a single i32 into this hasher.

Writes a single i64 into this hasher.

Writes a single i128 into this hasher.

Writes a single isize into this hasher.

Implementors