Expand description
Generic hashing support.
This module provides a generic way to compute the hash of a value.
Hashes are most commonly used with HashMap and HashSet.
The simplest way to make a type hashable is to use #[derive(Hash)]:
§Examples
use std::hash::{DefaultHasher, Hash, Hasher};
#[derive(Hash)]
struct Person {
    id: u32,
    name: String,
    phone: u64,
}
let person1 = Person {
    id: 5,
    name: "Janet".to_string(),
    phone: 555_666_7777,
};
let person2 = Person {
    id: 5,
    name: "Bob".to_string(),
    phone: 555_666_7777,
};
assert!(calculate_hash(&person1) != calculate_hash(&person2));
fn calculate_hash<T: Hash>(t: &T) -> u64 {
    let mut s = DefaultHasher::new();
    t.hash(&mut s);
    s.finish()
}If you need more control over how a value is hashed, you need to implement
the Hash trait:
use std::hash::{DefaultHasher, Hash, Hasher};
struct Person {
    id: u32,
    name: String,
    phone: u64,
}
impl Hash for Person {
    fn hash<H: Hasher>(&self, state: &mut H) {
        self.id.hash(state);
        self.phone.hash(state);
    }
}
let person1 = Person {
    id: 5,
    name: "Janet".to_string(),
    phone: 555_666_7777,
};
let person2 = Person {
    id: 5,
    name: "Bob".to_string(),
    phone: 555_666_7777,
};
assert_eq!(calculate_hash(&person1), calculate_hash(&person2));
fn calculate_hash<T: Hash>(t: &T) -> u64 {
    let mut s = DefaultHasher::new();
    t.hash(&mut s);
    s.finish()
}Structs§
- SipHasherDeprecated An implementation of SipHash 2-4.
Traits§
- A trait for creating instances ofHasher.
- A hashable type.
- A trait for hashing an arbitrary stream of bytes.
Derive Macros§
- Derive macro generating an impl of the traitHash.