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Move RandomState and DefaultHasher into std::hash, but in a sneaky way
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,90 @@ | ||
| //! 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`]. | ||
| //! | ||
| //! [hash]: https://en.wikipedia.org/wiki/Hash_function | ||
| //! [`HashMap`]: ../../std/collections/struct.HashMap.html | ||
| //! [`HashSet`]: ../../std/collections/struct.HashSet.html | ||
| //! | ||
| //! The simplest way to make a type hashable is to use `#[derive(Hash)]`: | ||
| //! | ||
| //! # Examples | ||
| //! | ||
| //! ```rust | ||
| //! use std::collections::hash_map::DefaultHasher; | ||
| //! use std::hash::{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: | ||
| //! | ||
| //! ```rust | ||
| //! use std::collections::hash_map::DefaultHasher; | ||
| //! use std::hash::{Hash, Hasher}; | ||
| //! | ||
| //! struct Person { | ||
| //! id: u32, | ||
| //! # #[allow(dead_code)] | ||
| //! 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() | ||
| //! } | ||
| //! ``` | ||
| #![stable(feature = "rust1", since = "1.0.0")] | ||
|
|
||
| pub(crate) mod private; | ||
|
|
||
| #[stable(feature = "rust1", since = "1.0.0")] | ||
| pub use core::hash::*; |
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