1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105
// Copyright 2014 The Rust Project Developers. See the COPYRIGHT // file at the top-level directory of this distribution and at // http://rust-lang.org/COPYRIGHT. // // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your // option. This file may not be copied, modified, or distributed // except according to those terms. //! Generic hashing support. //! //! This module provides a generic way to compute the hash of a value. The //! simplest way to make a type hashable is to use `#[deriving(Hash)]`: //! //! # Example //! //! ```rust //! use std::hash; //! use std::hash::Hash; //! //! #[deriving(Hash)] //! struct Person { //! id: uint, //! 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!(hash::hash(&person1) != hash::hash(&person2)); //! ``` //! //! If you need more control over how a value is hashed, you need to implement //! the trait `Hash`: //! //! ```rust //! use std::hash; //! use std::hash::Hash; //! use std::hash::sip::SipState; //! //! struct Person { //! id: uint, //! name: String, //! phone: u64, //! } //! //! impl Hash for Person { //! fn hash(&self, state: &mut SipState) { //! 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!(hash::hash(&person1) == hash::hash(&person2)); //! ``` #![experimental] pub use core::hash::{Hash, Hasher, Writer, hash, sip}; use core::kinds::Sized; use default::Default; use rand::Rng; use rand; /// `RandomSipHasher` computes the SipHash algorithm from a stream of bytes /// initialized with random keys. #[deriving(Clone)] pub struct RandomSipHasher { hasher: sip::SipHasher, } impl RandomSipHasher { /// Construct a new `RandomSipHasher` that is initialized with random keys. #[inline] pub fn new() -> RandomSipHasher { let mut r = rand::thread_rng(); let r0 = r.gen(); let r1 = r.gen(); RandomSipHasher { hasher: sip::SipHasher::new_with_keys(r0, r1), } } } impl Hasher<sip::SipState> for RandomSipHasher { #[inline] fn hash<Sized? T: Hash<sip::SipState>>(&self, value: &T) -> u64 { self.hasher.hash(value) } } #[stable] impl Default for RandomSipHasher { #[stable] #[inline] fn default() -> RandomSipHasher { RandomSipHasher::new() } }