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collections: move hashmap's example to the struct.

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Most people go straight to the struct, not looking at the module, so the
example was well hidden.
This commit is contained in:
Huon Wilson 2014-03-13 22:31:56 +11:00
parent 6cbba7c54e
commit d06266995c
1 changed files with 53 additions and 53 deletions
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106
src/libcollections/hashmap.rs
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@ -9,56 +9,6 @@
// except according to those terms.
//! Unordered containers, implemented as hash-tables (`HashSet` and `HashMap` types)
//!
//! The tables use a keyed hash with new random keys generated for each container, so the ordering
//! of a set of keys in a hash table is randomized.
//!
//! This is currently implemented with robin hood hashing, as described in [1][2][3].
//!
//! # Example
//!
//! ```rust
//! use collections::HashMap;
//!
//! // type inference lets us omit an explicit type signature (which
//! // would be `HashMap<&str, &str>` in this example).
//! let mut book_reviews = HashMap::new();
//!
//! // review some books.
//! book_reviews.insert("Adventures of Hucklebury Fin", "My favorite book.");
//! book_reviews.insert("Grimms' Fairy Tales", "Masterpiece.");
//! book_reviews.insert("Pride and Prejudice", "Very enjoyable.");
//! book_reviews.insert("The Adventures of Sherlock Holmes", "Eye lyked it alot.");
//!
//! // check for a specific one.
//! if !book_reviews.contains_key(& &"Les Misérables") {
//! println!("We've got {} reviews, but Les Misérables ain't one.",
//! book_reviews.len());
//! }
//!
//! // oops, this review has a lot of spelling mistakes, let's delete it.
//! book_reviews.remove(& &"The Adventures of Sherlock Holmes");
//!
//! // look up the values associated with some keys.
//! let to_find = ["Pride and Prejudice", "Alice's Adventure in Wonderland"];
//! for book in to_find.iter() {
//! match book_reviews.find(book) {
//! Some(review) => println!("{}: {}", *book, *review),
//! None => println!("{} is unreviewed.", *book)
//! }
//! }
//!
//! // iterate over everything.
//! for (book, review) in book_reviews.iter() {
//! println!("{}: \"{}\"", *book, *review);
//! }
//! ```
//!
//! Relevant papers/articles:
//!
//! [1]: Pedro Celis. ["Robin Hood Hashing"](https://cs.uwaterloo.ca/research/tr/1986/CS-86-14.pdf)
//! [2]: (http://codecapsule.com/2013/11/11/robin-hood-hashing/)
//! [3]: (http://codecapsule.com/2013/11/17/robin-hood-hashing-backward-shift-deletion/)
use std::container::{Container, Mutable, Map, MutableMap, Set, MutableSet};
use std::clone::Clone;
@ -667,14 +617,64 @@ static INITIAL_LOAD_FACTOR: Fraction = (9, 10);
// `table::RawTable::new`, but I'm not confident it works for all sane alignments,
// especially if a type needs more alignment than `malloc` provides.
/// A hash map implementation which uses linear probing with Robin Hood bucket
/// stealing.
/// A hash map implementation which uses linear probing with Robin
/// Hood bucket stealing.
///
/// The hashes are all keyed by the task-local random number generator
/// on creation by default. This can be overriden with one of the constructors.
/// on creation by default, this means the ordering of the keys is
/// randomized, but makes the tables more resistant to
/// denial-of-service attacks (Hash DoS). This behaviour can be
/// overriden with one of the constructors.
///
/// It is required that the keys implement the `Eq` and `Hash` traits, although
/// this can frequently be achieved by using `#[deriving(Eq, Hash)]`.
///
/// Relevant papers/articles:
///
/// 1. Pedro Celis. ["Robin Hood Hashing"](https://cs.uwaterloo.ca/research/tr/1986/CS-86-14.pdf)
/// 2. Emmanuel Goossaert. ["Robin Hood
/// hashing"](http://codecapsule.com/2013/11/11/robin-hood-hashing/)
/// 3. Emmanuel Goossaert. ["Robin Hood hashing: backward shift
/// deletion"](http://codecapsule.com/2013/11/17/robin-hood-hashing-backward-shift-deletion/)
///
/// # Example
///
/// ```rust
/// use collections::HashMap;
///
/// // type inference lets us omit an explicit type signature (which
/// // would be `HashMap<&str, &str>` in this example).
/// let mut book_reviews = HashMap::new();
///
/// // review some books.
/// book_reviews.insert("Adventures of Hucklebury Fin", "My favorite book.");
/// book_reviews.insert("Grimms' Fairy Tales", "Masterpiece.");
/// book_reviews.insert("Pride and Prejudice", "Very enjoyable.");
/// book_reviews.insert("The Adventures of Sherlock Holmes", "Eye lyked it alot.");
///
/// // check for a specific one.
/// if !book_reviews.contains_key(& &"Les Misérables") {
/// println!("We've got {} reviews, but Les Misérables ain't one.",
/// book_reviews.len());
/// }
///
/// // oops, this review has a lot of spelling mistakes, let's delete it.
/// book_reviews.remove(& &"The Adventures of Sherlock Holmes");
///
/// // look up the values associated with some keys.
/// let to_find = ["Pride and Prejudice", "Alice's Adventure in Wonderland"];
/// for book in to_find.iter() {
/// match book_reviews.find(book) {
/// Some(review) => println!("{}: {}", *book, *review),
/// None => println!("{} is unreviewed.", *book)
/// }
/// }
///
/// // iterate over everything.
/// for (book, review) in book_reviews.iter() {
/// println!("{}: \"{}\"", *book, *review);
/// }
/// ```
#[deriving(Clone)]
pub struct HashMap<K, V, H = sip::SipHasher> {
// All hashes are keyed on these values, to prevent hash collision attacks.