2758 lines
83 KiB
Rust
2758 lines
83 KiB
Rust
#[cfg(test)]
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mod tests;
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use self::Entry::*;
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use hashbrown::hash_map as base;
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use crate::borrow::Borrow;
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use crate::cell::Cell;
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use crate::collections::TryReserveError;
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use crate::fmt::{self, Debug};
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#[allow(deprecated)]
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use crate::hash::{BuildHasher, Hash, Hasher, SipHasher13};
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use crate::iter::{FromIterator, FusedIterator};
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use crate::ops::Index;
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use crate::sys;
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/// A hash map implemented with quadratic probing and SIMD lookup.
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///
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/// By default, `HashMap` uses a hashing algorithm selected to provide
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/// resistance against HashDoS attacks. The algorithm is randomly seeded, and a
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/// reasonable best-effort is made to generate this seed from a high quality,
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/// secure source of randomness provided by the host without blocking the
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/// program. Because of this, the randomness of the seed depends on the output
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/// quality of the system's random number generator when the seed is created.
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/// In particular, seeds generated when the system's entropy pool is abnormally
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/// low such as during system boot may be of a lower quality.
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///
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/// The default hashing algorithm is currently SipHash 1-3, though this is
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/// subject to change at any point in the future. While its performance is very
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/// competitive for medium sized keys, other hashing algorithms will outperform
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/// it for small keys such as integers as well as large keys such as long
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/// strings, though those algorithms will typically *not* protect against
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/// attacks such as HashDoS.
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///
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/// The hashing algorithm can be replaced on a per-`HashMap` basis using the
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/// [`default`], [`with_hasher`], and [`with_capacity_and_hasher`] methods. Many
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/// alternative algorithms are available on crates.io, such as the [`fnv`] crate.
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///
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/// It is required that the keys implement the [`Eq`] and [`Hash`] traits, although
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/// this can frequently be achieved by using `#[derive(PartialEq, Eq, Hash)]`.
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/// If you implement these yourself, it is important that the following
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/// property holds:
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///
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/// ```text
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/// k1 == k2 -> hash(k1) == hash(k2)
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/// ```
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///
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/// In other words, if two keys are equal, their hashes must be equal.
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///
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/// It is a logic error for a key to be modified in such a way that the key's
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/// hash, as determined by the [`Hash`] trait, or its equality, as determined by
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/// the [`Eq`] trait, changes while it is in the map. This is normally only
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/// possible through [`Cell`], [`RefCell`], global state, I/O, or unsafe code.
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///
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/// The hash table implementation is a Rust port of Google's [SwissTable].
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/// The original C++ version of SwissTable can be found [here], and this
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/// [CppCon talk] gives an overview of how the algorithm works.
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///
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/// [SwissTable]: https://abseil.io/blog/20180927-swisstables
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/// [here]: https://github.com/abseil/abseil-cpp/blob/master/absl/container/internal/raw_hash_set.h
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/// [CppCon talk]: https://www.youtube.com/watch?v=ncHmEUmJZf4
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::HashMap;
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///
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/// // Type inference lets us omit an explicit type signature (which
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/// // would be `HashMap<String, String>` in this example).
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/// let mut book_reviews = HashMap::new();
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///
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/// // Review some books.
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/// book_reviews.insert(
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/// "Adventures of Huckleberry Finn".to_string(),
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/// "My favorite book.".to_string(),
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/// );
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/// book_reviews.insert(
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/// "Grimms' Fairy Tales".to_string(),
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/// "Masterpiece.".to_string(),
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/// );
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/// book_reviews.insert(
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/// "Pride and Prejudice".to_string(),
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/// "Very enjoyable.".to_string(),
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/// );
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/// book_reviews.insert(
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/// "The Adventures of Sherlock Holmes".to_string(),
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/// "Eye lyked it alot.".to_string(),
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/// );
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///
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/// // Check for a specific one.
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/// // When collections store owned values (String), they can still be
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/// // queried using references (&str).
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/// if !book_reviews.contains_key("Les Misérables") {
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/// println!("We've got {} reviews, but Les Misérables ain't one.",
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/// book_reviews.len());
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/// }
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///
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/// // oops, this review has a lot of spelling mistakes, let's delete it.
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/// book_reviews.remove("The Adventures of Sherlock Holmes");
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///
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/// // Look up the values associated with some keys.
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/// let to_find = ["Pride and Prejudice", "Alice's Adventure in Wonderland"];
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/// for &book in &to_find {
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/// match book_reviews.get(book) {
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/// Some(review) => println!("{}: {}", book, review),
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/// None => println!("{} is unreviewed.", book)
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/// }
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/// }
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///
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/// // Look up the value for a key (will panic if the key is not found).
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/// println!("Review for Jane: {}", book_reviews["Pride and Prejudice"]);
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///
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/// // Iterate over everything.
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/// for (book, review) in &book_reviews {
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/// println!("{}: \"{}\"", book, review);
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/// }
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/// ```
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///
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/// `HashMap` also implements an [`Entry API`](#method.entry), which allows
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/// for more complex methods of getting, setting, updating and removing keys and
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/// their values:
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///
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/// ```
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/// use std::collections::HashMap;
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///
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/// // type inference lets us omit an explicit type signature (which
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/// // would be `HashMap<&str, u8>` in this example).
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/// let mut player_stats = HashMap::new();
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///
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/// fn random_stat_buff() -> u8 {
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/// // could actually return some random value here - let's just return
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/// // some fixed value for now
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/// 42
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/// }
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///
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/// // insert a key only if it doesn't already exist
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/// player_stats.entry("health").or_insert(100);
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///
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/// // insert a key using a function that provides a new value only if it
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/// // doesn't already exist
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/// player_stats.entry("defence").or_insert_with(random_stat_buff);
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///
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/// // update a key, guarding against the key possibly not being set
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/// let stat = player_stats.entry("attack").or_insert(100);
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/// *stat += random_stat_buff();
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/// ```
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///
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/// The easiest way to use `HashMap` with a custom key type is to derive [`Eq`] and [`Hash`].
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/// We must also derive [`PartialEq`].
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///
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/// [`RefCell`]: crate::cell::RefCell
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/// [`Cell`]: crate::cell::Cell
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/// [`default`]: Default::default
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/// [`with_hasher`]: Self::with_hasher
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/// [`with_capacity_and_hasher`]: Self::with_capacity_and_hasher
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/// [`fnv`]: https://crates.io/crates/fnv
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///
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/// ```
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/// use std::collections::HashMap;
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///
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/// #[derive(Hash, Eq, PartialEq, Debug)]
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/// struct Viking {
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/// name: String,
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/// country: String,
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/// }
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///
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/// impl Viking {
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/// /// Creates a new Viking.
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/// fn new(name: &str, country: &str) -> Viking {
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/// Viking { name: name.to_string(), country: country.to_string() }
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/// }
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/// }
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///
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/// // Use a HashMap to store the vikings' health points.
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/// let mut vikings = HashMap::new();
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///
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/// vikings.insert(Viking::new("Einar", "Norway"), 25);
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/// vikings.insert(Viking::new("Olaf", "Denmark"), 24);
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/// vikings.insert(Viking::new("Harald", "Iceland"), 12);
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///
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/// // Use derived implementation to print the status of the vikings.
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/// for (viking, health) in &vikings {
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/// println!("{:?} has {} hp", viking, health);
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/// }
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/// ```
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///
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/// A `HashMap` with fixed list of elements can be initialized from an array:
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///
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/// ```
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/// use std::collections::HashMap;
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///
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/// let timber_resources: HashMap<&str, i32> = [("Norway", 100), ("Denmark", 50), ("Iceland", 10)]
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/// .iter().cloned().collect();
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/// // use the values stored in map
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/// ```
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#[derive(Clone)]
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#[cfg_attr(not(test), rustc_diagnostic_item = "hashmap_type")]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub struct HashMap<K, V, S = RandomState> {
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base: base::HashMap<K, V, S>,
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}
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impl<K, V> HashMap<K, V, RandomState> {
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/// Creates an empty `HashMap`.
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///
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/// The hash map is initially created with a capacity of 0, so it will not allocate until it
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/// is first inserted into.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::HashMap;
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/// let mut map: HashMap<&str, i32> = HashMap::new();
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/// ```
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#[inline]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn new() -> HashMap<K, V, RandomState> {
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Default::default()
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}
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/// Creates an empty `HashMap` with the specified capacity.
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///
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/// The hash map will be able to hold at least `capacity` elements without
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/// reallocating. If `capacity` is 0, the hash map will not allocate.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::HashMap;
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/// let mut map: HashMap<&str, i32> = HashMap::with_capacity(10);
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/// ```
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#[inline]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn with_capacity(capacity: usize) -> HashMap<K, V, RandomState> {
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HashMap::with_capacity_and_hasher(capacity, Default::default())
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}
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}
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impl<K, V, S> HashMap<K, V, S> {
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/// Creates an empty `HashMap` which will use the given hash builder to hash
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/// keys.
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///
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/// The created map has the default initial capacity.
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///
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/// Warning: `hash_builder` is normally randomly generated, and
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/// is designed to allow HashMaps to be resistant to attacks that
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/// cause many collisions and very poor performance. Setting it
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/// manually using this function can expose a DoS attack vector.
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///
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/// The `hash_builder` passed should implement the [`BuildHasher`] trait for
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/// the HashMap to be useful, see its documentation for details.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::HashMap;
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/// use std::collections::hash_map::RandomState;
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///
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/// let s = RandomState::new();
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/// let mut map = HashMap::with_hasher(s);
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/// map.insert(1, 2);
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/// ```
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#[inline]
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#[stable(feature = "hashmap_build_hasher", since = "1.7.0")]
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pub fn with_hasher(hash_builder: S) -> HashMap<K, V, S> {
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HashMap { base: base::HashMap::with_hasher(hash_builder) }
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}
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/// Creates an empty `HashMap` with the specified capacity, using `hash_builder`
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/// to hash the keys.
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///
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/// The hash map will be able to hold at least `capacity` elements without
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/// reallocating. If `capacity` is 0, the hash map will not allocate.
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///
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/// Warning: `hash_builder` is normally randomly generated, and
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/// is designed to allow HashMaps to be resistant to attacks that
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/// cause many collisions and very poor performance. Setting it
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/// manually using this function can expose a DoS attack vector.
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///
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/// The `hash_builder` passed should implement the [`BuildHasher`] trait for
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/// the HashMap to be useful, see its documentation for details.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::HashMap;
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/// use std::collections::hash_map::RandomState;
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///
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/// let s = RandomState::new();
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/// let mut map = HashMap::with_capacity_and_hasher(10, s);
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/// map.insert(1, 2);
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/// ```
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#[inline]
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#[stable(feature = "hashmap_build_hasher", since = "1.7.0")]
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pub fn with_capacity_and_hasher(capacity: usize, hash_builder: S) -> HashMap<K, V, S> {
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HashMap { base: base::HashMap::with_capacity_and_hasher(capacity, hash_builder) }
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}
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/// Returns the number of elements the map can hold without reallocating.
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///
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/// This number is a lower bound; the `HashMap<K, V>` might be able to hold
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/// more, but is guaranteed to be able to hold at least this many.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::HashMap;
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/// let map: HashMap<i32, i32> = HashMap::with_capacity(100);
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/// assert!(map.capacity() >= 100);
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/// ```
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#[inline]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn capacity(&self) -> usize {
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self.base.capacity()
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}
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/// An iterator visiting all keys in arbitrary order.
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/// The iterator element type is `&'a K`.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::HashMap;
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///
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/// let mut map = HashMap::new();
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/// map.insert("a", 1);
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/// map.insert("b", 2);
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/// map.insert("c", 3);
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///
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/// for key in map.keys() {
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/// println!("{}", key);
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/// }
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn keys(&self) -> Keys<'_, K, V> {
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Keys { inner: self.iter() }
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}
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/// An iterator visiting all values in arbitrary order.
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/// The iterator element type is `&'a V`.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::HashMap;
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///
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/// let mut map = HashMap::new();
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/// map.insert("a", 1);
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/// map.insert("b", 2);
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/// map.insert("c", 3);
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///
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/// for val in map.values() {
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/// println!("{}", val);
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/// }
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn values(&self) -> Values<'_, K, V> {
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Values { inner: self.iter() }
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}
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/// An iterator visiting all values mutably in arbitrary order.
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/// The iterator element type is `&'a mut V`.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::HashMap;
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///
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/// let mut map = HashMap::new();
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///
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/// map.insert("a", 1);
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/// map.insert("b", 2);
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/// map.insert("c", 3);
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///
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/// for val in map.values_mut() {
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/// *val = *val + 10;
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/// }
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///
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/// for val in map.values() {
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/// println!("{}", val);
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/// }
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/// ```
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#[stable(feature = "map_values_mut", since = "1.10.0")]
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pub fn values_mut(&mut self) -> ValuesMut<'_, K, V> {
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ValuesMut { inner: self.iter_mut() }
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}
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/// An iterator visiting all key-value pairs in arbitrary order.
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/// The iterator element type is `(&'a K, &'a V)`.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::HashMap;
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///
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/// let mut map = HashMap::new();
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/// map.insert("a", 1);
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/// map.insert("b", 2);
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/// map.insert("c", 3);
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///
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/// for (key, val) in map.iter() {
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/// println!("key: {} val: {}", key, val);
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/// }
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn iter(&self) -> Iter<'_, K, V> {
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Iter { base: self.base.iter() }
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}
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/// An iterator visiting all key-value pairs in arbitrary order,
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/// with mutable references to the values.
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/// The iterator element type is `(&'a K, &'a mut V)`.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::HashMap;
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///
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/// let mut map = HashMap::new();
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/// map.insert("a", 1);
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/// map.insert("b", 2);
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/// map.insert("c", 3);
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///
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/// // Update all values
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/// for (_, val) in map.iter_mut() {
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/// *val *= 2;
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/// }
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///
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/// for (key, val) in &map {
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/// println!("key: {} val: {}", key, val);
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/// }
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn iter_mut(&mut self) -> IterMut<'_, K, V> {
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IterMut { base: self.base.iter_mut() }
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}
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/// Returns the number of elements in the map.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::HashMap;
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///
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/// let mut a = HashMap::new();
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/// assert_eq!(a.len(), 0);
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/// a.insert(1, "a");
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/// assert_eq!(a.len(), 1);
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn len(&self) -> usize {
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self.base.len()
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}
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/// Returns `true` if the map contains no elements.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::HashMap;
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///
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/// let mut a = HashMap::new();
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/// assert!(a.is_empty());
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/// a.insert(1, "a");
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/// assert!(!a.is_empty());
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/// ```
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#[inline]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn is_empty(&self) -> bool {
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self.base.is_empty()
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}
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|
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/// Clears the map, returning all key-value pairs as an iterator. Keeps the
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/// allocated memory for reuse.
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///
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/// # Examples
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|
///
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/// ```
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/// use std::collections::HashMap;
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///
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/// let mut a = HashMap::new();
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/// a.insert(1, "a");
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/// a.insert(2, "b");
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///
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/// for (k, v) in a.drain().take(1) {
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/// assert!(k == 1 || k == 2);
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/// assert!(v == "a" || v == "b");
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/// }
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///
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/// assert!(a.is_empty());
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/// ```
|
|
#[inline]
|
|
#[stable(feature = "drain", since = "1.6.0")]
|
|
pub fn drain(&mut self) -> Drain<'_, K, V> {
|
|
Drain { base: self.base.drain() }
|
|
}
|
|
|
|
/// Clears the map, removing all key-value pairs. Keeps the allocated memory
|
|
/// for reuse.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
///
|
|
/// let mut a = HashMap::new();
|
|
/// a.insert(1, "a");
|
|
/// a.clear();
|
|
/// assert!(a.is_empty());
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[inline]
|
|
pub fn clear(&mut self) {
|
|
self.base.clear();
|
|
}
|
|
|
|
/// Returns a reference to the map's [`BuildHasher`].
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
/// use std::collections::hash_map::RandomState;
|
|
///
|
|
/// let hasher = RandomState::new();
|
|
/// let map: HashMap<i32, i32> = HashMap::with_hasher(hasher);
|
|
/// let hasher: &RandomState = map.hasher();
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "hashmap_public_hasher", since = "1.9.0")]
|
|
pub fn hasher(&self) -> &S {
|
|
self.base.hasher()
|
|
}
|
|
}
|
|
|
|
impl<K, V, S> HashMap<K, V, S>
|
|
where
|
|
K: Eq + Hash,
|
|
S: BuildHasher,
|
|
{
|
|
/// Reserves capacity for at least `additional` more elements to be inserted
|
|
/// in the `HashMap`. The collection may reserve more space to avoid
|
|
/// frequent reallocations.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// Panics if the new allocation size overflows [`usize`].
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
/// let mut map: HashMap<&str, i32> = HashMap::new();
|
|
/// map.reserve(10);
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn reserve(&mut self, additional: usize) {
|
|
self.base.reserve(additional)
|
|
}
|
|
|
|
/// Tries to reserve capacity for at least `additional` more elements to be inserted
|
|
/// in the given `HashMap<K,V>`. The collection may reserve more space to avoid
|
|
/// frequent reallocations.
|
|
///
|
|
/// # Errors
|
|
///
|
|
/// If the capacity overflows, or the allocator reports a failure, then an error
|
|
/// is returned.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// #![feature(try_reserve)]
|
|
/// use std::collections::HashMap;
|
|
/// let mut map: HashMap<&str, isize> = HashMap::new();
|
|
/// map.try_reserve(10).expect("why is the test harness OOMing on 10 bytes?");
|
|
/// ```
|
|
#[inline]
|
|
#[unstable(feature = "try_reserve", reason = "new API", issue = "48043")]
|
|
pub fn try_reserve(&mut self, additional: usize) -> Result<(), TryReserveError> {
|
|
self.base.try_reserve(additional).map_err(map_try_reserve_error)
|
|
}
|
|
|
|
/// Shrinks the capacity of the map as much as possible. It will drop
|
|
/// down as much as possible while maintaining the internal rules
|
|
/// and possibly leaving some space in accordance with the resize policy.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
///
|
|
/// let mut map: HashMap<i32, i32> = HashMap::with_capacity(100);
|
|
/// map.insert(1, 2);
|
|
/// map.insert(3, 4);
|
|
/// assert!(map.capacity() >= 100);
|
|
/// map.shrink_to_fit();
|
|
/// assert!(map.capacity() >= 2);
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn shrink_to_fit(&mut self) {
|
|
self.base.shrink_to_fit();
|
|
}
|
|
|
|
/// Shrinks the capacity of the map with a lower limit. It will drop
|
|
/// down no lower than the supplied limit while maintaining the internal rules
|
|
/// and possibly leaving some space in accordance with the resize policy.
|
|
///
|
|
/// Panics if the current capacity is smaller than the supplied
|
|
/// minimum capacity.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// #![feature(shrink_to)]
|
|
/// use std::collections::HashMap;
|
|
///
|
|
/// let mut map: HashMap<i32, i32> = HashMap::with_capacity(100);
|
|
/// map.insert(1, 2);
|
|
/// map.insert(3, 4);
|
|
/// assert!(map.capacity() >= 100);
|
|
/// map.shrink_to(10);
|
|
/// assert!(map.capacity() >= 10);
|
|
/// map.shrink_to(0);
|
|
/// assert!(map.capacity() >= 2);
|
|
/// ```
|
|
#[inline]
|
|
#[unstable(feature = "shrink_to", reason = "new API", issue = "56431")]
|
|
pub fn shrink_to(&mut self, min_capacity: usize) {
|
|
assert!(self.capacity() >= min_capacity, "Tried to shrink to a larger capacity");
|
|
self.base.shrink_to(min_capacity);
|
|
}
|
|
|
|
/// Gets the given key's corresponding entry in the map for in-place manipulation.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
///
|
|
/// let mut letters = HashMap::new();
|
|
///
|
|
/// for ch in "a short treatise on fungi".chars() {
|
|
/// let counter = letters.entry(ch).or_insert(0);
|
|
/// *counter += 1;
|
|
/// }
|
|
///
|
|
/// assert_eq!(letters[&'s'], 2);
|
|
/// assert_eq!(letters[&'t'], 3);
|
|
/// assert_eq!(letters[&'u'], 1);
|
|
/// assert_eq!(letters.get(&'y'), None);
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn entry(&mut self, key: K) -> Entry<'_, K, V> {
|
|
map_entry(self.base.rustc_entry(key))
|
|
}
|
|
|
|
/// Returns a reference to the value corresponding to the key.
|
|
///
|
|
/// The key may be any borrowed form of the map's key type, but
|
|
/// [`Hash`] and [`Eq`] on the borrowed form *must* match those for
|
|
/// the key type.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
///
|
|
/// let mut map = HashMap::new();
|
|
/// map.insert(1, "a");
|
|
/// assert_eq!(map.get(&1), Some(&"a"));
|
|
/// assert_eq!(map.get(&2), None);
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[inline]
|
|
pub fn get<Q: ?Sized>(&self, k: &Q) -> Option<&V>
|
|
where
|
|
K: Borrow<Q>,
|
|
Q: Hash + Eq,
|
|
{
|
|
self.base.get(k)
|
|
}
|
|
|
|
/// Returns the key-value pair corresponding to the supplied key.
|
|
///
|
|
/// The supplied key may be any borrowed form of the map's key type, but
|
|
/// [`Hash`] and [`Eq`] on the borrowed form *must* match those for
|
|
/// the key type.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
///
|
|
/// let mut map = HashMap::new();
|
|
/// map.insert(1, "a");
|
|
/// assert_eq!(map.get_key_value(&1), Some((&1, &"a")));
|
|
/// assert_eq!(map.get_key_value(&2), None);
|
|
/// ```
|
|
#[stable(feature = "map_get_key_value", since = "1.40.0")]
|
|
#[inline]
|
|
pub fn get_key_value<Q: ?Sized>(&self, k: &Q) -> Option<(&K, &V)>
|
|
where
|
|
K: Borrow<Q>,
|
|
Q: Hash + Eq,
|
|
{
|
|
self.base.get_key_value(k)
|
|
}
|
|
|
|
/// Returns `true` if the map contains a value for the specified key.
|
|
///
|
|
/// The key may be any borrowed form of the map's key type, but
|
|
/// [`Hash`] and [`Eq`] on the borrowed form *must* match those for
|
|
/// the key type.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
///
|
|
/// let mut map = HashMap::new();
|
|
/// map.insert(1, "a");
|
|
/// assert_eq!(map.contains_key(&1), true);
|
|
/// assert_eq!(map.contains_key(&2), false);
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[inline]
|
|
pub fn contains_key<Q: ?Sized>(&self, k: &Q) -> bool
|
|
where
|
|
K: Borrow<Q>,
|
|
Q: Hash + Eq,
|
|
{
|
|
self.base.contains_key(k)
|
|
}
|
|
|
|
/// Returns a mutable reference to the value corresponding to the key.
|
|
///
|
|
/// The key may be any borrowed form of the map's key type, but
|
|
/// [`Hash`] and [`Eq`] on the borrowed form *must* match those for
|
|
/// the key type.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
///
|
|
/// let mut map = HashMap::new();
|
|
/// map.insert(1, "a");
|
|
/// if let Some(x) = map.get_mut(&1) {
|
|
/// *x = "b";
|
|
/// }
|
|
/// assert_eq!(map[&1], "b");
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[inline]
|
|
pub fn get_mut<Q: ?Sized>(&mut self, k: &Q) -> Option<&mut V>
|
|
where
|
|
K: Borrow<Q>,
|
|
Q: Hash + Eq,
|
|
{
|
|
self.base.get_mut(k)
|
|
}
|
|
|
|
/// Inserts a key-value pair into the map.
|
|
///
|
|
/// If the map did not have this key present, [`None`] is returned.
|
|
///
|
|
/// If the map did have this key present, the value is updated, and the old
|
|
/// value is returned. The key is not updated, though; this matters for
|
|
/// types that can be `==` without being identical. See the [module-level
|
|
/// documentation] for more.
|
|
///
|
|
/// [module-level documentation]: crate::collections#insert-and-complex-keys
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
///
|
|
/// let mut map = HashMap::new();
|
|
/// assert_eq!(map.insert(37, "a"), None);
|
|
/// assert_eq!(map.is_empty(), false);
|
|
///
|
|
/// map.insert(37, "b");
|
|
/// assert_eq!(map.insert(37, "c"), Some("b"));
|
|
/// assert_eq!(map[&37], "c");
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[inline]
|
|
pub fn insert(&mut self, k: K, v: V) -> Option<V> {
|
|
self.base.insert(k, v)
|
|
}
|
|
|
|
/// Removes a key from the map, returning the value at the key if the key
|
|
/// was previously in the map.
|
|
///
|
|
/// The key may be any borrowed form of the map's key type, but
|
|
/// [`Hash`] and [`Eq`] on the borrowed form *must* match those for
|
|
/// the key type.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
///
|
|
/// let mut map = HashMap::new();
|
|
/// map.insert(1, "a");
|
|
/// assert_eq!(map.remove(&1), Some("a"));
|
|
/// assert_eq!(map.remove(&1), None);
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[inline]
|
|
pub fn remove<Q: ?Sized>(&mut self, k: &Q) -> Option<V>
|
|
where
|
|
K: Borrow<Q>,
|
|
Q: Hash + Eq,
|
|
{
|
|
self.base.remove(k)
|
|
}
|
|
|
|
/// Removes a key from the map, returning the stored key and value if the
|
|
/// key was previously in the map.
|
|
///
|
|
/// The key may be any borrowed form of the map's key type, but
|
|
/// [`Hash`] and [`Eq`] on the borrowed form *must* match those for
|
|
/// the key type.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
///
|
|
/// # fn main() {
|
|
/// let mut map = HashMap::new();
|
|
/// map.insert(1, "a");
|
|
/// assert_eq!(map.remove_entry(&1), Some((1, "a")));
|
|
/// assert_eq!(map.remove(&1), None);
|
|
/// # }
|
|
/// ```
|
|
#[stable(feature = "hash_map_remove_entry", since = "1.27.0")]
|
|
#[inline]
|
|
pub fn remove_entry<Q: ?Sized>(&mut self, k: &Q) -> Option<(K, V)>
|
|
where
|
|
K: Borrow<Q>,
|
|
Q: Hash + Eq,
|
|
{
|
|
self.base.remove_entry(k)
|
|
}
|
|
|
|
/// Retains only the elements specified by the predicate.
|
|
///
|
|
/// In other words, remove all pairs `(k, v)` such that `f(&k,&mut v)` returns `false`.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
///
|
|
/// let mut map: HashMap<i32, i32> = (0..8).map(|x|(x, x*10)).collect();
|
|
/// map.retain(|&k, _| k % 2 == 0);
|
|
/// assert_eq!(map.len(), 4);
|
|
/// ```
|
|
#[stable(feature = "retain_hash_collection", since = "1.18.0")]
|
|
#[inline]
|
|
pub fn retain<F>(&mut self, f: F)
|
|
where
|
|
F: FnMut(&K, &mut V) -> bool,
|
|
{
|
|
self.base.retain(f)
|
|
}
|
|
|
|
/// Creates a consuming iterator visiting all the keys in arbitrary order.
|
|
/// The map cannot be used after calling this.
|
|
/// The iterator element type is `K`.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// #![feature(map_into_keys_values)]
|
|
/// use std::collections::HashMap;
|
|
///
|
|
/// let mut map = HashMap::new();
|
|
/// map.insert("a", 1);
|
|
/// map.insert("b", 2);
|
|
/// map.insert("c", 3);
|
|
///
|
|
/// let vec: Vec<&str> = map.into_keys().collect();
|
|
/// ```
|
|
#[inline]
|
|
#[unstable(feature = "map_into_keys_values", issue = "75294")]
|
|
pub fn into_keys(self) -> IntoKeys<K, V> {
|
|
IntoKeys { inner: self.into_iter() }
|
|
}
|
|
|
|
/// Creates a consuming iterator visiting all the values in arbitrary order.
|
|
/// The map cannot be used after calling this.
|
|
/// The iterator element type is `V`.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// #![feature(map_into_keys_values)]
|
|
/// use std::collections::HashMap;
|
|
///
|
|
/// let mut map = HashMap::new();
|
|
/// map.insert("a", 1);
|
|
/// map.insert("b", 2);
|
|
/// map.insert("c", 3);
|
|
///
|
|
/// let vec: Vec<i32> = map.into_values().collect();
|
|
/// ```
|
|
#[inline]
|
|
#[unstable(feature = "map_into_keys_values", issue = "75294")]
|
|
pub fn into_values(self) -> IntoValues<K, V> {
|
|
IntoValues { inner: self.into_iter() }
|
|
}
|
|
}
|
|
|
|
impl<K, V, S> HashMap<K, V, S>
|
|
where
|
|
S: BuildHasher,
|
|
{
|
|
/// Creates a raw entry builder for the HashMap.
|
|
///
|
|
/// Raw entries provide the lowest level of control for searching and
|
|
/// manipulating a map. They must be manually initialized with a hash and
|
|
/// then manually searched. After this, insertions into a vacant entry
|
|
/// still require an owned key to be provided.
|
|
///
|
|
/// Raw entries are useful for such exotic situations as:
|
|
///
|
|
/// * Hash memoization
|
|
/// * Deferring the creation of an owned key until it is known to be required
|
|
/// * Using a search key that doesn't work with the Borrow trait
|
|
/// * Using custom comparison logic without newtype wrappers
|
|
///
|
|
/// Because raw entries provide much more low-level control, it's much easier
|
|
/// to put the HashMap into an inconsistent state which, while memory-safe,
|
|
/// will cause the map to produce seemingly random results. Higher-level and
|
|
/// more foolproof APIs like `entry` should be preferred when possible.
|
|
///
|
|
/// In particular, the hash used to initialized the raw entry must still be
|
|
/// consistent with the hash of the key that is ultimately stored in the entry.
|
|
/// This is because implementations of HashMap may need to recompute hashes
|
|
/// when resizing, at which point only the keys are available.
|
|
///
|
|
/// Raw entries give mutable access to the keys. This must not be used
|
|
/// to modify how the key would compare or hash, as the map will not re-evaluate
|
|
/// where the key should go, meaning the keys may become "lost" if their
|
|
/// location does not reflect their state. For instance, if you change a key
|
|
/// so that the map now contains keys which compare equal, search may start
|
|
/// acting erratically, with two keys randomly masking each other. Implementations
|
|
/// are free to assume this doesn't happen (within the limits of memory-safety).
|
|
#[inline]
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub fn raw_entry_mut(&mut self) -> RawEntryBuilderMut<'_, K, V, S> {
|
|
RawEntryBuilderMut { map: self }
|
|
}
|
|
|
|
/// Creates a raw immutable entry builder for the HashMap.
|
|
///
|
|
/// Raw entries provide the lowest level of control for searching and
|
|
/// manipulating a map. They must be manually initialized with a hash and
|
|
/// then manually searched.
|
|
///
|
|
/// This is useful for
|
|
/// * Hash memoization
|
|
/// * Using a search key that doesn't work with the Borrow trait
|
|
/// * Using custom comparison logic without newtype wrappers
|
|
///
|
|
/// Unless you are in such a situation, higher-level and more foolproof APIs like
|
|
/// `get` should be preferred.
|
|
///
|
|
/// Immutable raw entries have very limited use; you might instead want `raw_entry_mut`.
|
|
#[inline]
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub fn raw_entry(&self) -> RawEntryBuilder<'_, K, V, S> {
|
|
RawEntryBuilder { map: self }
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<K, V, S> PartialEq for HashMap<K, V, S>
|
|
where
|
|
K: Eq + Hash,
|
|
V: PartialEq,
|
|
S: BuildHasher,
|
|
{
|
|
fn eq(&self, other: &HashMap<K, V, S>) -> bool {
|
|
if self.len() != other.len() {
|
|
return false;
|
|
}
|
|
|
|
self.iter().all(|(key, value)| other.get(key).map_or(false, |v| *value == *v))
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<K, V, S> Eq for HashMap<K, V, S>
|
|
where
|
|
K: Eq + Hash,
|
|
V: Eq,
|
|
S: BuildHasher,
|
|
{
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<K, V, S> Debug for HashMap<K, V, S>
|
|
where
|
|
K: Debug,
|
|
V: Debug,
|
|
{
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
f.debug_map().entries(self.iter()).finish()
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<K, V, S> Default for HashMap<K, V, S>
|
|
where
|
|
S: Default,
|
|
{
|
|
/// Creates an empty `HashMap<K, V, S>`, with the `Default` value for the hasher.
|
|
#[inline]
|
|
fn default() -> HashMap<K, V, S> {
|
|
HashMap::with_hasher(Default::default())
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<K, Q: ?Sized, V, S> Index<&Q> for HashMap<K, V, S>
|
|
where
|
|
K: Eq + Hash + Borrow<Q>,
|
|
Q: Eq + Hash,
|
|
S: BuildHasher,
|
|
{
|
|
type Output = V;
|
|
|
|
/// Returns a reference to the value corresponding to the supplied key.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// Panics if the key is not present in the `HashMap`.
|
|
#[inline]
|
|
fn index(&self, key: &Q) -> &V {
|
|
self.get(key).expect("no entry found for key")
|
|
}
|
|
}
|
|
|
|
/// An iterator over the entries of a `HashMap`.
|
|
///
|
|
/// This `struct` is created by the [`iter`] method on [`HashMap`]. See its
|
|
/// documentation for more.
|
|
///
|
|
/// [`iter`]: HashMap::iter
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub struct Iter<'a, K: 'a, V: 'a> {
|
|
base: base::Iter<'a, K, V>,
|
|
}
|
|
|
|
// FIXME(#26925) Remove in favor of `#[derive(Clone)]`
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<K, V> Clone for Iter<'_, K, V> {
|
|
#[inline]
|
|
fn clone(&self) -> Self {
|
|
Iter { base: self.base.clone() }
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "std_debug", since = "1.16.0")]
|
|
impl<K: Debug, V: Debug> fmt::Debug for Iter<'_, K, V> {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
f.debug_list().entries(self.clone()).finish()
|
|
}
|
|
}
|
|
|
|
/// A mutable iterator over the entries of a `HashMap`.
|
|
///
|
|
/// This `struct` is created by the [`iter_mut`] method on [`HashMap`]. See its
|
|
/// documentation for more.
|
|
///
|
|
/// [`iter_mut`]: HashMap::iter_mut
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub struct IterMut<'a, K: 'a, V: 'a> {
|
|
base: base::IterMut<'a, K, V>,
|
|
}
|
|
|
|
impl<'a, K, V> IterMut<'a, K, V> {
|
|
/// Returns a iterator of references over the remaining items.
|
|
#[inline]
|
|
pub(super) fn iter(&self) -> Iter<'_, K, V> {
|
|
Iter { base: self.base.rustc_iter() }
|
|
}
|
|
}
|
|
|
|
/// An owning iterator over the entries of a `HashMap`.
|
|
///
|
|
/// This `struct` is created by the [`into_iter`] method on [`HashMap`]
|
|
/// (provided by the `IntoIterator` trait). See its documentation for more.
|
|
///
|
|
/// [`into_iter`]: IntoIterator::into_iter
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub struct IntoIter<K, V> {
|
|
base: base::IntoIter<K, V>,
|
|
}
|
|
|
|
impl<K, V> IntoIter<K, V> {
|
|
/// Returns a iterator of references over the remaining items.
|
|
#[inline]
|
|
pub(super) fn iter(&self) -> Iter<'_, K, V> {
|
|
Iter { base: self.base.rustc_iter() }
|
|
}
|
|
}
|
|
|
|
/// An iterator over the keys of a `HashMap`.
|
|
///
|
|
/// This `struct` is created by the [`keys`] method on [`HashMap`]. See its
|
|
/// documentation for more.
|
|
///
|
|
/// [`keys`]: HashMap::keys
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub struct Keys<'a, K: 'a, V: 'a> {
|
|
inner: Iter<'a, K, V>,
|
|
}
|
|
|
|
// FIXME(#26925) Remove in favor of `#[derive(Clone)]`
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<K, V> Clone for Keys<'_, K, V> {
|
|
#[inline]
|
|
fn clone(&self) -> Self {
|
|
Keys { inner: self.inner.clone() }
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "std_debug", since = "1.16.0")]
|
|
impl<K: Debug, V> fmt::Debug for Keys<'_, K, V> {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
f.debug_list().entries(self.clone()).finish()
|
|
}
|
|
}
|
|
|
|
/// An iterator over the values of a `HashMap`.
|
|
///
|
|
/// This `struct` is created by the [`values`] method on [`HashMap`]. See its
|
|
/// documentation for more.
|
|
///
|
|
/// [`values`]: HashMap::values
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub struct Values<'a, K: 'a, V: 'a> {
|
|
inner: Iter<'a, K, V>,
|
|
}
|
|
|
|
// FIXME(#26925) Remove in favor of `#[derive(Clone)]`
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<K, V> Clone for Values<'_, K, V> {
|
|
#[inline]
|
|
fn clone(&self) -> Self {
|
|
Values { inner: self.inner.clone() }
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "std_debug", since = "1.16.0")]
|
|
impl<K, V: Debug> fmt::Debug for Values<'_, K, V> {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
f.debug_list().entries(self.clone()).finish()
|
|
}
|
|
}
|
|
|
|
/// A draining iterator over the entries of a `HashMap`.
|
|
///
|
|
/// This `struct` is created by the [`drain`] method on [`HashMap`]. See its
|
|
/// documentation for more.
|
|
///
|
|
/// [`drain`]: HashMap::drain
|
|
#[stable(feature = "drain", since = "1.6.0")]
|
|
pub struct Drain<'a, K: 'a, V: 'a> {
|
|
base: base::Drain<'a, K, V>,
|
|
}
|
|
|
|
impl<'a, K, V> Drain<'a, K, V> {
|
|
/// Returns a iterator of references over the remaining items.
|
|
#[inline]
|
|
pub(super) fn iter(&self) -> Iter<'_, K, V> {
|
|
Iter { base: self.base.rustc_iter() }
|
|
}
|
|
}
|
|
|
|
/// A mutable iterator over the values of a `HashMap`.
|
|
///
|
|
/// This `struct` is created by the [`values_mut`] method on [`HashMap`]. See its
|
|
/// documentation for more.
|
|
///
|
|
/// [`values_mut`]: HashMap::values_mut
|
|
#[stable(feature = "map_values_mut", since = "1.10.0")]
|
|
pub struct ValuesMut<'a, K: 'a, V: 'a> {
|
|
inner: IterMut<'a, K, V>,
|
|
}
|
|
|
|
/// An owning iterator over the keys of a `HashMap`.
|
|
///
|
|
/// This `struct` is created by the [`into_keys`] method on [`HashMap`].
|
|
/// See its documentation for more.
|
|
///
|
|
/// [`into_keys`]: HashMap::into_keys
|
|
#[unstable(feature = "map_into_keys_values", issue = "75294")]
|
|
pub struct IntoKeys<K, V> {
|
|
inner: IntoIter<K, V>,
|
|
}
|
|
|
|
/// An owning iterator over the values of a `HashMap`.
|
|
///
|
|
/// This `struct` is created by the [`into_values`] method on [`HashMap`].
|
|
/// See its documentation for more.
|
|
///
|
|
/// [`into_values`]: HashMap::into_values
|
|
#[unstable(feature = "map_into_keys_values", issue = "75294")]
|
|
pub struct IntoValues<K, V> {
|
|
inner: IntoIter<K, V>,
|
|
}
|
|
|
|
/// A builder for computing where in a HashMap a key-value pair would be stored.
|
|
///
|
|
/// See the [`HashMap::raw_entry_mut`] docs for usage examples.
|
|
///
|
|
/// [`HashMap::raw_entry_mut`]: HashMap::raw_entry_mut
|
|
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub struct RawEntryBuilderMut<'a, K: 'a, V: 'a, S: 'a> {
|
|
map: &'a mut HashMap<K, V, S>,
|
|
}
|
|
|
|
/// A view into a single entry in a map, which may either be vacant or occupied.
|
|
///
|
|
/// This is a lower-level version of [`Entry`].
|
|
///
|
|
/// This `enum` is constructed through the [`raw_entry_mut`] method on [`HashMap`],
|
|
/// then calling one of the methods of that [`RawEntryBuilderMut`].
|
|
///
|
|
/// [`Entry`]: enum.Entry.html
|
|
/// [`raw_entry_mut`]: HashMap::raw_entry_mut
|
|
/// [`RawEntryBuilderMut`]: struct.RawEntryBuilderMut.html
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub enum RawEntryMut<'a, K: 'a, V: 'a, S: 'a> {
|
|
/// An occupied entry.
|
|
Occupied(RawOccupiedEntryMut<'a, K, V, S>),
|
|
/// A vacant entry.
|
|
Vacant(RawVacantEntryMut<'a, K, V, S>),
|
|
}
|
|
|
|
/// A view into an occupied entry in a `HashMap`.
|
|
/// It is part of the [`RawEntryMut`] enum.
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub struct RawOccupiedEntryMut<'a, K: 'a, V: 'a, S: 'a> {
|
|
base: base::RawOccupiedEntryMut<'a, K, V, S>,
|
|
}
|
|
|
|
/// A view into a vacant entry in a `HashMap`.
|
|
/// It is part of the [`RawEntryMut`] enum.
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub struct RawVacantEntryMut<'a, K: 'a, V: 'a, S: 'a> {
|
|
base: base::RawVacantEntryMut<'a, K, V, S>,
|
|
}
|
|
|
|
/// A builder for computing where in a HashMap a key-value pair would be stored.
|
|
///
|
|
/// See the [`HashMap::raw_entry`] docs for usage examples.
|
|
///
|
|
/// [`HashMap::raw_entry`]: HashMap::raw_entry
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub struct RawEntryBuilder<'a, K: 'a, V: 'a, S: 'a> {
|
|
map: &'a HashMap<K, V, S>,
|
|
}
|
|
|
|
impl<'a, K, V, S> RawEntryBuilderMut<'a, K, V, S>
|
|
where
|
|
S: BuildHasher,
|
|
{
|
|
/// Creates a `RawEntryMut` from the given key.
|
|
#[inline]
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub fn from_key<Q: ?Sized>(self, k: &Q) -> RawEntryMut<'a, K, V, S>
|
|
where
|
|
K: Borrow<Q>,
|
|
Q: Hash + Eq,
|
|
{
|
|
map_raw_entry(self.map.base.raw_entry_mut().from_key(k))
|
|
}
|
|
|
|
/// Creates a `RawEntryMut` from the given key and its hash.
|
|
#[inline]
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub fn from_key_hashed_nocheck<Q: ?Sized>(self, hash: u64, k: &Q) -> RawEntryMut<'a, K, V, S>
|
|
where
|
|
K: Borrow<Q>,
|
|
Q: Eq,
|
|
{
|
|
map_raw_entry(self.map.base.raw_entry_mut().from_key_hashed_nocheck(hash, k))
|
|
}
|
|
|
|
/// Creates a `RawEntryMut` from the given hash.
|
|
#[inline]
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub fn from_hash<F>(self, hash: u64, is_match: F) -> RawEntryMut<'a, K, V, S>
|
|
where
|
|
for<'b> F: FnMut(&'b K) -> bool,
|
|
{
|
|
map_raw_entry(self.map.base.raw_entry_mut().from_hash(hash, is_match))
|
|
}
|
|
}
|
|
|
|
impl<'a, K, V, S> RawEntryBuilder<'a, K, V, S>
|
|
where
|
|
S: BuildHasher,
|
|
{
|
|
/// Access an entry by key.
|
|
#[inline]
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub fn from_key<Q: ?Sized>(self, k: &Q) -> Option<(&'a K, &'a V)>
|
|
where
|
|
K: Borrow<Q>,
|
|
Q: Hash + Eq,
|
|
{
|
|
self.map.base.raw_entry().from_key(k)
|
|
}
|
|
|
|
/// Access an entry by a key and its hash.
|
|
#[inline]
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub fn from_key_hashed_nocheck<Q: ?Sized>(self, hash: u64, k: &Q) -> Option<(&'a K, &'a V)>
|
|
where
|
|
K: Borrow<Q>,
|
|
Q: Hash + Eq,
|
|
{
|
|
self.map.base.raw_entry().from_key_hashed_nocheck(hash, k)
|
|
}
|
|
|
|
/// Access an entry by hash.
|
|
#[inline]
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub fn from_hash<F>(self, hash: u64, is_match: F) -> Option<(&'a K, &'a V)>
|
|
where
|
|
F: FnMut(&K) -> bool,
|
|
{
|
|
self.map.base.raw_entry().from_hash(hash, is_match)
|
|
}
|
|
}
|
|
|
|
impl<'a, K, V, S> RawEntryMut<'a, K, V, S> {
|
|
/// Ensures a value is in the entry by inserting the default if empty, and returns
|
|
/// mutable references to the key and value in the entry.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// #![feature(hash_raw_entry)]
|
|
/// use std::collections::HashMap;
|
|
///
|
|
/// let mut map: HashMap<&str, u32> = HashMap::new();
|
|
///
|
|
/// map.raw_entry_mut().from_key("poneyland").or_insert("poneyland", 3);
|
|
/// assert_eq!(map["poneyland"], 3);
|
|
///
|
|
/// *map.raw_entry_mut().from_key("poneyland").or_insert("poneyland", 10).1 *= 2;
|
|
/// assert_eq!(map["poneyland"], 6);
|
|
/// ```
|
|
#[inline]
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub fn or_insert(self, default_key: K, default_val: V) -> (&'a mut K, &'a mut V)
|
|
where
|
|
K: Hash,
|
|
S: BuildHasher,
|
|
{
|
|
match self {
|
|
RawEntryMut::Occupied(entry) => entry.into_key_value(),
|
|
RawEntryMut::Vacant(entry) => entry.insert(default_key, default_val),
|
|
}
|
|
}
|
|
|
|
/// Ensures a value is in the entry by inserting the result of the default function if empty,
|
|
/// and returns mutable references to the key and value in the entry.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// #![feature(hash_raw_entry)]
|
|
/// use std::collections::HashMap;
|
|
///
|
|
/// let mut map: HashMap<&str, String> = HashMap::new();
|
|
///
|
|
/// map.raw_entry_mut().from_key("poneyland").or_insert_with(|| {
|
|
/// ("poneyland", "hoho".to_string())
|
|
/// });
|
|
///
|
|
/// assert_eq!(map["poneyland"], "hoho".to_string());
|
|
/// ```
|
|
#[inline]
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub fn or_insert_with<F>(self, default: F) -> (&'a mut K, &'a mut V)
|
|
where
|
|
F: FnOnce() -> (K, V),
|
|
K: Hash,
|
|
S: BuildHasher,
|
|
{
|
|
match self {
|
|
RawEntryMut::Occupied(entry) => entry.into_key_value(),
|
|
RawEntryMut::Vacant(entry) => {
|
|
let (k, v) = default();
|
|
entry.insert(k, v)
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Provides in-place mutable access to an occupied entry before any
|
|
/// potential inserts into the map.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// #![feature(hash_raw_entry)]
|
|
/// use std::collections::HashMap;
|
|
///
|
|
/// let mut map: HashMap<&str, u32> = HashMap::new();
|
|
///
|
|
/// map.raw_entry_mut()
|
|
/// .from_key("poneyland")
|
|
/// .and_modify(|_k, v| { *v += 1 })
|
|
/// .or_insert("poneyland", 42);
|
|
/// assert_eq!(map["poneyland"], 42);
|
|
///
|
|
/// map.raw_entry_mut()
|
|
/// .from_key("poneyland")
|
|
/// .and_modify(|_k, v| { *v += 1 })
|
|
/// .or_insert("poneyland", 0);
|
|
/// assert_eq!(map["poneyland"], 43);
|
|
/// ```
|
|
#[inline]
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub fn and_modify<F>(self, f: F) -> Self
|
|
where
|
|
F: FnOnce(&mut K, &mut V),
|
|
{
|
|
match self {
|
|
RawEntryMut::Occupied(mut entry) => {
|
|
{
|
|
let (k, v) = entry.get_key_value_mut();
|
|
f(k, v);
|
|
}
|
|
RawEntryMut::Occupied(entry)
|
|
}
|
|
RawEntryMut::Vacant(entry) => RawEntryMut::Vacant(entry),
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'a, K, V, S> RawOccupiedEntryMut<'a, K, V, S> {
|
|
/// Gets a reference to the key in the entry.
|
|
#[inline]
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub fn key(&self) -> &K {
|
|
self.base.key()
|
|
}
|
|
|
|
/// Gets a mutable reference to the key in the entry.
|
|
#[inline]
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub fn key_mut(&mut self) -> &mut K {
|
|
self.base.key_mut()
|
|
}
|
|
|
|
/// Converts the entry into a mutable reference to the key in the entry
|
|
/// with a lifetime bound to the map itself.
|
|
#[inline]
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub fn into_key(self) -> &'a mut K {
|
|
self.base.into_key()
|
|
}
|
|
|
|
/// Gets a reference to the value in the entry.
|
|
#[inline]
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub fn get(&self) -> &V {
|
|
self.base.get()
|
|
}
|
|
|
|
/// Converts the OccupiedEntry into a mutable reference to the value in the entry
|
|
/// with a lifetime bound to the map itself.
|
|
#[inline]
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub fn into_mut(self) -> &'a mut V {
|
|
self.base.into_mut()
|
|
}
|
|
|
|
/// Gets a mutable reference to the value in the entry.
|
|
#[inline]
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub fn get_mut(&mut self) -> &mut V {
|
|
self.base.get_mut()
|
|
}
|
|
|
|
/// Gets a reference to the key and value in the entry.
|
|
#[inline]
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub fn get_key_value(&mut self) -> (&K, &V) {
|
|
self.base.get_key_value()
|
|
}
|
|
|
|
/// Gets a mutable reference to the key and value in the entry.
|
|
#[inline]
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub fn get_key_value_mut(&mut self) -> (&mut K, &mut V) {
|
|
self.base.get_key_value_mut()
|
|
}
|
|
|
|
/// Converts the OccupiedEntry into a mutable reference to the key and value in the entry
|
|
/// with a lifetime bound to the map itself.
|
|
#[inline]
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub fn into_key_value(self) -> (&'a mut K, &'a mut V) {
|
|
self.base.into_key_value()
|
|
}
|
|
|
|
/// Sets the value of the entry, and returns the entry's old value.
|
|
#[inline]
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub fn insert(&mut self, value: V) -> V {
|
|
self.base.insert(value)
|
|
}
|
|
|
|
/// Sets the value of the entry, and returns the entry's old value.
|
|
#[inline]
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub fn insert_key(&mut self, key: K) -> K {
|
|
self.base.insert_key(key)
|
|
}
|
|
|
|
/// Takes the value out of the entry, and returns it.
|
|
#[inline]
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub fn remove(self) -> V {
|
|
self.base.remove()
|
|
}
|
|
|
|
/// Take the ownership of the key and value from the map.
|
|
#[inline]
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub fn remove_entry(self) -> (K, V) {
|
|
self.base.remove_entry()
|
|
}
|
|
}
|
|
|
|
impl<'a, K, V, S> RawVacantEntryMut<'a, K, V, S> {
|
|
/// Sets the value of the entry with the VacantEntry's key,
|
|
/// and returns a mutable reference to it.
|
|
#[inline]
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub fn insert(self, key: K, value: V) -> (&'a mut K, &'a mut V)
|
|
where
|
|
K: Hash,
|
|
S: BuildHasher,
|
|
{
|
|
self.base.insert(key, value)
|
|
}
|
|
|
|
/// Sets the value of the entry with the VacantEntry's key,
|
|
/// and returns a mutable reference to it.
|
|
#[inline]
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
pub fn insert_hashed_nocheck(self, hash: u64, key: K, value: V) -> (&'a mut K, &'a mut V)
|
|
where
|
|
K: Hash,
|
|
S: BuildHasher,
|
|
{
|
|
self.base.insert_hashed_nocheck(hash, key, value)
|
|
}
|
|
}
|
|
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
impl<K, V, S> Debug for RawEntryBuilderMut<'_, K, V, S> {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
f.debug_struct("RawEntryBuilder").finish()
|
|
}
|
|
}
|
|
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
impl<K: Debug, V: Debug, S> Debug for RawEntryMut<'_, K, V, S> {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
match *self {
|
|
RawEntryMut::Vacant(ref v) => f.debug_tuple("RawEntry").field(v).finish(),
|
|
RawEntryMut::Occupied(ref o) => f.debug_tuple("RawEntry").field(o).finish(),
|
|
}
|
|
}
|
|
}
|
|
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
impl<K: Debug, V: Debug, S> Debug for RawOccupiedEntryMut<'_, K, V, S> {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
f.debug_struct("RawOccupiedEntryMut")
|
|
.field("key", self.key())
|
|
.field("value", self.get())
|
|
.finish()
|
|
}
|
|
}
|
|
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
impl<K, V, S> Debug for RawVacantEntryMut<'_, K, V, S> {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
f.debug_struct("RawVacantEntryMut").finish()
|
|
}
|
|
}
|
|
|
|
#[unstable(feature = "hash_raw_entry", issue = "56167")]
|
|
impl<K, V, S> Debug for RawEntryBuilder<'_, K, V, S> {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
f.debug_struct("RawEntryBuilder").finish()
|
|
}
|
|
}
|
|
|
|
/// A view into a single entry in a map, which may either be vacant or occupied.
|
|
///
|
|
/// This `enum` is constructed from the [`entry`] method on [`HashMap`].
|
|
///
|
|
/// [`entry`]: HashMap::entry
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub enum Entry<'a, K: 'a, V: 'a> {
|
|
/// An occupied entry.
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
Occupied(#[stable(feature = "rust1", since = "1.0.0")] OccupiedEntry<'a, K, V>),
|
|
|
|
/// A vacant entry.
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
Vacant(#[stable(feature = "rust1", since = "1.0.0")] VacantEntry<'a, K, V>),
|
|
}
|
|
|
|
#[stable(feature = "debug_hash_map", since = "1.12.0")]
|
|
impl<K: Debug, V: Debug> Debug for Entry<'_, K, V> {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
match *self {
|
|
Vacant(ref v) => f.debug_tuple("Entry").field(v).finish(),
|
|
Occupied(ref o) => f.debug_tuple("Entry").field(o).finish(),
|
|
}
|
|
}
|
|
}
|
|
|
|
/// A view into an occupied entry in a `HashMap`.
|
|
/// It is part of the [`Entry`] enum.
|
|
///
|
|
/// [`Entry`]: enum.Entry.html
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub struct OccupiedEntry<'a, K: 'a, V: 'a> {
|
|
base: base::RustcOccupiedEntry<'a, K, V>,
|
|
}
|
|
|
|
#[stable(feature = "debug_hash_map", since = "1.12.0")]
|
|
impl<K: Debug, V: Debug> Debug for OccupiedEntry<'_, K, V> {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
f.debug_struct("OccupiedEntry").field("key", self.key()).field("value", self.get()).finish()
|
|
}
|
|
}
|
|
|
|
/// A view into a vacant entry in a `HashMap`.
|
|
/// It is part of the [`Entry`] enum.
|
|
///
|
|
/// [`Entry`]: enum.Entry.html
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub struct VacantEntry<'a, K: 'a, V: 'a> {
|
|
base: base::RustcVacantEntry<'a, K, V>,
|
|
}
|
|
|
|
#[stable(feature = "debug_hash_map", since = "1.12.0")]
|
|
impl<K: Debug, V> Debug for VacantEntry<'_, K, V> {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
f.debug_tuple("VacantEntry").field(self.key()).finish()
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, K, V, S> IntoIterator for &'a HashMap<K, V, S> {
|
|
type Item = (&'a K, &'a V);
|
|
type IntoIter = Iter<'a, K, V>;
|
|
|
|
#[inline]
|
|
fn into_iter(self) -> Iter<'a, K, V> {
|
|
self.iter()
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, K, V, S> IntoIterator for &'a mut HashMap<K, V, S> {
|
|
type Item = (&'a K, &'a mut V);
|
|
type IntoIter = IterMut<'a, K, V>;
|
|
|
|
#[inline]
|
|
fn into_iter(self) -> IterMut<'a, K, V> {
|
|
self.iter_mut()
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<K, V, S> IntoIterator for HashMap<K, V, S> {
|
|
type Item = (K, V);
|
|
type IntoIter = IntoIter<K, V>;
|
|
|
|
/// Creates a consuming iterator, that is, one that moves each key-value
|
|
/// pair out of the map in arbitrary order. The map cannot be used after
|
|
/// calling this.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
///
|
|
/// let mut map = HashMap::new();
|
|
/// map.insert("a", 1);
|
|
/// map.insert("b", 2);
|
|
/// map.insert("c", 3);
|
|
///
|
|
/// // Not possible with .iter()
|
|
/// let vec: Vec<(&str, i32)> = map.into_iter().collect();
|
|
/// ```
|
|
#[inline]
|
|
fn into_iter(self) -> IntoIter<K, V> {
|
|
IntoIter { base: self.base.into_iter() }
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, K, V> Iterator for Iter<'a, K, V> {
|
|
type Item = (&'a K, &'a V);
|
|
|
|
#[inline]
|
|
fn next(&mut self) -> Option<(&'a K, &'a V)> {
|
|
self.base.next()
|
|
}
|
|
#[inline]
|
|
fn size_hint(&self) -> (usize, Option<usize>) {
|
|
self.base.size_hint()
|
|
}
|
|
}
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<K, V> ExactSizeIterator for Iter<'_, K, V> {
|
|
#[inline]
|
|
fn len(&self) -> usize {
|
|
self.base.len()
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "fused", since = "1.26.0")]
|
|
impl<K, V> FusedIterator for Iter<'_, K, V> {}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, K, V> Iterator for IterMut<'a, K, V> {
|
|
type Item = (&'a K, &'a mut V);
|
|
|
|
#[inline]
|
|
fn next(&mut self) -> Option<(&'a K, &'a mut V)> {
|
|
self.base.next()
|
|
}
|
|
#[inline]
|
|
fn size_hint(&self) -> (usize, Option<usize>) {
|
|
self.base.size_hint()
|
|
}
|
|
}
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<K, V> ExactSizeIterator for IterMut<'_, K, V> {
|
|
#[inline]
|
|
fn len(&self) -> usize {
|
|
self.base.len()
|
|
}
|
|
}
|
|
#[stable(feature = "fused", since = "1.26.0")]
|
|
impl<K, V> FusedIterator for IterMut<'_, K, V> {}
|
|
|
|
#[stable(feature = "std_debug", since = "1.16.0")]
|
|
impl<K, V> fmt::Debug for IterMut<'_, K, V>
|
|
where
|
|
K: fmt::Debug,
|
|
V: fmt::Debug,
|
|
{
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
f.debug_list().entries(self.iter()).finish()
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<K, V> Iterator for IntoIter<K, V> {
|
|
type Item = (K, V);
|
|
|
|
#[inline]
|
|
fn next(&mut self) -> Option<(K, V)> {
|
|
self.base.next()
|
|
}
|
|
#[inline]
|
|
fn size_hint(&self) -> (usize, Option<usize>) {
|
|
self.base.size_hint()
|
|
}
|
|
}
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<K, V> ExactSizeIterator for IntoIter<K, V> {
|
|
#[inline]
|
|
fn len(&self) -> usize {
|
|
self.base.len()
|
|
}
|
|
}
|
|
#[stable(feature = "fused", since = "1.26.0")]
|
|
impl<K, V> FusedIterator for IntoIter<K, V> {}
|
|
|
|
#[stable(feature = "std_debug", since = "1.16.0")]
|
|
impl<K: Debug, V: Debug> fmt::Debug for IntoIter<K, V> {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
f.debug_list().entries(self.iter()).finish()
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, K, V> Iterator for Keys<'a, K, V> {
|
|
type Item = &'a K;
|
|
|
|
#[inline]
|
|
fn next(&mut self) -> Option<&'a K> {
|
|
self.inner.next().map(|(k, _)| k)
|
|
}
|
|
#[inline]
|
|
fn size_hint(&self) -> (usize, Option<usize>) {
|
|
self.inner.size_hint()
|
|
}
|
|
}
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<K, V> ExactSizeIterator for Keys<'_, K, V> {
|
|
#[inline]
|
|
fn len(&self) -> usize {
|
|
self.inner.len()
|
|
}
|
|
}
|
|
#[stable(feature = "fused", since = "1.26.0")]
|
|
impl<K, V> FusedIterator for Keys<'_, K, V> {}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, K, V> Iterator for Values<'a, K, V> {
|
|
type Item = &'a V;
|
|
|
|
#[inline]
|
|
fn next(&mut self) -> Option<&'a V> {
|
|
self.inner.next().map(|(_, v)| v)
|
|
}
|
|
#[inline]
|
|
fn size_hint(&self) -> (usize, Option<usize>) {
|
|
self.inner.size_hint()
|
|
}
|
|
}
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<K, V> ExactSizeIterator for Values<'_, K, V> {
|
|
#[inline]
|
|
fn len(&self) -> usize {
|
|
self.inner.len()
|
|
}
|
|
}
|
|
#[stable(feature = "fused", since = "1.26.0")]
|
|
impl<K, V> FusedIterator for Values<'_, K, V> {}
|
|
|
|
#[stable(feature = "map_values_mut", since = "1.10.0")]
|
|
impl<'a, K, V> Iterator for ValuesMut<'a, K, V> {
|
|
type Item = &'a mut V;
|
|
|
|
#[inline]
|
|
fn next(&mut self) -> Option<&'a mut V> {
|
|
self.inner.next().map(|(_, v)| v)
|
|
}
|
|
#[inline]
|
|
fn size_hint(&self) -> (usize, Option<usize>) {
|
|
self.inner.size_hint()
|
|
}
|
|
}
|
|
#[stable(feature = "map_values_mut", since = "1.10.0")]
|
|
impl<K, V> ExactSizeIterator for ValuesMut<'_, K, V> {
|
|
#[inline]
|
|
fn len(&self) -> usize {
|
|
self.inner.len()
|
|
}
|
|
}
|
|
#[stable(feature = "fused", since = "1.26.0")]
|
|
impl<K, V> FusedIterator for ValuesMut<'_, K, V> {}
|
|
|
|
#[stable(feature = "std_debug", since = "1.16.0")]
|
|
impl<K, V> fmt::Debug for ValuesMut<'_, K, V>
|
|
where
|
|
K: fmt::Debug,
|
|
V: fmt::Debug,
|
|
{
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
f.debug_list().entries(self.inner.iter()).finish()
|
|
}
|
|
}
|
|
|
|
#[unstable(feature = "map_into_keys_values", issue = "75294")]
|
|
impl<K, V> Iterator for IntoKeys<K, V> {
|
|
type Item = K;
|
|
|
|
#[inline]
|
|
fn next(&mut self) -> Option<K> {
|
|
self.inner.next().map(|(k, _)| k)
|
|
}
|
|
#[inline]
|
|
fn size_hint(&self) -> (usize, Option<usize>) {
|
|
self.inner.size_hint()
|
|
}
|
|
}
|
|
#[unstable(feature = "map_into_keys_values", issue = "75294")]
|
|
impl<K, V> ExactSizeIterator for IntoKeys<K, V> {
|
|
#[inline]
|
|
fn len(&self) -> usize {
|
|
self.inner.len()
|
|
}
|
|
}
|
|
#[unstable(feature = "map_into_keys_values", issue = "75294")]
|
|
impl<K, V> FusedIterator for IntoKeys<K, V> {}
|
|
|
|
#[unstable(feature = "map_into_keys_values", issue = "75294")]
|
|
impl<K: Debug, V: Debug> fmt::Debug for IntoKeys<K, V> {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
f.debug_list().entries(self.inner.iter().map(|(k, _)| k)).finish()
|
|
}
|
|
}
|
|
|
|
#[unstable(feature = "map_into_keys_values", issue = "75294")]
|
|
impl<K, V> Iterator for IntoValues<K, V> {
|
|
type Item = V;
|
|
|
|
#[inline]
|
|
fn next(&mut self) -> Option<V> {
|
|
self.inner.next().map(|(_, v)| v)
|
|
}
|
|
#[inline]
|
|
fn size_hint(&self) -> (usize, Option<usize>) {
|
|
self.inner.size_hint()
|
|
}
|
|
}
|
|
#[unstable(feature = "map_into_keys_values", issue = "75294")]
|
|
impl<K, V> ExactSizeIterator for IntoValues<K, V> {
|
|
#[inline]
|
|
fn len(&self) -> usize {
|
|
self.inner.len()
|
|
}
|
|
}
|
|
#[unstable(feature = "map_into_keys_values", issue = "75294")]
|
|
impl<K, V> FusedIterator for IntoValues<K, V> {}
|
|
|
|
#[unstable(feature = "map_into_keys_values", issue = "75294")]
|
|
impl<K: Debug, V: Debug> fmt::Debug for IntoValues<K, V> {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
f.debug_list().entries(self.inner.iter().map(|(_, v)| v)).finish()
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "drain", since = "1.6.0")]
|
|
impl<'a, K, V> Iterator for Drain<'a, K, V> {
|
|
type Item = (K, V);
|
|
|
|
#[inline]
|
|
fn next(&mut self) -> Option<(K, V)> {
|
|
self.base.next()
|
|
}
|
|
#[inline]
|
|
fn size_hint(&self) -> (usize, Option<usize>) {
|
|
self.base.size_hint()
|
|
}
|
|
}
|
|
#[stable(feature = "drain", since = "1.6.0")]
|
|
impl<K, V> ExactSizeIterator for Drain<'_, K, V> {
|
|
#[inline]
|
|
fn len(&self) -> usize {
|
|
self.base.len()
|
|
}
|
|
}
|
|
#[stable(feature = "fused", since = "1.26.0")]
|
|
impl<K, V> FusedIterator for Drain<'_, K, V> {}
|
|
|
|
#[stable(feature = "std_debug", since = "1.16.0")]
|
|
impl<K, V> fmt::Debug for Drain<'_, K, V>
|
|
where
|
|
K: fmt::Debug,
|
|
V: fmt::Debug,
|
|
{
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
f.debug_list().entries(self.iter()).finish()
|
|
}
|
|
}
|
|
|
|
impl<'a, K, V> Entry<'a, K, V> {
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
/// Ensures a value is in the entry by inserting the default if empty, and returns
|
|
/// a mutable reference to the value in the entry.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
///
|
|
/// let mut map: HashMap<&str, u32> = HashMap::new();
|
|
///
|
|
/// map.entry("poneyland").or_insert(3);
|
|
/// assert_eq!(map["poneyland"], 3);
|
|
///
|
|
/// *map.entry("poneyland").or_insert(10) *= 2;
|
|
/// assert_eq!(map["poneyland"], 6);
|
|
/// ```
|
|
#[inline]
|
|
pub fn or_insert(self, default: V) -> &'a mut V {
|
|
match self {
|
|
Occupied(entry) => entry.into_mut(),
|
|
Vacant(entry) => entry.insert(default),
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
/// Ensures a value is in the entry by inserting the result of the default function if empty,
|
|
/// and returns a mutable reference to the value in the entry.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
///
|
|
/// let mut map: HashMap<&str, String> = HashMap::new();
|
|
/// let s = "hoho".to_string();
|
|
///
|
|
/// map.entry("poneyland").or_insert_with(|| s);
|
|
///
|
|
/// assert_eq!(map["poneyland"], "hoho".to_string());
|
|
/// ```
|
|
#[inline]
|
|
pub fn or_insert_with<F: FnOnce() -> V>(self, default: F) -> &'a mut V {
|
|
match self {
|
|
Occupied(entry) => entry.into_mut(),
|
|
Vacant(entry) => entry.insert(default()),
|
|
}
|
|
}
|
|
|
|
#[unstable(feature = "or_insert_with_key", issue = "71024")]
|
|
/// Ensures a value is in the entry by inserting, if empty, the result of the default function,
|
|
/// which takes the key as its argument, and returns a mutable reference to the value in the
|
|
/// entry.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// #![feature(or_insert_with_key)]
|
|
/// use std::collections::HashMap;
|
|
///
|
|
/// let mut map: HashMap<&str, usize> = HashMap::new();
|
|
///
|
|
/// map.entry("poneyland").or_insert_with_key(|key| key.chars().count());
|
|
///
|
|
/// assert_eq!(map["poneyland"], 9);
|
|
/// ```
|
|
#[inline]
|
|
pub fn or_insert_with_key<F: FnOnce(&K) -> V>(self, default: F) -> &'a mut V {
|
|
match self {
|
|
Occupied(entry) => entry.into_mut(),
|
|
Vacant(entry) => {
|
|
let value = default(entry.key());
|
|
entry.insert(value)
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Returns a reference to this entry's key.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
///
|
|
/// let mut map: HashMap<&str, u32> = HashMap::new();
|
|
/// assert_eq!(map.entry("poneyland").key(), &"poneyland");
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "map_entry_keys", since = "1.10.0")]
|
|
pub fn key(&self) -> &K {
|
|
match *self {
|
|
Occupied(ref entry) => entry.key(),
|
|
Vacant(ref entry) => entry.key(),
|
|
}
|
|
}
|
|
|
|
/// Provides in-place mutable access to an occupied entry before any
|
|
/// potential inserts into the map.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
///
|
|
/// let mut map: HashMap<&str, u32> = HashMap::new();
|
|
///
|
|
/// map.entry("poneyland")
|
|
/// .and_modify(|e| { *e += 1 })
|
|
/// .or_insert(42);
|
|
/// assert_eq!(map["poneyland"], 42);
|
|
///
|
|
/// map.entry("poneyland")
|
|
/// .and_modify(|e| { *e += 1 })
|
|
/// .or_insert(42);
|
|
/// assert_eq!(map["poneyland"], 43);
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "entry_and_modify", since = "1.26.0")]
|
|
pub fn and_modify<F>(self, f: F) -> Self
|
|
where
|
|
F: FnOnce(&mut V),
|
|
{
|
|
match self {
|
|
Occupied(mut entry) => {
|
|
f(entry.get_mut());
|
|
Occupied(entry)
|
|
}
|
|
Vacant(entry) => Vacant(entry),
|
|
}
|
|
}
|
|
|
|
/// Sets the value of the entry, and returns an OccupiedEntry.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// #![feature(entry_insert)]
|
|
/// use std::collections::HashMap;
|
|
///
|
|
/// let mut map: HashMap<&str, String> = HashMap::new();
|
|
/// let entry = map.entry("poneyland").insert("hoho".to_string());
|
|
///
|
|
/// assert_eq!(entry.key(), &"poneyland");
|
|
/// ```
|
|
#[inline]
|
|
#[unstable(feature = "entry_insert", issue = "65225")]
|
|
pub fn insert(self, value: V) -> OccupiedEntry<'a, K, V> {
|
|
match self {
|
|
Occupied(mut entry) => {
|
|
entry.insert(value);
|
|
entry
|
|
}
|
|
Vacant(entry) => entry.insert_entry(value),
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'a, K, V: Default> Entry<'a, K, V> {
|
|
#[stable(feature = "entry_or_default", since = "1.28.0")]
|
|
/// Ensures a value is in the entry by inserting the default value if empty,
|
|
/// and returns a mutable reference to the value in the entry.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # fn main() {
|
|
/// use std::collections::HashMap;
|
|
///
|
|
/// let mut map: HashMap<&str, Option<u32>> = HashMap::new();
|
|
/// map.entry("poneyland").or_default();
|
|
///
|
|
/// assert_eq!(map["poneyland"], None);
|
|
/// # }
|
|
/// ```
|
|
#[inline]
|
|
pub fn or_default(self) -> &'a mut V {
|
|
match self {
|
|
Occupied(entry) => entry.into_mut(),
|
|
Vacant(entry) => entry.insert(Default::default()),
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'a, K, V> OccupiedEntry<'a, K, V> {
|
|
/// Gets a reference to the key in the entry.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
///
|
|
/// let mut map: HashMap<&str, u32> = HashMap::new();
|
|
/// map.entry("poneyland").or_insert(12);
|
|
/// assert_eq!(map.entry("poneyland").key(), &"poneyland");
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "map_entry_keys", since = "1.10.0")]
|
|
pub fn key(&self) -> &K {
|
|
self.base.key()
|
|
}
|
|
|
|
/// Take the ownership of the key and value from the map.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
/// use std::collections::hash_map::Entry;
|
|
///
|
|
/// let mut map: HashMap<&str, u32> = HashMap::new();
|
|
/// map.entry("poneyland").or_insert(12);
|
|
///
|
|
/// if let Entry::Occupied(o) = map.entry("poneyland") {
|
|
/// // We delete the entry from the map.
|
|
/// o.remove_entry();
|
|
/// }
|
|
///
|
|
/// assert_eq!(map.contains_key("poneyland"), false);
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "map_entry_recover_keys2", since = "1.12.0")]
|
|
pub fn remove_entry(self) -> (K, V) {
|
|
self.base.remove_entry()
|
|
}
|
|
|
|
/// Gets a reference to the value in the entry.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
/// use std::collections::hash_map::Entry;
|
|
///
|
|
/// let mut map: HashMap<&str, u32> = HashMap::new();
|
|
/// map.entry("poneyland").or_insert(12);
|
|
///
|
|
/// if let Entry::Occupied(o) = map.entry("poneyland") {
|
|
/// assert_eq!(o.get(), &12);
|
|
/// }
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn get(&self) -> &V {
|
|
self.base.get()
|
|
}
|
|
|
|
/// Gets a mutable reference to the value in the entry.
|
|
///
|
|
/// If you need a reference to the `OccupiedEntry` which may outlive the
|
|
/// destruction of the `Entry` value, see [`into_mut`].
|
|
///
|
|
/// [`into_mut`]: Self::into_mut
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
/// use std::collections::hash_map::Entry;
|
|
///
|
|
/// let mut map: HashMap<&str, u32> = HashMap::new();
|
|
/// map.entry("poneyland").or_insert(12);
|
|
///
|
|
/// assert_eq!(map["poneyland"], 12);
|
|
/// if let Entry::Occupied(mut o) = map.entry("poneyland") {
|
|
/// *o.get_mut() += 10;
|
|
/// assert_eq!(*o.get(), 22);
|
|
///
|
|
/// // We can use the same Entry multiple times.
|
|
/// *o.get_mut() += 2;
|
|
/// }
|
|
///
|
|
/// assert_eq!(map["poneyland"], 24);
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn get_mut(&mut self) -> &mut V {
|
|
self.base.get_mut()
|
|
}
|
|
|
|
/// Converts the OccupiedEntry into a mutable reference to the value in the entry
|
|
/// with a lifetime bound to the map itself.
|
|
///
|
|
/// If you need multiple references to the `OccupiedEntry`, see [`get_mut`].
|
|
///
|
|
/// [`get_mut`]: Self::get_mut
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
/// use std::collections::hash_map::Entry;
|
|
///
|
|
/// let mut map: HashMap<&str, u32> = HashMap::new();
|
|
/// map.entry("poneyland").or_insert(12);
|
|
///
|
|
/// assert_eq!(map["poneyland"], 12);
|
|
/// if let Entry::Occupied(o) = map.entry("poneyland") {
|
|
/// *o.into_mut() += 10;
|
|
/// }
|
|
///
|
|
/// assert_eq!(map["poneyland"], 22);
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn into_mut(self) -> &'a mut V {
|
|
self.base.into_mut()
|
|
}
|
|
|
|
/// Sets the value of the entry, and returns the entry's old value.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
/// use std::collections::hash_map::Entry;
|
|
///
|
|
/// let mut map: HashMap<&str, u32> = HashMap::new();
|
|
/// map.entry("poneyland").or_insert(12);
|
|
///
|
|
/// if let Entry::Occupied(mut o) = map.entry("poneyland") {
|
|
/// assert_eq!(o.insert(15), 12);
|
|
/// }
|
|
///
|
|
/// assert_eq!(map["poneyland"], 15);
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn insert(&mut self, value: V) -> V {
|
|
self.base.insert(value)
|
|
}
|
|
|
|
/// Takes the value out of the entry, and returns it.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
/// use std::collections::hash_map::Entry;
|
|
///
|
|
/// let mut map: HashMap<&str, u32> = HashMap::new();
|
|
/// map.entry("poneyland").or_insert(12);
|
|
///
|
|
/// if let Entry::Occupied(o) = map.entry("poneyland") {
|
|
/// assert_eq!(o.remove(), 12);
|
|
/// }
|
|
///
|
|
/// assert_eq!(map.contains_key("poneyland"), false);
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn remove(self) -> V {
|
|
self.base.remove()
|
|
}
|
|
|
|
/// Replaces the entry, returning the old key and value. The new key in the hash map will be
|
|
/// the key used to create this entry.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// #![feature(map_entry_replace)]
|
|
/// use std::collections::hash_map::{Entry, HashMap};
|
|
/// use std::rc::Rc;
|
|
///
|
|
/// let mut map: HashMap<Rc<String>, u32> = HashMap::new();
|
|
/// map.insert(Rc::new("Stringthing".to_string()), 15);
|
|
///
|
|
/// let my_key = Rc::new("Stringthing".to_string());
|
|
///
|
|
/// if let Entry::Occupied(entry) = map.entry(my_key) {
|
|
/// // Also replace the key with a handle to our other key.
|
|
/// let (old_key, old_value): (Rc<String>, u32) = entry.replace_entry(16);
|
|
/// }
|
|
///
|
|
/// ```
|
|
#[inline]
|
|
#[unstable(feature = "map_entry_replace", issue = "44286")]
|
|
pub fn replace_entry(self, value: V) -> (K, V) {
|
|
self.base.replace_entry(value)
|
|
}
|
|
|
|
/// Replaces the key in the hash map with the key used to create this entry.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// #![feature(map_entry_replace)]
|
|
/// use std::collections::hash_map::{Entry, HashMap};
|
|
/// use std::rc::Rc;
|
|
///
|
|
/// let mut map: HashMap<Rc<String>, u32> = HashMap::new();
|
|
/// let known_strings: Vec<Rc<String>> = Vec::new();
|
|
///
|
|
/// // Initialise known strings, run program, etc.
|
|
///
|
|
/// reclaim_memory(&mut map, &known_strings);
|
|
///
|
|
/// fn reclaim_memory(map: &mut HashMap<Rc<String>, u32>, known_strings: &[Rc<String>] ) {
|
|
/// for s in known_strings {
|
|
/// if let Entry::Occupied(entry) = map.entry(Rc::clone(s)) {
|
|
/// // Replaces the entry's key with our version of it in `known_strings`.
|
|
/// entry.replace_key();
|
|
/// }
|
|
/// }
|
|
/// }
|
|
/// ```
|
|
#[inline]
|
|
#[unstable(feature = "map_entry_replace", issue = "44286")]
|
|
pub fn replace_key(self) -> K {
|
|
self.base.replace_key()
|
|
}
|
|
}
|
|
|
|
impl<'a, K: 'a, V: 'a> VacantEntry<'a, K, V> {
|
|
/// Gets a reference to the key that would be used when inserting a value
|
|
/// through the `VacantEntry`.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
///
|
|
/// let mut map: HashMap<&str, u32> = HashMap::new();
|
|
/// assert_eq!(map.entry("poneyland").key(), &"poneyland");
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "map_entry_keys", since = "1.10.0")]
|
|
pub fn key(&self) -> &K {
|
|
self.base.key()
|
|
}
|
|
|
|
/// Take ownership of the key.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
/// use std::collections::hash_map::Entry;
|
|
///
|
|
/// let mut map: HashMap<&str, u32> = HashMap::new();
|
|
///
|
|
/// if let Entry::Vacant(v) = map.entry("poneyland") {
|
|
/// v.into_key();
|
|
/// }
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "map_entry_recover_keys2", since = "1.12.0")]
|
|
pub fn into_key(self) -> K {
|
|
self.base.into_key()
|
|
}
|
|
|
|
/// Sets the value of the entry with the VacantEntry's key,
|
|
/// and returns a mutable reference to it.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
/// use std::collections::hash_map::Entry;
|
|
///
|
|
/// let mut map: HashMap<&str, u32> = HashMap::new();
|
|
///
|
|
/// if let Entry::Vacant(o) = map.entry("poneyland") {
|
|
/// o.insert(37);
|
|
/// }
|
|
/// assert_eq!(map["poneyland"], 37);
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn insert(self, value: V) -> &'a mut V {
|
|
self.base.insert(value)
|
|
}
|
|
|
|
/// Sets the value of the entry with the VacantEntry's key,
|
|
/// and returns an OccupiedEntry.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
/// use std::collections::hash_map::Entry;
|
|
///
|
|
/// let mut map: HashMap<&str, u32> = HashMap::new();
|
|
///
|
|
/// if let Entry::Vacant(o) = map.entry("poneyland") {
|
|
/// o.insert(37);
|
|
/// }
|
|
/// assert_eq!(map["poneyland"], 37);
|
|
/// ```
|
|
#[inline]
|
|
fn insert_entry(self, value: V) -> OccupiedEntry<'a, K, V> {
|
|
let base = self.base.insert_entry(value);
|
|
OccupiedEntry { base }
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<K, V, S> FromIterator<(K, V)> for HashMap<K, V, S>
|
|
where
|
|
K: Eq + Hash,
|
|
S: BuildHasher + Default,
|
|
{
|
|
fn from_iter<T: IntoIterator<Item = (K, V)>>(iter: T) -> HashMap<K, V, S> {
|
|
let mut map = HashMap::with_hasher(Default::default());
|
|
map.extend(iter);
|
|
map
|
|
}
|
|
}
|
|
|
|
/// Inserts all new key-values from the iterator and replaces values with existing
|
|
/// keys with new values returned from the iterator.
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<K, V, S> Extend<(K, V)> for HashMap<K, V, S>
|
|
where
|
|
K: Eq + Hash,
|
|
S: BuildHasher,
|
|
{
|
|
#[inline]
|
|
fn extend<T: IntoIterator<Item = (K, V)>>(&mut self, iter: T) {
|
|
self.base.extend(iter)
|
|
}
|
|
|
|
#[inline]
|
|
fn extend_one(&mut self, (k, v): (K, V)) {
|
|
self.base.insert(k, v);
|
|
}
|
|
|
|
#[inline]
|
|
fn extend_reserve(&mut self, additional: usize) {
|
|
// self.base.extend_reserve(additional);
|
|
// FIXME: hashbrown should implement this method.
|
|
// But until then, use the same reservation logic:
|
|
|
|
// Reserve the entire hint lower bound if the map is empty.
|
|
// Otherwise reserve half the hint (rounded up), so the map
|
|
// will only resize twice in the worst case.
|
|
let reserve = if self.is_empty() { additional } else { (additional + 1) / 2 };
|
|
self.base.reserve(reserve);
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "hash_extend_copy", since = "1.4.0")]
|
|
impl<'a, K, V, S> Extend<(&'a K, &'a V)> for HashMap<K, V, S>
|
|
where
|
|
K: Eq + Hash + Copy,
|
|
V: Copy,
|
|
S: BuildHasher,
|
|
{
|
|
#[inline]
|
|
fn extend<T: IntoIterator<Item = (&'a K, &'a V)>>(&mut self, iter: T) {
|
|
self.base.extend(iter)
|
|
}
|
|
|
|
#[inline]
|
|
fn extend_one(&mut self, (&k, &v): (&'a K, &'a V)) {
|
|
self.base.insert(k, v);
|
|
}
|
|
|
|
#[inline]
|
|
fn extend_reserve(&mut self, additional: usize) {
|
|
Extend::<(K, V)>::extend_reserve(self, additional)
|
|
}
|
|
}
|
|
|
|
/// `RandomState` is the default state for [`HashMap`] types.
|
|
///
|
|
/// A particular instance `RandomState` will create the same instances of
|
|
/// [`Hasher`], but the hashers created by two different `RandomState`
|
|
/// instances are unlikely to produce the same result for the same values.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::HashMap;
|
|
/// use std::collections::hash_map::RandomState;
|
|
///
|
|
/// let s = RandomState::new();
|
|
/// let mut map = HashMap::with_hasher(s);
|
|
/// map.insert(1, 2);
|
|
/// ```
|
|
#[derive(Clone)]
|
|
#[stable(feature = "hashmap_build_hasher", since = "1.7.0")]
|
|
pub struct RandomState {
|
|
k0: u64,
|
|
k1: u64,
|
|
}
|
|
|
|
impl RandomState {
|
|
/// Constructs a new `RandomState` that is initialized with random keys.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::hash_map::RandomState;
|
|
///
|
|
/// let s = RandomState::new();
|
|
/// ```
|
|
#[inline]
|
|
#[allow(deprecated)]
|
|
// rand
|
|
#[stable(feature = "hashmap_build_hasher", since = "1.7.0")]
|
|
pub fn new() -> RandomState {
|
|
// Historically this function did not cache keys from the OS and instead
|
|
// simply always called `rand::thread_rng().gen()` twice. In #31356 it
|
|
// was discovered, however, that because we re-seed the thread-local RNG
|
|
// from the OS periodically that this can cause excessive slowdown when
|
|
// many hash maps are created on a thread. To solve this performance
|
|
// trap we cache the first set of randomly generated keys per-thread.
|
|
//
|
|
// Later in #36481 it was discovered that exposing a deterministic
|
|
// iteration order allows a form of DOS attack. To counter that we
|
|
// increment one of the seeds on every RandomState creation, giving
|
|
// every corresponding HashMap a different iteration order.
|
|
thread_local!(static KEYS: Cell<(u64, u64)> = {
|
|
Cell::new(sys::hashmap_random_keys())
|
|
});
|
|
|
|
KEYS.with(|keys| {
|
|
let (k0, k1) = keys.get();
|
|
keys.set((k0.wrapping_add(1), k1));
|
|
RandomState { k0, k1 }
|
|
})
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "hashmap_build_hasher", since = "1.7.0")]
|
|
impl BuildHasher for RandomState {
|
|
type Hasher = DefaultHasher;
|
|
#[inline]
|
|
#[allow(deprecated)]
|
|
fn build_hasher(&self) -> DefaultHasher {
|
|
DefaultHasher(SipHasher13::new_with_keys(self.k0, self.k1))
|
|
}
|
|
}
|
|
|
|
/// The default [`Hasher`] used by [`RandomState`].
|
|
///
|
|
/// The internal algorithm is not specified, and so it and its hashes should
|
|
/// not be relied upon over releases.
|
|
#[stable(feature = "hashmap_default_hasher", since = "1.13.0")]
|
|
#[allow(deprecated)]
|
|
#[derive(Clone, Debug)]
|
|
pub struct DefaultHasher(SipHasher13);
|
|
|
|
impl DefaultHasher {
|
|
/// Creates a new `DefaultHasher`.
|
|
///
|
|
/// This hasher is not guaranteed to be the same as all other
|
|
/// `DefaultHasher` instances, but is the same as all other `DefaultHasher`
|
|
/// instances created through `new` or `default`.
|
|
#[stable(feature = "hashmap_default_hasher", since = "1.13.0")]
|
|
#[allow(deprecated)]
|
|
pub fn new() -> DefaultHasher {
|
|
DefaultHasher(SipHasher13::new_with_keys(0, 0))
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "hashmap_default_hasher", since = "1.13.0")]
|
|
impl Default for DefaultHasher {
|
|
// FIXME: here should link `new` to [DefaultHasher::new], but it occurs intra-doc link
|
|
// resolution failure when re-exporting libstd items. When #56922 fixed,
|
|
// link `new` to [DefaultHasher::new] again.
|
|
/// Creates a new `DefaultHasher` using `new`.
|
|
/// See its documentation for more.
|
|
fn default() -> DefaultHasher {
|
|
DefaultHasher::new()
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "hashmap_default_hasher", since = "1.13.0")]
|
|
impl Hasher for DefaultHasher {
|
|
#[inline]
|
|
fn write(&mut self, msg: &[u8]) {
|
|
self.0.write(msg)
|
|
}
|
|
|
|
#[inline]
|
|
fn finish(&self) -> u64 {
|
|
self.0.finish()
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "hashmap_build_hasher", since = "1.7.0")]
|
|
impl Default for RandomState {
|
|
/// Constructs a new `RandomState`.
|
|
#[inline]
|
|
fn default() -> RandomState {
|
|
RandomState::new()
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "std_debug", since = "1.16.0")]
|
|
impl fmt::Debug for RandomState {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
f.pad("RandomState { .. }")
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn map_entry<'a, K: 'a, V: 'a>(raw: base::RustcEntry<'a, K, V>) -> Entry<'a, K, V> {
|
|
match raw {
|
|
base::RustcEntry::Occupied(base) => Entry::Occupied(OccupiedEntry { base }),
|
|
base::RustcEntry::Vacant(base) => Entry::Vacant(VacantEntry { base }),
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn map_try_reserve_error(err: hashbrown::TryReserveError) -> TryReserveError {
|
|
match err {
|
|
hashbrown::TryReserveError::CapacityOverflow => TryReserveError::CapacityOverflow,
|
|
hashbrown::TryReserveError::AllocError { layout } => {
|
|
TryReserveError::AllocError { layout, non_exhaustive: () }
|
|
}
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn map_raw_entry<'a, K: 'a, V: 'a, S: 'a>(
|
|
raw: base::RawEntryMut<'a, K, V, S>,
|
|
) -> RawEntryMut<'a, K, V, S> {
|
|
match raw {
|
|
base::RawEntryMut::Occupied(base) => RawEntryMut::Occupied(RawOccupiedEntryMut { base }),
|
|
base::RawEntryMut::Vacant(base) => RawEntryMut::Vacant(RawVacantEntryMut { base }),
|
|
}
|
|
}
|
|
|
|
#[allow(dead_code)]
|
|
fn assert_covariance() {
|
|
fn map_key<'new>(v: HashMap<&'static str, u8>) -> HashMap<&'new str, u8> {
|
|
v
|
|
}
|
|
fn map_val<'new>(v: HashMap<u8, &'static str>) -> HashMap<u8, &'new str> {
|
|
v
|
|
}
|
|
fn iter_key<'a, 'new>(v: Iter<'a, &'static str, u8>) -> Iter<'a, &'new str, u8> {
|
|
v
|
|
}
|
|
fn iter_val<'a, 'new>(v: Iter<'a, u8, &'static str>) -> Iter<'a, u8, &'new str> {
|
|
v
|
|
}
|
|
fn into_iter_key<'new>(v: IntoIter<&'static str, u8>) -> IntoIter<&'new str, u8> {
|
|
v
|
|
}
|
|
fn into_iter_val<'new>(v: IntoIter<u8, &'static str>) -> IntoIter<u8, &'new str> {
|
|
v
|
|
}
|
|
fn keys_key<'a, 'new>(v: Keys<'a, &'static str, u8>) -> Keys<'a, &'new str, u8> {
|
|
v
|
|
}
|
|
fn keys_val<'a, 'new>(v: Keys<'a, u8, &'static str>) -> Keys<'a, u8, &'new str> {
|
|
v
|
|
}
|
|
fn values_key<'a, 'new>(v: Values<'a, &'static str, u8>) -> Values<'a, &'new str, u8> {
|
|
v
|
|
}
|
|
fn values_val<'a, 'new>(v: Values<'a, u8, &'static str>) -> Values<'a, u8, &'new str> {
|
|
v
|
|
}
|
|
fn drain<'new>(
|
|
d: Drain<'static, &'static str, &'static str>,
|
|
) -> Drain<'new, &'new str, &'new str> {
|
|
d
|
|
}
|
|
}
|