From 698f8c2f01ea549d77d7dc3338a12e04c11057b9 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 17 Apr 2024 14:02:58 +0200 Subject: Adding upstream version 1.64.0+dfsg1. Signed-off-by: Daniel Baumann --- library/std/src/collections/hash/map.rs | 3276 +++++++++++++++++++++++++++++++ 1 file changed, 3276 insertions(+) create mode 100644 library/std/src/collections/hash/map.rs (limited to 'library/std/src/collections/hash/map.rs') diff --git a/library/std/src/collections/hash/map.rs b/library/std/src/collections/hash/map.rs new file mode 100644 index 000000000..db811343f --- /dev/null +++ b/library/std/src/collections/hash/map.rs @@ -0,0 +1,3276 @@ +#[cfg(test)] +mod tests; + +use self::Entry::*; + +use hashbrown::hash_map as base; + +use crate::borrow::Borrow; +use crate::cell::Cell; +use crate::collections::TryReserveError; +use crate::collections::TryReserveErrorKind; +use crate::fmt::{self, Debug}; +#[allow(deprecated)] +use crate::hash::{BuildHasher, Hash, Hasher, SipHasher13}; +use crate::iter::FusedIterator; +use crate::ops::Index; +use crate::sys; + +/// A [hash map] implemented with quadratic probing and SIMD lookup. +/// +/// By default, `HashMap` uses a hashing algorithm selected to provide +/// resistance against HashDoS attacks. The algorithm is randomly seeded, and a +/// reasonable best-effort is made to generate this seed from a high quality, +/// secure source of randomness provided by the host without blocking the +/// program. Because of this, the randomness of the seed depends on the output +/// quality of the system's random number generator when the seed is created. +/// In particular, seeds generated when the system's entropy pool is abnormally +/// low such as during system boot may be of a lower quality. +/// +/// The default hashing algorithm is currently SipHash 1-3, though this is +/// subject to change at any point in the future. While its performance is very +/// competitive for medium sized keys, other hashing algorithms will outperform +/// it for small keys such as integers as well as large keys such as long +/// strings, though those algorithms will typically *not* protect against +/// attacks such as HashDoS. +/// +/// The hashing algorithm can be replaced on a per-`HashMap` basis using the +/// [`default`], [`with_hasher`], and [`with_capacity_and_hasher`] methods. +/// There are many alternative [hashing algorithms available on crates.io]. +/// +/// It is required that the keys implement the [`Eq`] and [`Hash`] traits, although +/// this can frequently be achieved by using `#[derive(PartialEq, Eq, Hash)]`. +/// If you implement these yourself, it is important that the following +/// property holds: +/// +/// ```text +/// k1 == k2 -> hash(k1) == hash(k2) +/// ``` +/// +/// In other words, if two keys are equal, their hashes must be equal. +/// +/// It is a logic error for a key to be modified in such a way that the key's +/// hash, as determined by the [`Hash`] trait, or its equality, as determined by +/// the [`Eq`] trait, changes while it is in the map. This is normally only +/// possible through [`Cell`], [`RefCell`], global state, I/O, or unsafe code. +/// The behavior resulting from such a logic error is not specified, but will +/// be encapsulated to the `HashMap` that observed the logic error and not +/// result in undefined behavior. This could include panics, incorrect results, +/// aborts, memory leaks, and non-termination. +/// +/// The hash table implementation is a Rust port of Google's [SwissTable]. +/// The original C++ version of SwissTable can be found [here], and this +/// [CppCon talk] gives an overview of how the algorithm works. +/// +/// [hash map]: crate::collections#use-a-hashmap-when +/// [hashing algorithms available on crates.io]: https://crates.io/keywords/hasher +/// [SwissTable]: https://abseil.io/blog/20180927-swisstables +/// [here]: https://github.com/abseil/abseil-cpp/blob/master/absl/container/internal/raw_hash_set.h +/// [CppCon talk]: https://www.youtube.com/watch?v=ncHmEUmJZf4 +/// +/// # Examples +/// +/// ``` +/// use std::collections::HashMap; +/// +/// // Type inference lets us omit an explicit type signature (which +/// // would be `HashMap` in this example). +/// let mut book_reviews = HashMap::new(); +/// +/// // Review some books. +/// book_reviews.insert( +/// "Adventures of Huckleberry Finn".to_string(), +/// "My favorite book.".to_string(), +/// ); +/// book_reviews.insert( +/// "Grimms' Fairy Tales".to_string(), +/// "Masterpiece.".to_string(), +/// ); +/// book_reviews.insert( +/// "Pride and Prejudice".to_string(), +/// "Very enjoyable.".to_string(), +/// ); +/// book_reviews.insert( +/// "The Adventures of Sherlock Holmes".to_string(), +/// "Eye lyked it alot.".to_string(), +/// ); +/// +/// // Check for a specific one. +/// // When collections store owned values (String), they can still be +/// // queried using references (&str). +/// if !book_reviews.contains_key("Les Misérables") { +/// println!("We've got {} reviews, but Les Misérables ain't one.", +/// book_reviews.len()); +/// } +/// +/// // oops, this review has a lot of spelling mistakes, let's delete it. +/// book_reviews.remove("The Adventures of Sherlock Holmes"); +/// +/// // Look up the values associated with some keys. +/// let to_find = ["Pride and Prejudice", "Alice's Adventure in Wonderland"]; +/// for &book in &to_find { +/// match book_reviews.get(book) { +/// Some(review) => println!("{book}: {review}"), +/// None => println!("{book} is unreviewed.") +/// } +/// } +/// +/// // Look up the value for a key (will panic if the key is not found). +/// println!("Review for Jane: {}", book_reviews["Pride and Prejudice"]); +/// +/// // Iterate over everything. +/// for (book, review) in &book_reviews { +/// println!("{book}: \"{review}\""); +/// } +/// ``` +/// +/// A `HashMap` with a known list of items can be initialized from an array: +/// +/// ``` +/// use std::collections::HashMap; +/// +/// let solar_distance = HashMap::from([ +/// ("Mercury", 0.4), +/// ("Venus", 0.7), +/// ("Earth", 1.0), +/// ("Mars", 1.5), +/// ]); +/// ``` +/// +/// `HashMap` implements an [`Entry` API](#method.entry), which allows +/// for complex methods of getting, setting, updating and removing keys and +/// their values: +/// +/// ``` +/// use std::collections::HashMap; +/// +/// // type inference lets us omit an explicit type signature (which +/// // would be `HashMap<&str, u8>` in this example). +/// let mut player_stats = HashMap::new(); +/// +/// fn random_stat_buff() -> u8 { +/// // could actually return some random value here - let's just return +/// // some fixed value for now +/// 42 +/// } +/// +/// // insert a key only if it doesn't already exist +/// player_stats.entry("health").or_insert(100); +/// +/// // insert a key using a function that provides a new value only if it +/// // doesn't already exist +/// player_stats.entry("defence").or_insert_with(random_stat_buff); +/// +/// // update a key, guarding against the key possibly not being set +/// let stat = player_stats.entry("attack").or_insert(100); +/// *stat += random_stat_buff(); +/// +/// // modify an entry before an insert with in-place mutation +/// player_stats.entry("mana").and_modify(|mana| *mana += 200).or_insert(100); +/// ``` +/// +/// The easiest way to use `HashMap` with a custom key type is to derive [`Eq`] and [`Hash`]. +/// We must also derive [`PartialEq`]. +/// +/// [`RefCell`]: crate::cell::RefCell +/// [`Cell`]: crate::cell::Cell +/// [`default`]: Default::default +/// [`with_hasher`]: Self::with_hasher +/// [`with_capacity_and_hasher`]: Self::with_capacity_and_hasher +/// +/// ``` +/// use std::collections::HashMap; +/// +/// #[derive(Hash, Eq, PartialEq, Debug)] +/// struct Viking { +/// name: String, +/// country: String, +/// } +/// +/// impl Viking { +/// /// Creates a new Viking. +/// fn new(name: &str, country: &str) -> Viking { +/// Viking { name: name.to_string(), country: country.to_string() } +/// } +/// } +/// +/// // Use a HashMap to store the vikings' health points. +/// let vikings = HashMap::from([ +/// (Viking::new("Einar", "Norway"), 25), +/// (Viking::new("Olaf", "Denmark"), 24), +/// (Viking::new("Harald", "Iceland"), 12), +/// ]); +/// +/// // Use derived implementation to print the status of the vikings. +/// for (viking, health) in &vikings { +/// println!("{viking:?} has {health} hp"); +/// } +/// ``` + +#[cfg_attr(not(test), rustc_diagnostic_item = "HashMap")] +#[stable(feature = "rust1", since = "1.0.0")] +#[rustc_insignificant_dtor] +pub struct HashMap { + base: base::HashMap, +} + +impl HashMap { + /// Creates an empty `HashMap`. + /// + /// The hash map is initially created with a capacity of 0, so it will not allocate until it + /// is first inserted into. + /// + /// # Examples + /// + /// ``` + /// use std::collections::HashMap; + /// let mut map: HashMap<&str, i32> = HashMap::new(); + /// ``` + #[inline] + #[must_use] + #[stable(feature = "rust1", since = "1.0.0")] + pub fn new() -> HashMap { + Default::default() + } + + /// Creates an empty `HashMap` with at least the specified capacity. + /// + /// The hash map will be able to hold at least `capacity` elements without + /// reallocating. This method is allowed to allocate for more elements than + /// `capacity`. If `capacity` is 0, the hash set will not allocate. + /// + /// # Examples + /// + /// ``` + /// use std::collections::HashMap; + /// let mut map: HashMap<&str, i32> = HashMap::with_capacity(10); + /// ``` + #[inline] + #[must_use] + #[stable(feature = "rust1", since = "1.0.0")] + pub fn with_capacity(capacity: usize) -> HashMap { + HashMap::with_capacity_and_hasher(capacity, Default::default()) + } +} + +impl HashMap { + /// Creates an empty `HashMap` which will use the given hash builder to hash + /// keys. + /// + /// The created map has the default initial capacity. + /// + /// Warning: `hash_builder` is normally randomly generated, and + /// is designed to allow HashMaps to be resistant to attacks that + /// cause many collisions and very poor performance. Setting it + /// manually using this function can expose a DoS attack vector. + /// + /// The `hash_builder` passed should implement the [`BuildHasher`] trait for + /// the HashMap to be useful, see its documentation for details. + /// + /// # 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); + /// ``` + #[inline] + #[stable(feature = "hashmap_build_hasher", since = "1.7.0")] + pub fn with_hasher(hash_builder: S) -> HashMap { + HashMap { base: base::HashMap::with_hasher(hash_builder) } + } + + /// Creates an empty `HashMap` with at least the specified capacity, using + /// `hasher` to hash the keys. + /// + /// The hash map will be able to hold at least `capacity` elements without + /// reallocating. This method is allowed to allocate for more elements than + /// `capacity`. If `capacity` is 0, the hash map will not allocate. + /// + /// Warning: `hasher` is normally randomly generated, and + /// is designed to allow HashMaps to be resistant to attacks that + /// cause many collisions and very poor performance. Setting it + /// manually using this function can expose a DoS attack vector. + /// + /// The `hasher` passed should implement the [`BuildHasher`] trait for + /// the HashMap to be useful, see its documentation for details. + /// + /// # Examples + /// + /// ``` + /// use std::collections::HashMap; + /// use std::collections::hash_map::RandomState; + /// + /// let s = RandomState::new(); + /// let mut map = HashMap::with_capacity_and_hasher(10, s); + /// map.insert(1, 2); + /// ``` + #[inline] + #[stable(feature = "hashmap_build_hasher", since = "1.7.0")] + pub fn with_capacity_and_hasher(capacity: usize, hasher: S) -> HashMap { + HashMap { base: base::HashMap::with_capacity_and_hasher(capacity, hasher) } + } + + /// Returns the number of elements the map can hold without reallocating. + /// + /// This number is a lower bound; the `HashMap` might be able to hold + /// more, but is guaranteed to be able to hold at least this many. + /// + /// # Examples + /// + /// ``` + /// use std::collections::HashMap; + /// let map: HashMap = HashMap::with_capacity(100); + /// assert!(map.capacity() >= 100); + /// ``` + #[inline] + #[stable(feature = "rust1", since = "1.0.0")] + pub fn capacity(&self) -> usize { + self.base.capacity() + } + + /// An iterator visiting all keys in arbitrary order. + /// The iterator element type is `&'a K`. + /// + /// # Examples + /// + /// ``` + /// use std::collections::HashMap; + /// + /// let map = HashMap::from([ + /// ("a", 1), + /// ("b", 2), + /// ("c", 3), + /// ]); + /// + /// for key in map.keys() { + /// println!("{key}"); + /// } + /// ``` + /// + /// # Performance + /// + /// In the current implementation, iterating over keys takes O(capacity) time + /// instead of O(len) because it internally visits empty buckets too. + #[stable(feature = "rust1", since = "1.0.0")] + pub fn keys(&self) -> Keys<'_, K, V> { + Keys { inner: self.iter() } + } + + /// 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 + /// + /// ``` + /// use std::collections::HashMap; + /// + /// let map = HashMap::from([ + /// ("a", 1), + /// ("b", 2), + /// ("c", 3), + /// ]); + /// + /// let mut vec: Vec<&str> = map.into_keys().collect(); + /// // The `IntoKeys` iterator produces keys in arbitrary order, so the + /// // keys must be sorted to test them against a sorted array. + /// vec.sort_unstable(); + /// assert_eq!(vec, ["a", "b", "c"]); + /// ``` + /// + /// # Performance + /// + /// In the current implementation, iterating over keys takes O(capacity) time + /// instead of O(len) because it internally visits empty buckets too. + #[inline] + #[rustc_lint_query_instability] + #[stable(feature = "map_into_keys_values", since = "1.54.0")] + pub fn into_keys(self) -> IntoKeys { + IntoKeys { inner: self.into_iter() } + } + + /// An iterator visiting all values in arbitrary order. + /// The iterator element type is `&'a V`. + /// + /// # Examples + /// + /// ``` + /// use std::collections::HashMap; + /// + /// let map = HashMap::from([ + /// ("a", 1), + /// ("b", 2), + /// ("c", 3), + /// ]); + /// + /// for val in map.values() { + /// println!("{val}"); + /// } + /// ``` + /// + /// # Performance + /// + /// In the current implementation, iterating over values takes O(capacity) time + /// instead of O(len) because it internally visits empty buckets too. + #[stable(feature = "rust1", since = "1.0.0")] + pub fn values(&self) -> Values<'_, K, V> { + Values { inner: self.iter() } + } + + /// An iterator visiting all values mutably in arbitrary order. + /// The iterator element type is `&'a mut V`. + /// + /// # Examples + /// + /// ``` + /// use std::collections::HashMap; + /// + /// let mut map = HashMap::from([ + /// ("a", 1), + /// ("b", 2), + /// ("c", 3), + /// ]); + /// + /// for val in map.values_mut() { + /// *val = *val + 10; + /// } + /// + /// for val in map.values() { + /// println!("{val}"); + /// } + /// ``` + /// + /// # Performance + /// + /// In the current implementation, iterating over values takes O(capacity) time + /// instead of O(len) because it internally visits empty buckets too. + #[stable(feature = "map_values_mut", since = "1.10.0")] + pub fn values_mut(&mut self) -> ValuesMut<'_, K, V> { + ValuesMut { inner: self.iter_mut() } + } + + /// 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 + /// + /// ``` + /// use std::collections::HashMap; + /// + /// let map = HashMap::from([ + /// ("a", 1), + /// ("b", 2), + /// ("c", 3), + /// ]); + /// + /// let mut vec: Vec = map.into_values().collect(); + /// // The `IntoValues` iterator produces values in arbitrary order, so + /// // the values must be sorted to test them against a sorted array. + /// vec.sort_unstable(); + /// assert_eq!(vec, [1, 2, 3]); + /// ``` + /// + /// # Performance + /// + /// In the current implementation, iterating over values takes O(capacity) time + /// instead of O(len) because it internally visits empty buckets too. + #[inline] + #[rustc_lint_query_instability] + #[stable(feature = "map_into_keys_values", since = "1.54.0")] + pub fn into_values(self) -> IntoValues { + IntoValues { inner: self.into_iter() } + } + + /// An iterator visiting all key-value pairs in arbitrary order. + /// The iterator element type is `(&'a K, &'a V)`. + /// + /// # Examples + /// + /// ``` + /// use std::collections::HashMap; + /// + /// let map = HashMap::from([ + /// ("a", 1), + /// ("b", 2), + /// ("c", 3), + /// ]); + /// + /// for (key, val) in map.iter() { + /// println!("key: {key} val: {val}"); + /// } + /// ``` + /// + /// # Performance + /// + /// In the current implementation, iterating over map takes O(capacity) time + /// instead of O(len) because it internally visits empty buckets too. + #[rustc_lint_query_instability] + #[stable(feature = "rust1", since = "1.0.0")] + pub fn iter(&self) -> Iter<'_, K, V> { + Iter { base: self.base.iter() } + } + + /// An iterator visiting all key-value pairs in arbitrary order, + /// with mutable references to the values. + /// The iterator element type is `(&'a K, &'a mut V)`. + /// + /// # Examples + /// + /// ``` + /// use std::collections::HashMap; + /// + /// let mut map = HashMap::from([ + /// ("a", 1), + /// ("b", 2), + /// ("c", 3), + /// ]); + /// + /// // Update all values + /// for (_, val) in map.iter_mut() { + /// *val *= 2; + /// } + /// + /// for (key, val) in &map { + /// println!("key: {key} val: {val}"); + /// } + /// ``` + /// + /// # Performance + /// + /// In the current implementation, iterating over map takes O(capacity) time + /// instead of O(len) because it internally visits empty buckets too. + #[rustc_lint_query_instability] + #[stable(feature = "rust1", since = "1.0.0")] + pub fn iter_mut(&mut self) -> IterMut<'_, K, V> { + IterMut { base: self.base.iter_mut() } + } + + /// Returns the number of elements in the map. + /// + /// # Examples + /// + /// ``` + /// use std::collections::HashMap; + /// + /// let mut a = HashMap::new(); + /// assert_eq!(a.len(), 0); + /// a.insert(1, "a"); + /// assert_eq!(a.len(), 1); + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + pub fn len(&self) -> usize { + self.base.len() + } + + /// Returns `true` if the map contains no elements. + /// + /// # Examples + /// + /// ``` + /// use std::collections::HashMap; + /// + /// let mut a = HashMap::new(); + /// assert!(a.is_empty()); + /// a.insert(1, "a"); + /// assert!(!a.is_empty()); + /// ``` + #[inline] + #[stable(feature = "rust1", since = "1.0.0")] + pub fn is_empty(&self) -> bool { + self.base.is_empty() + } + + /// Clears the map, returning all key-value pairs as an iterator. Keeps the + /// allocated memory for reuse. + /// + /// If the returned iterator is dropped before being fully consumed, it + /// drops the remaining key-value pairs. The returned iterator keeps a + /// mutable borrow on the map to optimize its implementation. + /// + /// # Examples + /// + /// ``` + /// use std::collections::HashMap; + /// + /// let mut a = HashMap::new(); + /// a.insert(1, "a"); + /// a.insert(2, "b"); + /// + /// for (k, v) in a.drain().take(1) { + /// assert!(k == 1 || k == 2); + /// assert!(v == "a" || v == "b"); + /// } + /// + /// assert!(a.is_empty()); + /// ``` + #[inline] + #[rustc_lint_query_instability] + #[stable(feature = "drain", since = "1.6.0")] + pub fn drain(&mut self) -> Drain<'_, K, V> { + Drain { base: self.base.drain() } + } + + /// Creates an iterator which uses a closure to determine if an element should be removed. + /// + /// If the closure returns true, the element is removed from the map and yielded. + /// If the closure returns false, or panics, the element remains in the map and will not be + /// yielded. + /// + /// Note that `drain_filter` lets you mutate every value in the filter closure, regardless of + /// whether you choose to keep or remove it. + /// + /// If the iterator is only partially consumed or not consumed at all, each of the remaining + /// elements will still be subjected to the closure and removed and dropped if it returns true. + /// + /// It is unspecified how many more elements will be subjected to the closure + /// if a panic occurs in the closure, or a panic occurs while dropping an element, + /// or if the `DrainFilter` value is leaked. + /// + /// # Examples + /// + /// Splitting a map into even and odd keys, reusing the original map: + /// + /// ``` + /// #![feature(hash_drain_filter)] + /// use std::collections::HashMap; + /// + /// let mut map: HashMap = (0..8).map(|x| (x, x)).collect(); + /// let drained: HashMap = map.drain_filter(|k, _v| k % 2 == 0).collect(); + /// + /// let mut evens = drained.keys().copied().collect::>(); + /// let mut odds = map.keys().copied().collect::>(); + /// evens.sort(); + /// odds.sort(); + /// + /// assert_eq!(evens, vec![0, 2, 4, 6]); + /// assert_eq!(odds, vec![1, 3, 5, 7]); + /// ``` + #[inline] + #[rustc_lint_query_instability] + #[unstable(feature = "hash_drain_filter", issue = "59618")] + pub fn drain_filter(&mut self, pred: F) -> DrainFilter<'_, K, V, F> + where + F: FnMut(&K, &mut V) -> bool, + { + DrainFilter { base: self.base.drain_filter(pred) } + } + + /// Retains only the elements specified by the predicate. + /// + /// In other words, remove all pairs `(k, v)` for which `f(&k, &mut v)` returns `false`. + /// The elements are visited in unsorted (and unspecified) order. + /// + /// # Examples + /// + /// ``` + /// use std::collections::HashMap; + /// + /// let mut map: HashMap = (0..8).map(|x| (x, x*10)).collect(); + /// map.retain(|&k, _| k % 2 == 0); + /// assert_eq!(map.len(), 4); + /// ``` + /// + /// # Performance + /// + /// In the current implementation, this operation takes O(capacity) time + /// instead of O(len) because it internally visits empty buckets too. + #[inline] + #[rustc_lint_query_instability] + #[stable(feature = "retain_hash_collection", since = "1.18.0")] + pub fn retain(&mut self, f: F) + where + F: FnMut(&K, &mut V) -> bool, + { + self.base.retain(f) + } + + /// 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()); + /// ``` + #[inline] + #[stable(feature = "rust1", since = "1.0.0")] + 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 = 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 HashMap +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 speculatively + /// avoid frequent reallocations. After calling `reserve`, + /// capacity will be greater than or equal to `self.len() + additional`. + /// Does nothing if capacity is already sufficient. + /// + /// # 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 `HashMap`. The collection may reserve more space to speculatively + /// avoid frequent reallocations. After calling `reserve`, + /// capacity will be greater than or equal to `self.len() + additional` if + /// it returns `Ok(())`. + /// Does nothing if capacity is already sufficient. + /// + /// # Errors + /// + /// If the capacity overflows, or the allocator reports a failure, then an error + /// is returned. + /// + /// # Examples + /// + /// ``` + /// use std::collections::HashMap; + /// + /// let mut map: HashMap<&str, isize> = HashMap::new(); + /// map.try_reserve(10).expect("why is the test harness OOMing on a handful of bytes?"); + /// ``` + #[inline] + #[stable(feature = "try_reserve", since = "1.57.0")] + 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 = 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. + /// + /// If the current capacity is less than the lower limit, this is a no-op. + /// + /// # Examples + /// + /// ``` + /// use std::collections::HashMap; + /// + /// let mut map: HashMap = 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] + #[stable(feature = "shrink_to", since = "1.56.0")] + pub fn shrink_to(&mut self, min_capacity: usize) { + 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() { + /// letters.entry(ch).and_modify(|counter| *counter += 1).or_insert(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(&self, k: &Q) -> Option<&V> + where + K: Borrow, + 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); + /// ``` + #[inline] + #[stable(feature = "map_get_key_value", since = "1.40.0")] + pub fn get_key_value(&self, k: &Q) -> Option<(&K, &V)> + where + K: Borrow, + Q: Hash + Eq, + { + self.base.get_key_value(k) + } + + /// Attempts to get mutable references to `N` values in the map at once. + /// + /// Returns an array of length `N` with the results of each query. For soundness, at most one + /// mutable reference will be returned to any value. `None` will be returned if any of the + /// keys are duplicates or missing. + /// + /// # Examples + /// + /// ``` + /// #![feature(map_many_mut)] + /// use std::collections::HashMap; + /// + /// let mut libraries = HashMap::new(); + /// libraries.insert("Bodleian Library".to_string(), 1602); + /// libraries.insert("Athenæum".to_string(), 1807); + /// libraries.insert("Herzogin-Anna-Amalia-Bibliothek".to_string(), 1691); + /// libraries.insert("Library of Congress".to_string(), 1800); + /// + /// let got = libraries.get_many_mut([ + /// "Athenæum", + /// "Library of Congress", + /// ]); + /// assert_eq!( + /// got, + /// Some([ + /// &mut 1807, + /// &mut 1800, + /// ]), + /// ); + /// + /// // Missing keys result in None + /// let got = libraries.get_many_mut([ + /// "Athenæum", + /// "New York Public Library", + /// ]); + /// assert_eq!(got, None); + /// + /// // Duplicate keys result in None + /// let got = libraries.get_many_mut([ + /// "Athenæum", + /// "Athenæum", + /// ]); + /// assert_eq!(got, None); + /// ``` + #[inline] + #[unstable(feature = "map_many_mut", issue = "97601")] + pub fn get_many_mut(&mut self, ks: [&Q; N]) -> Option<[&'_ mut V; N]> + where + K: Borrow, + Q: Hash + Eq, + { + self.base.get_many_mut(ks) + } + + /// Attempts to get mutable references to `N` values in the map at once, without validating that + /// the values are unique. + /// + /// Returns an array of length `N` with the results of each query. `None` will be returned if + /// any of the keys are missing. + /// + /// For a safe alternative see [`get_many_mut`](Self::get_many_mut). + /// + /// # Safety + /// + /// Calling this method with overlapping keys is *[undefined behavior]* even if the resulting + /// references are not used. + /// + /// [undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html + /// + /// # Examples + /// + /// ``` + /// #![feature(map_many_mut)] + /// use std::collections::HashMap; + /// + /// let mut libraries = HashMap::new(); + /// libraries.insert("Bodleian Library".to_string(), 1602); + /// libraries.insert("Athenæum".to_string(), 1807); + /// libraries.insert("Herzogin-Anna-Amalia-Bibliothek".to_string(), 1691); + /// libraries.insert("Library of Congress".to_string(), 1800); + /// + /// let got = libraries.get_many_mut([ + /// "Athenæum", + /// "Library of Congress", + /// ]); + /// assert_eq!( + /// got, + /// Some([ + /// &mut 1807, + /// &mut 1800, + /// ]), + /// ); + /// + /// // Missing keys result in None + /// let got = libraries.get_many_mut([ + /// "Athenæum", + /// "New York Public Library", + /// ]); + /// assert_eq!(got, None); + /// ``` + #[inline] + #[unstable(feature = "map_many_mut", issue = "97601")] + pub unsafe fn get_many_unchecked_mut( + &mut self, + ks: [&Q; N], + ) -> Option<[&'_ mut V; N]> + where + K: Borrow, + Q: Hash + Eq, + { + self.base.get_many_unchecked_mut(ks) + } + + /// 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); + /// ``` + #[inline] + #[stable(feature = "rust1", since = "1.0.0")] + pub fn contains_key(&self, k: &Q) -> bool + where + K: Borrow, + 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"); + /// ``` + #[inline] + #[stable(feature = "rust1", since = "1.0.0")] + pub fn get_mut(&mut self, k: &Q) -> Option<&mut V> + where + K: Borrow, + 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"); + /// ``` + #[inline] + #[stable(feature = "rust1", since = "1.0.0")] + pub fn insert(&mut self, k: K, v: V) -> Option { + self.base.insert(k, v) + } + + /// Tries to insert a key-value pair into the map, and returns + /// a mutable reference to the value in the entry. + /// + /// If the map already had this key present, nothing is updated, and + /// an error containing the occupied entry and the value is returned. + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// #![feature(map_try_insert)] + /// + /// use std::collections::HashMap; + /// + /// let mut map = HashMap::new(); + /// assert_eq!(map.try_insert(37, "a").unwrap(), &"a"); + /// + /// let err = map.try_insert(37, "b").unwrap_err(); + /// assert_eq!(err.entry.key(), &37); + /// assert_eq!(err.entry.get(), &"a"); + /// assert_eq!(err.value, "b"); + /// ``` + #[unstable(feature = "map_try_insert", issue = "82766")] + pub fn try_insert(&mut self, key: K, value: V) -> Result<&mut V, OccupiedError<'_, K, V>> { + match self.entry(key) { + Occupied(entry) => Err(OccupiedError { entry, value }), + Vacant(entry) => Ok(entry.insert(value)), + } + } + + /// 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); + /// ``` + #[inline] + #[stable(feature = "rust1", since = "1.0.0")] + pub fn remove(&mut self, k: &Q) -> Option + where + K: Borrow, + 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); + /// # } + /// ``` + #[inline] + #[stable(feature = "hash_map_remove_entry", since = "1.27.0")] + pub fn remove_entry(&mut self, k: &Q) -> Option<(K, V)> + where + K: Borrow, + Q: Hash + Eq, + { + self.base.remove_entry(k) + } +} + +impl HashMap +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 Clone for HashMap +where + K: Clone, + V: Clone, + S: Clone, +{ + #[inline] + fn clone(&self) -> Self { + Self { base: self.base.clone() } + } + + #[inline] + fn clone_from(&mut self, other: &Self) { + self.base.clone_from(&other.base); + } +} + +#[stable(feature = "rust1", since = "1.0.0")] +impl PartialEq for HashMap +where + K: Eq + Hash, + V: PartialEq, + S: BuildHasher, +{ + fn eq(&self, other: &HashMap) -> 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 Eq for HashMap +where + K: Eq + Hash, + V: Eq, + S: BuildHasher, +{ +} + +#[stable(feature = "rust1", since = "1.0.0")] +impl Debug for HashMap +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 Default for HashMap +where + S: Default, +{ + /// Creates an empty `HashMap`, with the `Default` value for the hasher. + #[inline] + fn default() -> HashMap { + HashMap::with_hasher(Default::default()) + } +} + +#[stable(feature = "rust1", since = "1.0.0")] +impl Index<&Q> for HashMap +where + K: Eq + Hash + Borrow, + 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") + } +} + +#[stable(feature = "std_collections_from_array", since = "1.56.0")] +// Note: as what is currently the most convenient built-in way to construct +// a HashMap, a simple usage of this function must not *require* the user +// to provide a type annotation in order to infer the third type parameter +// (the hasher parameter, conventionally "S"). +// To that end, this impl is defined using RandomState as the concrete +// type of S, rather than being generic over `S: BuildHasher + Default`. +// It is expected that users who want to specify a hasher will manually use +// `with_capacity_and_hasher`. +// If type parameter defaults worked on impls, and if type parameter +// defaults could be mixed with const generics, then perhaps +// this could be generalized. +// See also the equivalent impl on HashSet. +impl From<[(K, V); N]> for HashMap +where + K: Eq + Hash, +{ + /// # Examples + /// + /// ``` + /// use std::collections::HashMap; + /// + /// let map1 = HashMap::from([(1, 2), (3, 4)]); + /// let map2: HashMap<_, _> = [(1, 2), (3, 4)].into(); + /// assert_eq!(map1, map2); + /// ``` + fn from(arr: [(K, V); N]) -> Self { + Self::from_iter(arr) + } +} + +/// 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 +/// +/// # Example +/// +/// ``` +/// use std::collections::HashMap; +/// +/// let map = HashMap::from([ +/// ("a", 1), +/// ]); +/// let iter = map.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 Clone for Iter<'_, K, V> { + #[inline] + fn clone(&self) -> Self { + Iter { base: self.base.clone() } + } +} + +#[stable(feature = "std_debug", since = "1.16.0")] +impl 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 +/// +/// # Example +/// +/// ``` +/// use std::collections::HashMap; +/// +/// let mut map = HashMap::from([ +/// ("a", 1), +/// ]); +/// let iter = map.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 an 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 +/// [`IntoIterator`]: crate::iter::IntoIterator +/// +/// # Example +/// +/// ``` +/// use std::collections::HashMap; +/// +/// let map = HashMap::from([ +/// ("a", 1), +/// ]); +/// let iter = map.into_iter(); +/// ``` +#[stable(feature = "rust1", since = "1.0.0")] +pub struct IntoIter { + base: base::IntoIter, +} + +impl IntoIter { + /// Returns an 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 +/// +/// # Example +/// +/// ``` +/// use std::collections::HashMap; +/// +/// let map = HashMap::from([ +/// ("a", 1), +/// ]); +/// let iter_keys = map.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 Clone for Keys<'_, K, V> { + #[inline] + fn clone(&self) -> Self { + Keys { inner: self.inner.clone() } + } +} + +#[stable(feature = "std_debug", since = "1.16.0")] +impl 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 +/// +/// # Example +/// +/// ``` +/// use std::collections::HashMap; +/// +/// let map = HashMap::from([ +/// ("a", 1), +/// ]); +/// let iter_values = map.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 Clone for Values<'_, K, V> { + #[inline] + fn clone(&self) -> Self { + Values { inner: self.inner.clone() } + } +} + +#[stable(feature = "std_debug", since = "1.16.0")] +impl 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 +/// +/// # Example +/// +/// ``` +/// use std::collections::HashMap; +/// +/// let mut map = HashMap::from([ +/// ("a", 1), +/// ]); +/// let iter = map.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 an iterator of references over the remaining items. + #[inline] + pub(super) fn iter(&self) -> Iter<'_, K, V> { + Iter { base: self.base.rustc_iter() } + } +} + +/// A draining, filtering iterator over the entries of a `HashMap`. +/// +/// This `struct` is created by the [`drain_filter`] method on [`HashMap`]. +/// +/// [`drain_filter`]: HashMap::drain_filter +/// +/// # Example +/// +/// ``` +/// #![feature(hash_drain_filter)] +/// +/// use std::collections::HashMap; +/// +/// let mut map = HashMap::from([ +/// ("a", 1), +/// ]); +/// let iter = map.drain_filter(|_k, v| *v % 2 == 0); +/// ``` +#[unstable(feature = "hash_drain_filter", issue = "59618")] +pub struct DrainFilter<'a, K, V, F> +where + F: FnMut(&K, &mut V) -> bool, +{ + base: base::DrainFilter<'a, K, V, F>, +} + +/// 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 +/// +/// # Example +/// +/// ``` +/// use std::collections::HashMap; +/// +/// let mut map = HashMap::from([ +/// ("a", 1), +/// ]); +/// let iter_values = map.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 +/// +/// # Example +/// +/// ``` +/// use std::collections::HashMap; +/// +/// let map = HashMap::from([ +/// ("a", 1), +/// ]); +/// let iter_keys = map.into_keys(); +/// ``` +#[stable(feature = "map_into_keys_values", since = "1.54.0")] +pub struct IntoKeys { + inner: IntoIter, +} + +/// 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 +/// +/// # Example +/// +/// ``` +/// use std::collections::HashMap; +/// +/// let map = HashMap::from([ +/// ("a", 1), +/// ]); +/// let iter_keys = map.into_values(); +/// ``` +#[stable(feature = "map_into_keys_values", since = "1.54.0")] +pub struct IntoValues { + inner: IntoIter, +} + +/// 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. +#[unstable(feature = "hash_raw_entry", issue = "56167")] +pub struct RawEntryBuilderMut<'a, K: 'a, V: 'a, S: 'a> { + map: &'a mut HashMap, +} + +/// 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`]. +/// +/// [`raw_entry_mut`]: HashMap::raw_entry_mut +#[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. +#[unstable(feature = "hash_raw_entry", issue = "56167")] +pub struct RawEntryBuilder<'a, K: 'a, V: 'a, S: 'a> { + map: &'a HashMap, +} + +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(self, k: &Q) -> RawEntryMut<'a, K, V, S> + where + K: Borrow, + 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(self, hash: u64, k: &Q) -> RawEntryMut<'a, K, V, S> + where + K: Borrow, + 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(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(self, k: &Q) -> Option<(&'a K, &'a V)> + where + K: Borrow, + 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(self, hash: u64, k: &Q) -> Option<(&'a K, &'a V)> + where + K: Borrow, + 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(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(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(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] + #[must_use] + #[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] + #[must_use] + #[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] + #[must_use = "`self` will be dropped if the result is not used"] + #[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] + #[must_use] + #[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] + #[must_use = "`self` will be dropped if the result is not used"] + #[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] + #[must_use] + #[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] + #[must_use] + #[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] + #[must_use = "`self` will be dropped if the result is not used"] + #[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 Debug for RawEntryBuilderMut<'_, K, V, S> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("RawEntryBuilder").finish_non_exhaustive() + } +} + +#[unstable(feature = "hash_raw_entry", issue = "56167")] +impl 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 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_non_exhaustive() + } +} + +#[unstable(feature = "hash_raw_entry", issue = "56167")] +impl Debug for RawVacantEntryMut<'_, K, V, S> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("RawVacantEntryMut").finish_non_exhaustive() + } +} + +#[unstable(feature = "hash_raw_entry", issue = "56167")] +impl Debug for RawEntryBuilder<'_, K, V, S> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("RawEntryBuilder").finish_non_exhaustive() + } +} + +/// 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")] +#[cfg_attr(not(test), rustc_diagnostic_item = "HashMapEntry")] +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 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. +#[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 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_non_exhaustive() + } +} + +/// A view into a vacant entry in a `HashMap`. +/// It is part of the [`Entry`] enum. +#[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 Debug for VacantEntry<'_, K, V> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_tuple("VacantEntry").field(self.key()).finish() + } +} + +/// The error returned by [`try_insert`](HashMap::try_insert) when the key already exists. +/// +/// Contains the occupied entry, and the value that was not inserted. +#[unstable(feature = "map_try_insert", issue = "82766")] +pub struct OccupiedError<'a, K: 'a, V: 'a> { + /// The entry in the map that was already occupied. + pub entry: OccupiedEntry<'a, K, V>, + /// The value which was not inserted, because the entry was already occupied. + pub value: V, +} + +#[unstable(feature = "map_try_insert", issue = "82766")] +impl Debug for OccupiedError<'_, K, V> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("OccupiedError") + .field("key", self.entry.key()) + .field("old_value", self.entry.get()) + .field("new_value", &self.value) + .finish_non_exhaustive() + } +} + +#[unstable(feature = "map_try_insert", issue = "82766")] +impl<'a, K: Debug, V: Debug> fmt::Display for OccupiedError<'a, K, V> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + write!( + f, + "failed to insert {:?}, key {:?} already exists with value {:?}", + self.value, + self.entry.key(), + self.entry.get(), + ) + } +} + +#[stable(feature = "rust1", since = "1.0.0")] +impl<'a, K, V, S> IntoIterator for &'a HashMap { + type Item = (&'a K, &'a V); + type IntoIter = Iter<'a, K, V>; + + #[inline] + #[rustc_lint_query_instability] + 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 { + type Item = (&'a K, &'a mut V); + type IntoIter = IterMut<'a, K, V>; + + #[inline] + #[rustc_lint_query_instability] + fn into_iter(self) -> IterMut<'a, K, V> { + self.iter_mut() + } +} + +#[stable(feature = "rust1", since = "1.0.0")] +impl IntoIterator for HashMap { + type Item = (K, V); + type IntoIter = IntoIter; + + /// 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 map = HashMap::from([ + /// ("a", 1), + /// ("b", 2), + /// ("c", 3), + /// ]); + /// + /// // Not possible with .iter() + /// let vec: Vec<(&str, i32)> = map.into_iter().collect(); + /// ``` + #[inline] + #[rustc_lint_query_instability] + fn into_iter(self) -> IntoIter { + 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) { + self.base.size_hint() + } +} +#[stable(feature = "rust1", since = "1.0.0")] +impl ExactSizeIterator for Iter<'_, K, V> { + #[inline] + fn len(&self) -> usize { + self.base.len() + } +} + +#[stable(feature = "fused", since = "1.26.0")] +impl 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) { + self.base.size_hint() + } +} +#[stable(feature = "rust1", since = "1.0.0")] +impl ExactSizeIterator for IterMut<'_, K, V> { + #[inline] + fn len(&self) -> usize { + self.base.len() + } +} +#[stable(feature = "fused", since = "1.26.0")] +impl FusedIterator for IterMut<'_, K, V> {} + +#[stable(feature = "std_debug", since = "1.16.0")] +impl 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 Iterator for IntoIter { + type Item = (K, V); + + #[inline] + fn next(&mut self) -> Option<(K, V)> { + self.base.next() + } + #[inline] + fn size_hint(&self) -> (usize, Option) { + self.base.size_hint() + } +} +#[stable(feature = "rust1", since = "1.0.0")] +impl ExactSizeIterator for IntoIter { + #[inline] + fn len(&self) -> usize { + self.base.len() + } +} +#[stable(feature = "fused", since = "1.26.0")] +impl FusedIterator for IntoIter {} + +#[stable(feature = "std_debug", since = "1.16.0")] +impl fmt::Debug for IntoIter { + 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) { + self.inner.size_hint() + } +} +#[stable(feature = "rust1", since = "1.0.0")] +impl ExactSizeIterator for Keys<'_, K, V> { + #[inline] + fn len(&self) -> usize { + self.inner.len() + } +} +#[stable(feature = "fused", since = "1.26.0")] +impl 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) { + self.inner.size_hint() + } +} +#[stable(feature = "rust1", since = "1.0.0")] +impl ExactSizeIterator for Values<'_, K, V> { + #[inline] + fn len(&self) -> usize { + self.inner.len() + } +} +#[stable(feature = "fused", since = "1.26.0")] +impl 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) { + self.inner.size_hint() + } +} +#[stable(feature = "map_values_mut", since = "1.10.0")] +impl ExactSizeIterator for ValuesMut<'_, K, V> { + #[inline] + fn len(&self) -> usize { + self.inner.len() + } +} +#[stable(feature = "fused", since = "1.26.0")] +impl FusedIterator for ValuesMut<'_, K, V> {} + +#[stable(feature = "std_debug", since = "1.16.0")] +impl fmt::Debug for ValuesMut<'_, K, V> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_list().entries(self.inner.iter().map(|(_, val)| val)).finish() + } +} + +#[stable(feature = "map_into_keys_values", since = "1.54.0")] +impl Iterator for IntoKeys { + type Item = K; + + #[inline] + fn next(&mut self) -> Option { + self.inner.next().map(|(k, _)| k) + } + #[inline] + fn size_hint(&self) -> (usize, Option) { + self.inner.size_hint() + } +} +#[stable(feature = "map_into_keys_values", since = "1.54.0")] +impl ExactSizeIterator for IntoKeys { + #[inline] + fn len(&self) -> usize { + self.inner.len() + } +} +#[stable(feature = "map_into_keys_values", since = "1.54.0")] +impl FusedIterator for IntoKeys {} + +#[stable(feature = "map_into_keys_values", since = "1.54.0")] +impl fmt::Debug for IntoKeys { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_list().entries(self.inner.iter().map(|(k, _)| k)).finish() + } +} + +#[stable(feature = "map_into_keys_values", since = "1.54.0")] +impl Iterator for IntoValues { + type Item = V; + + #[inline] + fn next(&mut self) -> Option { + self.inner.next().map(|(_, v)| v) + } + #[inline] + fn size_hint(&self) -> (usize, Option) { + self.inner.size_hint() + } +} +#[stable(feature = "map_into_keys_values", since = "1.54.0")] +impl ExactSizeIterator for IntoValues { + #[inline] + fn len(&self) -> usize { + self.inner.len() + } +} +#[stable(feature = "map_into_keys_values", since = "1.54.0")] +impl FusedIterator for IntoValues {} + +#[stable(feature = "map_into_keys_values", since = "1.54.0")] +impl fmt::Debug for IntoValues { + 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) { + self.base.size_hint() + } +} +#[stable(feature = "drain", since = "1.6.0")] +impl ExactSizeIterator for Drain<'_, K, V> { + #[inline] + fn len(&self) -> usize { + self.base.len() + } +} +#[stable(feature = "fused", since = "1.26.0")] +impl FusedIterator for Drain<'_, K, V> {} + +#[stable(feature = "std_debug", since = "1.16.0")] +impl 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() + } +} + +#[unstable(feature = "hash_drain_filter", issue = "59618")] +impl Iterator for DrainFilter<'_, K, V, F> +where + F: FnMut(&K, &mut V) -> bool, +{ + type Item = (K, V); + + #[inline] + fn next(&mut self) -> Option<(K, V)> { + self.base.next() + } + #[inline] + fn size_hint(&self) -> (usize, Option) { + self.base.size_hint() + } +} + +#[unstable(feature = "hash_drain_filter", issue = "59618")] +impl FusedIterator for DrainFilter<'_, K, V, F> where F: FnMut(&K, &mut V) -> bool {} + +#[unstable(feature = "hash_drain_filter", issue = "59618")] +impl<'a, K, V, F> fmt::Debug for DrainFilter<'a, K, V, F> +where + F: FnMut(&K, &mut V) -> bool, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("DrainFilter").finish_non_exhaustive() + } +} + +impl<'a, K, V> Entry<'a, K, V> { + /// 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] + #[stable(feature = "rust1", since = "1.0.0")] + pub fn or_insert(self, default: V) -> &'a mut V { + match self { + Occupied(entry) => entry.into_mut(), + Vacant(entry) => entry.insert(default), + } + } + + /// 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] + #[stable(feature = "rust1", since = "1.0.0")] + pub fn or_insert_with V>(self, default: F) -> &'a mut V { + match self { + Occupied(entry) => entry.into_mut(), + Vacant(entry) => entry.insert(default()), + } + } + + /// Ensures a value is in the entry by inserting, if empty, the result of the default function. + /// This method allows for generating key-derived values for insertion by providing the default + /// function a reference to the key that was moved during the `.entry(key)` method call. + /// + /// The reference to the moved key is provided so that cloning or copying the key is + /// unnecessary, unlike with `.or_insert_with(|| ... )`. + /// + /// # Examples + /// + /// ``` + /// 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] + #[stable(feature = "or_insert_with_key", since = "1.50.0")] + pub fn or_insert_with_key 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(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_entry("hoho".to_string()); + /// + /// assert_eq!(entry.key(), &"poneyland"); + /// ``` + #[inline] + #[unstable(feature = "entry_insert", issue = "65225")] + pub fn insert_entry(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> { + /// 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> = HashMap::new(); + /// map.entry("poneyland").or_default(); + /// + /// assert_eq!(map["poneyland"], None); + /// # } + /// ``` + #[inline] + #[stable(feature = "entry_or_default", since = "1.28.0")] + 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, 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, 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, u32> = HashMap::new(); + /// let known_strings: Vec> = Vec::new(); + /// + /// // Initialise known strings, run program, etc. + /// + /// reclaim_memory(&mut map, &known_strings); + /// + /// fn reclaim_memory(map: &mut HashMap, u32>, known_strings: &[Rc] ) { + /// 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 + /// + /// ``` + /// #![feature(entry_insert)] + /// 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_entry(37); + /// } + /// assert_eq!(map["poneyland"], 37); + /// ``` + #[inline] + #[unstable(feature = "entry_insert", issue = "65225")] + pub 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 FromIterator<(K, V)> for HashMap +where + K: Eq + Hash, + S: BuildHasher + Default, +{ + fn from_iter>(iter: T) -> HashMap { + 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 Extend<(K, V)> for HashMap +where + K: Eq + Hash, + S: BuildHasher, +{ + #[inline] + fn extend>(&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); + } +} + +#[stable(feature = "hash_extend_copy", since = "1.4.0")] +impl<'a, K, V, S> Extend<(&'a K, &'a V)> for HashMap +where + K: Eq + Hash + Copy, + V: Copy, + S: BuildHasher, +{ + #[inline] + fn extend>(&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 + #[must_use] + #[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")] + #[inline] + #[allow(deprecated)] + #[must_use] + pub fn new() -> DefaultHasher { + DefaultHasher(SipHasher13::new_with_keys(0, 0)) + } +} + +#[stable(feature = "hashmap_default_hasher", since = "1.13.0")] +impl Default for DefaultHasher { + /// Creates a new `DefaultHasher` using [`new`]. + /// See its documentation for more. + /// + /// [`new`]: DefaultHasher::new + #[inline] + fn default() -> DefaultHasher { + DefaultHasher::new() + } +} + +#[stable(feature = "hashmap_default_hasher", since = "1.13.0")] +impl Hasher for DefaultHasher { + // The underlying `SipHasher13` doesn't override the other + // `write_*` methods, so it's ok not to forward them here. + + #[inline] + fn write(&mut self, msg: &[u8]) { + self.0.write(msg) + } + + #[inline] + fn write_str(&mut self, s: &str) { + self.0.write_str(s); + } + + #[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.debug_struct("RandomState").finish_non_exhaustive() + } +} + +#[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] +pub(super) fn map_try_reserve_error(err: hashbrown::TryReserveError) -> TryReserveError { + match err { + hashbrown::TryReserveError::CapacityOverflow => { + TryReserveErrorKind::CapacityOverflow.into() + } + hashbrown::TryReserveError::AllocError { layout } => { + TryReserveErrorKind::AllocError { layout, non_exhaustive: () }.into() + } + } +} + +#[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) -> HashMap { + 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) -> IntoIter { + 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 + } +} -- cgit v1.2.3