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+//! This is the core implementation that doesn't depend on the hasher at all.
+//!
+//! The methods of `IndexMapCore` don't use any Hash properties of K.
+//!
+//! It's cleaner to separate them out, then the compiler checks that we are not
+//! using Hash at all in these methods.
+//!
+//! However, we should probably not let this show in the public API or docs.
+
+mod entry;
+
+pub mod raw_entry_v1;
+
+use hashbrown::hash_table;
+
+use crate::vec::{self, Vec};
+use crate::TryReserveError;
+use core::mem;
+use core::ops::RangeBounds;
+
+use crate::util::simplify_range;
+use crate::{Bucket, Equivalent, HashValue};
+
+type Indices = hash_table::HashTable<usize>;
+type Entries<K, V> = Vec<Bucket<K, V>>;
+
+pub use entry::{Entry, IndexedEntry, OccupiedEntry, VacantEntry};
+
+/// Core of the map that does not depend on S
+#[derive(Debug)]
+pub(crate) struct IndexMapCore<K, V> {
+ /// indices mapping from the entry hash to its index.
+ indices: Indices,
+ /// entries is a dense vec maintaining entry order.
+ entries: Entries<K, V>,
+}
+
+/// Mutable references to the parts of an `IndexMapCore`.
+///
+/// When using `HashTable::find_entry`, that takes hold of `&mut indices`, so we have to borrow our
+/// `&mut entries` separately, and there's no way to go back to a `&mut IndexMapCore`. So this type
+/// is used to implement methods on the split references, and `IndexMapCore` can also call those to
+/// avoid duplication.
+struct RefMut<'a, K, V> {
+ indices: &'a mut Indices,
+ entries: &'a mut Entries<K, V>,
+}
+
+#[inline(always)]
+fn get_hash<K, V>(entries: &[Bucket<K, V>]) -> impl Fn(&usize) -> u64 + '_ {
+ move |&i| entries[i].hash.get()
+}
+
+#[inline]
+fn equivalent<'a, K, V, Q: ?Sized + Equivalent<K>>(
+ key: &'a Q,
+ entries: &'a [Bucket<K, V>],
+) -> impl Fn(&usize) -> bool + 'a {
+ move |&i| Q::equivalent(key, &entries[i].key)
+}
+
+#[inline]
+fn erase_index(table: &mut Indices, hash: HashValue, index: usize) {
+ if let Ok(entry) = table.find_entry(hash.get(), move |&i| i == index) {
+ entry.remove();
+ } else if cfg!(debug_assertions) {
+ panic!("index not found");
+ }
+}
+
+#[inline]
+fn update_index(table: &mut Indices, hash: HashValue, old: usize, new: usize) {
+ let index = table
+ .find_mut(hash.get(), move |&i| i == old)
+ .expect("index not found");
+ *index = new;
+}
+
+/// Inserts many entries into the indices table without reallocating,
+/// and without regard for duplication.
+///
+/// ***Panics*** if there is not sufficient capacity already.
+fn insert_bulk_no_grow<K, V>(indices: &mut Indices, entries: &[Bucket<K, V>]) {
+ assert!(indices.capacity() - indices.len() >= entries.len());
+ for entry in entries {
+ indices.insert_unique(entry.hash.get(), indices.len(), |_| unreachable!());
+ }
+}
+
+impl<K, V> Clone for IndexMapCore<K, V>
+where
+ K: Clone,
+ V: Clone,
+{
+ fn clone(&self) -> Self {
+ let mut new = Self::new();
+ new.clone_from(self);
+ new
+ }
+
+ fn clone_from(&mut self, other: &Self) {
+ self.indices.clone_from(&other.indices);
+ if self.entries.capacity() < other.entries.len() {
+ // If we must resize, match the indices capacity.
+ let additional = other.entries.len() - self.entries.len();
+ self.borrow_mut().reserve_entries(additional);
+ }
+ self.entries.clone_from(&other.entries);
+ }
+}
+
+impl<K, V> crate::Entries for IndexMapCore<K, V> {
+ type Entry = Bucket<K, V>;
+
+ #[inline]
+ fn into_entries(self) -> Vec<Self::Entry> {
+ self.entries
+ }
+
+ #[inline]
+ fn as_entries(&self) -> &[Self::Entry] {
+ &self.entries
+ }
+
+ #[inline]
+ fn as_entries_mut(&mut self) -> &mut [Self::Entry] {
+ &mut self.entries
+ }
+
+ fn with_entries<F>(&mut self, f: F)
+ where
+ F: FnOnce(&mut [Self::Entry]),
+ {
+ f(&mut self.entries);
+ self.rebuild_hash_table();
+ }
+}
+
+impl<K, V> IndexMapCore<K, V> {
+ /// The maximum capacity before the `entries` allocation would exceed `isize::MAX`.
+ const MAX_ENTRIES_CAPACITY: usize = (isize::MAX as usize) / mem::size_of::<Bucket<K, V>>();
+
+ #[inline]
+ pub(crate) const fn new() -> Self {
+ IndexMapCore {
+ indices: Indices::new(),
+ entries: Vec::new(),
+ }
+ }
+
+ #[inline]
+ fn borrow_mut(&mut self) -> RefMut<'_, K, V> {
+ RefMut::new(&mut self.indices, &mut self.entries)
+ }
+
+ #[inline]
+ pub(crate) fn with_capacity(n: usize) -> Self {
+ IndexMapCore {
+ indices: Indices::with_capacity(n),
+ entries: Vec::with_capacity(n),
+ }
+ }
+
+ #[inline]
+ pub(crate) fn len(&self) -> usize {
+ self.indices.len()
+ }
+
+ #[inline]
+ pub(crate) fn capacity(&self) -> usize {
+ Ord::min(self.indices.capacity(), self.entries.capacity())
+ }
+
+ pub(crate) fn clear(&mut self) {
+ self.indices.clear();
+ self.entries.clear();
+ }
+
+ pub(crate) fn truncate(&mut self, len: usize) {
+ if len < self.len() {
+ self.erase_indices(len, self.entries.len());
+ self.entries.truncate(len);
+ }
+ }
+
+ #[track_caller]
+ pub(crate) fn drain<R>(&mut self, range: R) -> vec::Drain<'_, Bucket<K, V>>
+ where
+ R: RangeBounds<usize>,
+ {
+ let range = simplify_range(range, self.entries.len());
+ self.erase_indices(range.start, range.end);
+ self.entries.drain(range)
+ }
+
+ #[cfg(feature = "rayon")]
+ pub(crate) fn par_drain<R>(&mut self, range: R) -> rayon::vec::Drain<'_, Bucket<K, V>>
+ where
+ K: Send,
+ V: Send,
+ R: RangeBounds<usize>,
+ {
+ use rayon::iter::ParallelDrainRange;
+ let range = simplify_range(range, self.entries.len());
+ self.erase_indices(range.start, range.end);
+ self.entries.par_drain(range)
+ }
+
+ #[track_caller]
+ pub(crate) fn split_off(&mut self, at: usize) -> Self {
+ let len = self.entries.len();
+ assert!(
+ at <= len,
+ "index out of bounds: the len is {len} but the index is {at}. Expected index <= len"
+ );
+
+ self.erase_indices(at, self.entries.len());
+ let entries = self.entries.split_off(at);
+
+ let mut indices = Indices::with_capacity(entries.len());
+ insert_bulk_no_grow(&mut indices, &entries);
+ Self { indices, entries }
+ }
+
+ #[track_caller]
+ pub(crate) fn split_splice<R>(&mut self, range: R) -> (Self, vec::IntoIter<Bucket<K, V>>)
+ where
+ R: RangeBounds<usize>,
+ {
+ let range = simplify_range(range, self.len());
+ self.erase_indices(range.start, self.entries.len());
+ let entries = self.entries.split_off(range.end);
+ let drained = self.entries.split_off(range.start);
+
+ let mut indices = Indices::with_capacity(entries.len());
+ insert_bulk_no_grow(&mut indices, &entries);
+ (Self { indices, entries }, drained.into_iter())
+ }
+
+ /// Append from another map without checking whether items already exist.
+ pub(crate) fn append_unchecked(&mut self, other: &mut Self) {
+ self.reserve(other.len());
+ insert_bulk_no_grow(&mut self.indices, &other.entries);
+ self.entries.append(&mut other.entries);
+ other.indices.clear();
+ }
+
+ /// Reserve capacity for `additional` more key-value pairs.
+ pub(crate) fn reserve(&mut self, additional: usize) {
+ self.indices.reserve(additional, get_hash(&self.entries));
+ // Only grow entries if necessary, since we also round up capacity.
+ if additional > self.entries.capacity() - self.entries.len() {
+ self.borrow_mut().reserve_entries(additional);
+ }
+ }
+
+ /// Reserve capacity for `additional` more key-value pairs, without over-allocating.
+ pub(crate) fn reserve_exact(&mut self, additional: usize) {
+ self.indices.reserve(additional, get_hash(&self.entries));
+ self.entries.reserve_exact(additional);
+ }
+
+ /// Try to reserve capacity for `additional` more key-value pairs.
+ pub(crate) fn try_reserve(&mut self, additional: usize) -> Result<(), TryReserveError> {
+ self.indices
+ .try_reserve(additional, get_hash(&self.entries))
+ .map_err(TryReserveError::from_hashbrown)?;
+ // Only grow entries if necessary, since we also round up capacity.
+ if additional > self.entries.capacity() - self.entries.len() {
+ self.try_reserve_entries(additional)
+ } else {
+ Ok(())
+ }
+ }
+
+ /// Try to reserve entries capacity, rounded up to match the indices
+ fn try_reserve_entries(&mut self, additional: usize) -> Result<(), TryReserveError> {
+ // Use a soft-limit on the maximum capacity, but if the caller explicitly
+ // requested more, do it and let them have the resulting error.
+ let new_capacity = Ord::min(self.indices.capacity(), Self::MAX_ENTRIES_CAPACITY);
+ let try_add = new_capacity - self.entries.len();
+ if try_add > additional && self.entries.try_reserve_exact(try_add).is_ok() {
+ return Ok(());
+ }
+ self.entries
+ .try_reserve_exact(additional)
+ .map_err(TryReserveError::from_alloc)
+ }
+
+ /// Try to reserve capacity for `additional` more key-value pairs, without over-allocating.
+ pub(crate) fn try_reserve_exact(&mut self, additional: usize) -> Result<(), TryReserveError> {
+ self.indices
+ .try_reserve(additional, get_hash(&self.entries))
+ .map_err(TryReserveError::from_hashbrown)?;
+ self.entries
+ .try_reserve_exact(additional)
+ .map_err(TryReserveError::from_alloc)
+ }
+
+ /// Shrink the capacity of the map with a lower bound
+ pub(crate) fn shrink_to(&mut self, min_capacity: usize) {
+ self.indices
+ .shrink_to(min_capacity, get_hash(&self.entries));
+ self.entries.shrink_to(min_capacity);
+ }
+
+ /// Remove the last key-value pair
+ pub(crate) fn pop(&mut self) -> Option<(K, V)> {
+ if let Some(entry) = self.entries.pop() {
+ let last = self.entries.len();
+ erase_index(&mut self.indices, entry.hash, last);
+ Some((entry.key, entry.value))
+ } else {
+ None
+ }
+ }
+
+ /// Return the index in `entries` where an equivalent key can be found
+ pub(crate) fn get_index_of<Q>(&self, hash: HashValue, key: &Q) -> Option<usize>
+ where
+ Q: ?Sized + Equivalent<K>,
+ {
+ let eq = equivalent(key, &self.entries);
+ self.indices.find(hash.get(), eq).copied()
+ }
+
+ /// Append a key-value pair to `entries`,
+ /// *without* checking whether it already exists.
+ fn push_entry(&mut self, hash: HashValue, key: K, value: V) {
+ if self.entries.len() == self.entries.capacity() {
+ // Reserve our own capacity synced to the indices,
+ // rather than letting `Vec::push` just double it.
+ self.borrow_mut().reserve_entries(1);
+ }
+ self.entries.push(Bucket { hash, key, value });
+ }
+
+ pub(crate) fn insert_full(&mut self, hash: HashValue, key: K, value: V) -> (usize, Option<V>)
+ where
+ K: Eq,
+ {
+ let eq = equivalent(&key, &self.entries);
+ let hasher = get_hash(&self.entries);
+ match self.indices.entry(hash.get(), eq, hasher) {
+ hash_table::Entry::Occupied(entry) => {
+ let i = *entry.get();
+ (i, Some(mem::replace(&mut self.entries[i].value, value)))
+ }
+ hash_table::Entry::Vacant(entry) => {
+ let i = self.entries.len();
+ entry.insert(i);
+ self.push_entry(hash, key, value);
+ debug_assert_eq!(self.indices.len(), self.entries.len());
+ (i, None)
+ }
+ }
+ }
+
+ /// Same as `insert_full`, except it also replaces the key
+ pub(crate) fn replace_full(
+ &mut self,
+ hash: HashValue,
+ key: K,
+ value: V,
+ ) -> (usize, Option<(K, V)>)
+ where
+ K: Eq,
+ {
+ let eq = equivalent(&key, &self.entries);
+ let hasher = get_hash(&self.entries);
+ match self.indices.entry(hash.get(), eq, hasher) {
+ hash_table::Entry::Occupied(entry) => {
+ let i = *entry.get();
+ let entry = &mut self.entries[i];
+ let kv = (
+ mem::replace(&mut entry.key, key),
+ mem::replace(&mut entry.value, value),
+ );
+ (i, Some(kv))
+ }
+ hash_table::Entry::Vacant(entry) => {
+ let i = self.entries.len();
+ entry.insert(i);
+ self.push_entry(hash, key, value);
+ debug_assert_eq!(self.indices.len(), self.entries.len());
+ (i, None)
+ }
+ }
+ }
+
+ /// Remove an entry by shifting all entries that follow it
+ pub(crate) fn shift_remove_full<Q>(&mut self, hash: HashValue, key: &Q) -> Option<(usize, K, V)>
+ where
+ Q: ?Sized + Equivalent<K>,
+ {
+ let eq = equivalent(key, &self.entries);
+ match self.indices.find_entry(hash.get(), eq) {
+ Ok(entry) => {
+ let (index, _) = entry.remove();
+ let (key, value) = self.borrow_mut().shift_remove_finish(index);
+ Some((index, key, value))
+ }
+ Err(_) => None,
+ }
+ }
+
+ /// Remove an entry by shifting all entries that follow it
+ #[inline]
+ pub(crate) fn shift_remove_index(&mut self, index: usize) -> Option<(K, V)> {
+ self.borrow_mut().shift_remove_index(index)
+ }
+
+ #[inline]
+ #[track_caller]
+ pub(super) fn move_index(&mut self, from: usize, to: usize) {
+ self.borrow_mut().move_index(from, to);
+ }
+
+ #[inline]
+ #[track_caller]
+ pub(crate) fn swap_indices(&mut self, a: usize, b: usize) {
+ self.borrow_mut().swap_indices(a, b);
+ }
+
+ /// Remove an entry by swapping it with the last
+ pub(crate) fn swap_remove_full<Q>(&mut self, hash: HashValue, key: &Q) -> Option<(usize, K, V)>
+ where
+ Q: ?Sized + Equivalent<K>,
+ {
+ let eq = equivalent(key, &self.entries);
+ match self.indices.find_entry(hash.get(), eq) {
+ Ok(entry) => {
+ let (index, _) = entry.remove();
+ let (key, value) = self.borrow_mut().swap_remove_finish(index);
+ Some((index, key, value))
+ }
+ Err(_) => None,
+ }
+ }
+
+ /// Remove an entry by swapping it with the last
+ #[inline]
+ pub(crate) fn swap_remove_index(&mut self, index: usize) -> Option<(K, V)> {
+ self.borrow_mut().swap_remove_index(index)
+ }
+
+ /// Erase `start..end` from `indices`, and shift `end..` indices down to `start..`
+ ///
+ /// All of these items should still be at their original location in `entries`.
+ /// This is used by `drain`, which will let `Vec::drain` do the work on `entries`.
+ fn erase_indices(&mut self, start: usize, end: usize) {
+ let (init, shifted_entries) = self.entries.split_at(end);
+ let (start_entries, erased_entries) = init.split_at(start);
+
+ let erased = erased_entries.len();
+ let shifted = shifted_entries.len();
+ let half_capacity = self.indices.capacity() / 2;
+
+ // Use a heuristic between different strategies
+ if erased == 0 {
+ // Degenerate case, nothing to do
+ } else if start + shifted < half_capacity && start < erased {
+ // Reinsert everything, as there are few kept indices
+ self.indices.clear();
+
+ // Reinsert stable indices, then shifted indices
+ insert_bulk_no_grow(&mut self.indices, start_entries);
+ insert_bulk_no_grow(&mut self.indices, shifted_entries);
+ } else if erased + shifted < half_capacity {
+ // Find each affected index, as there are few to adjust
+
+ // Find erased indices
+ for (i, entry) in (start..).zip(erased_entries) {
+ erase_index(&mut self.indices, entry.hash, i);
+ }
+
+ // Find shifted indices
+ for ((new, old), entry) in (start..).zip(end..).zip(shifted_entries) {
+ update_index(&mut self.indices, entry.hash, old, new);
+ }
+ } else {
+ // Sweep the whole table for adjustments
+ let offset = end - start;
+ self.indices.retain(move |i| {
+ if *i >= end {
+ *i -= offset;
+ true
+ } else {
+ *i < start
+ }
+ });
+ }
+
+ debug_assert_eq!(self.indices.len(), start + shifted);
+ }
+
+ pub(crate) fn retain_in_order<F>(&mut self, mut keep: F)
+ where
+ F: FnMut(&mut K, &mut V) -> bool,
+ {
+ self.entries
+ .retain_mut(|entry| keep(&mut entry.key, &mut entry.value));
+ if self.entries.len() < self.indices.len() {
+ self.rebuild_hash_table();
+ }
+ }
+
+ fn rebuild_hash_table(&mut self) {
+ self.indices.clear();
+ insert_bulk_no_grow(&mut self.indices, &self.entries);
+ }
+
+ pub(crate) fn reverse(&mut self) {
+ self.entries.reverse();
+
+ // No need to save hash indices, can easily calculate what they should
+ // be, given that this is an in-place reversal.
+ let len = self.entries.len();
+ for i in &mut self.indices {
+ *i = len - *i - 1;
+ }
+ }
+}
+
+/// Reserve entries capacity, rounded up to match the indices (via `try_capacity`).
+fn reserve_entries<K, V>(entries: &mut Entries<K, V>, additional: usize, try_capacity: usize) {
+ // Use a soft-limit on the maximum capacity, but if the caller explicitly
+ // requested more, do it and let them have the resulting panic.
+ let try_capacity = try_capacity.min(IndexMapCore::<K, V>::MAX_ENTRIES_CAPACITY);
+ let try_add = try_capacity - entries.len();
+ if try_add > additional && entries.try_reserve_exact(try_add).is_ok() {
+ return;
+ }
+ entries.reserve_exact(additional);
+}
+
+impl<'a, K, V> RefMut<'a, K, V> {
+ #[inline]
+ fn new(indices: &'a mut Indices, entries: &'a mut Entries<K, V>) -> Self {
+ Self { indices, entries }
+ }
+
+ /// Reserve entries capacity, rounded up to match the indices
+ #[inline]
+ fn reserve_entries(&mut self, additional: usize) {
+ reserve_entries(self.entries, additional, self.indices.capacity());
+ }
+
+ /// Insert a key-value pair in `entries`,
+ /// *without* checking whether it already exists.
+ fn insert_unique(self, hash: HashValue, key: K, value: V) -> OccupiedEntry<'a, K, V> {
+ let i = self.indices.len();
+ debug_assert_eq!(i, self.entries.len());
+ let entry = self
+ .indices
+ .insert_unique(hash.get(), i, get_hash(self.entries));
+ if self.entries.len() == self.entries.capacity() {
+ // We can't call `indices.capacity()` while this `entry` has borrowed it, so we'll have
+ // to amortize growth on our own. It's still an improvement over the basic `Vec::push`
+ // doubling though, since we also consider `MAX_ENTRIES_CAPACITY`.
+ reserve_entries(self.entries, 1, 2 * self.entries.capacity());
+ }
+ self.entries.push(Bucket { hash, key, value });
+ OccupiedEntry::new(self.entries, entry)
+ }
+
+ /// Insert a key-value pair in `entries` at a particular index,
+ /// *without* checking whether it already exists.
+ fn shift_insert_unique(&mut self, index: usize, hash: HashValue, key: K, value: V) {
+ let end = self.indices.len();
+ assert!(index <= end);
+ // Increment others first so we don't have duplicate indices.
+ self.increment_indices(index, end);
+ let entries = &*self.entries;
+ self.indices.insert_unique(hash.get(), index, move |&i| {
+ // Adjust for the incremented indices to find hashes.
+ debug_assert_ne!(i, index);
+ let i = if i < index { i } else { i - 1 };
+ entries[i].hash.get()
+ });
+ if self.entries.len() == self.entries.capacity() {
+ // Reserve our own capacity synced to the indices,
+ // rather than letting `Vec::insert` just double it.
+ self.reserve_entries(1);
+ }
+ self.entries.insert(index, Bucket { hash, key, value });
+ }
+
+ /// Remove an entry by shifting all entries that follow it
+ fn shift_remove_index(&mut self, index: usize) -> Option<(K, V)> {
+ match self.entries.get(index) {
+ Some(entry) => {
+ erase_index(self.indices, entry.hash, index);
+ Some(self.shift_remove_finish(index))
+ }
+ None => None,
+ }
+ }
+
+ /// Remove an entry by shifting all entries that follow it
+ ///
+ /// The index should already be removed from `self.indices`.
+ fn shift_remove_finish(&mut self, index: usize) -> (K, V) {
+ // Correct indices that point to the entries that followed the removed entry.
+ self.decrement_indices(index + 1, self.entries.len());
+
+ // Use Vec::remove to actually remove the entry.
+ let entry = self.entries.remove(index);
+ (entry.key, entry.value)
+ }
+
+ /// Remove an entry by swapping it with the last
+ fn swap_remove_index(&mut self, index: usize) -> Option<(K, V)> {
+ match self.entries.get(index) {
+ Some(entry) => {
+ erase_index(self.indices, entry.hash, index);
+ Some(self.swap_remove_finish(index))
+ }
+ None => None,
+ }
+ }
+
+ /// Finish removing an entry by swapping it with the last
+ ///
+ /// The index should already be removed from `self.indices`.
+ fn swap_remove_finish(&mut self, index: usize) -> (K, V) {
+ // use swap_remove, but then we need to update the index that points
+ // to the other entry that has to move
+ let entry = self.entries.swap_remove(index);
+
+ // correct index that points to the entry that had to swap places
+ if let Some(entry) = self.entries.get(index) {
+ // was not last element
+ // examine new element in `index` and find it in indices
+ let last = self.entries.len();
+ update_index(self.indices, entry.hash, last, index);
+ }
+
+ (entry.key, entry.value)
+ }
+
+ /// Decrement all indices in the range `start..end`.
+ ///
+ /// The index `start - 1` should not exist in `self.indices`.
+ /// All entries should still be in their original positions.
+ fn decrement_indices(&mut self, start: usize, end: usize) {
+ // Use a heuristic between a full sweep vs. a `find()` for every shifted item.
+ let shifted_entries = &self.entries[start..end];
+ if shifted_entries.len() > self.indices.capacity() / 2 {
+ // Shift all indices in range.
+ for i in &mut *self.indices {
+ if start <= *i && *i < end {
+ *i -= 1;
+ }
+ }
+ } else {
+ // Find each entry in range to shift its index.
+ for (i, entry) in (start..end).zip(shifted_entries) {
+ update_index(self.indices, entry.hash, i, i - 1);
+ }
+ }
+ }
+
+ /// Increment all indices in the range `start..end`.
+ ///
+ /// The index `end` should not exist in `self.indices`.
+ /// All entries should still be in their original positions.
+ fn increment_indices(&mut self, start: usize, end: usize) {
+ // Use a heuristic between a full sweep vs. a `find()` for every shifted item.
+ let shifted_entries = &self.entries[start..end];
+ if shifted_entries.len() > self.indices.capacity() / 2 {
+ // Shift all indices in range.
+ for i in &mut *self.indices {
+ if start <= *i && *i < end {
+ *i += 1;
+ }
+ }
+ } else {
+ // Find each entry in range to shift its index, updated in reverse so
+ // we never have duplicated indices that might have a hash collision.
+ for (i, entry) in (start..end).zip(shifted_entries).rev() {
+ update_index(self.indices, entry.hash, i, i + 1);
+ }
+ }
+ }
+
+ #[track_caller]
+ fn move_index(&mut self, from: usize, to: usize) {
+ let from_hash = self.entries[from].hash;
+ let _ = self.entries[to]; // explicit bounds check
+ if from != to {
+ // Use a sentinel index so other indices don't collide.
+ update_index(self.indices, from_hash, from, usize::MAX);
+
+ // Update all other indices and rotate the entry positions.
+ if from < to {
+ self.decrement_indices(from + 1, to + 1);
+ self.entries[from..=to].rotate_left(1);
+ } else if to < from {
+ self.increment_indices(to, from);
+ self.entries[to..=from].rotate_right(1);
+ }
+
+ // Change the sentinel index to its final position.
+ update_index(self.indices, from_hash, usize::MAX, to);
+ }
+ }
+
+ #[track_caller]
+ fn swap_indices(&mut self, a: usize, b: usize) {
+ // If they're equal and in-bounds, there's nothing to do.
+ if a == b && a < self.entries.len() {
+ return;
+ }
+
+ // We'll get a "nice" bounds-check from indexing `entries`,
+ // and then we expect to find it in the table as well.
+ match self.indices.get_many_mut(
+ [self.entries[a].hash.get(), self.entries[b].hash.get()],
+ move |i, &x| if i == 0 { x == a } else { x == b },
+ ) {
+ [Some(ref_a), Some(ref_b)] => {
+ mem::swap(ref_a, ref_b);
+ self.entries.swap(a, b);
+ }
+ _ => panic!("indices not found"),
+ }
+ }
+}
+
+#[test]
+fn assert_send_sync() {
+ fn assert_send_sync<T: Send + Sync>() {}
+ assert_send_sync::<IndexMapCore<i32, i32>>();
+ assert_send_sync::<Entry<'_, i32, i32>>();
+ assert_send_sync::<IndexedEntry<'_, i32, i32>>();
+ assert_send_sync::<raw_entry_v1::RawEntryMut<'_, i32, i32, ()>>();
+}
generated by cgit v1.2.3 (git 2.39.1) at 2026-02-02 22:38:43 +0000