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use super::id::{Id, IdIndex, IdTag, MAXIMUM_CAPACITY}; use rand::{self, Rng}; use std::marker::PhantomData; use std::mem; use std::ops::{Index, IndexMut}; use std::slice::{Iter as SliceIter, IterMut as SliceIterMut}; /// An `IdSlab` stores an unordered collection of elements with fast access by opaque `Id`-s. /// /// Inserting an element returns an `Id` which may later be used for lookup and deletion. It /// supports O(1) insertion, deletion and id-lookup. Ordering is unstable when elements are /// added and removed. /// /// The maximum number of elements which can be stored in an `IdSlab` is `MAXIMUM_CAPACITY` /// (currently 2^32). This keeps `Id`-s at 64bits. A future version may support custom types for /// the `Id`-s making the capacity-id-size trade-off customisable. /// /// Example /// --- /// ``` /// use idcontain::{IdSlab, Id}; /// /// let mut id_slab: IdSlab<&'static str> = IdSlab::new(); /// /// // The `Id` type encodes the type of the value, to statically prevent errors caused by mixing /// // id-s. /// let hello_id: Id<&'static str> = id_slab.insert("hello"); /// let world_id = id_slab.insert("world"); /// /// assert_eq!(id_slab[hello_id], "hello"); /// assert_eq!(id_slab[world_id], "world"); /// /// assert_eq!(id_slab.remove(world_id), Some("world")); // The value is returned on deletion. /// assert!(!id_slab.contains(world_id)); /// /// // New id-s are different from previous ones, even though the memory is reused. /// let new_world_id = id_slab.insert("new world"); /// assert!(new_world_id != world_id); /// ``` /// /// Id Reuse /// --- /// Removing an `Id` will cause future lookups with that `Id` to fail (either returning `None` for /// `get` and `remove`, or panicking for indexing), but this feature is 'best-effort' and should /// not be relied on for memory safety or security. /// /// In particular removing and adding an element 2^32 times will cause that `Id` to be reused. This /// is, for most workloads unlikely and is made even less likely when operations are more mixed /// (adding more elements and removing them in between). /// /// /// Id Mixing /// --- /// Using an `Id` from a different `IdSlab` will fail at compile time, unless both `IdSlab`-s are of /// the same type. You are encouraged to newtype liberally to make leverage this as much as /// possible. /// /// When using `Id`-s of the same type, lookups are still most likely going to fail at runtime: /// /// ``` /// # use idcontain::IdSlab; /// let mut id_slab_1 = IdSlab::new(); /// let id1 = id_slab_1.insert(1); /// /// let mut id_slab_2 = IdSlab::new(); /// let id2 = id_slab_2.insert(1); /// /// assert!(id1 != id2); /// assert!(!id_slab_1.contains(id2)); /// assert!(!id_slab_2.contains(id1)); /// ``` /// /// The mechanism behind this is built on the same tagging mechanism used for preventing `Id` reuse /// of the same `IdSlab`. As such, this feature is also best-effort and should not be used for /// memory safety or security. /// /// For all other situations, it's probably fine. The probability curve follows the birthday /// paradox equation with `m=2^32 / avg_num_elements_per_id_slab` and `n=num_id_slabs`. So, for /// instance, 10 `IdSlab`-s with 1000 elements each, gives a collision probability of about /// `(n^2/2m) = 0.001%` or 1 in 100,000. #[derive(Clone, Debug)] pub struct IdSlab<T> { slots: Vec<TaggedSlot<T>>, first_free: IdIndex, seed_tag: IdTag, len: usize, } impl<T> IdSlab<T> { /// Creates a new `IdSlab` with zero capacity. /// /// The first insertion will cause an allocation. pub fn new() -> Self { Self::with_capacity(0) } /// Creates a new `IdSlab` with a given capacity. /// /// As long as number of elements stays under this capacity, no re-allocation will be /// triggered. pub fn with_capacity(capacity: usize) -> Self { Self::with_capacity_and_seed_tag(capacity, default_seed_tag()) } /// Creates a new `IdSlab` with a given capacity and seed tag. /// /// This is an advanced feature which may cause more `Id` collisions between your `IdSlab`-s if /// used incorrectly. /// /// The `seed_tag` of an `IdSlab` is the tag assigned to new slots. Removing elements increments /// this tag and wraps around, providing the mechanism for `Id` reuse prevention and `Id` /// mixing detection. /// /// The `new` and `with_capacity` constructors set the seed tag to a random number, but better /// strategies exist for preventing collisions if you know your workload. pub fn with_capacity_and_seed_tag(capacity: usize, seed_tag: IdTag) -> Self { assert!(capacity <= MAXIMUM_CAPACITY); IdSlab { slots: if capacity == 0 { Vec::new() } else { Vec::with_capacity(capacity) }, first_free: 0, seed_tag: seed_tag, len: 0, } } /// Returns the number of elements in the `IdSlab`. /// /// Panics /// --- /// None. /// /// Example /// --- /// ``` /// # use idcontain::IdSlab; /// let mut id_slab = IdSlab::new(); /// assert_eq!(id_slab.len(), 0); /// /// let id = id_slab.insert(1); /// assert_eq!(id_slab.len(), 1); /// /// id_slab.remove(id); /// assert_eq!(id_slab.len(), 0); /// ``` pub fn len(&self) -> usize { self.len } /// Returns true if the slab is empty. /// /// Panics /// --- /// None. /// /// Example /// --- /// ``` /// # use idcontain::IdSlab; /// let mut id_slab = IdSlab::new(); /// assert!(id_slab.is_empty()); /// /// let id = id_slab.insert(1); /// assert!(!id_slab.is_empty()); /// /// id_slab.remove(id); /// assert!(id_slab.is_empty()); /// ``` pub fn is_empty(&self) -> bool { self.len == 0 } /// Returns `true` if there exists an element with the given `Id`. /// /// See struct-level docs for caveats about `Id` reuse and mixing (almost always fine, but /// `contains` may give you false positives in pathological cases so don't rely on it for /// memory safety or security). /// /// Panics /// --- /// None. /// /// Example /// --- /// ``` /// # use idcontain::IdSlab; /// let mut id_slab = IdSlab::new(); /// assert_eq!(id_slab.len(), 0); /// /// let id = id_slab.insert(1); /// assert!(id_slab.contains(id)); /// /// id_slab.remove(id); /// assert!(!id_slab.contains(id)); /// ``` pub fn contains(&self, id: Id<T>) -> bool { match self.slots.get(id.index as usize) { Some(&TaggedSlot { slot: Slot::Occupied { .. }, tag, }) if tag == id.tag => true, _ => false, } } /// Returns a reference to an element by `Id` or `None` if it doesn't exist. /// /// Use indexing for a panicking version of this operation. /// /// Panics /// --- /// None. /// /// Example /// --- /// ``` /// # use idcontain::IdSlab; /// let mut id_slab = IdSlab::new(); /// let id = id_slab.insert(1); /// /// assert_eq!(id_slab.get(id), Some(&1)); /// /// id_slab.remove(id); /// assert_eq!(id_slab.get(id), None); /// ``` pub fn get(&self, id: Id<T>) -> Option<&T> { self.get_or_tagged_slot(id).ok() } /// Returns a mutable reference to an element by `Id` or `None` if it doesn't exist. /// /// Use indexing for a panicking version of this operation. /// /// Panics /// --- /// None. /// /// Example /// --- /// ``` /// # use idcontain::IdSlab; /// let mut id_slab = IdSlab::new(); /// let id = id_slab.insert(1); /// /// *id_slab.get_mut(id).unwrap() = 10; /// assert_eq!(id_slab[id], 10); /// /// id_slab.remove(id); /// assert_eq!(id_slab.get_mut(id), None); /// ``` pub fn get_mut(&mut self, id: Id<T>) -> Option<&mut T> { self.get_mut_or_tagged_slot(id).ok() } /// Inserts a new element into the `IdSlab`, returning its `Id<T>`. /// /// In general the `Id`-s do not get reused and should not collide with other `IdSlab`-s, but /// caveats apply, see the struct-level doc for more details. /// /// Panics /// --- /// If `self.len() == MAXIMUM_CAPACITY`. /// /// /// Example /// --- /// ``` /// # use idcontain::IdSlab; /// let mut id_slab = IdSlab::new(); /// let id1 = id_slab.insert(1); /// let id2 = id_slab.insert(2); /// /// assert_eq!(id_slab[id1], 1); /// assert_eq!(id_slab[id2], 2); /// /// // Id-s are not (caveats apply) shared between `IdSlab`-s. /// let mut new_id_slab = IdSlab::new(); /// let new_id1 = new_id_slab.insert(1); /// assert!(new_id1 != id1); /// /// // Id-s are not (caveats apply) reused. /// id_slab.remove(id1); /// let id3 = id_slab.insert(3); /// assert!(id3 != id1); /// ``` pub fn insert(&mut self, value: T) -> Id<T> { assert!(self.len() < MAXIMUM_CAPACITY); self.len += 1; if self.first_free < self.slots.len() as IdIndex { let index = self.first_free; let tagged_slot = &mut self.slots[self.first_free as usize]; match mem::replace(&mut tagged_slot.slot, Slot::Occupied { value: value }) { Slot::Free { next_free } => self.first_free = next_free, Slot::Occupied { .. } => panic!("Occupied slot in free list."), } Id { tag: tagged_slot.tag, index: index, _data: PhantomData, } } else { self.slots.push(TaggedSlot { tag: self.seed_tag, slot: Slot::Occupied { value: value }, }); self.first_free = self.slots.len() as IdIndex; Id { index: self.first_free - 1, tag: self.seed_tag, _data: PhantomData, } } } /// Removes an element by `Id` returning its value. /// /// Returns `None` if no element with the given `Id` exists. See the struct level docs for the /// pathological cases where this may not be the case. /// /// Panics /// --- /// None. /// /// Example /// --- /// ``` /// # use idcontain::IdSlab; /// let mut id_slab = IdSlab::new(); /// let id1 = id_slab.insert(1); /// /// assert_eq!(id_slab[id1], 1); /// assert_eq!(id_slab.remove(id1), Some(1)); /// /// assert!(!id_slab.contains(id1)); /// assert_eq!(id_slab.remove(id1), None); /// ``` pub fn remove(&mut self, id: Id<T>) -> Option<T> { let IdSlab { ref mut slots, ref mut len, ref mut first_free, .. } = *self; slots.get_mut(id.index as usize).and_then(|tagged_slot| { if tagged_slot.tag == id.tag { match mem::replace( &mut tagged_slot.slot, Slot::Free { next_free: *first_free, }, ) { Slot::Occupied { value } => { *len = len.checked_sub(1).expect("invalid len in remove()"); tagged_slot.tag = tagged_slot.tag.wrapping_add(1); *first_free = id.index; Some(value) } rollback @ Slot::Free { .. } => { tagged_slot.slot = rollback; None } } } else { None } }) } /// Iterates over references to the elements in the `IdSlab`. /// /// While this operation has good cache locality, its worst-case complexity is /// `O(max_number_of_elements_ever)`. I.e. there are pathological cases where adding and /// removing 1 million elements, then adding one element back will cause iteration to be `O(1 /// million)`. /// /// The iteration order is unspecified, but it doesn't change unless the `IdSlab` is mutated. /// /// Panics /// --- /// None. /// /// Example /// --- /// ``` /// # use idcontain::IdSlab; /// let mut id_slab = IdSlab::new(); /// id_slab.insert(1); /// id_slab.insert(2); /// id_slab.insert(3); /// /// for i in id_slab.iter() { /// println!("{}", i); // Prints 1, 2, 3. /// } /// /// // Can use `&id_slab` instead: /// for i in &id_slab { /// println!("{}", i); // Prints 1, 2, 3. /// } /// ``` pub fn iter(&self) -> Iter<T> { Iter { num_left: self.len(), iter: self.slots.iter(), } } /// Iterates over mutable references to the elements in the `IdSlab`. /// /// See `iter` for notes on complexity and iteration order. /// /// Panics /// --- /// None. /// /// Example /// --- /// ``` /// # use idcontain::IdSlab; /// let mut id_slab = IdSlab::new(); /// id_slab.insert(1); /// id_slab.insert(2); /// id_slab.insert(3); /// /// for value in id_slab.iter_mut() { // Or `&mut id_slab`. /// *value += 1; /// } /// /// for i in &id_slab { /// println!("{}", i); // Prints 2, 3, 4. /// } /// ``` pub fn iter_mut(&mut self) -> IterMut<T> { IterMut { num_left: self.len(), iter: self.slots.iter_mut(), } } fn get_or_tagged_slot(&self, id: Id<T>) -> Result<&T, Option<&TaggedSlot<T>>> { match self.slots.get(id.index as usize) { Some(&TaggedSlot { slot: Slot::Occupied { ref value }, tag, }) if tag == id.tag => Ok(value), tagged_slot => Err(tagged_slot), } } fn get_mut_or_tagged_slot(&mut self, id: Id<T>) -> Result<&mut T, Option<&mut TaggedSlot<T>>> { match self.slots.get_mut(id.index as usize) { Some(tagged_slot) => { if id.tag == tagged_slot.tag { match tagged_slot.slot { Slot::Occupied { ref mut value } => Ok(value), _ => Err(Some(tagged_slot)), } } else { Err(Some(tagged_slot)) } } _ => Err(None), } } /// Returns a reference to an element by index or `None` if it doesn't exist. /// /// This is a low-level operation that bypasses the tag check. Useful for building other /// containers on top. /// /// Panics /// --- /// None. /// /// Example /// --- /// ``` /// # use idcontain::IdSlab; /// let mut id_slab = IdSlab::new(); /// let id = id_slab.insert(1); /// /// assert_eq!(id_slab.by_index(0), Some(&1)); /// ``` pub fn by_index(&self, index: IdIndex) -> Option<&T> { match self.slots.get(index as usize) { Some(&TaggedSlot { slot: Slot::Occupied { ref value }, .. }) => Some(value), _ => None, } } /// Returns a mutable reference to an element by index or `None` if it doesn't exist. /// /// This is a low-level operation that bypasses the tag check. Useful for building other /// containers on top. /// /// Panics /// --- /// None. /// /// Example /// --- /// ``` /// # use idcontain::IdSlab; /// let mut id_slab = IdSlab::new(); /// let id = id_slab.insert(1); /// /// *id_slab.by_index_mut(0).unwrap() = 10; /// assert_eq!(id_slab[id], 10); /// ``` pub fn by_index_mut(&mut self, index: IdIndex) -> Option<&mut T> { match self.slots.get_mut(index as usize) { Some(&mut TaggedSlot { slot: Slot::Occupied { ref mut value }, .. }) => Some(value), _ => None, } } /// Returns the `Id` for a given occupied index. /// /// Returns `None` if the index is invalid. /// /// This is a low-level operation that bypasses the tag check. Useful for building other /// containers on top. /// /// Panics /// --- /// None. /// /// Example /// --- /// ``` /// # use idcontain::IdSlab; /// let mut id_slab = IdSlab::new(); /// let id = id_slab.insert(1); /// /// assert_eq!(id_slab.index_to_id(0), Some(id)); /// ``` pub fn index_to_id(&self, index: IdIndex) -> Option<Id<T>> { match self.slots.get(index as usize) { Some(&TaggedSlot { slot: Slot::Occupied { .. }, tag, }) => Some(Id { index: index, tag: tag, _data: PhantomData, }), _ => None, } } } impl<T> Default for IdSlab<T> { fn default() -> Self { Self::new() } } #[cold] #[inline(never)] fn panic_for_bad_id<T>( num_slots: usize, seed_tag: IdTag, len: usize, tagged_slot: Option<&TaggedSlot<T>>, id: Id<T>, ) -> ! { let reason = if id.index as usize > num_slots { format!( "index `{}` larger than number of slots `{}` (wrong `IdSlab`?)", id.index, num_slots ) } else if let Some(&TaggedSlot { tag, ref slot }) = tagged_slot { if tag > id.tag { if (tag - id.tag) < 100 { format!("tag `{}` older than slot tag `{}`, deleted?", id.tag, tag) } else { format!( "tag `{}` much older than slot tag `{}`, wrong `IdSlab` or deleted?", id.tag, tag ) } } else if tag < id.tag { format!( "tag `{}` newer than slot tag `{}`, wrong `IdSlab`?", id.tag, tag ) } else { match *slot { Slot::Free { .. } => format!( "tag `{}` matches, but the slot is free, wrong `IdSlab` with same \ seed_tag `{}`?", id.tag, seed_tag ), Slot::Occupied { .. } => "<IdSlab bug [occupied], please report!>".to_owned(), } } } else { "<IdSlab bug [no TaggedSlot], please report!>".to_owned() }; panic!( "Invalid id: {} (id={{ index=`{}`, tag=`{}` }}, id_slab={{ num_slots=`{}`, \ seed_tag=`{}`, len=`{}` }})", reason, id.index, id.tag, num_slots, seed_tag, len ) } impl<T> Index<Id<T>> for IdSlab<T> { type Output = T; fn index(&self, id: Id<T>) -> &Self::Output { self.get_or_tagged_slot(id).unwrap_or_else(|tagged_slot| { panic_for_bad_id(self.slots.len(), self.seed_tag, self.len, tagged_slot, id) }) } } impl<T> IndexMut<Id<T>> for IdSlab<T> { fn index_mut(&mut self, id: Id<T>) -> &mut Self::Output { let num_slots = self.slots.len(); let &mut IdSlab { seed_tag, len, .. } = self; self.get_mut_or_tagged_slot(id) .unwrap_or_else(|tagged_slot| { panic_for_bad_id( num_slots, seed_tag, len, tagged_slot.map(|tagged_slot| &*tagged_slot), id, ) }) } } /// The type returned by `IdSlab.iter()`. #[derive(Clone, Debug)] pub struct Iter<'a, T: 'a> { num_left: usize, iter: SliceIter<'a, TaggedSlot<T>>, } impl<'a, T: 'a> Iterator for Iter<'a, T> { type Item = &'a T; fn next(&mut self) -> Option<Self::Item> { while self.num_left > 0 { let tagged_slot = self.iter.next().expect("Too few elements in Iter"); if let TaggedSlot { slot: Slot::Occupied { ref value }, .. } = *tagged_slot { self.num_left -= 1; return Some(value); } } None } fn size_hint(&self) -> (usize, Option<usize>) { (self.num_left, Some(self.num_left)) } } impl<'a, T: 'a> DoubleEndedIterator for Iter<'a, T> { fn next_back(&mut self) -> Option<Self::Item> { while self.num_left > 0 { let tagged_slot = self.iter.next_back().expect("Too few elements in Iter"); if let TaggedSlot { slot: Slot::Occupied { ref value }, .. } = *tagged_slot { self.num_left -= 1; return Some(value); } } None } } impl<'a, T: 'a> ExactSizeIterator for Iter<'a, T> { fn len(&self) -> usize { self.num_left } } fn default_seed_tag() -> IdTag { rand::thread_rng().gen() } /// The type returned by `IdSlab.iter_mut()`. #[derive(Debug)] pub struct IterMut<'a, T: 'a> { iter: SliceIterMut<'a, TaggedSlot<T>>, num_left: usize, } impl<'a, T: 'a> Iterator for IterMut<'a, T> { type Item = &'a mut T; fn next(&mut self) -> Option<Self::Item> { while self.num_left > 0 { let tagged_slot = self.iter.next().expect("Too few elements in IterMut"); if let TaggedSlot { slot: Slot::Occupied { ref mut value }, .. } = *tagged_slot { self.num_left -= 1; return Some(value); } } None } fn size_hint(&self) -> (usize, Option<usize>) { (self.num_left, Some(self.num_left)) } } impl<'a, T: 'a> DoubleEndedIterator for IterMut<'a, T> { fn next_back(&mut self) -> Option<Self::Item> { while self.num_left > 0 { let tagged_slot = self.iter.next_back().expect("Too few elements in IterMut"); if let TaggedSlot { slot: Slot::Occupied { ref mut value }, .. } = *tagged_slot { self.num_left -= 1; return Some(value); } } None } } impl<'a, T: 'a> ExactSizeIterator for IterMut<'a, T> { fn len(&self) -> usize { self.num_left } } impl<'a, T: 'a> IntoIterator for &'a IdSlab<T> { type IntoIter = Iter<'a, T>; type Item = <Self::IntoIter as Iterator>::Item; fn into_iter(self) -> Self::IntoIter { self.iter() } } impl<'a, T: 'a> IntoIterator for &'a mut IdSlab<T> { type IntoIter = IterMut<'a, T>; type Item = <Self::IntoIter as Iterator>::Item; fn into_iter(self) -> Self::IntoIter { self.iter_mut() } } #[derive(Debug, Clone)] enum Slot<T> { Free { next_free: IdIndex }, Occupied { value: T }, } #[derive(Debug, Clone)] struct TaggedSlot<T> { tag: IdTag, slot: Slot<T>, } #[cfg(test)] mod tests { use super::super::id::Id; use super::IdSlab; use std::marker::PhantomData; #[test] fn len_iter_contains_on_empty() { let id_slab = IdSlab::<i32>::new(); assert_eq!(id_slab.len(), 0); assert_eq!(id_slab.iter().next(), None); assert!(!id_slab.contains(Id { index: 0, tag: 0, _data: PhantomData, })); } #[test] fn iter_mut_on_empty() { let mut id_slab = IdSlab::<String>::new(); assert_eq!(id_slab.iter_mut().next(), None); } #[test] fn id_slab_insert_then_get_and_index() { let mut id_slab = IdSlab::new(); let id_a = id_slab.insert(1); let id_b = id_slab.insert(2); let id_c = id_slab.insert(3); // Id-s all differ from each other. assert!(id_a != id_b); assert!(id_b != id_c); assert!(id_c != id_a); // `get` returns the correct values. assert_eq!(id_slab.get(id_a).map(|&x| x), Some(1)); assert_eq!(id_slab.get(id_b).map(|&x| x), Some(2)); assert_eq!(id_slab.get(id_c).map(|&x| x), Some(3)); // `get_mut` returns the correct values. assert_eq!(id_slab.get_mut(id_a).map(|&mut x| x), Some(1)); assert_eq!(id_slab.get_mut(id_b).map(|&mut x| x), Some(2)); assert_eq!(id_slab.get_mut(id_c).map(|&mut x| x), Some(3)); // `index` returns the correct values. assert_eq!(*(&id_slab[id_a]), 1); assert_eq!(*(&id_slab[id_b]), 2); assert_eq!(*(&id_slab[id_c]), 3); // `index` returns the correct values. assert_eq!(*(&mut id_slab[id_a]), 1); assert_eq!(*(&mut id_slab[id_b]), 2); assert_eq!(*(&mut id_slab[id_c]), 3); // Mutating through id_b then `get`-ing again works. id_slab[id_b] = 10; assert_eq!(id_slab[id_b], 10); } #[test] #[should_panic] fn id_slab_insert_then_remove_index_panics() { let mut id_slab = IdSlab::new(); let id = id_slab.insert(1); id_slab.remove(id); id_slab[id]; } #[test] #[should_panic] fn id_slab_insert_then_remove_index_mut_panics() { let mut id_slab = IdSlab::new(); let id = id_slab.insert(1); id_slab.remove(id); id_slab[id] = 10; } #[test] fn id_slab_insert_then_remove_get() { let mut id_slab = IdSlab::with_capacity(3); let id_a = id_slab.insert(1); let id_b = id_slab.insert(2); let id_c = id_slab.insert(3); assert_eq!(id_slab.remove(id_b), Some(2)); assert_eq!(id_slab.get(id_b), None); assert!(!id_slab.contains(id_b)); assert_eq!(id_slab[id_a], 1); assert_eq!(id_slab[id_c], 3); let id_d = id_slab.insert(5); assert_eq!(id_slab.remove(id_a), Some(1)); assert_eq!(id_slab.remove(id_a), None); assert_eq!(id_slab.remove(id_c), Some(3)); assert_eq!(id_slab.get(id_a), None); assert_eq!(id_slab.get(id_c), None); assert!(!id_slab.contains(id_a)); assert!(!id_slab.contains(id_b)); assert!(!id_slab.contains(id_c)); assert!(id_slab.contains(id_d)); let id_e = id_slab.insert(6); let id_f = id_slab.insert(7); assert!(id_d.tag == id_b.tag.wrapping_add(1)); assert!(id_d.index == id_b.index); assert!(id_e.tag == id_c.tag.wrapping_add(1)); assert!(id_e.index == id_c.index); assert!(id_f.tag == id_a.tag.wrapping_add(1)); assert!(id_f.index == id_a.index); } #[test] fn id_slab_insert_then_remove_iter() { let mut id_slab = IdSlab::with_capacity(3); let id_a = id_slab.insert(1); let id_b = id_slab.insert(2); id_slab.insert(3); id_slab.remove(id_b); id_slab.insert(4); let id_e = id_slab.insert(5); id_slab.remove(id_e); id_slab.remove(id_a); assert_eq!(&id_slab.iter().cloned().collect::<Vec<_>>()[..], &[4, 3]); assert_eq!( &id_slab.iter_mut().map(|&mut x| x).collect::<Vec<_>>()[..], &[4, 3] ); assert_eq!( &(&id_slab).into_iter().cloned().collect::<Vec<_>>()[..], &[4, 3] ); assert_eq!( &(&mut id_slab) .into_iter() .map(|&mut x| x) .collect::<Vec<_>>()[..], &[4, 3] ); } #[test] fn id_slab_ids_from_different_id_slabs() { let mut id_slab_1 = IdSlab::with_capacity(3); let mut id_slab_2 = IdSlab::with_capacity(4); let id_a_1 = id_slab_1.insert(1); let id_b_1 = id_slab_1.insert(2); let id_c_1 = id_slab_1.insert(3); let id_a_2 = id_slab_2.insert(1); let id_b_2 = id_slab_2.insert(2); let id_c_2 = id_slab_2.insert(3); let id_d_2 = id_slab_2.insert(4); assert_eq!(id_slab_1.get(id_a_2), None); assert_eq!(id_slab_1.get(id_b_2), None); assert_eq!(id_slab_1.get(id_c_2), None); assert_eq!(id_slab_1.get(id_d_2), None); assert_eq!(id_slab_1.get_mut(id_a_2), None); assert_eq!(id_slab_1.get_mut(id_b_2), None); assert_eq!(id_slab_1.get_mut(id_c_2), None); assert_eq!(id_slab_1.get_mut(id_d_2), None); assert!(!id_slab_1.contains(id_a_2)); assert!(!id_slab_1.contains(id_b_2)); assert!(!id_slab_1.contains(id_c_2)); assert!(!id_slab_1.contains(id_d_2)); assert_eq!(id_slab_1.remove(id_a_2), None); assert_eq!(id_slab_1.remove(id_b_2), None); assert_eq!(id_slab_1.remove(id_c_2), None); assert_eq!(id_slab_1.remove(id_d_2), None); assert_eq!(&id_slab_1.iter().cloned().collect::<Vec<_>>(), &[1, 2, 3]); assert_eq!(id_slab_2.get(id_a_1), None); assert_eq!(id_slab_2.get(id_b_1), None); assert_eq!(id_slab_2.get(id_c_1), None); assert_eq!(id_slab_2.get_mut(id_a_1), None); assert_eq!(id_slab_2.get_mut(id_b_1), None); assert_eq!(id_slab_2.get_mut(id_c_1), None); assert!(!id_slab_2.contains(id_a_1)); assert!(!id_slab_2.contains(id_b_1)); assert!(!id_slab_2.contains(id_c_1)); assert_eq!(id_slab_2.remove(id_a_1), None); assert_eq!(id_slab_2.remove(id_b_1), None); assert_eq!(id_slab_2.remove(id_c_1), None); assert_eq!( &id_slab_2.iter().cloned().collect::<Vec<_>>(), &[1, 2, 3, 4] ); } }