Struct slotmap::secondary::SecondaryMap [−][src]
pub struct SecondaryMap<K: Key, V> { /* fields omitted */ }
Secondary map, associate data with previously stored elements in a slot map.
A SecondaryMap
allows you to efficiently store additional information for
each element in a slot map. You can have multiple secondary maps per slot
map, but not multiple slot maps per secondary map. It is safe but
unspecified behavior if you use keys from multiple different slot maps in
the same SecondaryMap
.
A SecondaryMap
does not leak memory even if you never remove elements. In
return, when you remove a key from the primary slot map, after any insert
the space associated with the removed element may be reclaimed. Don’t expect
the values associated with a removed key to stick around after an insertion
has happened!
Unlike a SlotMap
, a SecondaryMap
s elements do not need to be
Slottable
. This means that if you can’t or don’t want to use nightly
Rust, and your data is not Slottable
, you can store that data as
secondary data.
Finally a note on memory complexity, the SecondaryMap
can use memory for
each slot in the primary slot map, and has to iterate over every slot during
iteration, regardless of whether you have inserted an associative value at
that key or not. If you have some property that you only expect to set for a
minority of keys, use a SparseSecondaryMap
, which is backed by a
HashMap
.
Example usage:
// Nightly Rust needed to store String which is not Copy. let mut players: SlotMap<_, &'static str> = SlotMap::new(); // But not for secondary maps. let mut nicks: SecondaryMap<_, String> = SecondaryMap::new(); let mut health = SecondaryMap::new(); let mut ammo = SecondaryMap::new(); let alice = players.insert("alice"); nicks.insert(alice, "the_dragon1".to_string()); let bob = players.insert("bob"); nicks.insert(bob, "bobby_".to_string()); for p in players.keys() { health.insert(p, 100); ammo.insert(p, 30); } // Alice attacks Bob with all her ammo! health[bob] -= ammo[alice] * 3; ammo[alice] = 0;
Implementations
impl<K: Key, V> SecondaryMap<K, V>
[src]
impl<K: Key, V> SecondaryMap<K, V>
[src]pub fn new() -> Self
[src]
Constructs a new, empty SecondaryMap
.
Examples
let mut sec: SecondaryMap<DefaultKey, i32> = SecondaryMap::new();
pub fn with_capacity(capacity: usize) -> Self
[src]
Creates an empty SecondaryMap
with the given capacity of slots.
The secondary map will not reallocate until it holds at least capacity
slots. Even inserting a single key-value pair might require as many
slots as the slot map the key comes from, so it’s recommended to match
the capacity of a secondary map to its corresponding slot map.
Examples
let mut sm: SlotMap<_, i32> = SlotMap::with_capacity(10); let mut sec: SecondaryMap<DefaultKey, i32> = SecondaryMap::with_capacity(sm.capacity());
pub fn len(&self) -> usize
[src]
Returns the number of elements in the secondary map.
Examples
let mut sm = SlotMap::new(); let k = sm.insert(4); let mut squared = SecondaryMap::new(); assert_eq!(squared.len(), 0); squared.insert(k, 16); assert_eq!(squared.len(), 1);
pub fn is_empty(&self) -> bool
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Returns if the secondary map is empty.
Examples
let mut sec: SecondaryMap<DefaultKey, i32> = SecondaryMap::new(); assert!(sec.is_empty());
pub fn capacity(&self) -> usize
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Returns the number of elements the SecondaryMap
can hold without
reallocating.
Examples
let mut sec: SecondaryMap<DefaultKey, i32> = SecondaryMap::with_capacity(10); assert!(sec.capacity() >= 10);
pub fn set_capacity(&mut self, new_capacity: usize)
[src]
Sets the capacity of the SecondaryMap
to new_capacity
, if it is
bigger than the current capacity.
It is recommended to set the capacity of a SecondaryMap
to the
capacity of its corresponding slot map before inserting many new
elements to prevent frequent reallocations. The collection may reserve
more space than requested.
Panics
Panics if the new allocation size overflows usize
.
Examples
let mut sec: SecondaryMap<DefaultKey, i32> = SecondaryMap::with_capacity(10); assert!(sec.capacity() >= 10); sec.set_capacity(1000); assert!(sec.capacity() >= 1000);
pub fn contains_key(&self, key: K) -> bool
[src]
Returns true
if the secondary map contains key
.
Examples
let mut sm = SlotMap::new(); let k = sm.insert(4); let mut squared = SecondaryMap::new(); assert!(!squared.contains_key(k)); squared.insert(k, 16); assert!(squared.contains_key(k));
pub fn insert(&mut self, key: K, value: V) -> Option<V>
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Inserts a value into the secondary map at the given key
. Can silently
fail if key
was removed from the originating slot map.
Returns None
if this key was not present in the map, the old value
otherwise.
Examples
let mut sm = SlotMap::new(); let k = sm.insert(4); let mut squared = SecondaryMap::new(); assert_eq!(squared.insert(k, 0), None); assert_eq!(squared.insert(k, 4), Some(0)); // You don't have to use insert if the key is already in the secondary map. squared[k] *= squared[k]; assert_eq!(squared[k], 16);
pub fn remove(&mut self, key: K) -> Option<V>
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Removes a key from the secondary map, returning the value at the key if
the key was not previously removed. If key
was removed from the
originating slot map, its corresponding entry in the secondary map may
or may not already be removed.
Examples
let mut sm = SlotMap::new(); let mut squared = SecondaryMap::new(); let k = sm.insert(4); squared.insert(k, 16); squared.remove(k); assert!(!squared.contains_key(k)); // It's not necessary to remove keys deleted from the primary slot map, they // get deleted automatically when their slots are reused on a subsequent insert. squared.insert(k, 16); sm.remove(k); // Remove k from the slot map, making an empty slot. let new_k = sm.insert(2); // Since sm only has one empty slot, this reuses it. assert!(!squared.contains_key(new_k)); // Space reuse does not mean equal keys. assert!(squared.contains_key(k)); // Slot has not been reused in squared yet. squared.insert(new_k, 4); assert!(!squared.contains_key(k)); // Old key is no longer available.
pub fn retain<F>(&mut self, f: F) where
F: FnMut(K, &mut V) -> bool,
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F: FnMut(K, &mut V) -> bool,
Retains only the elements specified by the predicate.
In other words, remove all key-value pairs (k, v)
such that
f(k, &mut v)
returns false. This method invalidates any removed keys.
This function must iterate over all slots, empty or not. In the face of many deleted elements it can be inefficient.
Examples
let mut sm = SlotMap::new(); let mut sec = SecondaryMap::new(); let k1 = sm.insert(0); sec.insert(k1, 10); let k2 = sm.insert(1); sec.insert(k2, 11); let k3 = sm.insert(2); sec.insert(k3, 12); sec.retain(|key, val| key == k1 || *val == 11); assert!(sec.contains_key(k1)); assert!(sec.contains_key(k2)); assert!(!sec.contains_key(k3)); assert_eq!(2, sec.len());
pub fn clear(&mut self)
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Clears the secondary map. Keeps the allocated memory for reuse.
This function must iterate over all slots, empty or not. In the face of many deleted elements it can be inefficient.
Examples
let mut sm = SlotMap::new(); let mut sec = SecondaryMap::new(); for i in 0..10 { sec.insert(sm.insert(i), i); } assert_eq!(sec.len(), 10); sec.clear(); assert_eq!(sec.len(), 0);
pub fn drain(&mut self) -> Drain<'_, K, V>ⓘ
[src]
Clears the slot map, returning all key-value pairs in arbitrary order as an iterator. Keeps the allocated memory for reuse.
This function must iterate over all slots, empty or not. In the face of many deleted elements it can be inefficient.
Examples
let mut sm = SlotMap::new(); let k = sm.insert(0); let mut sec = SecondaryMap::new(); sec.insert(k, 1); let v: Vec<_> = sec.drain().collect(); assert_eq!(sec.len(), 0); assert_eq!(v, vec![(k, 1)]);
pub fn get(&self, key: K) -> Option<&V>
[src]
Returns a reference to the value corresponding to the key.
Examples
let mut sm = SlotMap::new(); let key = sm.insert("foo"); let mut sec = SecondaryMap::new(); sec.insert(key, "bar"); assert_eq!(sec.get(key), Some(&"bar")); sec.remove(key); assert_eq!(sec.get(key), None);
pub unsafe fn get_unchecked(&self, key: K) -> &V
[src]
Returns a reference to the value corresponding to the key without version or bounds checking.
Safety
This should only be used if contains_key(key)
is true. Otherwise it is
potentially unsafe.
Examples
let mut sm = SlotMap::new(); let key = sm.insert("foo"); let mut sec = SecondaryMap::new(); sec.insert(key, "bar"); assert_eq!(unsafe { sec.get_unchecked(key) }, &"bar"); sec.remove(key); // sec.get_unchecked(key) is now dangerous!
pub fn get_mut(&mut self, key: K) -> Option<&mut V>
[src]
Returns a mutable reference to the value corresponding to the key.
Examples
let mut sm = SlotMap::new(); let key = sm.insert("test"); let mut sec = SecondaryMap::new(); sec.insert(key, 3.5); if let Some(x) = sec.get_mut(key) { *x += 3.0; } assert_eq!(sec[key], 6.5);
pub unsafe fn get_unchecked_mut(&mut self, key: K) -> &mut V
[src]
Returns a mutable reference to the value corresponding to the key without version or bounds checking.
Safety
This should only be used if contains_key(key)
is true. Otherwise it is
potentially unsafe.
Examples
let mut sm = SlotMap::new(); let key = sm.insert("foo"); let mut sec = SecondaryMap::new(); sec.insert(key, "bar"); unsafe { *sec.get_unchecked_mut(key) = "baz" }; assert_eq!(sec[key], "baz"); sec.remove(key); // sec.get_unchecked_mut(key) is now dangerous!
pub fn iter(&self) -> Iter<'_, K, V>ⓘ
[src]
An iterator visiting all key-value pairs in arbitrary order. The
iterator element type is (K, &'a V)
.
This function must iterate over all slots, empty or not. In the face of many deleted elements it can be inefficient.
Examples
let mut sm = SlotMap::new(); let mut sec = SecondaryMap::new(); let k0 = sm.insert(0); sec.insert(k0, 10); let k1 = sm.insert(1); sec.insert(k1, 11); let k2 = sm.insert(2); sec.insert(k2, 12); for (k, v) in sm.iter() { println!("key: {:?}, val: {}", k, v); }
pub fn iter_mut(&mut self) -> IterMut<'_, K, V>ⓘ
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An iterator visiting all key-value pairs in arbitrary order, with
mutable references to the values. The iterator element type is
(K, &'a mut V)
.
This function must iterate over all slots, empty or not. In the face of many deleted elements it can be inefficient.
Examples
let mut sm = SlotMap::new(); let mut sec = SecondaryMap::new(); let k0 = sm.insert(1); sec.insert(k0, 10); let k1 = sm.insert(2); sec.insert(k1, 20); let k2 = sm.insert(3); sec.insert(k2, 30); for (k, v) in sec.iter_mut() { if k != k1 { *v *= -1; } } assert_eq!(sec[k0], -10); assert_eq!(sec[k1], 20); assert_eq!(sec[k2], -30);
pub fn keys(&self) -> Keys<'_, K, V>ⓘ
[src]
An iterator visiting all keys in arbitrary order. The iterator element
type is K
.
This function must iterate over all slots, empty or not. In the face of many deleted elements it can be inefficient.
Examples
let mut sm = SlotMap::new(); let mut sec = SecondaryMap::new(); let k0 = sm.insert(1); sec.insert(k0, 10); let k1 = sm.insert(2); sec.insert(k1, 20); let k2 = sm.insert(3); sec.insert(k2, 30); let keys: HashSet<_> = sec.keys().collect(); let check: HashSet<_> = vec![k0, k1, k2].into_iter().collect(); assert_eq!(keys, check);
pub fn values(&self) -> Values<'_, K, V>ⓘ
[src]
An iterator visiting all values in arbitrary order. The iterator element
type is &'a V
.
This function must iterate over all slots, empty or not. In the face of many deleted elements it can be inefficient.
Examples
let mut sm = SlotMap::new(); let mut sec = SecondaryMap::new(); let k0 = sm.insert(1); sec.insert(k0, 10); let k1 = sm.insert(2); sec.insert(k1, 20); let k2 = sm.insert(3); sec.insert(k2, 30); let values: HashSet<_> = sec.values().collect(); let check: HashSet<_> = vec![&10, &20, &30].into_iter().collect(); assert_eq!(values, check);
pub fn values_mut(&mut self) -> ValuesMut<'_, K, V>ⓘ
[src]
An iterator visiting all values mutably in arbitrary order. The iterator
element type is &'a mut V
.
This function must iterate over all slots, empty or not. In the face of many deleted elements it can be inefficient.
Examples
let mut sm = SlotMap::new(); let mut sec = SecondaryMap::new(); sec.insert(sm.insert(1), 10); sec.insert(sm.insert(2), 20); sec.insert(sm.insert(3), 30); sec.values_mut().for_each(|n| { *n *= 3 }); let values: HashSet<_> = sec.into_iter().map(|(_k, v)| v).collect(); let check: HashSet<_> = vec![30, 60, 90].into_iter().collect(); assert_eq!(values, check);
Trait Implementations
impl<K: Clone + Key, V: Clone> Clone for SecondaryMap<K, V>
[src]
impl<K: Clone + Key, V: Clone> Clone for SecondaryMap<K, V>
[src]fn clone(&self) -> SecondaryMap<K, V>
[src]
pub fn clone_from(&mut self, source: &Self)
1.0.0[src]
impl<'a, K: Key, V: 'a + Copy> Extend<(K, &'a V)> for SecondaryMap<K, V>
[src]
impl<'a, K: Key, V: 'a + Copy> Extend<(K, &'a V)> for SecondaryMap<K, V>
[src]fn extend<I: IntoIterator<Item = (K, &'a V)>>(&mut self, iter: I)
[src]
pub fn extend_one(&mut self, item: A)
[src]
pub fn extend_reserve(&mut self, additional: usize)
[src]
impl<K: Key, V> Extend<(K, V)> for SecondaryMap<K, V>
[src]
impl<K: Key, V> Extend<(K, V)> for SecondaryMap<K, V>
[src]fn extend<I: IntoIterator<Item = (K, V)>>(&mut self, iter: I)
[src]
pub fn extend_one(&mut self, item: A)
[src]
pub fn extend_reserve(&mut self, additional: usize)
[src]
impl<K: Key, V> FromIterator<(K, V)> for SecondaryMap<K, V>
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impl<K: Key, V> FromIterator<(K, V)> for SecondaryMap<K, V>
[src]fn from_iter<I: IntoIterator<Item = (K, V)>>(iter: I) -> Self
[src]
impl<K: Key, V> Index<K> for SecondaryMap<K, V>
[src]
impl<K: Key, V> Index<K> for SecondaryMap<K, V>
[src]impl<K: Key, V> IndexMut<K> for SecondaryMap<K, V>
[src]
impl<K: Key, V> IndexMut<K> for SecondaryMap<K, V>
[src]impl<'a, K: Key, V> IntoIterator for &'a SecondaryMap<K, V>
[src]
impl<'a, K: Key, V> IntoIterator for &'a SecondaryMap<K, V>
[src]impl<'a, K: Key, V> IntoIterator for &'a mut SecondaryMap<K, V>
[src]
impl<'a, K: Key, V> IntoIterator for &'a mut SecondaryMap<K, V>
[src]impl<K: Key, V> IntoIterator for SecondaryMap<K, V>
[src]
impl<K: Key, V> IntoIterator for SecondaryMap<K, V>
[src]impl<K: Key, V: PartialEq> PartialEq<SecondaryMap<K, V>> for SecondaryMap<K, V>
[src]
impl<K: Key, V: PartialEq> PartialEq<SecondaryMap<K, V>> for SecondaryMap<K, V>
[src]impl<K: Key, V: Eq> Eq for SecondaryMap<K, V>
[src]
Auto Trait Implementations
impl<K, V> RefUnwindSafe for SecondaryMap<K, V> where
V: RefUnwindSafe,
V: RefUnwindSafe,
impl<K, V> Send for SecondaryMap<K, V> where
V: Send,
V: Send,
impl<K, V> Sync for SecondaryMap<K, V> where
V: Sync,
V: Sync,
impl<K, V> Unpin for SecondaryMap<K, V> where
V: Unpin,
V: Unpin,
impl<K, V> UnwindSafe for SecondaryMap<K, V> where
V: UnwindSafe,
V: UnwindSafe,