Struct bevy_render::render_phase::ViewSortedRenderPhases
source · pub struct ViewSortedRenderPhases<SPI>(pub EntityHashMap<SortedRenderPhase<SPI>>)
where
SPI: SortedPhaseItem;
Expand description
Stores the rendering instructions for a single phase that sorts items in all views.
They’re cleared out every frame, but storing them in a resource like this allows us to reuse allocations.
Tuple Fields§
§0: EntityHashMap<SortedRenderPhase<SPI>>
Implementations§
source§impl<SPI> ViewSortedRenderPhases<SPI>where
SPI: SortedPhaseItem,
impl<SPI> ViewSortedRenderPhases<SPI>where
SPI: SortedPhaseItem,
pub fn insert_or_clear(&mut self, entity: Entity)
Methods from Deref<Target = EntityHashMap<SortedRenderPhase<SPI>>>§
sourcepub fn hasher(&self) -> &S
pub fn hasher(&self) -> &S
Returns a reference to the map’s BuildHasher
.
§Examples
use hashbrown::HashMap;
use hashbrown::hash_map::DefaultHashBuilder;
let hasher = DefaultHashBuilder::default();
let map: HashMap<i32, i32> = HashMap::with_hasher(hasher);
let hasher: &DefaultHashBuilder = map.hasher();
sourcepub fn capacity(&self) -> usize
pub fn capacity(&self) -> usize
Returns the number of elements the map can hold without reallocating.
This number is a lower bound; the HashMap<K, V>
might be able to hold
more, but is guaranteed to be able to hold at least this many.
§Examples
use hashbrown::HashMap;
let map: HashMap<i32, i32> = HashMap::with_capacity(100);
assert_eq!(map.len(), 0);
assert!(map.capacity() >= 100);
sourcepub fn keys(&self) -> Keys<'_, K, V>
pub fn keys(&self) -> Keys<'_, K, V>
An iterator visiting all keys in arbitrary order.
The iterator element type is &'a K
.
§Examples
use hashbrown::HashMap;
let mut map = HashMap::new();
map.insert("a", 1);
map.insert("b", 2);
map.insert("c", 3);
assert_eq!(map.len(), 3);
let mut vec: Vec<&str> = Vec::new();
for key in map.keys() {
println!("{}", key);
vec.push(*key);
}
// The `Keys` 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"]);
assert_eq!(map.len(), 3);
sourcepub fn values(&self) -> Values<'_, K, V>
pub fn values(&self) -> Values<'_, K, V>
An iterator visiting all values in arbitrary order.
The iterator element type is &'a V
.
§Examples
use hashbrown::HashMap;
let mut map = HashMap::new();
map.insert("a", 1);
map.insert("b", 2);
map.insert("c", 3);
assert_eq!(map.len(), 3);
let mut vec: Vec<i32> = Vec::new();
for val in map.values() {
println!("{}", val);
vec.push(*val);
}
// The `Values` 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]);
assert_eq!(map.len(), 3);
sourcepub fn values_mut(&mut self) -> ValuesMut<'_, K, V>
pub fn values_mut(&mut self) -> ValuesMut<'_, K, V>
An iterator visiting all values mutably in arbitrary order.
The iterator element type is &'a mut V
.
§Examples
use hashbrown::HashMap;
let mut map = HashMap::new();
map.insert("a", 1);
map.insert("b", 2);
map.insert("c", 3);
for val in map.values_mut() {
*val = *val + 10;
}
assert_eq!(map.len(), 3);
let mut vec: Vec<i32> = Vec::new();
for val in map.values() {
println!("{}", val);
vec.push(*val);
}
// The `Values` 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, [11, 12, 13]);
assert_eq!(map.len(), 3);
sourcepub fn iter(&self) -> Iter<'_, K, V>
pub fn iter(&self) -> Iter<'_, K, V>
An iterator visiting all key-value pairs in arbitrary order.
The iterator element type is (&'a K, &'a V)
.
§Examples
use hashbrown::HashMap;
let mut map = HashMap::new();
map.insert("a", 1);
map.insert("b", 2);
map.insert("c", 3);
assert_eq!(map.len(), 3);
let mut vec: Vec<(&str, i32)> = Vec::new();
for (key, val) in map.iter() {
println!("key: {} val: {}", key, val);
vec.push((*key, *val));
}
// The `Iter` iterator produces items in arbitrary order, so the
// items must be sorted to test them against a sorted array.
vec.sort_unstable();
assert_eq!(vec, [("a", 1), ("b", 2), ("c", 3)]);
assert_eq!(map.len(), 3);
sourcepub fn iter_mut(&mut self) -> IterMut<'_, K, V>
pub fn iter_mut(&mut self) -> IterMut<'_, K, V>
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 hashbrown::HashMap;
let mut map = HashMap::new();
map.insert("a", 1);
map.insert("b", 2);
map.insert("c", 3);
// Update all values
for (_, val) in map.iter_mut() {
*val *= 2;
}
assert_eq!(map.len(), 3);
let mut vec: Vec<(&str, i32)> = Vec::new();
for (key, val) in &map {
println!("key: {} val: {}", key, val);
vec.push((*key, *val));
}
// The `Iter` iterator produces items in arbitrary order, so the
// items must be sorted to test them against a sorted array.
vec.sort_unstable();
assert_eq!(vec, [("a", 2), ("b", 4), ("c", 6)]);
assert_eq!(map.len(), 3);
sourcepub fn len(&self) -> usize
pub fn len(&self) -> usize
Returns the number of elements in the map.
§Examples
use hashbrown::HashMap;
let mut a = HashMap::new();
assert_eq!(a.len(), 0);
a.insert(1, "a");
assert_eq!(a.len(), 1);
sourcepub fn is_empty(&self) -> bool
pub fn is_empty(&self) -> bool
Returns true
if the map contains no elements.
§Examples
use hashbrown::HashMap;
let mut a = HashMap::new();
assert!(a.is_empty());
a.insert(1, "a");
assert!(!a.is_empty());
sourcepub fn drain(&mut self) -> Drain<'_, K, V, A>
pub fn drain(&mut self) -> Drain<'_, K, V, A>
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 vector to optimize its implementation.
§Examples
use hashbrown::HashMap;
let mut a = HashMap::new();
a.insert(1, "a");
a.insert(2, "b");
let capacity_before_drain = a.capacity();
for (k, v) in a.drain().take(1) {
assert!(k == 1 || k == 2);
assert!(v == "a" || v == "b");
}
// As we can see, the map is empty and contains no element.
assert!(a.is_empty() && a.len() == 0);
// But map capacity is equal to old one.
assert_eq!(a.capacity(), capacity_before_drain);
let mut a = HashMap::new();
a.insert(1, "a");
a.insert(2, "b");
{ // Iterator is dropped without being consumed.
let d = a.drain();
}
// But the map is empty even if we do not use Drain iterator.
assert!(a.is_empty());
sourcepub fn retain<F>(&mut self, f: F)
pub fn retain<F>(&mut self, f: F)
Retains only the elements specified by the predicate. Keeps the allocated memory for reuse.
In other words, remove all pairs (k, v)
such that f(&k, &mut v)
returns false
.
The elements are visited in unsorted (and unspecified) order.
§Examples
use hashbrown::HashMap;
let mut map: HashMap<i32, i32> = (0..8).map(|x|(x, x*10)).collect();
assert_eq!(map.len(), 8);
map.retain(|&k, _| k % 2 == 0);
// We can see, that the number of elements inside map is changed.
assert_eq!(map.len(), 4);
let mut vec: Vec<(i32, i32)> = map.iter().map(|(&k, &v)| (k, v)).collect();
vec.sort_unstable();
assert_eq!(vec, [(0, 0), (2, 20), (4, 40), (6, 60)]);
sourcepub fn extract_if<F>(&mut self, f: F) -> ExtractIf<'_, K, V, F, A>
pub fn extract_if<F>(&mut self, f: F) -> ExtractIf<'_, K, V, F, A>
Drains elements which are true under the given predicate, and returns an iterator over the removed items.
In other words, move all pairs (k, v)
such that f(&k, &mut v)
returns true
out
into another iterator.
Note that extract_if
lets you mutate every value in the filter closure, regardless of
whether you choose to keep or remove it.
If the returned ExtractIf
is not exhausted, e.g. because it is dropped without iterating
or the iteration short-circuits, then the remaining elements will be retained.
Use retain()
with a negated predicate if you do not need the returned iterator.
Keeps the allocated memory for reuse.
§Examples
use hashbrown::HashMap;
let mut map: HashMap<i32, i32> = (0..8).map(|x| (x, x)).collect();
let drained: HashMap<i32, i32> = map.extract_if(|k, _v| k % 2 == 0).collect();
let mut evens = drained.keys().cloned().collect::<Vec<_>>();
let mut odds = map.keys().cloned().collect::<Vec<_>>();
evens.sort();
odds.sort();
assert_eq!(evens, vec![0, 2, 4, 6]);
assert_eq!(odds, vec![1, 3, 5, 7]);
let mut map: HashMap<i32, i32> = (0..8).map(|x| (x, x)).collect();
{ // Iterator is dropped without being consumed.
let d = map.extract_if(|k, _v| k % 2 != 0);
}
// ExtractIf was not exhausted, therefore no elements were drained.
assert_eq!(map.len(), 8);
sourcepub fn clear(&mut self)
pub fn clear(&mut self)
Clears the map, removing all key-value pairs. Keeps the allocated memory for reuse.
§Examples
use hashbrown::HashMap;
let mut a = HashMap::new();
a.insert(1, "a");
let capacity_before_clear = a.capacity();
a.clear();
// Map is empty.
assert!(a.is_empty());
// But map capacity is equal to old one.
assert_eq!(a.capacity(), capacity_before_clear);
sourcepub fn reserve(&mut self, additional: usize)
pub fn reserve(&mut self, additional: usize)
Reserves capacity for at least additional
more elements to be inserted
in the HashMap
. The collection may reserve more space to avoid
frequent reallocations.
§Panics
Panics if the new capacity exceeds isize::MAX
bytes and abort
the program
in case of allocation error. Use try_reserve
instead
if you want to handle memory allocation failure.
§Examples
use hashbrown::HashMap;
let mut map: HashMap<&str, i32> = HashMap::new();
// Map is empty and doesn't allocate memory
assert_eq!(map.capacity(), 0);
map.reserve(10);
// And now map can hold at least 10 elements
assert!(map.capacity() >= 10);
sourcepub fn try_reserve(&mut self, additional: usize) -> Result<(), TryReserveError>
pub fn try_reserve(&mut self, additional: usize) -> Result<(), TryReserveError>
Tries to reserve capacity for at least additional
more elements to be inserted
in the given HashMap<K,V>
. The collection may reserve more space to avoid
frequent reallocations.
§Errors
If the capacity overflows, or the allocator reports a failure, then an error is returned.
§Examples
use hashbrown::HashMap;
let mut map: HashMap<&str, isize> = HashMap::new();
// Map is empty and doesn't allocate memory
assert_eq!(map.capacity(), 0);
map.try_reserve(10).expect("why is the test harness OOMing on 10 bytes?");
// And now map can hold at least 10 elements
assert!(map.capacity() >= 10);
If the capacity overflows, or the allocator reports a failure, then an error is returned:
use hashbrown::HashMap;
use hashbrown::TryReserveError;
let mut map: HashMap<i32, i32> = HashMap::new();
match map.try_reserve(usize::MAX) {
Err(error) => match error {
TryReserveError::CapacityOverflow => {}
_ => panic!("TryReserveError::AllocError ?"),
},
_ => panic!(),
}
sourcepub fn shrink_to_fit(&mut self)
pub fn shrink_to_fit(&mut self)
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 hashbrown::HashMap;
let mut map: HashMap<i32, i32> = HashMap::with_capacity(100);
map.insert(1, 2);
map.insert(3, 4);
assert!(map.capacity() >= 100);
map.shrink_to_fit();
assert!(map.capacity() >= 2);
sourcepub fn shrink_to(&mut self, min_capacity: usize)
pub fn shrink_to(&mut self, min_capacity: usize)
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.
This function does nothing if the current capacity is smaller than the supplied minimum capacity.
§Examples
use hashbrown::HashMap;
let mut map: HashMap<i32, i32> = HashMap::with_capacity(100);
map.insert(1, 2);
map.insert(3, 4);
assert!(map.capacity() >= 100);
map.shrink_to(10);
assert!(map.capacity() >= 10);
map.shrink_to(0);
assert!(map.capacity() >= 2);
map.shrink_to(10);
assert!(map.capacity() >= 2);
sourcepub fn entry(&mut self, key: K) -> Entry<'_, K, V, S, A>
pub fn entry(&mut self, key: K) -> Entry<'_, K, V, S, A>
Gets the given key’s corresponding entry in the map for in-place manipulation.
§Examples
use hashbrown::HashMap;
let mut letters = HashMap::new();
for ch in "a short treatise on fungi".chars() {
let counter = letters.entry(ch).or_insert(0);
*counter += 1;
}
assert_eq!(letters[&'s'], 2);
assert_eq!(letters[&'t'], 3);
assert_eq!(letters[&'u'], 1);
assert_eq!(letters.get(&'y'), None);
sourcepub fn entry_ref<'a, 'b, Q>(
&'a mut self,
key: &'b Q
) -> EntryRef<'a, 'b, K, Q, V, S, A>
pub fn entry_ref<'a, 'b, Q>( &'a mut self, key: &'b Q ) -> EntryRef<'a, 'b, K, Q, V, S, A>
Gets the given key’s corresponding entry by reference in the map for in-place manipulation.
§Examples
use hashbrown::HashMap;
let mut words: HashMap<String, usize> = HashMap::new();
let source = ["poneyland", "horseyland", "poneyland", "poneyland"];
for (i, &s) in source.iter().enumerate() {
let counter = words.entry_ref(s).or_insert(0);
*counter += 1;
}
assert_eq!(words["poneyland"], 3);
assert_eq!(words["horseyland"], 1);
sourcepub fn get<Q>(&self, k: &Q) -> Option<&V>
pub fn get<Q>(&self, k: &Q) -> Option<&V>
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 hashbrown::HashMap;
let mut map = HashMap::new();
map.insert(1, "a");
assert_eq!(map.get(&1), Some(&"a"));
assert_eq!(map.get(&2), None);
sourcepub fn get_key_value<Q>(&self, k: &Q) -> Option<(&K, &V)>
pub fn get_key_value<Q>(&self, k: &Q) -> Option<(&K, &V)>
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 hashbrown::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);
sourcepub fn get_key_value_mut<Q>(&mut self, k: &Q) -> Option<(&K, &mut V)>
pub fn get_key_value_mut<Q>(&mut self, k: &Q) -> Option<(&K, &mut V)>
Returns the key-value pair corresponding to the supplied key, with a mutable reference to value.
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 hashbrown::HashMap;
let mut map = HashMap::new();
map.insert(1, "a");
let (k, v) = map.get_key_value_mut(&1).unwrap();
assert_eq!(k, &1);
assert_eq!(v, &mut "a");
*v = "b";
assert_eq!(map.get_key_value_mut(&1), Some((&1, &mut "b")));
assert_eq!(map.get_key_value_mut(&2), None);
sourcepub fn contains_key<Q>(&self, k: &Q) -> bool
pub fn contains_key<Q>(&self, k: &Q) -> bool
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 hashbrown::HashMap;
let mut map = HashMap::new();
map.insert(1, "a");
assert_eq!(map.contains_key(&1), true);
assert_eq!(map.contains_key(&2), false);
sourcepub fn get_mut<Q>(&mut self, k: &Q) -> Option<&mut V>
pub fn get_mut<Q>(&mut self, k: &Q) -> Option<&mut V>
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 hashbrown::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");
assert_eq!(map.get_mut(&2), None);
sourcepub fn get_many_mut<Q, const N: usize>(
&mut self,
ks: [&Q; N]
) -> Option<[&mut V; N]>
pub fn get_many_mut<Q, const N: usize>( &mut self, ks: [&Q; N] ) -> Option<[&mut V; N]>
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
use hashbrown::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);
sourcepub unsafe fn get_many_unchecked_mut<Q, const N: usize>(
&mut self,
ks: [&Q; N]
) -> Option<[&mut V; N]>
pub unsafe fn get_many_unchecked_mut<Q, const N: usize>( &mut self, ks: [&Q; N] ) -> Option<[&mut V; N]>
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
.
§Safety
Calling this method with overlapping keys is undefined behavior even if the resulting references are not used.
§Examples
use hashbrown::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);
sourcepub fn get_many_key_value_mut<Q, const N: usize>(
&mut self,
ks: [&Q; N]
) -> Option<[(&K, &mut V); N]>
pub fn get_many_key_value_mut<Q, const N: usize>( &mut self, ks: [&Q; N] ) -> Option<[(&K, &mut V); N]>
Attempts to get mutable references to N
values in the map at once, with immutable
references to the corresponding keys.
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
use hashbrown::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_key_value_mut([
"Bodleian Library",
"Herzogin-Anna-Amalia-Bibliothek",
]);
assert_eq!(
got,
Some([
(&"Bodleian Library".to_string(), &mut 1602),
(&"Herzogin-Anna-Amalia-Bibliothek".to_string(), &mut 1691),
]),
);
// Missing keys result in None
let got = libraries.get_many_key_value_mut([
"Bodleian Library",
"Gewandhaus",
]);
assert_eq!(got, None);
// Duplicate keys result in None
let got = libraries.get_many_key_value_mut([
"Bodleian Library",
"Herzogin-Anna-Amalia-Bibliothek",
"Herzogin-Anna-Amalia-Bibliothek",
]);
assert_eq!(got, None);
sourcepub unsafe fn get_many_key_value_unchecked_mut<Q, const N: usize>(
&mut self,
ks: [&Q; N]
) -> Option<[(&K, &mut V); N]>
pub unsafe fn get_many_key_value_unchecked_mut<Q, const N: usize>( &mut self, ks: [&Q; N] ) -> Option<[(&K, &mut V); N]>
Attempts to get mutable references to N
values in the map at once, with immutable
references to the corresponding keys, 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_key_value_mut
.
§Safety
Calling this method with overlapping keys is undefined behavior even if the resulting references are not used.
§Examples
use hashbrown::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_key_value_mut([
"Bodleian Library",
"Herzogin-Anna-Amalia-Bibliothek",
]);
assert_eq!(
got,
Some([
(&"Bodleian Library".to_string(), &mut 1602),
(&"Herzogin-Anna-Amalia-Bibliothek".to_string(), &mut 1691),
]),
);
// Missing keys result in None
let got = libraries.get_many_key_value_mut([
"Bodleian Library",
"Gewandhaus",
]);
assert_eq!(got, None);
sourcepub fn insert(&mut self, k: K, v: V) -> Option<V>
pub fn insert(&mut self, k: K, v: V) -> Option<V>
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 std::collections
module-level documentation for more.
§Examples
use hashbrown::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");
sourcepub fn insert_unique_unchecked(&mut self, k: K, v: V) -> (&K, &mut V)
pub fn insert_unique_unchecked(&mut self, k: K, v: V) -> (&K, &mut V)
Insert a key-value pair into the map without checking if the key already exists in the map.
Returns a reference to the key and value just inserted.
This operation is safe if a key does not exist in the map.
However, if a key exists in the map already, the behavior is unspecified: this operation may panic, loop forever, or any following operation with the map may panic, loop forever or return arbitrary result.
That said, this operation (and following operations) are guaranteed to not violate memory safety.
This operation is faster than regular insert, because it does not perform lookup before insertion.
This operation is useful during initial population of the map. For example, when constructing a map from another map, we know that keys are unique.
§Examples
use hashbrown::HashMap;
let mut map1 = HashMap::new();
assert_eq!(map1.insert(1, "a"), None);
assert_eq!(map1.insert(2, "b"), None);
assert_eq!(map1.insert(3, "c"), None);
assert_eq!(map1.len(), 3);
let mut map2 = HashMap::new();
for (key, value) in map1.into_iter() {
map2.insert_unique_unchecked(key, value);
}
let (key, value) = map2.insert_unique_unchecked(4, "d");
assert_eq!(key, &4);
assert_eq!(value, &mut "d");
*value = "e";
assert_eq!(map2[&1], "a");
assert_eq!(map2[&2], "b");
assert_eq!(map2[&3], "c");
assert_eq!(map2[&4], "e");
assert_eq!(map2.len(), 4);
sourcepub fn try_insert(
&mut self,
key: K,
value: V
) -> Result<&mut V, OccupiedError<'_, K, V, S, A>>
pub fn try_insert( &mut self, key: K, value: V ) -> Result<&mut V, OccupiedError<'_, K, V, S, A>>
Tries to insert a key-value pair into the map, and returns a mutable reference to the value in the entry.
§Errors
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:
use hashbrown::HashMap;
use hashbrown::hash_map::OccupiedError;
let mut map = HashMap::new();
assert_eq!(map.try_insert(37, "a").unwrap(), &"a");
match map.try_insert(37, "b") {
Err(OccupiedError { entry, value }) => {
assert_eq!(entry.key(), &37);
assert_eq!(entry.get(), &"a");
assert_eq!(value, "b");
}
_ => panic!()
}
sourcepub fn remove<Q>(&mut self, k: &Q) -> Option<V>
pub fn remove<Q>(&mut self, k: &Q) -> Option<V>
Removes a key from the map, returning the value at the key if the key was previously in the map. Keeps the allocated memory for reuse.
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 hashbrown::HashMap;
let mut map = HashMap::new();
// The map is empty
assert!(map.is_empty() && map.capacity() == 0);
map.insert(1, "a");
assert_eq!(map.remove(&1), Some("a"));
assert_eq!(map.remove(&1), None);
// Now map holds none elements
assert!(map.is_empty());
sourcepub fn remove_entry<Q>(&mut self, k: &Q) -> Option<(K, V)>
pub fn remove_entry<Q>(&mut self, k: &Q) -> Option<(K, V)>
Removes a key from the map, returning the stored key and value if the key was previously in the map. Keeps the allocated memory for reuse.
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 hashbrown::HashMap;
let mut map = HashMap::new();
// The map is empty
assert!(map.is_empty() && map.capacity() == 0);
map.insert(1, "a");
assert_eq!(map.remove_entry(&1), Some((1, "a")));
assert_eq!(map.remove(&1), None);
// Now map hold none elements
assert!(map.is_empty());
sourcepub fn raw_entry_mut(&mut self) -> RawEntryBuilderMut<'_, K, V, S, A>
pub fn raw_entry_mut(&mut self) -> RawEntryBuilderMut<'_, K, V, S, A>
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).
§Examples
use core::hash::{BuildHasher, Hash};
use hashbrown::hash_map::{HashMap, RawEntryMut};
let mut map = HashMap::new();
map.extend([("a", 100), ("b", 200), ("c", 300)]);
fn compute_hash<K: Hash + ?Sized, S: BuildHasher>(hash_builder: &S, key: &K) -> u64 {
use core::hash::Hasher;
let mut state = hash_builder.build_hasher();
key.hash(&mut state);
state.finish()
}
// Existing key (insert and update)
match map.raw_entry_mut().from_key(&"a") {
RawEntryMut::Vacant(_) => unreachable!(),
RawEntryMut::Occupied(mut view) => {
assert_eq!(view.get(), &100);
let v = view.get_mut();
let new_v = (*v) * 10;
*v = new_v;
assert_eq!(view.insert(1111), 1000);
}
}
assert_eq!(map[&"a"], 1111);
assert_eq!(map.len(), 3);
// Existing key (take)
let hash = compute_hash(map.hasher(), &"c");
match map.raw_entry_mut().from_key_hashed_nocheck(hash, &"c") {
RawEntryMut::Vacant(_) => unreachable!(),
RawEntryMut::Occupied(view) => {
assert_eq!(view.remove_entry(), ("c", 300));
}
}
assert_eq!(map.raw_entry().from_key(&"c"), None);
assert_eq!(map.len(), 2);
// Nonexistent key (insert and update)
let key = "d";
let hash = compute_hash(map.hasher(), &key);
match map.raw_entry_mut().from_hash(hash, |q| *q == key) {
RawEntryMut::Occupied(_) => unreachable!(),
RawEntryMut::Vacant(view) => {
let (k, value) = view.insert("d", 4000);
assert_eq!((*k, *value), ("d", 4000));
*value = 40000;
}
}
assert_eq!(map[&"d"], 40000);
assert_eq!(map.len(), 3);
match map.raw_entry_mut().from_hash(hash, |q| *q == key) {
RawEntryMut::Vacant(_) => unreachable!(),
RawEntryMut::Occupied(view) => {
assert_eq!(view.remove_entry(), ("d", 40000));
}
}
assert_eq!(map.get(&"d"), None);
assert_eq!(map.len(), 2);
sourcepub fn raw_entry(&self) -> RawEntryBuilder<'_, K, V, S, A>
pub fn raw_entry(&self) -> RawEntryBuilder<'_, K, V, S, A>
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
.
§Examples
use core::hash::{BuildHasher, Hash};
use hashbrown::HashMap;
let mut map = HashMap::new();
map.extend([("a", 100), ("b", 200), ("c", 300)]);
fn compute_hash<K: Hash + ?Sized, S: BuildHasher>(hash_builder: &S, key: &K) -> u64 {
use core::hash::Hasher;
let mut state = hash_builder.build_hasher();
key.hash(&mut state);
state.finish()
}
for k in ["a", "b", "c", "d", "e", "f"] {
let hash = compute_hash(map.hasher(), k);
let v = map.get(&k).cloned();
let kv = v.as_ref().map(|v| (&k, v));
println!("Key: {} and value: {:?}", k, v);
assert_eq!(map.raw_entry().from_key(&k), kv);
assert_eq!(map.raw_entry().from_hash(hash, |q| *q == k), kv);
assert_eq!(map.raw_entry().from_key_hashed_nocheck(hash, &k), kv);
}
Trait Implementations§
source§impl<SPI> Default for ViewSortedRenderPhases<SPI>where
SPI: SortedPhaseItem,
impl<SPI> Default for ViewSortedRenderPhases<SPI>where
SPI: SortedPhaseItem,
source§impl<SPI> Deref for ViewSortedRenderPhases<SPI>where
SPI: SortedPhaseItem,
impl<SPI> Deref for ViewSortedRenderPhases<SPI>where
SPI: SortedPhaseItem,
§type Target = HashMap<Entity, SortedRenderPhase<SPI>, EntityHash>
type Target = HashMap<Entity, SortedRenderPhase<SPI>, EntityHash>
source§impl<SPI> DerefMut for ViewSortedRenderPhases<SPI>where
SPI: SortedPhaseItem,
impl<SPI> DerefMut for ViewSortedRenderPhases<SPI>where
SPI: SortedPhaseItem,
impl<SPI> Resource for ViewSortedRenderPhases<SPI>
Auto Trait Implementations§
impl<SPI> Freeze for ViewSortedRenderPhases<SPI>
impl<SPI> RefUnwindSafe for ViewSortedRenderPhases<SPI>where
SPI: RefUnwindSafe,
impl<SPI> Send for ViewSortedRenderPhases<SPI>
impl<SPI> Sync for ViewSortedRenderPhases<SPI>
impl<SPI> Unpin for ViewSortedRenderPhases<SPI>where
SPI: Unpin,
impl<SPI> UnwindSafe for ViewSortedRenderPhases<SPI>where
SPI: UnwindSafe,
Blanket Implementations§
source§impl<T, U> AsBindGroupShaderType<U> for T
impl<T, U> AsBindGroupShaderType<U> for T
source§fn as_bind_group_shader_type(&self, _images: &RenderAssets<GpuImage>) -> U
fn as_bind_group_shader_type(&self, _images: &RenderAssets<GpuImage>) -> U
T
ShaderType
for self
. When used in AsBindGroup
derives, it is safe to assume that all images in self
exist.source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
source§impl<T> Downcast for Twhere
T: Any,
impl<T> Downcast for Twhere
T: Any,
source§fn into_any(self: Box<T>) -> Box<dyn Any>
fn into_any(self: Box<T>) -> Box<dyn Any>
Box<dyn Trait>
(where Trait: Downcast
) to Box<dyn Any>
. Box<dyn Any>
can
then be further downcast
into Box<ConcreteType>
where ConcreteType
implements Trait
.source§fn into_any_rc(self: Rc<T>) -> Rc<dyn Any>
fn into_any_rc(self: Rc<T>) -> Rc<dyn Any>
Rc<Trait>
(where Trait: Downcast
) to Rc<Any>
. Rc<Any>
can then be
further downcast
into Rc<ConcreteType>
where ConcreteType
implements Trait
.source§fn as_any(&self) -> &(dyn Any + 'static)
fn as_any(&self) -> &(dyn Any + 'static)
&Trait
(where Trait: Downcast
) to &Any
. This is needed since Rust cannot
generate &Any
’s vtable from &Trait
’s.source§fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)
fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)
&mut Trait
(where Trait: Downcast
) to &Any
. This is needed since Rust cannot
generate &mut Any
’s vtable from &mut Trait
’s.source§impl<T> DowncastSync for T
impl<T> DowncastSync for T
source§impl<T> FromWorld for Twhere
T: Default,
impl<T> FromWorld for Twhere
T: Default,
source§fn from_world(_world: &mut World) -> T
fn from_world(_world: &mut World) -> T
Self
using data from the given World
.