Struct tiny_ecs::MapRefMut

pub struct MapRefMut<'a, T> { /* fields omitted */ }

Mutable reference container for VecMap returned by Entities::borrow_mut()

This struct is required to contain a hidden borrow to the requested VecMap. The reason for this is so we can borrow multiple VecMap, but not break the borrow checker rules for borrows on a single VecMap.

Methods from Deref<Target = VecMap<T>>

pub fn capacity(&self) -> usize

Returns the number of elements the VecMap can hold without reallocating.

Examples

use vec_map::VecMap;
let map: VecMap<String> = VecMap::with_capacity(10);
assert!(map.capacity() >= 10);

pub fn reserve_len(&mut self, len: usize)

Reserves capacity for the given VecMap to contain len distinct keys. In the case of VecMap this means reallocations will not occur as long as all inserted keys are less than len.

The collection may reserve more space to avoid frequent reallocations.

Examples

use vec_map::VecMap;
let mut map: VecMap<&str> = VecMap::new();
map.reserve_len(10);
assert!(map.capacity() >= 10);

pub fn reserve_len_exact(&mut self, len: usize)

Reserves the minimum capacity for the given VecMap to contain len distinct keys. In the case of VecMap this means reallocations will not occur as long as all inserted keys are less than len.

Note that the allocator may give the collection more space than it requests. Therefore capacity cannot be relied upon to be precisely minimal. Prefer reserve_len if future insertions are expected.

Examples

use vec_map::VecMap;
let mut map: VecMap<&str> = VecMap::new();
map.reserve_len_exact(10);
assert!(map.capacity() >= 10);

pub fn shrink_to_fit(&mut self)

Trims the VecMap of any excess capacity.

The collection may reserve more space to avoid frequent reallocations.

Examples

use vec_map::VecMap;
let mut map: VecMap<&str> = VecMap::with_capacity(10);
map.shrink_to_fit();
assert_eq!(map.capacity(), 0);

pub fn keys(&self) -> Keys<V>

Returns an iterator visiting all keys in ascending order of the keys. The iterator's element type is usize.

pub fn values(&self) -> Values<V>

Returns an iterator visiting all values in ascending order of the keys. The iterator's element type is &'r V.

pub fn values_mut(&mut self) -> ValuesMut<V>

Returns an iterator visiting all values in ascending order of the keys. The iterator's element type is &'r mut V.

pub fn iter(&self) -> Iter<V>

Returns an iterator visiting all key-value pairs in ascending order of the keys. The iterator's element type is (usize, &'r V).

Examples

use vec_map::VecMap;

let mut map = VecMap::new();
map.insert(1, "a");
map.insert(3, "c");
map.insert(2, "b");

// Print `1: a` then `2: b` then `3: c`
for (key, value) in map.iter() {
    println!("{}: {}", key, value);
}

pub fn iter_mut(&mut self) -> IterMut<V>

Returns an iterator visiting all key-value pairs in ascending order of the keys, with mutable references to the values. The iterator's element type is (usize, &'r mut V).

Examples

use vec_map::VecMap;

let mut map = VecMap::new();
map.insert(1, "a");
map.insert(2, "b");
map.insert(3, "c");

for (key, value) in map.iter_mut() {
    *value = "x";
}

for (key, value) in &map {
    assert_eq!(value, &"x");
}

pub fn append(&mut self, other: &mut VecMap<V>)

Moves all elements from other into the map while overwriting existing keys.

Examples

use vec_map::VecMap;

let mut a = VecMap::new();
a.insert(1, "a");
a.insert(2, "b");

let mut b = VecMap::new();
b.insert(3, "c");
b.insert(4, "d");

a.append(&mut b);

assert_eq!(a.len(), 4);
assert_eq!(b.len(), 0);
assert_eq!(a[1], "a");
assert_eq!(a[2], "b");
assert_eq!(a[3], "c");
assert_eq!(a[4], "d");

pub fn split_off(&mut self, at: usize) -> VecMap<V>

Splits the collection into two at the given key.

Returns a newly allocated Self. self contains elements [0, at), and the returned Self contains elements [at, max_key).

Note that the capacity of self does not change.

Examples

use vec_map::VecMap;

let mut a = VecMap::new();
a.insert(1, "a");
a.insert(2, "b");
a.insert(3, "c");
a.insert(4, "d");

let b = a.split_off(3);

assert_eq!(a[1], "a");
assert_eq!(a[2], "b");

assert_eq!(b[3], "c");
assert_eq!(b[4], "d");

pub fn drain(&mut self) -> Drain<V>

Returns an iterator visiting all key-value pairs in ascending order of the keys, emptying (but not consuming) the original VecMap. The iterator's element type is (usize, &'r V). Keeps the allocated memory for reuse.

Examples

use vec_map::VecMap;

let mut map = VecMap::new();
map.insert(1, "a");
map.insert(3, "c");
map.insert(2, "b");

let vec: Vec<(usize, &str)> = map.drain().collect();

assert_eq!(vec, [(1, "a"), (2, "b"), (3, "c")]);

pub fn len(&self) -> usize

Returns the number of elements in the map.

Examples

use vec_map::VecMap;

let mut a = VecMap::new();
assert_eq!(a.len(), 0);
a.insert(1, "a");
assert_eq!(a.len(), 1);

pub fn is_empty(&self) -> bool

Returns true if the map contains no elements.

Examples

use vec_map::VecMap;

let mut a = VecMap::new();
assert!(a.is_empty());
a.insert(1, "a");
assert!(!a.is_empty());

pub fn clear(&mut self)

Clears the map, removing all key-value pairs.

Examples

use vec_map::VecMap;

let mut a = VecMap::new();
a.insert(1, "a");
a.clear();
assert!(a.is_empty());

pub fn get(&self, key: usize) -> Option<&V>

Returns a reference to the value corresponding to the key.

Examples

use vec_map::VecMap;

let mut map = VecMap::new();
map.insert(1, "a");
assert_eq!(map.get(1), Some(&"a"));
assert_eq!(map.get(2), None);

pub fn contains_key(&self, key: usize) -> bool

Returns true if the map contains a value for the specified key.

Examples

use vec_map::VecMap;

let mut map = VecMap::new();
map.insert(1, "a");
assert_eq!(map.contains_key(1), true);
assert_eq!(map.contains_key(2), false);

pub fn get_mut(&mut self, key: usize) -> Option<&mut V>

Returns a mutable reference to the value corresponding to the key.

Examples

use vec_map::VecMap;

let mut map = VecMap::new();
map.insert(1, "a");
if let Some(x) = map.get_mut(1) {
    *x = "b";
}
assert_eq!(map[1], "b");

pub fn insert(&mut self, key: usize, value: V) -> Option<V>

Inserts a key-value pair into the map. If the key already had a value present in the map, that value is returned. Otherwise, None is returned.

Examples

use vec_map::VecMap;

let mut map = VecMap::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");

pub fn remove(&mut self, key: usize) -> Option<V>

Removes a key from the map, returning the value at the key if the key was previously in the map.

Examples

use vec_map::VecMap;

let mut map = VecMap::new();
map.insert(1, "a");
assert_eq!(map.remove(1), Some("a"));
assert_eq!(map.remove(1), None);

pub fn entry(&mut self, key: usize) -> Entry<V>

Gets the given key's corresponding entry in the map for in-place manipulation.

Examples

use vec_map::VecMap;

let mut count: VecMap<u32> = VecMap::new();

// count the number of occurrences of numbers in the vec
for x in vec![1, 2, 1, 2, 3, 4, 1, 2, 4] {
    *count.entry(x).or_insert(0) += 1;
}

assert_eq!(count[1], 3);

pub fn retain<F>(&mut self, f: F) where
    F: FnMut(usize, &mut V) -> bool, 

Retains only the elements specified by the predicate.

In other words, remove all pairs (k, v) such that f(&k, &mut v) returns false.

Examples

use vec_map::VecMap;

let mut map: VecMap<usize> = (0..8).map(|x|(x, x*10)).collect();
map.retain(|k, _| k % 2 == 0);
assert_eq!(map.len(), 4);

Trait Implementations

impl<'a, T> DerefMut for MapRefMut<'a, T>

fn deref_mut(&mut self) -> &mut VecMap<T>

Mutably dereferences the value.

impl<'a, T: Debug> Debug for MapRefMut<'a, T>

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.

impl<'a, T> Deref for MapRefMut<'a, T>

type Target = VecMap<T>

The resulting type after dereferencing.

fn deref(&self) -> &VecMap<T>

Dereferences the value.