Struct polymap::typemap::TypeMap

pub struct TypeMap { /* fields omitted */ }

A container for values of varying types.

Values contained in a TypeMap are stored uniquely according to their type. This means that, for each possible type, only one value may be stored in a single TypeMap instance.

If you would like to store multiple values of a given type, mapped to individual keys, use PolyMap.

Example

use polymap::TypeMap;

let mut map = TypeMap::new();

// Stores a `&str` value
map.insert("Hello, world!");

// Stores an `i32` value
map.insert(123);

// Gets a reference to the stored value
let &foo: &&str = map.get().unwrap();
assert_eq!(foo, "Hello, world!");

let &bar: &i32 = map.get().unwrap();
assert_eq!(bar, 123);

Notes

Values are stored in an internal buffer that is reallocated when filled. Methods reserve_data, reserve_data_exact, and constructor with_capacity can be used to reserve a larger buffer ahead of time to prevent expensive reallocation and move operations.

Methods

impl TypeMap

fn new() -> TypeMap

Constructs a new TypeMap.

fn with_capacity(n: usize, size: usize) -> TypeMap

Constructs a new PolyMap with space reserved for n fields and size bytes of data.

fn clear(&mut self)

Removes all key-value pairs from the map, calling any destructors on stored values.

fn contains<T: Any>(&self) -> bool

Returns whether the map contains a value of the given type.

fn data_capacity(&self) -> usize

Returns the capacity, in bytes, of the internal data buffer.

fn data_size(&self) -> usize

Returns the size, in bytes, of the internal data buffer.

fn get<T: Any>(&self) -> Option<&T>

Returns a reference to the value of the given type.

If no value of the given type exists, None is returned.

fn get_mut<T: Any>(&mut self) -> Option<&mut T>

Returns a mutable reference to the value of the given type.

If no value of the given type exists, None is returned.

fn insert<T: Any>(&mut self, t: T) -> Option<T>

Inserts a value into the map. If a value of the same type is already present, that value is returned. Otherwise, None is returned.

fn len(&self) -> usize

Returns the number of elements in the map.

fn remove<T: Any>(&mut self) -> Option<T>

Removes a value of the given type from the map, returning it. If no value of the type exists, None is returned.

fn reserve_data(&mut self, additional: usize)

Reserves capacity for at least additional additional bytes of storage space within the internal data buffer.

fn reserve_data_exact(&mut self, additional: usize)

Reserves space for at least n bytes in the internal data buffer. Does nothing if the capacity is already sufficient.

fn reserve_fields(&mut self, additional: usize)

Reserves capacity for at least additional additional fields.

fn reserve_fields_exact(&mut self, additional: usize)

Reserves space for at least n fields. Does nothing if the capacity is already sufficient.

fn shrink_data_to_fit(&mut self)

Shrinks the internal data buffer as close as possible to the size of the currently contained elements.

Trait Implementations

impl Default for TypeMap

fn default() -> TypeMap

Returns the "default value" for a type.