Struct puff_rs::types::map_builder::MapBuilder

pub struct MapBuilder<K, V>(_);

Fast Key Value structure for local construction.

Puff’s MapBuilder type uses std::collections::hash_map::HashMap under the hood. HashMaps are not sharable structures and so need to be wrapped in an Arc to be shared between threads and cheaply copied. You should use a MapBuilder and convert it into a Map when you are done writing to it.

Maps can only be constructed from types implementing IntoMapBuilder.

Examples

use puff_rs::types::MapBuilder;

let mut builder = MapBuilder::new();
builder.insert(42, 0);
let map = builder.into_map();

Implementations

impl<K, T> MapBuilder<K, T>where
    K: Puff + Hash + Eq,
    T: Puff,

pub fn new() -> MapBuilder<K, T>

Creates an empty MapBuilder.

The hash map is initially created with a capacity of 0, so it will not allocate until it is first inserted into.

Examples

use puff_rs::types::{Text, MapBuilder};
let mut map: MapBuilder<Text, i32> = MapBuilder::new();

pub fn with_capacity(capacity: usize) -> MapBuilder<K, T>

Creates an empty MapBuilder with the specified capacity.

The hash map will be able to hold at least capacity elements without reallocating. If capacity is 0, the hash map will not allocate.

Examples

use puff_rs::types::{Text, MapBuilder};
let mut map: MapBuilder<Text, i32> = MapBuilder::with_capacity(10);

pub fn insert(&mut self, key: K, item: T) -> Option<T>

Inserts a key-value pair into the MapBuilder.

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 [module-level documentation] for more.

Examples

use puff_rs::types::MapBuilder;

let mut map = MapBuilder::new();
assert_eq!(map.insert(37, 42), None);
assert_eq!(map.is_empty(), false);

map.insert(37, 10);
assert_eq!(map.insert(37, 13), Some(10));

pub fn get(&self, index: K) -> Option<T>

Returns a reference to the value corresponding to the key.

Examples

use puff_rs::types::MapBuilder;

let mut map = MapBuilder::new();
map.insert(1, 2);
assert_eq!(map.get(1), Some(2));

pub fn is_empty(&self) -> bool

Returns true if the map contains no elements.

Examples

use puff_rs::types::MapBuilder;
let map: MapBuilder<usize, usize> = MapBuilder::new();
assert!(map.is_empty())

pub fn len(&self) -> usize

Returns the number of elements in the MapBuilder.

Examples

use puff_rs::types::MapBuilder;

let mut map = MapBuilder::new();
assert_eq!(map.len(), 0);
map.insert(1, 2);
assert_eq!(map.len(), 1);

pub fn into_map(self) -> Map<K, T>

Convert the MapBuilder into a Read-Only Map that can be shared between Tasks.

Trait Implementations

impl<K: Clone, V: Clone> Clone for MapBuilder<K, V>

fn clone(&self) -> MapBuilder<K, V>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<K: Puff + Hash + Eq, V: Puff> Into<MapBuilder<K, V>> for HashMap<K, V>

fn into(self) -> MapBuilder<K, V>

Converts this type into the (usually inferred) input type.

impl<K: Puff + Hash + Eq, V: Puff> Into<MapBuilder<K, V>> for Vec<(K, V)>

fn into(self) -> MapBuilder<K, V>

Converts this type into the (usually inferred) input type.