Struct Index 

pub struct Index(/* private fields */);

A generational index into an Arena

You get a new Index for each element that you insert into an Arena.

Example

let mut arena = Arena::new();
let index = arena.insert("test");
assert_eq!("test", arena[index]);

Implementations

impl Index

pub const fn into_parts(self) -> (u32, Generation)

Deconstruct this Index into its offset and its generation.

The offset is a position in a continuous array. When the array-cell at its offset is re-used after it has been removed, the generation for this cell is incremented.

The offset is a position in a continuous array.

Example

let mut arena = Arena::new();
let index0 = arena.insert("test");
let index1 = arena.insert("test2");
assert_eq!((0, Generation::ONE), index0.into_parts());
assert_eq!((1, Generation::ONE), index1.into_parts());

pub const fn offset(self) -> u32

Returns the offset of this Index.

The offset is a position in a continuous array.

Example

let mut arena = Arena::new();
let index0 = arena.insert("test");
let index1 = arena.insert("test2");
assert_eq!(0, index0.offset());
assert_eq!(1, index1.offset());

pub const fn generation(self) -> Generation

Returns the generation of this Index.

When the array-cell at its offset is re-used after it has been removed, the generation for this cell is incremented.

Example

let mut arena = Arena::new();
let index = arena.insert("test");
assert_eq!(Generation::ONE, index.generation());
arena.remove(index);
let index = arena.insert("test2");
assert_eq!(2, index.generation().get());

Trait Implementations

impl Clone for Index

fn clone(&self) -> Index

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Index

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

Formats the value using the given formatter.

impl Hash for Index

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<T> Index<Index> for Arena<T>

type Output = T

The returned type after indexing.

fn index(&self, index: Index) -> &T

Performs the indexing (container[index]) operation.

impl<T> Index<Index> for Mirror<T>

type Output = T

The returned type after indexing.

fn index(&self, index: Index) -> &T

Performs the indexing (container[index]) operation.

impl<T> IndexMut<Index> for Arena<T>

fn index_mut(&mut self, index: Index) -> &mut T

Performs the mutable indexing (container[index]) operation.

impl<T> IndexMut<Index> for Mirror<T>

fn index_mut(&mut self, index: Index) -> &mut T

Performs the mutable indexing (container[index]) operation.

impl Ord for Index

fn cmp(&self, other: &Index) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for Index

fn eq(&self, other: &Index) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for Index

fn partial_cmp(&self, other: &Index) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Copy for Index

impl Eq for Index

impl StructuralPartialEq for Index