Struct Arena 

pub struct Arena<T, const BITARRAY_LEN: usize, const LEN: usize> { /* private fields */ }

• LEN - Number of elements stored per bucket. Must be less than or equal to u32::MAX, divisible by usize::BITS and it must not be 0.

• BITARRAY_LEN - Number of usize in the bitmap per bucket. Must be equal to LEN / usize::BITS.

  For best performance, try to set this to number of CPUs that are going to access Arena concurrently.

Arena stores the elements in buckets to ensure that the address for elements are stable while improving efficiency.

Every bucket is of size LEN.

The larger LEN is, the more compact the Arena will be, however it might also waste space if it is unused.

And, allocating a large chunk of memory takes more time.

Arena internally stores the array of buckets as a triomphe::ThinArc and use ArcSwapAny to grow the array atomically, without blocking any reader.

Examples

If you provides Arena with invalid LEM or BITARRAY_LEN, then your code will panic at runtime:

use concurrent_arena::*;
let arena = Arena::<u32, 1, 100>::new();

To make it a compile time failure, you need to call max_buckets:

use concurrent_arena::*;
const MAX_BUCKETS: u32 = Arena::<u32, 1, 100>::max_buckets();

Implementations

impl<T, const BITARRAY_LEN: usize, const LEN: usize> Arena<T, BITARRAY_LEN, LEN>

pub const fn max_buckets() -> u32

Maximum buckets Arena can have.

impl<T: Send + Sync, const BITARRAY_LEN: usize, const LEN: usize> Arena<T, BITARRAY_LEN, LEN>

pub fn new() -> Self

Would preallocate 2 buckets.

pub fn with_capacity(cap: u32) -> Self

pub fn try_insert( &self, value: T, ) -> Result<ArenaArc<T, BITARRAY_LEN, LEN>, (T, u32)>

Return Ok(arc) on success, or Err((value, len)) where value is the input param value and len is the length of the Arena at the time of insertion.

This function is lock-free.

pub fn try_reserve(&self, new_len: u32) -> bool

Try to reserve min(new_len, Self::max_buckets()) buckets.

This function is technically lock-free.

pub fn reserve(&self, new_len: u32)

Reserve min(new_len, Self::max_buckets()) buckets.

pub fn insert(&self, value: T) -> ArenaArc<T, BITARRAY_LEN, LEN>

Insert one value.

If there isn’t enough buckets, then try to reserve one bucket and restart the operation.

impl<T: Send + Sync, const BITARRAY_LEN: usize, const LEN: usize> Arena<T, BITARRAY_LEN, LEN>

pub fn remove(&self, slot: u32) -> Option<ArenaArc<T, BITARRAY_LEN, LEN>>

May enter busy loop if the slot is not fully initialized.

This function is lock free.

pub fn get(&self, slot: u32) -> Option<ArenaArc<T, BITARRAY_LEN, LEN>>

May enter busy loop if the slot is not fully initialized.

This function is lock free.

pub fn len(&self) -> u32

Return number of buckets allocated.

This function is lock free.

pub fn is_empty(&self) -> bool

This function is lock free.

Trait Implementations

impl<T: Debug, const BITARRAY_LEN: usize, const LEN: usize> Debug for Arena<T, BITARRAY_LEN, LEN>

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

Formats the value using the given formatter.

impl<T: Sync + Send, const BITARRAY_LEN: usize, const LEN: usize> Default for Arena<T, BITARRAY_LEN, LEN>

fn default() -> Self

Returns the “default value” for a type.