SlotAllocator

Hands out the same handles as SlotMap, for values kept in your own arrays. Each handle names a slot, and SlotAllocator:SlotOf gives a live handle’s slot, so arrays indexed by slot hold the values. A slot is reused 32,767 times, then retired, so a handle to a freed slot never matches again.

local Slots = Collections.SlotAllocator.new()
local Names = {}
local Handle, Slot = Slots:Allocate()
Names[Slot] = "goblin"
Slots:Free(Handle)
print(Slots:IsAlive(Handle), Slots:SlotOf(Handle)) -- false nil

Summary

Member	Description
.PackHandle()	Builds a handle from a slot and a generation, as Collections.PackHandle does.
.UnpackHandle()	Splits a handle into its slot and generation, as Collections.UnpackHandle does.
.new()	Creates an empty allocator.
:Allocate()	Takes the lowest free slot and returns a handle to it.
:IsAlive()	Whether Handle’s slot is still allocated to it.
:SlotOf()	Returns a live Handle’s slot, or nil once it is freed.
:Free()	Frees Handle’s slot, and returns false if Handle was not live.
:Count()	How many handles are live.
:Capacity()	How many slots fit before it next grows.
:Clear()	Frees every slot at once.
Config	Settings for SlotAllocator.new.

Functions

PackHandle

function SlotAllocator.PackHandle(Slot: number, Generation: number): number

Builds a handle from a slot and a generation, as Collections.PackHandle does.

UnpackHandle

function SlotAllocator.UnpackHandle(Handle: number): (number, number)

Splits a handle into its slot and generation, as Collections.UnpackHandle does.

new

function SlotAllocator.new(Config: Config?): SlotAllocator

Creates an empty allocator.

Methods

Allocate

function SlotAllocator:Allocate(): (number, number)

Takes the lowest free slot and returns a handle to it.

Returns	Description
number	the handle
number	its slot

IsAlive

function SlotAllocator:IsAlive(Handle: number): boolean

Whether Handle’s slot is still allocated to it.

SlotOf

function SlotAllocator:SlotOf(Handle: number): number?

Returns a live Handle’s slot, or nil once it is freed.

Free

function SlotAllocator:Free(Handle: number): boolean

Frees Handle’s slot, and returns false if Handle was not live.

Count

function SlotAllocator:Count(): number

How many handles are live.

Capacity

function SlotAllocator:Capacity(): number

How many slots fit before it next grows.

Clear

function SlotAllocator:Clear()

Frees every slot at once. Every handle given out so far stops matching.

Types

Config

export type Config = {
	InitialCapacity: number?,
	OnGrow: ((Old: number, New: number) -> ())?,
}

Settings for SlotAllocator.new.

Field	Type	Description
InitialCapacity	number?	slots to make room for up front, 8 by default, rounded up to a power of two
OnGrow	((Old: number, New: number) -> ())?	called with the old and new capacity whenever it grows