Small but Inefficient ID alloc

id_alloc.lua

local MaxConcurrent = 512 -- Max concurrent active objects
local TopID = 0 -- Current top-most id.

local OccupiedCount = 0
local Occupied = {}

local function allocID(n)
	if OccupiedCount >= MaxConcurrent then return end
	local new = (n or TopID) % MaxConcurrent + 1
	if Occupied[new] then
		return allocID(new)
	else
		Occupied[new] = true
		OccupiedCount = OccupiedCount + 1
		TopID = new
		return new
	end
end

local function dropID(id)
	if Occupied[id] then
		Occupied[id] = nil
		OccupiedCount = OccupiedCount - 1
		return true
	end
	return false
end