---@diagnostic disable
local LUA_REFNIL = -1 -- lib_aux.c
local FREELIST_REF = 0

local function __ref(value, t)
  if value == nil then return LUA_REFNIL end
  if t == nil then t = __registry end
  local ref = t[FREELIST_REF]
  if ref ~= nil and ref ~= 0 then
    t[FREELIST_REF] = t[ref]
  else
    ref = #t + 1
  end
  t[ref] = value
  return ref
end

local function __unref(ref, t)
  if ref < 0 then return nil end
  if t == nil then t = __registry end
  local value = t[ref]
  t[ref] = t[FREELIST_REF]
  t[FREELIST_REF] = ref
  return value
end