Ficsit Networks [UUID Module]

local uuid = {}

local function fold(init, op, ...)
  local result = init
  local args = table.pack(...)
  for i = 1, args.n do
    result = op(result, args[i])
  end
  return result
end

local function band(...)
  return fold(0xFFFFFFFF, function(a, b) return a & b end, ...)
end

local function bor(...)
  return fold(0, function(a, b) return a | b end, ...)
end

function uuid.next()
  local sets = {4, 2, 2, 2, 6}
  local result = ""
  local pos = 0

  for _, set in ipairs(sets) do
    if result:len() > 0 then
      result = result .. "-"
    end
    for _ = 1, set do
      local byte = math.random(0, 255)
      if pos == 6 then
        byte = bor(band(byte, 0x0F), 0x40)
      elseif pos == 8 then
        byte = bor(band(byte, 0x3F), 0x80)
      end
      result = result .. string.format("%02x", byte)
      pos = pos + 1
    end
  end

  return result
end

return uuid