lua genimei function

imei.lua

function serialize(obj)  
    local lua = ""  
    local t = type(obj)  
    if t == "number" then  
        lua = lua .. obj  
    elseif t == "boolean" then  
        lua = lua .. tostring(obj)  
    elseif t == "string" then  
        lua = lua .. string.format("%q", obj)  
    elseif t == "table" then  
        lua = lua .. "{\n"  
    for k, v in pairs(obj) do  
        lua = lua .. "[" .. serialize(k) .. "]=" .. serialize(v) .. ",\n"  
    end  
    local metatable = getmetatable(obj)  
        if metatable ~= nil and type(metatable.__index) == "table" then  
        for k, v in pairs(metatable.__index) do  
            lua = lua .. "[" .. serialize(k) .. "]=" .. serialize(v) .. ",\n"  
        end  
    end  
        lua = lua .. "}"  
    elseif t == "nil" then  
        return nil  
    else  
        error("can not serialize a " .. t .. " type.")  
    end  
    return lua  
end  
  
function unserialize(lua)  
    local t = type(lua)  
    if t == "nil" or lua == "" then  
        return nil  
    elseif t == "number" or t == "string" or t == "boolean" then  
        lua = tostring(lua)  
    else  
        error("can not unserialize a " .. t .. " type.")  
    end  
    lua = "return " .. lua  
    local func = loadstring(lua)  
    if func == nil then  
        return nil  
    end  
    return func()  
end 

function split(s, delimiter)
    result = {};
    for match in (s..delimiter):gmatch("(.-)"..delimiter) do
        table.insert(result, match);
    end
    return result;
end
math.randomseed(tostring(os.time()):reverse():sub(1, 6))
function random_val(_start, _end)
	
	return math.random(_start, _end) 
end

function gen_imei()
	local ret = ""
	local pos
	local str = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }
	local sum = 0
	local final_digit = 0
	local t = 0
	local len_offset = 0
	local len = 15
	local rbi = { "01", "10", "30", "33", "35", "44", "45", "49", "50", "51", "52", "53", "54", "86", "91", "98", "99" }
	local arr = rbi[random_val(1, #rbi)]
	print(arr)
	str[1] = tonumber(string.sub(arr, 1, 1))
	str[2] = tonumber(string.sub(arr, 2))
	pos = 3
	while pos < len do
		str[pos] = random_val(0, 9)
		pos = pos + 1
	end
	len_offset = (len + 1) % 2;
	pos = 1
	while pos < len do
		print(pos)
		if (pos + len_offset) % 2 == 0 then
			t = str[pos] * 2
			if t > 9 then
				t = t - 9
			end
			sum = sum + t
		else
			sum = sum + str[pos]
		end
		pos = pos + 1
	end
	final_digit = (10 - (sum % 10)) % 10
	str[len] = final_digit
	for _,v in ipairs(str) do
		ret = ret .. tostring(v)
	end
	return ret
end

print(gen_imei())