module to shift ipv4 from ip to number and from number to ip

ip.lua

local ip = {}

function ip.to_number (ip_str)
    if type(ip_str) ~= "string" then return -1 end

    local chunks = { ip_str:match("(%d+)%.(%d+)%.(%d+)%.(%d+)") }
    if #chunks == 4 then
        for k , v in pairs(chunks) do
            if tonumber(v) > 255 then return -1 end
            chunks[k] = tonumber(v) or 0
        end

        return chunks[1] * 2 ^ 24 + -- << 24 |
               chunks[2] * 2 ^ 16 + -- << 16 |
               chunks[3] * 2 ^ 8  + -- << 8  |
               chunks[4]
    else
        return -1
    end
end

function ip.from_number (ip_num)
    if type(ip_num) ~= "number" then return nil end

    local oc1 = (math.floor(ip_num / 2 ^ 24))
    local oc2 = (math.floor(ip_num / 2 ^ 16)) % 2 ^ 8
    local oc3 = (math.floor(ip_num / 2 ^  8)) % 2 ^ 8
    local oc4 = (ip_num) % 2 ^ 8

    local msg = "%i.%i.%i.%i"
    return msg:format(oc1, oc2, oc3, oc4)
end

return ip