Deep Storage Unit Monitor

--DSU Display
function exists(path)
        local file = assert(io.open(path, "r"))
        if file ~= nil then
                file:close()
                return true
        end

        return false
end

function getTable(path)
        if exists(path) then
                local file = io.open(path, "r")
                local lines = {}
                local i = 1
                local line = file:read("*l")
                while line ~= nil do
                        lines[i] = line
                        line = file:read("*l")
                        i = i + 1
                end
                file:close()
                return lines
        end
        return {}
end

function tablelength(T)
    local count = 0
    for _ in pairs(T) do count = count + 1 end
    return count
end

function formateNumber(n) --http://richard.warburton.it
    local left,num,right = string.match(n,'^([^%d]*%d)(%d*)(.-)$')
    return left..(num:reverse():gsub('(%d%d%d)','%1,'):reverse())..right
end

-- Variables
local dsus = {}
local id = os.getComputerID()
local config = getTable(id.."/config")
local begin = tonumber(string.sub(config[1],string.find(config[1],":")+2))
local stop = tonumber(string.sub(config[2],string.find(config[2],":")+2))
local monitorvalue = tonumber(string.sub(config[3],string.find(config[3],":")+2))
local monitor = peripheral.wrap("monitor_" .. monitorvalue)
local x, y = monitor.getSize()
local n = 1


for i = begin, stop do
    dsus[n] = peripheral.wrap("deep_storage_unit_" .. i)
    n = n + 1
end


if tablelength(dsus) > y then
    print("Monitor zu klein..")
    sleep(5)
end

monitor.clear()

while true do
    local line = 1
    local line2 = 1 + begin
    for _ in pairs(dsus) do
        if dsus[line].getStoredItems() ~= nil then
            local qty = dsus[line].getStoredItems()["qty"]
            local name = dsus[line].getStoredItems()["display_name"]
            monitor.setCursorPos(1, line)
            monitor.clearLine()
            monitor.setTextColor(colors.orange)
            monitor.write(formateNumber(qty) .. "x ")
            monitor.setTextColor(colors.lime)
            monitor.write(name .. "'s")
        else
            monitor.setCursorPos(1, line)
            monitor.clearLine()
            monitor.setTextColor(colors.red)
            monitor.write("DSU ".. line2 .. " ist leer!")
        end
        line = line + 1
        line2 = line2+ 1
    end
    sleep(0)
end