utils 3.0

local tempvarlist = {}

function termwrite(message)
  cx, cy = term.getCursorPos()
  mx, my = term.getSize()
  term.write(message)
  if(cy == my) then
    term.scroll(1)
    term.setCursorPos(1, cy)
  else
    term.setCursorPos(1, cy + 1)
  end
end

function copytable(t)
  local t2 = {}
  for k,v in pairs(t) do
    t2[k] = v
  end
  return t2
end

function download(source, destination)
  local tmpF = http.get(source)
  sleep(5)
  local txt = tmpF:readAll()
  local file = io.open(destination, "w")
  file:write(txt)
  file:close()
end

local function save(filename)
  if(fs.exists(filename)) then
    fs.delete(filename)
  end
  file = fs.open(filename, "w")
  for k, v in pairs(tempvarlist) do
    file.writeLine(textutils.serialize({k, v}))
  end
  file:close()
end

local function load(filename)
  tempvarlist = {}
  if(not fs.exists(filename)) then
    save(filename)
  end
  file = fs.open(filename, "r")
  line = file.readLine()
  while((line ~= nil) and (line ~= "")) do
    pref = textutils.unserialize(line)
    tempvarlist[pref[1]] = pref[2]
    line = file.readLine()
  end
  file:close()
end

function saveVar(filename, entry, value, default)
  load(filename)
  if(value == nil) then
    tempvarlist[entry] = default
  else
    tempvarlist[entry] = value
  end
  save(filename)
end

function loadVar(filename, entry, default)
  load(filename)
  value = tempvarlist[entry]
  if(value == nil) then
    return default
  else
    return value
  end
end

function deleteVar(filename, entry)
  load(filename)
  tempvarlist[entry] = nil
  save(filename)
end

function containsVar(filename, entry)
  load(filename)
  return(tempvarlist[entry] ~= nil)
end