collection of functions

--collection of function that can be used in door locks
--they are ment to be copy pasted into lock programs
--many of them aren't tested yet
--some of the code is experimental

--function to set to enable or disable ctrl-t
--http://www.computercraft.info/forums2/index.php?/topic/2732-disable-ctrlt/
local pullEventCopy = os.pullEvent
function setCtrlT(value)
 if value then
  os.pullEvent = pullEventCopy
 else
  os.pullEvent = os.pullEventRaw
 end
end



--clears the screen and sets the cursor to 1 1
function clear()
 term.clear()
 term.setCursorPos(1, 1)
end



--needs the loadString function
--loads the entire contents of the file into
--a string and then uses unserilize
function loadValue(path)
 return textutils.unserialize(loadString(path))
end

--opens the file then reads the entire contents into a string
--which is then returned
--if there is any error nil is returned
function loadString(path)
 if type(path)~="string" then
  return nil
 end

 local succes=true
 if  not fs.exists(path) then
  return nil
 end
 local h=fs.open(path, "r")
 if h==nil then
  return nil
 end
 local value=h.readAll()
 h.close()
 return value
end




--serializes the value into a string
--and then saves the string into a
--file with the given path
function saveValue(path,value)
 return saveString(path,textutils.serialize(value))
end





--saves the given string value into
--a file with the given path
--overwriting any contents if there are any
function saveString(path,value)
 if type(path)~="string" or type(value)~="string" then
  return false
 end
 local h = fs.open(path, "w")
 h.write(value)
 h.close()
 return true
end




--loads the lines from the given file
--returns nil if there is an error
--else returns an array with the lines
--indexed from 1 upwards
function loadLines(path)
 if type(path)~="string" or not fs.exists(path) then
  return nil
 end
 local h=fs.open(path, "r")
 if h==nil then
  return nil
 end
 local res={}
 while(true) do
  local value=h.readLine()
  if value==nil then break end
  res[#res+1]=value
 end
 h.close()
 return res
end


function saveLines(path,lines)
 for _,line inipairs(lines) do

 end
end




--returns an iterator of the words from the line
--splits on spaces
function wordIterator(line)
 return line:gmatch("%S+")
end




--takes the lines from a perms file and
--adds them to a lookup table which can
--be used to check the perms of an user
function toPermsTable(lines)
 if type(lines)~="table" then return nil end
 local users={}
 for _,line in lines do
  local username=nil
  for _,word in wordIterator(line) do
   if username==nil then
    username=word
    if users[username]==nil then
     users[username]={}
    end
   else
    users[username][word]=true
   end
  end
 end
end




function hasPerm(permsTable,username,perm)
 return permsTable[username]~=nil and permsTable[username][perm]~=nil
end



function loadPerms(path)
 local lines=loadLines(path)
 if lines==nil then return nil end
 return toPermsTable(lines)
end





function savePerms(permsTable)
 local lines={}
 for username,perms in pairs(permsTable) do
  local lineTable={username}
  for perm,_ in pairs(perms) do
   lineTable[#lineTable+1]=perm
  end
  lines[#lines+1]=table.concat(lineTable, " ")
 end
 saveLines(lines)
end



function appendString(path,str)
 --open code from wiki
 --Opens path in either append or write mode, depending on whether it already exists or not.
 local h = fs.open(path, fs.exists(path) and "a" or "w")
 if h==nil then
  return false
 end
 h.writeLine(str)
 h.close()
 return true
end




function appendUser(userName,permission)
  if(userName==nil) then
   print("UserName is nil...")
   return
  end
  local append=""
  if type(permission)=="string" and #permission>0 then
   append=" "..permission
  end
  appendString(permsPath,userName..append)
end



--downloads the given file and then returns 2
function pastebin(shellObj, path,code,overwrite)
  if overwrite then
   fs.delete(path)
  end
  shellObj.run("pastebin","get", code, path)
  return 2
end

function loadLines(path)
 if type(path)~="string" then error("Error (loadLines): path should be a string",2) end
 if  not fs.exists(path) then
  return nil
 end
 local h=fs.open(path, "r")
 if h==nil then
  return nil
 end
 local res={}
 while(true) do
  local line=h.readLine()
  if line==nil then break end
  res[#res+1]=line
 end
 h.close()
 return res
end



function getWords(line)
 if type(line)~="string" then error("Error (getWords): line should be a string",2) end
 local words={}
 --"%S+"
 --"%a+"
 for word in string.gmatch(line, "%S+") do
  words[#words+1]=word
 end
 return words
end