GateSim - Logical Gate Simulator

-----------------------------------------------
--LOGICAL GATE/FLIP-FLOP SIMULATOR BY CRAGRIM--
-----------------------------------------------
--INSTRUCTIONS--
--http://www.promethea-ftb.com/index.php?threads/cragrims-computercraft-thread.639/#post-2881
----------------
--DECLARATIONS--
----------------

--version
local strVersion = "0.2"

--get command line arguments in a table
local tblArgs = { ... }

--count number of elements in the argument table
local intArgsCount = 0 --declare it empty
if next(tblArgs) == nil then
   --check if table is empty (do nothing)
else
    --for each element add 1
    for _ in pairs(tblArgs) do
        intArgsCount = intArgsCount + 1
    end
end

--has an error occured?
local bolErr = false

--get the name of the program if named other than "gatesim"
local GATESIM = shell.getRunningProgram()

--default latch state off
local latch_memory = "0"

--declare special characters to avoid misshaps
strLP = [[(]] --left parentheses
strRP = [[)]] --right parentheses
strQ = [["]] --doublequote

-------------
--FUNCTIONS--
-------------

    -------------------
    --STRING HANDLING--
    -------------------

--Put quotes around this
function strQuote(this)
    return strQ..this..strQ
end


--Put parentheses around that
function strParen(that)
    return strLP..that..strRP
end

    ----------------------
    --COSMETIC FUNCTIONS--
    ----------------------

function ClearScreen()
    term.clear()
    term.setCursorPos(1,1)
end

function Pause()
    write("Press any key to continue...")
    read()
end

    ---------------------------------
    --STARTUP INFORMATIVE FUNCTIONS--
    ---------------------------------

--Print information about current gate
function StartInfo(gateType,gateDescription)
    ClearScreen()
    print("LOGICAL GATE/FLIP-FLOP SIMULATOR BY CRAGRIM")
    print("Program Version: "..strVersion)
    print("Computer Label: "..ComputerLabel())
    print("")
    print("CURRENTLY SIMULATING: "..gateType)
    print(gateDescription)
    print("")
    print("InputA: "..strInputA)
    print("InputB: "..strInputB)
    print("OutputA: "..strOutputA)
    print("OutputB: "..strOutputB)
    print("Variable: "..strVariable1)
    print("")
    SaveGateSetting(gateType)
    if bolErr == false then
        print("")
        print("Program is now running! Hold CTRL+T to abort...")
    end
end

--Print information if no gate was entered
function PrintDescription()
    ClearScreen()
    print("LOGICAL GATE/FLIP-FLOP SIMULATOR BY CRAGRIM")
    print("Program Version: "..strVersion)
    print("Computer Label: "..ComputerLabel())
    print("")
    print("AVAILABLE GATE FUNCTIONS:")
    print("not, and, nand, or, nor, xor, xnor, rslatch, tflipflop, timer")
    print("")
    print("SYNTAX:")
    print(GATESIM.." [Gate] [InpA] [InpB] [OutA] [OutB] [Var]")
    print(strParen("Saves the setting after reboot"))
    print("")
    print("EXAMPLES:")
    print(GATESIM.." AND")
    print(GATESIM.." XOR left front back")
    print(GATESIM.." RSLATCH left right back front")
    print(GATESIM.." TIMER left right back front 2")
end


    -------------
    --FUNCTIONS--
    -------------

function SaveGateSetting(fnName)
    --Declare startup string to automatically launch gate program with side arguments on computer reboot
    local strStartup = "shell.run"..strParen(strQuote(GATESIM)..","..strQuote(fnName)..","..strQuote(strInputA)..","..strQuote(strInputB)..","..strQuote(strOutputA)..","..strQuote(strOutputB)..","..strQuote(strVariable1))

    --Write to startup program
    local fileWrite = fs.open ("startup", "w")
    fileWrite.write(strStartup)
    fileWrite.close()
    write("Saving settings to startup...")

    --Read the startup program to make sure it was actually saved, this is sometimes skipped on servers
    local fileRead=fs.open("startup", "r")
    if fileRead.readAll() == strStartup then
        print(" success!")
    else
        print(" writing error!")
        bolErr = true
    end
    fileRead.close()
end

--Save latch memory
function SaveState(num)
    if num == "1" then
        local fileWrite = fs.open ("latch_memory", "w")
        fileWrite.write("1")
        fileWrite.close()
    else
        local fileWrite = fs.open ("latch_memory", "w")
        fileWrite.write("0")
        fileWrite.close()
    end
end

--Load latch memory
function LoadState()
    if fs.exists("latch_memory") then
        local fileRead=fs.open("latch_memory", "r")
        temp_mem = fileRead.readAll()

        if temp_mem == "1" then
            return "1"
        else
            return "0"
        end
        fileRead.close()
    else
        SaveState("0")
    end
end

    ----------------------------
    --ERROR CHECKING FUNCTIONS--
    ----------------------------

--Wait for this to happen before updating in order to avoid lag
--Add more pullevents to reduce lag even more (I can't think of any more though)
function WaitForMe()
    os.pullEvent("redstone") --wait for a "redstone" event
end

--Check if the argument for side is valid or not
function CheckValidSide(mySide, defaultSide)
    if mySide ~= "" then
        count = 0
        --Go through the list of valid sides
        for k,v in pairs(rs.getSides()) do
            if mySide == v then
                count = count + 1
            end
        end

        if count > 0 then
            --The side is OK
            return mySide
        else
            --The side is not OK, use default instead
            return defaultSide
        end
    end
    --No argument added, use default
    return defaultSide
end


--Make sure you have set a computer label.. if not then automatically assign a random label
function ComputerLabel()
    if os.getComputerLabel() == nil then
        os.setComputerLabel("SomeComputer"..math.random(0,99999))
        return os.getComputerLabel()
    else
        return os.getComputerLabel()
    end
end

--Make sure that the entered value is an integer
function TypeCheck(number)
    number = tonumber(number)
    if type(number) ~= "number" then
        return 2
    else
        return number
    end
end


---------------------------
--INPUT/OUTPUT ASSIGNMENT--
---------------------------

--Assign input/output sides so that you can easily change this if you want
--Available: left/right/back/front/bottom/top
--I plan to maybe make configurable with additional input/outputs in the future, for now this will have to do

--gatesim [GateType]  [InputA]    [InputB]    [OutputA]    [OutputB]
--        tblArgs[1]  tblArgs[2]  tblArgs[3]  tblArgs[4]   tblArgs[5]
--                    "left"      "right"     "back"       "front"

--Make sure the sides are valid
strInputA = CheckValidSide(tblArgs[2], "left")
strInputB = CheckValidSide(tblArgs[3], "right")
strOutputA = CheckValidSide(tblArgs[4], "back")
strOutputB = CheckValidSide(tblArgs[5], "front")
strVariable1 = TypeCheck(tblArgs[6])

function InputA()
    return rs.getInput(strInputA)
end

function InputB()
    return rs.getInput(strInputB)
end

function OutputA(set)
    return rs.setOutput(strOutputA, set)
end

--This is not always used
function OutputB(set)
    return rs.setOutput(strOutputB, set)
end


----------------------------
--GATE SIMULATION PROGRAMS--
----------------------------


if tblArgs[1] == "AND" or tblArgs[1] == "and" then
    --Program AND
    StartInfo("AND","[OutA] is ON when [InpA] AND [InpB] is ON")
    while bolErr == false do
        WaitForMe()
        if InputA() == true and InputB() == true then
            OutputA(true)
        else
            OutputA(false)
        end
    end

elseif tblArgs[1] == "NAND" or tblArgs[1] == "nand" then
    --Program NAND
    StartInfo("NAND","[OutA] is OFF when [InpA] AND [InpB] is ON")
    while bolErr == false do
        WaitForMe()
        if InputA() == true and InputB() == true then
            OutputA(false)
        else
            OutputA(true)
        end
    end

elseif tblArgs[1] == "OR" or tblArgs[1] == "or" then
    --Program OR
    StartInfo("OR","[OutA] is ON when [InpA] OR [InpB] is ON")
    while bolErr == false do
        WaitForMe()
        if InputA() == true or InputB() == true then
            OutputA(true)
        else
            OutputA(false)
        end
    end

elseif tblArgs[1] == "NOR" or tblArgs[1] == "nor" then
    --Program OR
    StartInfo("NOR","[OutA] is OFF when [InpA] OR [InpB] is ON")
    while bolErr == false do
        WaitForMe()
        if InputA() == true or InputB() == true then
            OutputA(false)
        else
            OutputA(true)
        end
    end

elseif tblArgs[1] == "XOR" or tblArgs[1] == "xor" then
    --Program XOR
    StartInfo("XOR","[OutA] is ON when [InpA] and [InpB] is odd")
    while bolErr == false do
        WaitForMe()
        if InputA() == false and InputB() == false then
            OutputA(false)
        elseif InputA() == true and InputB() == true then
            OutputA(false)
        else
            OutputA(true)
        end
    end

elseif tblArgs[1] == "XNOR" or tblArgs[1] == "xnor" then
    --Program XNOR
    StartInfo("XNOR","[OutA] is OFF when [InpA] and [InpB] is odd")
    while bolErr == false do
        WaitForMe()
        if InputA() == false and InputB() == false then
            OutputA(true)
        elseif InputA() == true and InputB() == true then
            OutputA(true)
        else
            OutputA(false)
        end
    end

elseif tblArgs[1] == "TIMER" or tblArgs[1] == "timer" then
    --Program NOT
    StartInfo("TIMER","Pulses with [Var] delay when [InpA] is OFF")
    while bolErr == false do
        if InputA() == false then
            OutputA(true)
            sleep(strVariable1)
            OutputA(false)
            sleep(strVariable1)
        else
            OutputA(false)
            WaitForMe()
        end
    end

elseif tblArgs[1] == "NTIMER" or tblArgs[1] == "ntimer" then
    --Program NOT
    StartInfo("NTIMER","Pulses with [Var] delay when [InpA] is ON")
    while bolErr == false do
        if InputA() == false then
            OutputA(false)
            WaitForMe()
        else
            OutputA(true)
            sleep(strVariable1)
            OutputA(false)
            sleep(strVariable1)
        end
    end

elseif tblArgs[1] == "NOT" or tblArgs[1] == "not" then
    --Program NOT
    StartInfo("NOT","[OutA] is ON when [InpA] is OFF")
    while bolErr == false do
        WaitForMe()
        if InputA() == false then
            OutputA(true)
        else
            OutputA(false)
        end
    end

elseif tblArgs[1] == "RSLATCH" or tblArgs[1] == "rslatch" or tblArgs[1] == "rsnorlatch" or tblArgs[1] == "RSNORLATCH" then
    --Program RS Latch
    StartInfo("RSLATCH","[OutA] is STORED as ON when [InpA] is ON or STORED as OFF when [InptB] is ON. [OutB] is odd to [OutA]")
    while bolErr == false do
        --Load previous memory
        if LoadState() == "1" then
            OutputA(true)
            OutputB(false)
        else
            OutputA(false)
            OutputB(true)
        end

        WaitForMe()

        if InputA() == true then
            SaveState("1")
        elseif InputB() == true then
            SaveState("0")
        end
    end

elseif tblArgs[1] == "FLIPFLOP" or tblArgs[1] == "flipflop" or tblArgs[1] == "TFLIPFLOP" or tblArgs[1] == "tflipflop" then
    --Program RS Latch
    StartInfo("TFLIPFLOP","[OutA] toggles ON/OFF when [InpA] or [InpB] pulses. [OutB] is odd to [OutA]")
    while bolErr == false do
        --Load previous memory
        if LoadState() == "1" then
            OutputA(true)
            OutputB(false)
        else
            OutputA(false)
            OutputB(true)
        end

        while InputA() or InputB()  == true do
            sleep(1.0) --sleep 1 tick
        end

        WaitForMe()

        if InputA() == true or InputB() == true then
            if LoadState() == "1" then
                SaveState("0")
                --WaitForMe()
            else
                SaveState("1")
                --WaitForMe()
            end
        end

        --os.sleep(1)

    end

else
    --Print instructions
    PrintDescription()
end

--Some kind of error occured
if bolErr == true then
    print("An error occurred... program failed.")
    print("Please check your server settings or try again.")
end