var tapesize=100;
var displaylength=20;
var delay=0;
var choice="1";
var Tape0=0;
var TapeR = new Array(tapesize);
var TapeL = new Array(tapesize);

for (i=0; i<tapesize; i++){TapeR[i]=0; TapeL[i]=0}

var displayTapeL = new Array(displaylength);
var displayTapeR = new Array(displaylength);

var currentState = 0;
var stopped = false;
var inerror = false;
var  tapePosition=0;
var stepnumber=0;

function stoperror(){
 document.tm.statetable.value =  "out of memory"}

function statetable_setalphabet(alphabetlist)
{var n = alphabetlist.length;
for (j=0; j <n; j++) this.alphabet[j]=alphabetlist[j]
}

function statetable_setstate(statelist)
{var n = statelist.length;
for (j=0; j< n; j++) this.statedata[j]=statelist[j]
}

function statetable_setmove(movelist)
{var n = movelist.length;
for (j=0; j< n; j++) this.movedata[j]=movelist[j]
}


function statetable_setwrite(writelist)
{var n = writelist.length;
for (j=0; j< n; j++) this.writedata[j]=writelist[j]
}

function statetable_getstateValue(i, j){return this.statedata[i*this.asize + j]}
function statetable_getmoveValue(i, j){return this.movedata[i*this.asize + j]}
function statetable_getwriteValue(i, j){return this.writedata[i*this.asize + j]}



function writeStatetable()
{document.tm.statetable.value =  "";
for (i =0; i<this.snumber; i++)
  { for (j=0; j<this.asize; j++)
       {document.tm.statetable.value = document.tm.statetable.value + "  "  + i +  "      ";
if (i<10){document.tm.statetable.value = document.tm.statetable.value + "  "}
 document.tm.statetable.value = document.tm.statetable.value + this.alphabet[j] + "       " + this.alphabet[this.getwriteValue(i,j)] + "       " + this.getmoveValue(i,j) + "       " ;
if (this.getstateValue(i,j)==-1){document.tm.statetable.value = document.tm.statetable.value + "stop" + "\n"}
else {document.tm.statetable.value = document.tm.statetable.value + this.getstateValue(i,j) + "\n"}
      }
   }
}


function statetable(asize, snumber)
{
this.snumber= snumber;
this.asize = asize;
this.statedata = new Array(asize* snumber);
this.movedata = new Array(asize* snumber);
this.writedata = new Array(asize* snumber);

this.alphabet = new Array(asize);

this.setstate = statetable_setstate;
this.setmove = statetable_setmove;
this.setwrite = statetable_setwrite;
this.setalphabet = statetable_setalphabet;

this.getstateValue= statetable_getstateValue;
this.getmoveValue= statetable_getmoveValue;
this.getwriteValue= statetable_getwriteValue;

this.write = writeStatetable;

}


function writeTape()
{
for (i=0;  i < displaylength; i++) {displayTapeL[i] = exampleTable.alphabet[TapeL[displaylength-1-i]]}
for (i=0; i < displaylength; i++){displayTapeR[i] = exampleTable.alphabet[TapeR[i]]}
 document.tm.tape.value = displayTapeL.join(" | ") + "  |||  " + exampleTable.alphabet[Tape0] + "  |||  " + displayTapeR.join(" | ");
return;
}

function choosemachine()
{ choice= document.tm.menu.value;
document.tm.statetable.value = "You have chosen Machine " + choice}


function loadmachine(){

Tape0=0;
for (i=0; i<100; i++){TapeR[i]=0; TapeL[i]=0}
stopped=false;
inerror=false;
stepnumber=0;
currentState = 0;
tapePosition=0;


if (choice == "1") {

alphabetlist = new Array("_", "1");
statelist = new Array(0,1,2,1,3,2,3,4,-1,4);
movelist = new Array("R", "R", "R", "R", "L", "R", "L", "L", "R", "L");
writelist= new Array(0, 1, 1, 1, 0,1,0 ,0,0, 1);

Tape0=0;
TapeR[0]=1;
TapeR[1]=1;
TapeR[3]=1;
TapeR[4]=1;
TapeR[5]=1;
TapeR[6]=1;
TapeR[7]=1;
TapeR[8]=1;
TapeR[9]=1;

}


else if (choice=="2" ) {

alphabetlist = new Array("_", "1", "X");
statelist = new Array(1, 0, 0, 2, 3, 1, -1, 2, 2, 4, 3, 3, 8 ,5 , 4 , 6 ,5, 5,9,7,6,4,7,7,1,8, 8, 10,9,9,11,10,10,-1,11,11);
movelist = new Array("R", "R", "R", "L", "L", "R", "N", "L", "L", "L", "L", "L", "R", "R", "L", "R", "R", "R", 
"L", "L", "R", "L", "L", "L", "R", "R", "R", "L", "L", "L", "R", "L", "L", "N", "R", "R");
writelist= new Array(0,1,2,0,1,2,2,1,1,0,1,2,0,2,2,0,1,2,0,2,2,0,1,2,0,1,1,0,1,1,0,1,1,0,1,1);

Tape0=0;
TapeL[0]=1;
TapeL[1]=1;
TapeL[2]=1;

TapeR[0]=1;
TapeR[1]=1;
TapeR[2]=1;
TapeR[3]=1;
TapeR[4]=1;
TapeR[5]=1;

}

else if (choice=="3") {

alphabetlist = new Array("_", "1", "X");
statelist = new Array(1,1,1,2,2,2,3,3,3,4,3,3,
5, 4, 4, 6, 7, 5, 18, 6, 6, 8, 7, 7, 12 ,9 , 8 , 10 ,9, 9,13,11,10,8,11,11,5,12, 12, 14,13,13,15,14,14,16,15,15, 17, 16, 16, 4, 17, 17, 20, 18, 18, 21, 19, 19, 20, 19,  22, 21, 18, 21, -1, 23, 22, 23, 23, -1);
movelist = new Array("L", "L", "L", "L", "L", "L","R", "R", "R", "N","R","R",
"R", "R", "R", "L", "L", "R", "L", "L", "L", "L", "L", "L", "R", "R", "L", "R", "R", "R", 
"L", "L", "R", "L", "L", "L", "R", "R", "R", "L", "L", "L", "R", "L", "L", "L", "R", "R", "R","L" ,"N" ,"N", "R" ,"N", "R","L","L","L","R","R","N","R","R","N","L","N","L","L","N","N","N","N");
writelist= new Array
(0,0,0,1,1,1,1,1,1,0,1,2,
0,1,2,
0,1,2,
2,1,1,
0,1,2,
0,2,2,
0,1,2,
0,2,2,
0,1,2,
0,1,1,
0,1,1,
0,1,1,
0,1,1,
 1, 1, 2,
 0, 1, 2, 
0,1,2,
0,1,2,
0,0,2,
0,0,2,
0,1,2,
0,1,0);


TapeR[0]=1;
TapeR[1]=1;
TapeR[2]=1;
TapeR[3]=1;
TapeR[4]=1;



}


else return;

var statesnumber = statelist.length/alphabetlist.length;

exampleTable = new statetable(alphabetlist.length, statesnumber);


exampleTable.setalphabet(alphabetlist);
exampleTable.setstate(statelist);
exampleTable.setmove(movelist);
exampleTable.setwrite(writelist);

exampleTable.write();
document.tm.currentstate.value = currentState;
document.tm.tapepos.value =  tapePosition;
document.tm.stepn.value =  stepnumber;


writeTape();

}

function step(){
if (stopped) return;

var newState= exampleTable.getstateValue(currentState, Tape0);

var newMove= exampleTable.getmoveValue(currentState, Tape0);
var newWrite = exampleTable.getwriteValue(currentState, Tape0);

stepnumber=stepnumber+1;
Tape0=newWrite;


 if (newMove=="L")
   {tapePosition=tapePosition-1;
	if (TapeR[tapesize-1]!=0){stoperror(); stopped=true; inerror=true; return;}
    for (j=tapesize-1; j>0; j--){TapeR[j]=TapeR[j-1]}
  TapeR[0]=Tape0;
  Tape0=TapeL[0];
    for (j=0; j<tapesize-1; j++){TapeL[j]=TapeL[j+1]}
  TapeL[tapesize-1]=0
    }
    
if (newMove=="R")
 {tapePosition=tapePosition+1;
if (TapeL[tapesize-1]!=0){stoperror(); stopped=true; inerror=true; return;}
    for (j=tapesize-1; j>0; j--){TapeL[j]=TapeL[j-1]}
  TapeL[0]=Tape0;
  Tape0=TapeR[0];
    for (j=0; j<tapesize-1; j++){TapeR[j]=TapeR[j+1]}
  TapeR[tapesize-1]=0
    }


if (newState==-1){document.tm.currentstate.value ="Stopped"; writeTape(); stopped=true; return;}
else currentState = newState;
writeTape();
document.tm.currentstate.value = currentState;
document.tm.tapepos.value = tapePosition;
document.tm.stepn.value = stepnumber;
return;
}

function run() {
while (!stopped) {step(); setTimeout("run()", delay); return;}
 }


function breakoff(){stopped=true; return;}

function carryon(){if (!inerror) {stopped=false;} return;}