poizan42/brainfuck.htm

## brainfuck.htm
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<!--
Brainfuck interpreter in JavaScript
Made 2009 by Kasper F. Brandt
I hereby release this code (both html and JavaScript) into the public domain
-->
<html>
<head>
<title>Brainfuck interpreter</title>
<script type="text/javascript">
	var loopStack;
	var loopTime = 100;//time running in ms before we let the browser process events
	var cellRange = 256;
	var consoleBox, programBox, runBtn, statusLabel, stopBtn, cellRangeBox;
	var program;
	var pos;
	var ptr;
	var memory;

	var inputBuffer;
	var isWaitingForInput;
	var isRunning = false;
	var timeoutHandle;

	function setText(e, t)
	{
		if (e.innerText)
			e.innerText = t;
		else
			e.textContent = t;
	}

	function windowload()
	{
		consoleBox = document.getElementById("consoleBox");
		programBox = document.getElementById("programBox");
		runBtn = document.getElementById("runBtn");
		statusLabel = document.getElementById("statusLabel");
		stopBtn = document.getElementById("stopBtn");
		cellRangeBox = document.getElementById("cellRangeBox");
		runBtn.onclick = start;
		stopBtn.onclick = stop;
		consoleBox.onkeypress = consolekeypress;
		consoleBox.value="";
		updateStatus();
	}

	function input()
	{
		if (inputBuffer == "")
			return undefined;
		else
		{
			c = inputBuffer[0]
			inputBuffer = inputBuffer.substr(1);
			return c;
		}
	}

	function output(s)
	{
		consoleBox.value += s;
	}

	function ensureMemExists(p)
	{
		if (memory[p] === undefined)
			memory[p] = 0;
	}

	function step()
	{
		//0=step ended
		//1=fell out
		//2=waiting for input
		ensureMemExists(ptr+1);
		ensureMemExists(ptr-1);
		switch (program[pos])
		{
			case '>':
				ptr++;
				break;
			case '<':
				ptr--;
				break;
			case '+':
				memory[ptr]++;
				if (memory[ptr] >= cellRange)
					memory[ptr] = 0;
				break;
			case '-':
				memory[ptr]--;
				if (memory[ptr] < 0)
					memory[ptr] = cellRange -1;
				break;
			case '.':
				output(String.fromCharCode(memory[ptr]));
				break;
			case ',':
				var a = input();
				if (a == undefined)
					return 2;
				memory[ptr] = a.charCodeAt(0);
				break;
			case '[':
				var oldpos = pos;
				if (memory[ptr]==0)
				{
					var depth = 0;
					for (pos++; pos < program.length; pos++)
					{
						if (program[pos] == '[')
							depth++;
						else if (program[pos] == ']' && depth > 0)
							depth--;
						else if (program[pos] == ']')
							break;
					}
					if (pos == program.length)
					{
						//output("\n<"+oldpos+">at [: unmatched");
						return 1;
					}
				}
				if (program[pos] != ']')
				{
					loopStack.push(pos);
					//output("\n<"+pos+">push. length="+loopStack.length+"|");
				}
				/*else
					output("\n<"+oldpos+">moved to "+pos+". length="+loopStack.length+"|");*/
				break;
			case ']':
				if (loopStack.length == 0)
				{
					output("\n<"+pos+">at ]: unmatched");
					return 1;
				}
				var p = loopStack.pop();
				//output("\n<"+pos+">pop. p="+p+". length="+loopStack.length+"|");
				if (memory[ptr]!=0)
					pos = p-1;
		}
		pos++;
		if (pos >= program.length)
			return 1;
		return 0;
	}

	function run()
	{
		isRunning = true;
		updateStatus();
		var startTime = (new Date()).getTime();
		while ((new Date()).getTime() - startTime <= loopTime)
		{
			//output("<d>"+pos+"\n");
			switch (step())
			{
				case 0: //next step
					continue;
				case 1: //end reached (or unmatched [ ])
					isRunning = false;
					updateStatus();
					return;
				case 2: //no input available
					isWaitingForInput = true;
					updateStatus();
					return;
			}
		}
		updateStatus();
		//give the browser a chance to process events
		timeoutHandle = setTimeout('run();', 1);
	}

	function start()
	{
		pos = 0;
		ptr = 0;
		memory = [0];
		loopStack = [];
		inputBuffer = "";
		program = programBox.value;
		if (isNaN(cellRangeBox.value*1))
		{
			alert("Invalid cell size: "+cellRangeBox.value);
			return;
		}
		cellRange = cellRangeBox.value*1;
		cellRangeBox.value = cellRange;
		consoleBox.value = "";
		run();
	}

	function updateStatus()
	{
		programBox.readOnly = isRunning;
		runBtn.disabled = isRunning;
		cellRangeBox.disabled = isRunning;
		stopBtn.disabled = !isRunning;
		if (isRunning && isWaitingForInput)
			setText(statusLabel, "running - waiting for input");
		else if (isRunning)
			setText(statusLabel, "running");
		else
			setText(statusLabel, "not running");
	}

	function consolekeypress(e)
	{
		if (!e)
			var e = window.event;
		if (!isRunning)
			return;
		var c = e.charCode || e.keyCode;
		c = String.fromCharCode(c);
		inputBuffer += c;
		consoleBox.value += c;
		if (isWaitingForInput)
		{
			isWaitingForInput = false;
			run();
		}
	}

	function stop()
	{
		if (isWaitingForInput)
			isWaitingForInput = false;
		else if (isRunning)
		{
			clearTimeout(timeoutHandle);
			isRunning = false;
		}
		updateStatus();
	}
</script>
</head>
<body onload="windowload()">
<strong>Program</strong><br>
<textarea id="programBox" cols="80" rows="20">
</textarea><br>
Status: <span id="statusLabel">status...</span><br>
Cell size: <input id="cellRangeBox" value="256"><br>
<input type="button" value="run" id="runBtn"><input type="button" value="stop" id="stopBtn" disabled>
<br><hr>
<strong>Console</strong><br>
<textarea id="consoleBox" readonly cols="80" rows="20">
</textarea>
</body>
	<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
	"http://www.w3.org/TR/html4/strict.dtd">
	<!--
	Brainfuck interpreter in JavaScript
	Made 2009 by Kasper F. Brandt
	I hereby release this code (both html and JavaScript) into the public domain
	-->
	<html>
	<head>
	<title>Brainfuck interpreter</title>
	<script type="text/javascript">
	var loopStack;
	var loopTime = 100;//time running in ms before we let the browser process events
	var cellRange = 256;
	var consoleBox, programBox, runBtn, statusLabel, stopBtn, cellRangeBox;
	var program;
	var pos;
	var ptr;
	var memory;

	var inputBuffer;
	var isWaitingForInput;
	var isRunning = false;
	var timeoutHandle;

	function setText(e, t)
	{
	if (e.innerText)
	e.innerText = t;
	else
	e.textContent = t;
	}

	function windowload()
	{
	consoleBox = document.getElementById("consoleBox");
	programBox = document.getElementById("programBox");
	runBtn = document.getElementById("runBtn");
	statusLabel = document.getElementById("statusLabel");
	stopBtn = document.getElementById("stopBtn");
	cellRangeBox = document.getElementById("cellRangeBox");
	runBtn.onclick = start;
	stopBtn.onclick = stop;
	consoleBox.onkeypress = consolekeypress;
	consoleBox.value="";
	updateStatus();
	}

	function input()
	{
	if (inputBuffer == "")
	return undefined;
	else
	{
	c = inputBuffer[0]
	inputBuffer = inputBuffer.substr(1);
	return c;
	}
	}

	function output(s)
	{
	consoleBox.value += s;
	}

	function ensureMemExists(p)
	{
	if (memory[p] === undefined)
	memory[p] = 0;
	}

	function step()
	{
	//0=step ended
	//1=fell out
	//2=waiting for input
	ensureMemExists(ptr+1);
	ensureMemExists(ptr-1);
	switch (program[pos])
	{
	case '>':
	ptr++;
	break;
	case '<':
	ptr--;
	break;
	case '+':
	memory[ptr]++;
	if (memory[ptr] >= cellRange)
	memory[ptr] = 0;
	break;
	case '-':
	memory[ptr]--;
	if (memory[ptr] < 0)
	memory[ptr] = cellRange -1;
	break;
	case '.':
	output(String.fromCharCode(memory[ptr]));
	break;
	case ',':
	var a = input();
	if (a == undefined)
	return 2;
	memory[ptr] = a.charCodeAt(0);
	break;
	case '[':
	var oldpos = pos;
	if (memory[ptr]==0)
	{
	var depth = 0;
	for (pos++; pos < program.length; pos++)
	{
	if (program[pos] == '[')
	depth++;
	else if (program[pos] == ']' && depth > 0)
	depth--;
	else if (program[pos] == ']')
	break;
	}
	if (pos == program.length)
	{
	//output("\n<"+oldpos+">at [: unmatched");
	return 1;
	}
	}
	if (program[pos] != ']')
	{
	loopStack.push(pos);
	//output("\n<"+pos+">push. length="+loopStack.length+"\|");
	}
	/*else
	output("\n<"+oldpos+">moved to "+pos+". length="+loopStack.length+"\|");*/
	break;
	case ']':
	if (loopStack.length == 0)
	{
	output("\n<"+pos+">at ]: unmatched");
	return 1;
	}
	var p = loopStack.pop();
	//output("\n<"+pos+">pop. p="+p+". length="+loopStack.length+"\|");
	if (memory[ptr]!=0)
	pos = p-1;
	}
	pos++;
	if (pos >= program.length)
	return 1;
	return 0;
	}

	function run()
	{
	isRunning = true;
	updateStatus();
	var startTime = (new Date()).getTime();
	while ((new Date()).getTime() - startTime <= loopTime)
	{
	//output("<d>"+pos+"\n");
	switch (step())
	{
	case 0: //next step
	continue;
	case 1: //end reached (or unmatched [ ])
	isRunning = false;
	updateStatus();
	return;
	case 2: //no input available
	isWaitingForInput = true;
	updateStatus();
	return;
	}
	}
	updateStatus();
	//give the browser a chance to process events
	timeoutHandle = setTimeout('run();', 1);
	}

	function start()
	{
	pos = 0;
	ptr = 0;
	memory = [0];
	loopStack = [];
	inputBuffer = "";
	program = programBox.value;
	if (isNaN(cellRangeBox.value*1))
	{
	alert("Invalid cell size: "+cellRangeBox.value);
	return;
	}
	cellRange = cellRangeBox.value*1;
	cellRangeBox.value = cellRange;
	consoleBox.value = "";
	run();
	}

	function updateStatus()
	{
	programBox.readOnly = isRunning;
	runBtn.disabled = isRunning;
	cellRangeBox.disabled = isRunning;
	stopBtn.disabled = !isRunning;
	if (isRunning && isWaitingForInput)
	setText(statusLabel, "running - waiting for input");
	else if (isRunning)
	setText(statusLabel, "running");
	else
	setText(statusLabel, "not running");
	}

	function consolekeypress(e)
	{
	if (!e)
	var e = window.event;
	if (!isRunning)
	return;
	var c = e.charCode \|\| e.keyCode;
	c = String.fromCharCode(c);
	inputBuffer += c;
	consoleBox.value += c;
	if (isWaitingForInput)
	{
	isWaitingForInput = false;
	run();
	}
	}

	function stop()
	{
	if (isWaitingForInput)
	isWaitingForInput = false;
	else if (isRunning)
	{
	clearTimeout(timeoutHandle);
	isRunning = false;
	}
	updateStatus();
	}
	</script>
	</head>
	<body onload="windowload()">
	<strong>Program</strong><br>
	<textarea id="programBox" cols="80" rows="20">
	</textarea><br>
	Status: <span id="statusLabel">status...</span><br>
	Cell size: <input id="cellRangeBox" value="256"><br>
	<input type="button" value="run" id="runBtn"><input type="button" value="stop" id="stopBtn" disabled>
	<br><hr>
	<strong>Console</strong><br>
	<textarea id="consoleBox" readonly cols="80" rows="20">
	</textarea>
	</body>