terjanq · June 14, 2024 14:36
diff --git a/README.md b/README.md
diff --git a/bf.js b/bf.js
 let program, pc, buf, p;
 let statusCode = 0; // 0: not running, 1: running, 2: exit successfully, 3: exit with an error
 let output = '';
 let steps = 0;
 const maxSteps = 1000000;

 function checkStep() {
  steps++;
  if (steps > maxSteps) {
    throw new Error('maximum steps exceeded')
  }
 }

 function pinc() {
  p++;
 }

 function pdec() {
  p--;
 }

 function inc() {
  buf[p]++;
 }

 function dec() {
  buf[p]--;
 }

 function putc() {
  output += String.fromCharCode(buf[p]);
 }

 function getc() {
  console.err('not implemented');
 }

 function lbegin() {
  if (buf[p] === 0) {
    let i = pc+1;
    let depth = 1;
    while (i < program.length) {
      if (program[i] === '[') {
        depth++;
      }
      if (program[i] === ']') {
        depth--;
        if (depth === 0) {
          break;
        }
      }

      i++;
      checkStep();
    }

    if (depth === 0) {
      pc = i;
    }
    else {
      throw new Error('parenthesis mismatch')
    }
  }
 }

 function lend() {
  if (buf[p] !== 0) {
    let i = pc-1;
    let depth = 1;
    while (0 <= i) {
      if (program[i] === ']') {
        depth++;
      }
      if (program[i] === '[') {
        depth--;
        if (depth === 0) {
          break;
        }
      }

      i--;
      checkStep();
    }

    if (depth === 0) {
      pc = i;
    }
    else {
      throw new Error('parenthesis mismatch')
    }
  }
 }

 function writeOutput() {
  if (statusCode !== 3) {
    if (CONFIG.unsafeRender) {
      document.getElementById('output').innerHTML = output;
    } else {
      document.getElementById('output').innerText = output;
    }
  }
 }

 function initProgram() {
  // load program
  program = document.getElementById('program').innerText;
  document.getElementById('program').innerHTML = DOMPurify.sanitize(program).toString();

  // initialize
  pc = 0;
  buf = new Uint8Array(30000);
  p = 0;

  statusCode = 0;
 }

 function runProgram() {
  statusCode = 1;
  try {
    while (pc < program.length) {
      switch (program[pc]) {
        case '>':
          pinc();
          break;
        case '<':
          pdec();
          break;
        case '+':
          inc();
          break;
        case '-':
          dec();
          break;
        case '.':
          putc();
          break;
        case ',':
          getc(); // not implemented
          break;
        case '[':
          lbegin();
          break;
        case ']':
          lend();
          break;
        case '=':
          console.log('=)');
          break;
        case '/':
          console.log(':/');
          break;
        case ' ':
          break;
        default:
          throw new Error(`invalid op: ${program[pc]}`)
      }
  
      pc++;
      checkStep();
    }

    CONFIG = window.CONFIG || {
      unsafeRender: false
    };

    statusCode = 2;
  }
  catch {
    statusCode = 3;
    return;
  }
  // no xss please
  output = output.replaceAll('<', '&lt;').replaceAll('>', '&gt;')
  writeOutput();
 }

 window.addEventListener('DOMContentLoaded', function() {
  initProgram();
  runProgram();
 });
Type	Hostname	Value	TTL (seconds)
A	double.terjanq.me	127.0.0.1	30
A	double.terjanq.me	51.38.138.162	30
	let program, pc, buf, p;
	let statusCode = 0; // 0: not running, 1: running, 2: exit successfully, 3: exit with an error
	let output = '';
	let steps = 0;
	const maxSteps = 1000000;

	function checkStep() {
	steps++;
	if (steps > maxSteps) {
	throw new Error('maximum steps exceeded')
	}
	}

	function pinc() {
	p++;
	}

	function pdec() {
	p--;
	}

	function inc() {
	buf[p]++;
	}

	function dec() {
	buf[p]--;
	}

	function putc() {
	output += String.fromCharCode(buf[p]);
	}

	function getc() {
	console.err('not implemented');
	}

	function lbegin() {
	if (buf[p] === 0) {
	let i = pc+1;
	let depth = 1;
	while (i < program.length) {
	if (program[i] === '[') {
	depth++;
	}
	if (program[i] === ']') {
	depth--;
	if (depth === 0) {
	break;
	}
	}

	i++;
	checkStep();
	}

	if (depth === 0) {
	pc = i;
	}
	else {
	throw new Error('parenthesis mismatch')
	}
	}
	}

	function lend() {
	if (buf[p] !== 0) {
	let i = pc-1;
	let depth = 1;
	while (0 <= i) {
	if (program[i] === ']') {
	depth++;
	}
	if (program[i] === '[') {
	depth--;
	if (depth === 0) {
	break;
	}
	}

	i--;
	checkStep();
	}

	if (depth === 0) {
	pc = i;
	}
	else {
	throw new Error('parenthesis mismatch')
	}
	}
	}

	function writeOutput() {
	if (statusCode !== 3) {
	if (CONFIG.unsafeRender) {
	document.getElementById('output').innerHTML = output;
	} else {
	document.getElementById('output').innerText = output;
	}
	}
	}

	function initProgram() {
	// load program
	program = document.getElementById('program').innerText;
	document.getElementById('program').innerHTML = DOMPurify.sanitize(program).toString();

	// initialize
	pc = 0;
	buf = new Uint8Array(30000);
	p = 0;

	statusCode = 0;
	}

	function runProgram() {
	statusCode = 1;
	try {
	while (pc < program.length) {
	switch (program[pc]) {
	case '>':
	pinc();
	break;
	case '<':
	pdec();
	break;
	case '+':
	inc();
	break;
	case '-':
	dec();
	break;
	case '.':
	putc();
	break;
	case ',':
	getc(); // not implemented
	break;
	case '[':
	lbegin();
	break;
	case ']':
	lend();
	break;
	case '=':
	console.log('=)');
	break;
	case '/':
	console.log(':/');
	break;
	case ' ':
	break;
	default:
	throw new Error(`invalid op: ${program[pc]}`)
	}

	pc++;
	checkStep();
	}

	CONFIG = window.CONFIG \|\| {
	unsafeRender: false
	};

	statusCode = 2;
	}
	catch {
	statusCode = 3;
	return;
	}
	// no xss please
	output = output.replaceAll('<', '<').replaceAll('>', '>')
	writeOutput();
	}

	window.addEventListener('DOMContentLoaded', function() {
	initProgram();
	runProgram();
	});