JavaScript DHTML/Security/Brainfuck Converter Interpreter — различия между версиями

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Версия 12:59, 26 мая 2010

Brainfuck Converter/Interpreter in JavaScript

   <source lang="html4strict">

<html> 

 <head>
   
   <title>Brainfuck Converter/Interpreter</title>
   
   
   <script>

BF_ARRAY_LEN = 4000; arr = new Array(BF_ARRAY_LEN); function push(el, stack) { 

 stack[stack.length] = el;
 return stack;

} function peek(stack) { 

 return stack[stack.length-1];

} function pop(stack) { 

 return stack.slice(0,stack.length-2);

} function evalBF(codestr, outputField) { 

 outputField.value = "";
 for (i=0; i<BF_ARRAY_LEN; i++) arr[i] = 0;
 ptr = 0;
 loopstack = Array();
 i = 0;
 while (i < codestr.length)
 {
 switch (codestr.charAt(i))
 {
 case "[":
   if (arr[ptr]!=0) loopstack = push(i,loopstack);
   else i = codestr.indexOf("]",i);
   i++;
   break;
 case "]":
   i = peek(loopstack);
   loopstack = pop(loopstack);
   break;
 case "+":
   arr[ptr]++;
   i++;
   break;
 case "-":
   arr[ptr]--;
   i++;
   break;
 case "<":
   ptr--;
   i++;
   break;
 case ">":
   ptr++;
   i++;
   break;
 case ".":
   outputField.value += String.fromCharCode(arr[ptr]);
   i++;
   break;
 case ",":
   input = prompt("BF program input:","");
   arr[ptr] = input.charCodeAt(0);
   i++;
   break;
 default:
   i++;
   break;
 }
 }

} function strTimes(str,times) { 

 endstr = "";
 for (var i=0; i<times; i++) endstr += str;
 return endstr;

} function printDifference(diff,poschar,negchar) { 

 str = "";
 if (diff>0)
 for (var b=0; b<diff; b++) str += poschar;
 else
 for (var b=0; b<-diff; b++) str += negchar;
 return str;

} function writeBins(numBins,diff) { 

 str = strTimes("+",diff) + "[";
 for (var i=1; i<numBins; i++)
 {
 str += ">" + strTimes("+",i+1);
 }
 str += strTimes("<",numBins-1) + "-]";
 str += strTimes("+",diff);
 return str;

} function findClosestBin(val,bins,currbin) { 

 var minBin = 0;
 for (var b=1; b<bins.length; b++)
 {
 if (Math.abs(val-bins[b]) < Math.abs(val-bins[minBin])) minBin = b;
 }
 if (Math.abs(val-bins[minBin]) > Math.abs(val-bins[currbin])) return currbin;
 return minBin;

} function text2BF(textstr, numBins) { 

 if (numBins<=0) return "error: too few bins";
 var bins = new Array(numBins);
 var diff = Math.floor(127/numBins);
 for (var i=0; i<numBins; i++) bins[i] = (i + 1) * diff;
 var codestr = writeBins(numBins,diff);
 var i = 0;
 var currbin = 0;
 var newbin = 0;
 while (i < textstr.length)
 {
 c = textstr.charCodeAt(i);
 newbin = findClosestBin(c,bins,currbin);
 codestr += printDifference(newbin-currbin,">","<");
 codestr += printDifference(c-bins[newbin],"+","-");
 codestr += ".";
 currbin = newbin;
 bins[newbin] = c;
 i++;
 }
 return codestr;

} function smartText2BF(textstr, binField) { 

  var bestbin = 1;
  var results = new Array(16);
  var beststr = "";
  var resultstr = "";
  for (var i=1; i<=16; i++)
  {
  var str = text2BF(textstr, i);
  results[i-1] = str.length;
  
  if (results[i-1] < results[bestbin-1])
  {
    beststr = str;
    bestbin = i;
  }
  resultstr += i + ": " + results[i-1] + "\n";
  }
  binField.value = bestbin;
  return beststr;

} 

   </script>
 </head>
 <body>
   <form>
     Input:

     <textarea name="codestr" rows="4" cols="50" wrap="hard"></textarea>


     Bins (1-10): <input name="numBins" value="5" size="1" type="text">
     <input value="Text2BF" onclick="bfout.value = text2BF(codestr.value, numBins.value)" type="button">
     <input value="Smart Text2BF" onclick="bfout.value = smartText2BF(codestr.value, numBins)" type="button">
     <input value="Interpret" onclick="evalBF(codestr.value,bfout)" type="button">


     Output:

     <textarea name="bfout" rows="6" cols="50"></textarea>

   </form>
 </body>

</html> 

      </source>
Источник — «http://wbex.ru/index.php?title=JavaScript_DHTML/Security/Brainfuck_Converter_Interpreter&oldid=3662»