UG set torrent DHT free and remove UG tracker

<?php
Header("content-type: text/plain");
$parse_start_time = microtime(true);
$tag='_UG-DHT_';

if ($dh = opendir("./"))
{
    while (($f = readdir($dh)) !== false)
        if(!(($f==".")||($f=="..")) && filetype("./$f")!="dir" && strtolower(pathinfo($f, PATHINFO_EXTENSION))=="torrent" && substr($f, 0, strlen($tag))!=$tag )
        {
            $r=bdec(file_get_contents($f));
            if (isset($r["info"]["source"]) && $r["info"]["source"]=="Underground Gamer")
            {
                echo ($f.": ");
                $r["announce"]="http://localhost";
                unset($r["info"]["private"]);
                file_put_contents($tag.$f,benc($r));
                echo ("OK!\n");
            }
        }
    closedir($dh);
}
function info_hash($info)
{
    return strtoupper(bin2hex(pack("H*", sha1(benc($info)))));
}
echo (memory_get_peak_usage() / 1024 / 1024) . " MB of RAM, " . (microtime(true) - $parse_start_time) . " seconds.\n\n";

/*
  Bencoding OOP wrapper for PHP | by Proger_XP | In public domain
    http://proger.i-forge.net/BEncoded/7Tn

  Based on lightenc.php functions from
    http://wiki.theory.org/Decoding_encoding_bencoded_data_with_PHP
*/
/* lightenc.php */
function bdec($s, &$pos=0) {
  if($pos>=strlen($s)) {
    return null;
  }
  switch($s[$pos]){
  case 'd':
    $pos++;
    $retval=array();
    while ($s[$pos]!='e'){
      $key=bdec($s, $pos);
      $val=bdec($s, $pos);
      if ($key===null || $val===null)
        break;
      $retval[$key]=$val;
    }
    $retval["isDct"]=true;
    $pos++;
    return $retval;

  case 'l':
    $pos++;
    $retval=array();
    while ($s[$pos]!='e'){
      $val=bdec($s, $pos);
      if ($val===null)
        break;
      $retval[]=$val;
    }
    $pos++;
    return $retval;

  case 'i':
    $pos++;
    $digits=strpos($s, 'e', $pos)-$pos;
    // Proger_XP: changed (int) -> (float) to avoid trimming of values exceeding
    //            signed int's max value (2147483647).
    $val=(float)substr($s, $pos, $digits);
    $pos+=$digits+1;
    return $val;

//  case "0": case "1": case "2": case "3": case "4":
//  case "5": case "6": case "7": case "8": case "9":
  default:
    $digits=strpos($s, ':', $pos)-$pos;
    if ($digits<0 || $digits >20)
      return null;
    $len=(float)substr($s, $pos, $digits);
    $pos+=$digits+1;
    $str=substr($s, $pos, $len);
    $pos+=$len;
    //echo "pos: $pos str: [$str] len: $len digits: $digits\n";
    return (string)$str;
  }
  return null;
}

// Proger_XP: added added skipping for null values and $tempChar prefix for list/dicts.
function benc(&$d, $tempChar = null){
  if(is_array($d)){
    $ret="l";
    $isDict=!empty($d["isDct"]);
    if($isDict){
      $ret="d";
      // this is required by the specs, and BitTornado actualy chokes on unsorted dictionaries
      ksort($d, SORT_STRING);
    }
    foreach($d as $key=>$value) {
      if($isDict){
        // skip the isDct element, only if it's set by us
        if (!bskip($key, $value, $tempChar)) {
          $ret .= strlen($key).":$key";
        }
      } elseif (!is_int($key) and !is_float($key) and trim($key, '0..9') !== '') {
                // Proger_XP: added exception raising for non-numeric list keys.
                throw new Exception('Cannot bencode() a list - it contains a non-numeric key "'.$key.'".');
            }

      if (is_string($value)) {
        $ret.=strlen($value).":".$value;
      } elseif (is_int($value) or is_float($value)){
        $ret.="i${value}e";
      } else {
        $ret.=benc ($value);
      }
    }
    return $ret."e";
  } elseif (is_string($d)) { // fallback if we're given a single bencoded string or int
    return strlen($d).":".$d;
  } elseif (is_int($d) or is_float($d)) {
    return "i${d}e";
  } else {
    return null;
  }
}

// bskip by Proger_XP.
function bskip($key, &$value, $tempChar = null) {
  return ($key === 'isDct' and $value) or $value === null or strpos($key, $tempChar) === 0;
}
?>