How PHP reads the contents of torrent seed files (test available) _php tips

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<?php/** * Class Xbencoder * Author:Angus.Fenying * version:0.1 * date:2014-06-03 * * This class helps Str
 Ingify or parse Benc * codes.
 * All copyrights 2007-2014 fenying Studio Reserved.
  * * Class Xbencoder {const READY = 0;
  Const READ_STR = 1;
  Const READ_DICT = 2;
  Const READ_LIST = 3;
  Const READ_INT = 4;
  Const READ_KEY = 5;
  Public $y;
  Protected $z, $m, $n;
  protected $stat;
  protected $stack;
   /** * This method saves the status of current * Encode/decode work. * * Protected function push ($newY, $newStat) {Array_push ($this->stack, Array ($this->y, $this->z, $this-&G
    T;m, $this->n, $this->stat));
  List ($this->y, $this->z, $this->m, $this->n, $this->stat) = Array ($newY, 0, 0, 0, $newStat);
   /** * This method to restore the saved status of current * Encode/decode work.
    */protected function pop () {$t = Array_pop ($this->stack); if ($t) {if ($t [4] = = Self::read_dict{$t [0]->{$t [1]} = $this->y;
      $t [1] = 0;
      } elseif ($t [4] = = self::read_list) $t [0][] = $this->y;
    List ($this->y, $this->z, $this->m, $this->n, $this->stat) = $t;
   }/** * This method initializes the status of work.
   * You SHOULD call this method before EVERYTHING.
    * * Public Function init () {$this->stat = Self::ready;
    $this->stack = Array ();
  $this->z = $this->m = $this->n = 0;
   /** * This method decode $s ($l as length).
   * You can get $obj->y as the result.
    * * Public Function decode ($s, $l) {$this->y = 0;
            for ($i = 0; $i < $l + + $i) {switch ($this->stat) {case self::ready:if ($s [$i] = = ' d ') {
            $this->y = new Xbdict ();
          $this->stat = self::read_dict;
            } elseif ($s [$i] = = ' L ') {$this->y = array ();
          $this->stat = self::read_list; } bReak; Case Self::read_int:if ($s [$i] = = ' E ') {$this->y->val = substr ($s, $this->m, $i-$this-&
            GT;M);
          $this->pop ();
        } break;
          Case Self::read_str:if (Xbint::isnum ($s [$i])) continue;
            if ($s [$i] = ': ') {$this->z = substr ($s, $this->m, $i-$this->m);
            $this->y = substr ($s, $i + 1, $this->z + 0);
            $i + + $this->z;
          $this->pop ();
        } break;
          Case Self::read_key:if (Xbint::isnum ($s [$i])) continue;
            if ($s [$i] = ': ') {$this->n = substr ($s, $this->m, $i-$this->m);
            $this->z = substr ($s, $i + 1, $this->n + 0);
            $i + + $this->n;
          $this->stat = self::read_dict;
        } break;
            Case Self::read_dict:if ($s [$i] = = ' E ') {$this->pop (); BreaK
            } elseif (! $this->z) {$this->m = $i;
            $this->stat = Self::read_key;
          Break
              Case Self::read_list:switch ($s [$i]) {case ' E ': $this->pop ();
            Break
              Case ' d ': $this->push (New Xbdict (), self::read_dict);
            Break
              Case ' I ': $this->push (New Xbint (), self::read_int);
              $this->m = $i + 1;
            Break
              Case ' l ': $this->push (Array (), self::read_list);
            Break
                Default:if (Xbint::isnum ($s [$i])) {$this->push (", self::read_str)";
              $this->m = $i;
      }} break;
    }} $rtn = Empty ($this->stack);
    $this->init ();
  return $RTN;
   /** * This method encode the $obj->y into Bencode.
    */Public Function encode () {return $this-&GT;_ENCDO ($this->y); protected function _encstr ($STR) {return strlen ($STR). ':' .
  $STR;
    } protected function _encdo ($o) {if (is_string)) return $this->_encstr ($o); if ($o instanceof xbint) return ' I '. $o->val.
    ' E ';
      if ($o instanceof xbdict) {$r = ' d '; foreach ($o as $k => $c) $r. = $this->_encstr ($k).
      $this->_encdo ($c); Return $r.
    ' E ';
      } if (Is_array ($o)) {$r = ' l ';
      foreach ($o as $c) $r. = $this->_encdo ($c); Return $r.
    ' E ';
  }} class Xbdict {} class Xbint {public $val;
  Public function __construct ($val = 0) {$this->val = $val;
    The public static function Isnum ($CHR) {$chr = ord ($CHR);
    if ($chr <= && $chr >=) return true;
  return false;
}//Use instance $s = file_get_contents ("test.torrent");
$BC = new Xbencoder ();
$BC->init ();
$BC->decode ($s, strlen ($s)); Var_dump ($BC->y);

 

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