code: function _PutDec(&$txt, $val, $pos, $len) {
  		$x = '';
  		for ($i=0;$i<$len;$i++) {
  			if ($val==0) {
  				$z = 0;
  			} else {
  				$z = intval($val % 256);
  				if (($val<0) && ($z!=0)) { // ($z!=0) is very important, example: val=-420085702
  					// special opration for negative value. If the number id too big, PHP stores it into a signed integer. For example: crc32('coucou') => -256185401 instead of  4038781895. NegVal = BigVal - (MaxVal+1) = BigVal - 256^4
  					$val = ($val - $z)/256 -1;
  					$z = 256 + $z;
  				} else {
  					$val = ($val - $z)/256;
  				}
  			}
  			$x .= chr($z);
  		}
  		$txt = substr_replace($txt, $x, $pos, $len);
  	}
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