//G_tk计算
function getGTK($skey){
 $hash = 5381;
 for($i=0;$i<strlen($skey);++$i){
  $hash += ($hash << 5) + utf8_unicode($skey[$i]);
 }
 return $hash & 0x7fffffff;
}
function utf8_unicode($c) {
 switch(strlen($c)) {
  case 1:
  return ord($c);
  case 2:
  $n = (ord($c[0]) & 0x3f) << 6;
  $n += ord($c[1]) & 0x3f;
  return $n;
  case 3:
  $n = (ord($c[0]) & 0x1f) << 12;
  $n += (ord($c[1]) & 0x3f) << 6;
  $n += ord($c[2]) & 0x3f;
  return $n;
  case 4:
  $n = (ord($c[0]) & 0x0f) << 18;
  $n += (ord($c[1]) & 0x3f) << 12;
  $n += (ord($c[2]) & 0x3f) << 6;
  $n += ord($c[3]) & 0x3f;
  return $n;
 }
}