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<?php# gen_rand_string
 return function ($length, $chars = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ')
 {
 mt_srand((double)microtime() * 1000000);  #?????????????
 $r = '';
 $l = strlen($chars);
 for ($i = 0; $i < $length; $i++)
 {
 $r .= substr($chars, mt_rand(0, $l - 1), 1);
 }
 return $r;
 }?>
 
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