php生成唯一id/唯一标识符/唯一订单号

 /**
  * php 生成唯一id
  * https://blog.csdn.net/hzqghost/article/details/18914681
  */
 function guid($factor='',$prefix='',$suffix=''){
     list($usec, $sec) = explode(" ", microtime());
     $guid = $prefix. $factor. $_SERVER['HTTP_USER_AGENT'] . $_SERVER['REMOTE_ADDR']
            . $sec . $usec
            . mt_rand(0,1000000).time(). mt_rand(0,1000000).$suffix;
     $guid = substr(sha1($guid),8,32);
     $guid = base_convert($guid,16,36);
     return $prefix.$guid.$suffix;
 }

 //生成唯一标识符   //sha1()函数， "安全散列算法（SHA1）"
 function create_unique(){
     $data = $_SERVER['HTTP_USER_AGENT'].$_SERVER['REMOTE_ADDR'].time().rand();
     return sha1($data);//return md5(time().$data);   //return $data;
 }

 //生成24位唯一订单号
 function create_orderid(){
     return date('Ymd').substr(implode(NULL, array_map('ord', str_split(substr(uniqid(), 7, 13), 1))), 0, 8);
 }