PHP 随机生成字符串，验证码，礼包码等

PHP 随机生成字符串，验证码，礼包码等
可调整生成个数和位数

      $result=sp_gm_get_gift_code(1000);//随机生成1000个
        foreach($result as $key => $value){
            echo $value;
            echo "<br>";
        }

   function sp_gm_get_gift_code($number) {
        for ($i=0;$i<$number;$i++){
            $uniqid = uniqid('gm',true);
            $param_string = $_SERVER['HTTP_USER_AGENT'].$_SERVER['REMOTE_ADDR'].$_SERVER['SERVER_SOFTWARE'].time().rand().$uniqid;
            $sha1 = sha1($param_string);
            for(
                $a=$sha1,
                $s = '0123456789abcdefghijklmnopqrstuvwxyz',
                $d = '',
                $f = 0;
                $f < 7;
                $g = ord( $a[ $f ] ),
                $d .= $s[ ( $g ^ ord( $a[ $f + 8 ] ) ) - $g & 0x1F ],
                $f++
            );

            yield $d;
        }
    }