/**
 * 获取必应壁纸
 */
function get_img_bing()
{
    $url = "https://cdn.hankin.cn/hankin";
    $str = file_get_contents('http://cn.bing.com/HPImageArchive.aspx?idx=' . get_rand(0, 15) . '&n=1');
    if (preg_match("/<url>(.+?)<\/url>/ies", $str, $matches))
    {
        $imgurl = 'http://cn.bing.com' . $matches[1];
    }
    if ($imgurl)
    {
        return $imgurl;
    }
    else
    {
        return $url . "/random/material-" . mt_rand(1, 25) . ".png"; //苹果设备都不支持webp
    }
}
/**
 * 不重复随机
 * @param $start
 * @param $end
 * @return int
 */
function get_rand($start,$end)
{
    $numbers = range ($start, $end);
    shuffle ($numbers);
    $num=9999;
    $result = array_slice($numbers,0,$num);
    return rand($result['0'],$result['9999']);
}