PHP function to generate a list of page turning links (page numbers)

/**
* Generate page number list
*
* @param int $element_total_count Total number of elements
* @param int $current_page Current page
* @param int $per_page_elem_count Number of elements per page
* @param int $show_page_num Number of page numbers displayed in the list
* @param string $up_down_class Page up and down style
* @param string $num_class Number style of the current page number
* @param string $href Page link
* @param string $page_symbol Link parameter passing the page number
* @return string
*/
function get_page_link_list($element_total_count,$current_page=1,$per_page_elem_count=10,$show_page_num=10,$up_down_class,$num_class,$href,$page_symbol='p')
{
    if(empty($href))
    {
        //自动取得剔除页码参数的页面链接
        $page_name = basename($_SERVER['PHP_SELF']);
        $params = $_SERVER['QUERY_STRING'];
        $params_str = '';
        if(!empty($params))
        {
            $params = str_replace('&', '&', $params);
            $params_array = explode('&', $params);
            foreach($params_array as $param)
            {
                if(!empty($param))
                {
                    $index = strpos($param, '=');
                    if($index)
                    {
                        $key = substr($param, 0, $index);
                        if($key && $key != $page_symbol)
                            $params_str .= $param . '&';
                    }
                }
            }
        }
        if(!empty($params_str))
            $href = $page_name . '?' . $params_str;
        else
            $href = $page_name;

        $href = rtrim($href,'&');
    }

    $prefix = strpos($href,"?") ? "&" : "?";
    $prefix .= $page_symbol;

    $page_total_count = ceil($element_total_count/$per_page_elem_count);
    if(intval($element_total_count)< 1 || !isset($element_total_count))
    {
        return '';
    }
    if($element_total_count <= $per_page_elem_count)
        return '';
    if($current_page>$page_total_count)
        $current_page = 1;

    if(strpos($href,"#"))
    {
        $label = substr($href,strpos($href,"#"));
        $href = substr($href,0,strpos($href,"#"));
    }

    /* 生成页码 */
    if($current_page > ceil($show_page_num/2))
    {
        $start = $current_page - ceil($show_page_num/2);
        $end = (($current_page+ceil($show_page_num/2))<$page_total_count) ?
            $current_page+ceil($show_page_num/2)-1 : $page_total_count;
    }
    else
    {
        $start = 1;
        $end = ($show_page_num>$page_total_count) ? $page_total_count : $show_page_num;
    }
    if(!empty($num_class))
        $num_class_str = ' class="'.$num_class.'"';
    else
        $num_class_str = '';
    $page_num_string = '';

    for($i=$start;$i<=$end;$i++)
    {
        if(intval($i) == intval($current_page))
            $page_num_string .= ''.$i.'';
        else
            $page_num_string .= ''.$i.'';
    }

    /* 上下翻页 */
    $prev_page = (intval($current_page-1)>0)?intval($current_page-1):0;
    $next_page = (intval($current_page)<$page_total_count) ? intval($current_page+1) : 0;
    if(!empty($up_down_class))
        $up_down_class_str = ' class="'.$up_down_class.'"';
    else
        $up_down_class_str = '';

    $page_up_string = '';

    if(intval($prev_page) > 0)
        $page_up_string = '上一页';
    else
        $page_up_string = '上一页';
    $page_down_string = '';

    if(intval($next_page) > 0)
        $page_down_string .= '下一页';
    else
        $page_down_string .= '下一页';
    /* 返回结果 */
    return $page_up_string . $page_num_string . $page_down_string;
}
?>