A good php paging class code

/**
* filename: ext_page.class.php
* @package:phpbean
* @author :feifengxlq
* @copyright :Copyright 2006 feifengxlq
* @license:version 2.0
* description: paging class, Four paging modes
* 2.0 added functions: support custom styles, custom styles, support both PHP4 and PHP5,
* to see detail, please visit http://www.phpobject.net/blog/read.php?
 * example:
* mode four paging modes:
require_once('../libs/classes/page.class.php');
$page=new page(array('total'=>1000,'perpage' =>20));
echo 'mode:1'.$page->show();
echo 'mode:2'.$page->show(2 );
echo 'mode:3'.$page->show(3);
echo 'mode:4'.$page->show(4 );
Enable AJAX:
$ajaxpage=new page(array('total'=>1000,'perpage'=>20,'ajax'=>'ajax_page','page_name'=>'test' ));
echo 'mode:1'.$ajaxpage->show();
Adopt inherited custom paging display mode:
demo:http://www.phpobject.net/blog
*/
class page
{
/**
* config ,public
*/
var $page_name="PB_page";//page tag, Used to control the url page
var $next_page='>';//Next page
var $pre_page='<';//Previous page
var $first_page='First';//Homepage
var $ last_page='Last';//Last page
var $pre_bar='<<';//Previous paging bar
var $next_bar='>>';//Next paging bar
var $format_left ='[';
var $format_right=']';
var $is_ajax=false;//Whether AJAX paging mode is supported
/**
* private
*
*/
var $pagebarnum =10;//Control the number of record strips.
var $totalpage=0;//Total number of pages
var $ajax_action_name='';//AJAX action name
var $nowindex=1;//Current page
var $url="";//url address header
 var $offset=0;
/**
* constructor构造函数
*
* @param array $array['total'],$array['perpage'],$array['nowindex'],$array['url'],$array['ajax']
*/
function page($array)
{
if(is_array($array)){
if(!array_key_exists(' total',$array))$this->error(__FUNCTION__,'need a param of total');
$total=intval($array['total']);
$perpage=(array_key_exists('perpage' ,$array))?intval($array['perpage']):10;
$nowindex=(array_key_exists('nowindex',$array))?intval($array['nowindex']):'';
 $url=(array_key_exists('url',$array))?$array['url']:'';
}else{
$total=$array;
$perpage=10;
$nowindex='';
$url='';
}
if((!is_int($total))||($total<0))$this->error(__FUNCTION__,$total.' is not a positive integer!') ;
if((!is_int($perpage))||($perpage<=0))$this->error(__FUNCTION__,$perpage.' is not a positive integer!');
if(!empty( $array['page_name']))$this->set('page_name',$array['page_name']);//Set pagename
$this->_set_nowindex($nowindex);//Set the current page
$this->_set_url($url);//Set the link address
$this->totalpage=ceil($total/$perpage);
$this->offset=($this->nowindex- 1)*$perpage;
if(!empty($array['ajax']))$this->open_ajax($array['ajax']);//Open AJAX mode
}
/**
* Set the value of the specified variable name in the class. If the change does not belong to this class, an exception will be thrown
*
* @param string $var
* @param string $value
*/
function set($var,$value)
{
if(in_array($var,get_object_vars($this)))
$this->$var=$value;
else {
$this-> ;error(__FUNCTION__,$var." does not belong to PB_Page!");
}
}
/**
* Turn on inverted AJAX mode
*
* @param string $action The default ajax triggered action.
*/
function open_ajax($action)
{
$this->is_ajax=true;
$this->ajax_action_name=$action;
}
/**
* Get the code to display "next page"
*
* @param string $style
* @return string
*/
function next_page($style='')
{
if($this->nowindex<$this->totalpage){
return $this->_get_link($this->_get_url($this->nowindex+1),$this->next_page,$style);
}
return ''.$this->next_page.'';
}
/**
* Get the code to display "previous page"
*
* @param string $style
* @return string
*/
function pre_page($style='')
{
if($this->nowindex>1){
return $this->_get_link($this->_get_url($this->nowindex-1),$this->pre_page,$style);
}
return ''.$this->pre_page.'';
}
/**
* Get the code to display "Home Page"
*
* @return string
*/
function first_page($style='')
{
if($this->nowindex==1){
return ''.$this->first_page.'';
}
return $this->_get_link($this->_get_url(1),$this->first_page,$style);
}
/**
* Get the code to display the "last page"
*
* @return string
*/
function last_page($style='')
{
if($this->nowindex==$this->totalpage){
return ''.$this->last_page.'';
}
return $this->_get_link($this->_get_url($this->totalpage),$this->last_page,$style);
}
function nowbar($style='',$nowindex_style='')
{
$plus=ceil($this->pagebarnum/2);
if($this->pagebarnum-$plus+$this->nowindex>$this->totalpage)$plus=($this->pagebarnum-$this->totalpage+$this->nowindex);
$begin=$this->nowindex-$plus+1;
$begin=($begin>=1)?$begin:1;
$return='';
for($i=$begin;$i<$begin+$this->pagebarnum;$i++)
{
if($i<=$this->totalpage){
if($i!=$this->nowindex)
$return.=$this->_get_text($this->_get_link($this->_get_url($i),$i,$style));
else
$return.=$this->_get_text(''.$i.'');
}else{
break;
}
$return.="n";
}
unset($begin);
return $return;
}
/**
* Get the code to display the jump button
*
* @return string
*/
function select()
{
$return=''; 
for($i=1;$i<=$this->totalpage;$i++) 
{ 
if($i==$this->nowindex){ 
$return.=''.$i.''; 
}else{ 
$return.=''.$i.''; 
} 
} 
unset($i); 
$return.='';
return $return;
}
/**
* Get the value required for limit in the mysql statement
*
* @return string
*/
function offset()
{
return $this->offset;
}
/**
* Control paging display style
*
* @param int $mode
* @return string
*/
function show($mode=1)
{
switch ($mode)
{
case '1':
$this->next_page='下一页';
$this->pre_page='上一页';
return $this->pre_page().$this->nowbar().$this->next_page().'第'.$this->select().'页';
break;
case '2':
$this->next_page='下一页';
$this->pre_page='上一页';
$this->first_page='首页';
$this->last_page='尾页';
return $this->first_page().$this->pre_page().'[第'.$this->nowindex.'页]'.$this->next_page().$this->last_page().'第'.$this->select().'页';
break;
case '3':
$this->next_page='下一页';
$this->pre_page='上一页';
$this->first_page='首页';
$this->last_page='尾页';
return $this->first_page().$this->pre_page().$this->next_page().$this->last_page();
break;
case '4':
$this->next_page='下一页';
$this->pre_page='上一页';
return $this->pre_page().$this->nowbar().$this->next_page();
break;
case '5':
return $this->pre_bar().$this->pre_page().$this->nowbar().$this->next_page().$this->next_bar();
break;
}
}
/*------private function (私有方法)---------*/
/**@link: http://bbs.it-home.org
* Set url header address
* @param: String $url
* @return boolean
*/
function _set_url($url="")
{
if(!empty($url)){
//手动设置
$this->url=$url.((stristr($url,'?'))?'&':'?').$this->page_name."=";
}else{
//自动获取
if(empty($_SERVER['QUERY_STRING'])){
//不存在QUERY_STRING时
$this->url=$_SERVER['REQUEST_URI']."?".$this->page_name."=";
}else{
//
if(stristr($_SERVER['QUERY_STRING'],$this->page_name.'=')){
//地址存在页面参数
$this->url=str_replace($this->page_name.'='.$this->nowindex,'',$_SERVER['REQUEST_URI']);
$last=$this->url[strlen($this->url)-1];
if($last=='?'||$last=='&'){
$this->url.=$this->page_name."=";
}else{
$this->url.='&'.$this->page_name."=";
}
}else{
//
$this->url=$_SERVER['REQUEST_URI'].'&'.$this->page_name.'=';
}//end if
}//end if
}//end if
}
/**
* Set current page
*
*/
function _set_nowindex($nowindex)
{
if(empty($nowindex)){
//系统获取
if(isset($_GET[$this->page_name])){
$this->nowindex=intval($_GET[$this->page_name]);
}
}else{
//手动设置
$this->nowindex=intval($nowindex);
}
}
/**
* Return the address value for the specified page
*
* @param int $pageno
* @return string $url
*/
function _get_url($pageno=1)
{
return $this->url.$pageno;
}
/**
* Get pagination display text, for example, by default _get_text('1') will return [1]
*
* @param String $str
* @return string $url
*/
function _get_text($str)
{
return $this->format_left.$str.$this->format_right;
}
/**
* Get link address
*/
function _get_link($url,$text,$style=''){
$style=(empty($style))?'':'class="'.$style.'"';
if($this->is_ajax){
//如果是使用AJAX模式
return ''.$text.'';
}else{
return ''.$text.'';
}
}
/**
* Error handling methods
*/
function error($function,$errormsg)
{
die('Error in file '.__FILE__.' ,Function '.$function.'() :'.$errormsg);
}
}
$page=new page(array('total'=>1000,'perpage'=>20));
echo 'mode:1'.$page->show();
echo 'mode:2'.$page->show(2);
echo 'mode:3'.$page->show(3);
echo 'mode:4'.$page->show(4);
echo '开始AJAX模式:';
$ajaxpage=new page(array('total'=>1000,'perpage'=>20,'ajax'=>'ajax_page','page_name'=>'test'));
echo 'mode:1'.$ajaxpage->show();
?>