A class that makes paging (previous and next links) through MySQL results easy.

By : Jesse

<?php
/**************************************************************************************
* Class: Pager
* Author: Tsigo <tsigo@tsiris.com>
* Methods:
* findStart
* findPages
* pageList
* nextPrev
* Redistribute as you see fit.
**************************************************************************************/
class Pager
{
/***********************************************************************************
* int findStart (int limit)
* Returns the start offset based on $_GET['page'] and $limit
***********************************************************************************/
function findStart($limit)
{
if ((!isset($_GET['page'])) || ($_GET['page'] == "1"))
{
$start = 0;
$_GET['page'] = 1;
}
else
{
$start = ($_GET['page']-1) * $limit;
}

return $start;
}
/***********************************************************************************
* int findPages (int count, int limit)
* Returns the number of pages needed based on a count and a limit
***********************************************************************************/
function findPages($count, $limit)
{
$pages = (($count % $limit) == 0) ? $count / $limit : floor($count / $limit) + 1;

return $pages;
}
/***********************************************************************************
* string pageList (int curpage, int pages)
* Returns a list of pages in the format of "« < [pages] > »"
***********************************************************************************/
function pageList($curpage, $pages)
{
$page_list = "";

/* Print the first and previous page links if necessary */
if (($curpage != 1) && ($curpage))
{
$page_list .= " <a href=\"".$_SERVER['PHP_SELF']."?page=1\" title=\"First Page\">«</a> ";
}

if (($curpage-1) > 0)
{
$page_list .= "<a href=\"".$_SERVER['PHP_SELF']."?page=".($curpage-1)."\" title=\"Previous Page\"><</a> ";
}

/* Print the numeric page list; make the current page unlinked and bold */
for ($i=1; $i<=$pages; $i++)
{
if ($i == $curpage)
{
$page_list .= "<b>".$i."</b>";
}
else
{
$page_list .= "<a href=\"".$_SERVER['PHP_SELF']."?page=".$i."\" title=\"Page ".$i."\">".$i."</a>";
}
$page_list .= " ";
}

/* Print the Next and Last page links if necessary */
if (($curpage+1) <= $pages)
{
$page_list .= "<a href=\"".$_SERVER['PHP_SELF']."?page=".($curpage+1)."\" title=\"Next Page\">></a> ";
}

if (($curpage != $pages) && ($pages != 0))
{
$page_list .= "<a href=\"".$_SERVER['PHP_SELF']."?page=".$pages."\" title=\"Last Page\">»</a> ";
}
$page_list .= "</td>\n";

return $page_list;
}
/***********************************************************************************
* string nextPrev (int curpage, int pages)
* Returns "Previous | Next" string for individual pagination (it's a word!)
***********************************************************************************/
function nextPrev($curpage, $pages)
{
$next_prev = "";

if (($curpage-1) <= 0)
{
$next_prev .= "Previous";
}
else
{
$next_prev .= "<a href=\"".$_SERVER['PHP_SELF']."?page=".($curpage-1)."\">Previous</a>";
}

$next_prev .= " | ";

if (($curpage+1) > $pages)
{
$next_prev .= "Next";
}
else
{
$next_prev .= "<a href=\"".$_SERVER['PHP_SELF']."?page=".($curpage+1)."\">Next</a>";
}

return $next_prev;
}
}
?>


Example on how to use:


<?php
/* Instantiate class */
require_once("class.pager.php");
$p = new Pager;

/* Show many results per page? */
$limit = 100;

/* Find the start depending on $_GET['page'] (declared if it's null) */
$start = $p->findStart($limit);

/* Find the number of rows returned from a query; Note: Do NOT use a LIMIT clause in this query */
$count = mysql_num_rows(mysql_query("SELECT field FROM table"));

/* Find the number of pages based on $count and $limit */
$pages = $p->findPages($count, $limit);

/* Now we use the LIMIT clause to grab a range of rows */
$result = mysql_query("SELECT * FROM table LIMIT ".$start.", ".$limit);

/* Now get the page list and echo it */
$pagelist = $p->pageList($_GET['page'], $pages);
echo $pagelist;

/* Or you can use a simple "Previous | Next" listing if you don't want the numeric page listing */
//$next_prev = $p->nextPrev($_GET['page'], $pages);
//echo $next_prev;

/* From here you can do whatever you want with the data from the $result link. */
?>

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