Pagination like flickr, digg, github - the standard pagination pattern

pagination.php

<?php
// based on the work of Jason Coleman
// http://www.strangerstudios.com/blog/2006/07/paginate-your-site-like-digg/

/* 	The pagination function simply spits out a data structure
	that you can render any way you like. 
	
	See also the javascript version for node:
	https://gist.github.com/robmint/4651cf1c6f336e663dba
*/

$p = getPaginationString(2,150,15,1,"/","p=");

// simple text renderer
$out = '';
foreach($p as $v) {
	if($v['previous'])
		$out .= " < ";
	elseif ($v['next'])
		$out .= " > ";
	elseif ($v['ellipsis'])
		$out .= " ... ";
	elseif ($v['selected'])
		$out.= " [".$v['label']."] ";
	else {
		$out.= " ".$v['label']." ";
	}

}

// show data structure
print_r($p);

// show rendered output
print  $out . "\n";

function getPaginationString($page = 1, $totalitems, $limit = 15, $adjacents = 1, $targetpage = "/", $pagestring = "?page=")
{		
	//defaults
	if(!$adjacents) $adjacents = 1;
	if(!$limit) $limit = 15;
	if(!$page) $page = 1;
	if(!$targetpage) $targetpage = "/";
	
	//other vars
	$prev = $page - 1;									//previous page is page - 1
	$next = $page + 1;									//next page is page + 1
	$lastpage = ceil($totalitems / $limit);				//lastpage is = total items / items per page, rounded up.
	$lpm1 = $lastpage - 1;								//last page minus 1
	
	$pages = array();

	if($lastpage > 1)
	{	

		//previous button
		if ($page > 1) 
			$pages[] = array('previous' => true, 'url' => $targetpage . $pagestring . $prev);
		
		//pages	
		if ($lastpage < 7 + ($adjacents * 2))	//not enough pages to bother breaking it up
		{	
			for ($counter = 1; $counter <= $lastpage; $counter++)
			{
				if ($counter == $page)
					$pages[] = array('selected' => true, 'label' => $counter);
				else
					$pages[] = array('label' => $counter, 'url' => $targetpage . $pagestring . $counter);
			}
		}
		elseif($lastpage >= 7 + ($adjacents * 2))	//enough pages to hide some
		{
			//close to beginning; only hide later pages
			if($page < 1 + ($adjacents * 3))		
			{
				for ($counter = 1; $counter < 4 + ($adjacents * 2); $counter++)
				{
					if ($counter == $page)
						$pages[] = array('selected' => true, 'label' => $counter);
					else
						$pages[] = array('label' => $counter, 'url' => $targetpage . $pagestring . $counter);
					}
				$pages[] = array('ellipsis' => true);	
				$pages[] = array('label' => $lpm1, 'url' =>  $targetpage . $pagestring . $lpm1);
				$pages[] = array('label' => $lastpage, 'url' =>  $targetpage . $pagestring . $lastpage);
			}
			//in middle; hide some front and some back
			elseif($lastpage - ($adjacents * 2) > $page && $page > ($adjacents * 2))
			{
				$pages[] = array('label' => '1', 'url' => $targetpage . $pagestring . "1");
				$pages[] = array('label' => '2', 'url' => $targetpage . $pagestring . "2");
				$pages[] = array('ellipsis' => true);	

				for ($counter = $page - $adjacents; $counter <= $page + $adjacents; $counter++)
				{
					if ($counter == $page)
						$pages[] = array('selected' => true, 'label' => $counter);
					else
						$pages[] = array('label' => $counter, 'url' => $targetpage . $pagestring . $counter);
				}
				$pages[] = array('ellipsis' => true);	
				$pages[] = array('label' => $lpm1, 'url' =>  $targetpage . $pagestring . $lpm1);
				$pages[] = array('label' => $lastpage, 'url' =>  $targetpage . $pagestring . $lastpage);
			}
			//close to end; only hide early pages
			else
			{
				$pages[] = array('label' => '1', 'url' => $targetpage . $pagestring . "1");
				$pages[] = array('label' => '2', 'url' => $targetpage . $pagestring . "2");
				$pages[] = array('ellipsis' => true);	
				for ($counter = $lastpage - (1 + ($adjacents * 3)); $counter <= $lastpage; $counter++)
				{
					if ($counter == $page)
						$pages[] = array('selected' => true, 'label' => $counter);
					else
						$pages[] = array('label' => $counter, 'url' => $targetpage . $pagestring . $counter);
				}
			}
		}
		
		//next button
		if ($page < $counter - 1) 
			$pages[] = array('next' => true, 'url' => $targetpage . $pagestring . $next);
	}
	
	return $pages;

}