showing surrounding page numbers

Question

I've been doing some pagination recently and used the following:

if ( $totalPages > $pagesToShow ) {
    $start = $pageNumber - floor($pagesToShow/2);
    $end = $pageNumber + floor($pagesToShow/2);

    while ( $start < 1 ) {
        $start++;
        $end++;
    }

    while ( $end > $totalPages ) {
        $start--;
        $end--;
    }

} else {
    $start = 1;
    $end = $totalPages;
}

to work out where to start and end the list of surrounding pages. So that a paging list can be created like << < 1 2 3 4 5 > >>'.

Just wondering if there is a better method as using loops like that seems a little odd.

Answer 1

You can replace the first loop

while ( $start < 1 ) {
    $start++;
    $end++;
}

with

if($start < 1)
{
    $end += (1 - $start);
    $start = 1;
}

Something similar can be done for the second loop, but the other way around:

if ( $end > $totalPages ) {
    $start -= ($end - $totalPages);
    $end = $totalPages;
}

Edit: It is much easier to just trim the page numbers which are out of bounds, replace your example code with:

$start = $pageNumber - $pagesToShow;
$end = $pageNumber + $pagesToShow;

if($start < 1)
    $start = 1;

if($end > $totalPages)
    $end = $totalPages;

$pagesToShow is the maximum amount of pages to show before and after the current page (if not out of bounds)

Answer 2

You might look in to using the Zend_Paginator control. It works with simple Arrays, as well as many other things. It will even handle giving you simple access to previous/next page information.