PHP Pagination Function that changes with the page - php

Question

So i wrote a simple pagination function:
function pagination ( $iTotalItems )
{
if( is_array( $iTotalItems ) )
$totalItems = sizeof ( $iTotalItems );
if( is_int( $iTotalItems ) )
$totalItems = $iTotalItems;
$page = (int)( empty( $_GET['page'] ) ? 1 : $_GET['page'] );
if ($page <= 0) $page = 1;
$itemsPerPage = PAG_PER_PAGE;
$prev = $page - 1;
$next = $page + 1;
$prevlabel = "‹ Prev";
$nextlabel = "Next ›";
$totalPages = ceil( $iTotalItems / $itemsPerPage );
$perPage = $page == 'all' ? $totalItems : $itemsPerPage;
$adjacents = 2;
if( $totalItems > $itemsPerPage )
{
$filler = '';
$NumStart = '';
$NumEnd = '';
$pageNavigation = '<div class="Pagination">'. PHP_EOL;
$previousLink = $prev !== 0 ? "<a href='?p=items&page={$prev}'>{$prevlabel}</a>". PHP_EOL : "<span class='noneLink'>{$prevlabel}</span>". PHP_EOL;
$nextLink = $page < $totalPages ? "<a href='?p=items&page={$next}'>{$nextlabel}</a>". PHP_EOL : "<span class='noneLink'>{$nextlabel}</span>". PHP_EOL;
for( $i = 1; $i < $totalPages + 1; $i++ )
{
if( $i <= 10 ) { $NumStart .= $page == $i ? '<span class="noneLink">'.$i.'</span>' : ''.$i.''. PHP_EOL; }
else { $filler = '...'; }
if( $i > $totalPages - 3 ) {$NumEnd .= $page == $i ? "<span class='noneLink'>{$i}</span>" : "<a href='?p=items&page={$i}'>{$i}</a>". PHP_EOL; }
}
}
return $pageNavigation . $previousLink . $NumStart . $filler . $NumEnd . $nextLink . '</div>';
}
Now it works great and all but Im not sure how to make it change depending on the page. For example: with 40 pages and while on page 1 it looks like this.
‹ Prev 1 2 3 4 5 67 8 9 10 ...38 39 40 Next ›
However, even if im at page.. say 20 it still looks the same.
Whats the best and most simple way to code something like this while on page 1:
1 2 3 4 5 6 7 8 9 … 38 39 40 Next ›
and something like this while on page 15:
‹ Prev 1 2 3 … 11 12 13 14 15 16 17 18 19 … 38 39 40 Next ›
Thanks in advance!