pagenavi inspired

// buid-in page navigation; inspired by 'wp-pagenavi'
function page_navi() {
    global $wpdb, $wp_query;
    $posts_per_page = intval(get_query_var('posts_per_page'));
    $paged = intval(get_query_var('paged'));
    $numposts = $wp_query->found_posts;
    $max_page = intval($wp_query->max_num_pages);

    if (empty($paged) || $paged == 0)
        $paged = 1;

    $pages_to_show = 5;
    $pages_to_show_minus_1 = $pages_to_show - 1;
    $half_page_start = floor($pages_to_show_minus_1/2);
    $half_page_end = ceil($pages_to_show_minus_1/2);
    $start_page = $paged - $half_page_start;

    if ($start_page <= 0)
        $start_page = 1;

    $end_page = $paged + $half_page_end;
    if (($end_page - $start_page) != $pages_to_show_minus_1) {
        $end_page = $start_page + $pages_to_show_minus_1;
    }

    if ($end_page > $max_page) {
        $start_page = $max_page - $pages_to_show_minus_1;
        $end_page = $max_page;
    }

    if ($start_page <= 0)
        $start_page = 1;

if($max_page > 1) :
echo '<div class="wp-pagenavi">';
//one step back
if($paged>1) {
echo '<a class="first" href="'.get_pagenum_link($paged-1).'" title="link to '.get_pagenum_link($paged-1).'"><small>&lt;</small> back</a> '; }

//jump to first page
if($start_page!=1) :
if($paged==1) { //echo '<span class="first">1 &laquo;</span>';
} else {
echo '<a class="first" href="'.get_pagenum_link(1).'" title="link to '.get_pagenum_link(1).'">1 &laquo;</a> '; }
endif;

//centimal steps 100 steps back
if($paged>110)  :
echo '<a '; echo 'href="'.get_pagenum_link($paged-100).'" title="link to '.get_pagenum_link($paged-100).'">-100</a> ';
endif;

//decimal steps 10 steps back
if($paged>11)  :
echo '<a '; echo 'href="'.get_pagenum_link($paged-10).'" title="link to '.get_pagenum_link($paged-10).'">-10</a> ';
endif;

//from-to
for($i=$start_page;$i<=$end_page;$i++) :
if($i==$paged) { echo '<span class="current">'.$i.'</span>';
} else {
echo '<a '; echo 'href="'.get_pagenum_link($i).'" title="link to '.get_pagenum_link($i).'">'.$i.'</a>'; }
endfor;

//decimal steps 10 steps forward
if($paged<=$max_page-11) :
echo ' <a '; echo 'href="'.get_pagenum_link($paged+10).'" title="link to '.get_pagenum_link($paged+10).'">+10</a>';
endif;

//centimal steps 100 steps forward
if($paged<=$max_page-110) :
echo ' <a '; echo 'href="'.get_pagenum_link($paged+100).'" title="link to '.get_pagenum_link($paged+100).'">+100</a>';
endif;

//jump to last page
if($max_page>$end_page) :
if($paged==$max_page) { //echo '<span class="last">&raquo; '.$max_page.'</span>';
} else {
echo ' <a class="last" href="'.get_pagenum_link($max_page).'" title="link to '.get_pagenum_link($max_page).'">&raquo; '.$max_page.'</a>'; }
endif;

//one step forward
if($paged<$max_page) {
echo ' <a class="first" href="'.get_pagenum_link($paged+1).'" title="link to '.get_pagenum_link($paged+1).'">next <small>&gt;</small></a> '; }

echo '</div>';
endif;
}
// end of page_navi() function