Binary pagination generator

paginator.php

<?php

   /**
     * Generates a pagination array
     *
     * @param int $total_items
     * @param int $page_size
     * @param int $current_page
     * @return array $pagination
     */
     function pagination($total_items, $page_size, $current_page)
    {
        // 1115 8 1

        // 1115 / 8 = 130

        /// 1 ... 33 ...65 65 66..78 80 81... 130

        $l = (int)ceil($total_items / $page_size);
        $a = $current_page;

        if ($l > 11 && $a < 6) {
            $a = 1 + 5;
        }

        if ($l > 11 && ($l - $a) < 5) {
            $a = $l - 5;
        }

        $left  = $a - 1;
        $right = $l - $a;

        $p = array($a);

        if ($left > 0 && $left < 6) {
            $p = array_merge($p, range(1, $left));
        }

        if ($left == 6) {
            $p = array_merge($p, range($a - 3, $a - 1), array(1));
        }

        if ($left > 6) {
            array_push($p, 1, (int)(($a + 1)/2), $a - 1);
        }

        if ($right > 0 && $right < 6) {
            $p = array_merge($p, range($a + 1, $l));
        }

        if ($right == 6) {
            $p = array_merge($p, range($a + 1, $a + 3), array($l));
        }

        if ($right > 6) {
            array_push($p, $a + 1, (int)(($l + $a)/2), $l);
        }

        sort($p);

        return $p;
    }