Pagination that can be used on any website in bootstrap format

pagination.php

/**
 * @param int $total Total number of records
 * @param int $per_page How many records to display per page
 * @param int $current_page Current page number
 * @param string $link sprintf formatted string for page links $1 = page number
 * @return string in html ul-li format
 */
function pagination($total, $per_page, $current_page, $link)
{
    $boundry = 3; // How many pages to show around the current page

    $current_page = (int)$current_page ? (int)$current_page : 1;

    $html = '<ul class="pagination">';

    $count_remainder = $total / $per_page;
    $last = ceil($count_remainder);

    if ($current_page > 1) {
        $current_link = sprintf($link, $current_page - 1);
        $html .= '<li class="page-item"><a class="page-link" href="' . $current_link . '">&lt;&lt; Prev</a></li>';
    }
    if ($last > 1) {
        $has_gap = false;
        for ($i = 1; $i <= $last; $i++) {
            $show = false;
            if ($current_page == $i) {
                $sel = "active-pagination";
            } else {
                $sel = '';
            }

            if ($i == 1) {
                $show = true;
            }

            if ($i > ($current_page - $boundry) && $i < ($current_page + $boundry)) {
                $show = true;
            }

            if ($i == $last) {
                $show = true;
            }

            if ($show == true) {
                if ($has_gap == true) {
                    $html .= '<li class="page-item disabled"><a class="' . $sel . ' page-link">...</a></li>';
                }
                $has_gap = false;
                $current_link = sprintf($link, $i);
                $html .= '<li class="page-item'.($i==$current_page?' active':'').'"><a class="' . $sel . ' page-link" href="' . $current_link . '">' . $i . '</a></li>';
            } else $has_gap = true;
        }
    }


    if ($current_page != $last) {
        $current_link = sprintf($link, $current_page + 1);
        $html .= '<li class="page-item"><a class="page-link" href="' . $current_link . '">Next &gt;&gt;</a></li>';
    }

    $html .= '</ul>';

    return $html;
}

echo pagination($total_items, 15, $current_page, 'list.php?p=%d');