Einfache Seitennavigation (Pagination)

<?php
class Pagination
{
    protected
        $page_offset_current,   // (double) :   f.e. $_GET['page']
        $lines_count_all,       // (double) :   "SELECT COUNT(*) FROM tbl WHERE ..."
        $lines_per_page,        // (int)    :   how many lines per page are viewed
        $n,                     // (int)    :   nav:    Nx[link/button] [{page_offset_current}] Nx[link/button]
        $last_page_lines_count, // (int)    :   how many lines are viewed pm last page (min 1, up to max {lines_per_page})
        $pages_max_num,         // (double) :   number of pages we need to view all lines by viewing {lines_per_page} a page
        $n_left,                // (double) :   nav:    Nx[link/button] [{page_offset_current}] ...
        $n_right,               // (double) :   nav:    ... [{page_offset_current}] Nx[link/button]
        $page_previous,         // (double) :   nav:    [page_previous] Nx[link/button] [{page_offset_current}] ...
        $page_next,             // (double) :   nav:    ... [{page_offset_current}] Nx[link/button] [page_next]
        $page_jump_backwards,   // (double) :   nav:    [<<] [page_previous] Nx[link/button] [{page_offset_current}] ...
        $page_jump_forwards,    // (double) :   nav:    ... [{page_offset_current}] Nx[link/button] [page_next] [>>]
        $left_side_nav_num,     // (array)  :   contains left side nav numbers
        $right_side_nav_num;    // (array)  :   contains right side nav numbers




    public function __construct($page_offset_current, $lines_count_all, $lines_per_page=25, $n=5)
    {
        $this->page_offset_current  = (!$page_offset_current) ? 1 : (double)($page_offset_current);
        $this->lines_count_all      = (double)$lines_count_all;
        $this->lines_per_page       = (int)$lines_per_page;
        $this->n                    = (int)$n;
        $this->calc();
        return;
    }
    public function __destruct()
    {
        return;
    }
    final protected function calc()
    {
        $this->pages_max_num = floor($this->lines_count_all/$this->lines_per_page);
        (($this->last_page_lines_count=$this->lines_count_all-$this->pages_max_num*$this->lines_per_page) < 1)
            or (++$this->pages_max_num);
        ($this->page_offset_current <= $this->pages_max_num)
            or ($this->page_offset_current=$this->pages_max_num);
        ($this->page_offset_current >= 1)
            or ($this->page_offset_current=1);
        ($this->last_page_lines_count > 0)
            or ($this->last_page_lines_count=$this->lines_per_page);
        (($this->n_left=$this->page_offset_current-$this->n) > 0)
            or ($this->n_left=1);
        (($this->n_right=($this->n_left === 1) ? $this->n*2+1 : $this->page_offset_current+$this->n) < $this->pages_max_num)
            or (($this->n_right=$this->pages_max_num)and ($this->n_left-=$this->n-($this->pages_max_num-$this->page_offset_current)));
        ($this->n_left > 0)
            or ($this->n_left=1);
        (($this->page_previous=$this->page_offset_current-1) >= 1)
            or ($this->page_previous=1);
        (($this->page_next=$this->page_offset_current+1) <= $this->pages_max_num)
            or ($this->page_next=$this->pages_max_num);
        for(
            $i = $this->n_left, $this->left_side_nav_num = array();
            $i < $this->page_offset_current;
            $this->left_side_nav_num[$i] = $this->f($i),
            $i++
        );
        for(
            $i = $this->n_right, $this->right_side_nav_num = array();
            $i > $this->page_offset_current;
            $this->right_side_nav_num[$i] = $this->f($i),
            $i--
        );
        asort($this->right_side_nav_num);




        $page_jump = ($this->pages_max_num/$this->lines_per_page)*$this->n;
        ( ($this->page_jump_forwards=$this->page_offset_current+$page_jump) < $this->pages_max_num
            and $this->pages_max_num-$this->page_jump_forwards > $this->n*2
        ) or ($this->page_jump_forwards=$this->pages_max_num);




        ( ($this->page_jump_backwards=$this->page_offset_current-$page_jump) > 1
             and $this->page_jump_backwards > $this->n*2
        ) or ($this->page_jump_backwards=1);
        return;
    }
    final protected function f($n)
    { // returns numeric string
        return sprintf("%.0f", $n);
    }
    final public function getPageFirst()
    { // returns numeric string
        /* get first page offset
            [first] [<<] [prev] [1] [2] 3 [4] [5] [next] [>>] [last]
               ^
        */
        return '1';
    }
    final public function getPageLast()
    { // returns numeric string
        /* get last page offset
            [first] [<<] [prev] [1] [2] 3 [4] [5] [next] [>>] [last]
                                                                ^
        */
        return $this->getPagesMaxNum();
    }
    final public function getPagePrevious()
    { // returns numeric string
        /* get previous page offset
            [first] [<<] [prev] [1] [2] 3 [4] [5] [next] [>>] [last]
                            ^
        */
        return $this->f($this->page_previous);
    }
    final public function getPageNext()
    { // returns numeric string
        /* get next page offset
            [first] [<<] [prev] [1] [2] 3 [4] [5] [next] [>>] [last]
                                                    ^
        */
        return $this->f($this->page_next);
    }
    final public function getPageJumpBackward()
    { // returns numeric string
        /* get page offset to jump backwards a dynamic amount of pages
            [first] [<<] [prev] [1] [2] 3 [4] [5] [next] [>>] [last]
                     ^
        */
        return $this->f($this->page_jump_backwards);
    }
    final public function getPageJumpForward()
    { // returns numeric string
        /* get page offset to jump forward a dynamic amount of pages
            [first] [<<] [prev] [1] [2] 3 [4] [5] [next] [>>] [last]
                                                          ^
        */
        return $this->f($this->page_jump_forwards);
    }
    final public function getMiddle() // alias for ::getPageCurrent()
    { // returns numeric string
        /* get page offset for the current page
            [first] [<<] [prev] [1] [2] 3 [4] [5] [next] [>>] [last]
                                        ^
        */
        return $this->getPageCurrent();
    }
    final public function getLeft()
    { // returns array
        /* get array of page offsets for left side
            [first] [<<] [prev] [1] [2] 3 [4] [5] [next] [>>] [last]
                                 ^   ^
        */
        return $this->left_side_nav_num;
    }
    final public function getRight()
    { // returns array
        /* get array of page offsets for right side
            [first] [<<] [prev] [1] [2] 3 [4] [5] [next] [>>] [last]
                                           ^   ^
        */
        return $this->right_side_nav_num;
    }
    final public function getPageCurrent()
    { // returns numeric string
        /* get page offset for the current page
            [first] [<<] [prev] [1] [2] 3 [4] [5] [next] [>>] [last]
                                        ^
        */
        return $this->f($this->page_offset_current);
    }
    final public function getPagesMaxNum()
    { // returns numeric string
        /* get last page offset
            you are on page 3 of total 40000000
                                          ^
        */
        return $this->f($this->pages_max_num);
    }
    final public function getLinesCountAll()
    { // returns numeric string
        /* get count all lines (data sets) -- the given parameter $lines_count_all at ::__construct()
            viewing 25 lines per page (25 lines on the last page) of total 1000000000 lines
                                                                               ^
        */
        return $this->f($this->lines_count_all);
    }
    final public function getLinesPerPage()
    { // returns numeric string
        /* get count lines per page -- the given parameter $lines_per_page at ::__construct()
            viewing 25 lines per page (25 lines on the last page) of total 1000000000 lines
                    ^
        */
        return $this->f($this->lines_per_page);
    }
    final public function getLinesLastPage()
    { // returns numeric string
        /* get count lines for the last page
            viewing 25 lines per page (25 lines on the last page) of total 1000000000 lines
                                       ^
        explanation:
            we got 11 lines and viewing 5 lines at one page.
            so we got 2 pages with 5 lines, and a last page with 1 line.




            [first] [<<] [prev] 1 [2] [3] [next] [>>] [last]
                                ^ viewing 5 lines on that page (1-5)




            [first] [<<] [prev] [1] 2 [3] [next] [>>] [last]
                                    ^ viewing 5 lines on that page (6-10)




            [first] [<<] [prev] [1] [2] 3 [next] [>>] [last]
                                        ^ viewing 1 line on that page (11)




        */
        return $this->f($this->last_page_lines_count);
    }
    final public function getQueryOffset()
    { // returns int
        /* get current page offset for db query like
            SELECT ... FROM ... WHERE ... LIMIT 0, 25;
                                                ^
        */
        if(($offset=$this->getPageCurrent()-1) > 0){
            return $offset*$this->getLinesPerPage();
        }
        return 0;
    }
    final public function getQueryLimit()
    { // returns int
        /* get limit for db query like
            SELECT ... FROM ... WHERE ... LIMIT 0, 25;
                                                   ^
        */
        return $this->getLinesPerPage();
    }
    /*
    explanation/example/overview:
        example output:
            you are on page 5 of total 40000000
            viewing 25 lines per page (25 lines on the last page) of total 1000000000 lines
            [first] [<<] [prev] [2] [3] [4] 5 [6] [7] [8] [next] [>>] [last]




        placements:
        you are on page ::getPageCurrent() of total ::getPagesMaxNum()
        viewing ::getLinesPerPage() lines per page (::getLinesLastPage() lines on the last page) of total ::getLinesCountAll() lines
        [::getPageFirst()] [::getPageJumpBackward()] [::getPagePrevious()]
            foreach ::getLeft()
                ::getMiddle()
            foreach ::getRight()
        [::getPageNext()] [::getPageJumpForward()] [::getPageLast()]
    */
    /* query example:
        SELECT ... FROM ... WHERE ... LIMIT ::getQueryOffset(), ::getQueryLimit();
    */
}







/////////////////////////////
// create a new Pagination //
/////////////////////////////
/* $page_offset_current
    in this example we got the current page as GET-parameter "page" -- domain.com?page=1 */
$page_offset_current = isset($_GET['page']) ? $_GET['page'] : 1;




/* $lines_count_all
    here you would use your db query like
        $lines_count_all = ...("SELECT COUNT(*) FROM tbl WHERE ..."); */
$lines_count_all = 1000000000;




/* $lines_per_page (default 25)
    set how many lines (data sets) per page should be viewed at one page */
$lines_per_page = 25;




/* $n (default 5)
    how many choices to each direction (left/right)
            example $n = 3: [first] [<<] [prev] [1] [2] [3] 4 [5] [6] [7] [next] [>>] [last]
                                                 ^   ^   ^
                                                 3 on left, and 3 on right.*/
$n = 3;




// create new object from Pagination:
$Pagination = new Pagination($page_offset_current, $lines_count_all, $lines_per_page, $n);







/////////////////////////
// an example document //
/////////////////////////
?>
<!doctype html>
<html>
<head>
    <meta charset="utf-8">
    <title>Pagination Example</title>
    <style type="text/css">
        .code{
            clear:both;
            font-size:15px;
            color:#666;
            white-space:pre;
            font-family:monospace;
            display:block;
        }
    </style>
</head>
<body>
    <h1>Pagination Example</h1>
    <h3>can handle extremely large numbers (f.e. page 111111111111)</h3>
    <div>
        you are on page <?php echo $Pagination->getPageCurrent(); ?>
        of total <?php echo $Pagination->getPagesMaxNum(); ?>
    </div>
    <div>
        viewing <?php echo $Pagination->getLinesPerPage(); ?> lines per page
        (<?php echo $Pagination->getLinesLastPage(); ?> lines on the last page)
        of total <?php echo $Pagination->getLinesCountAll(); ?> lines
    </div>




    <form action="" method="GET">
        <input type="number" name="page" value="" placeholder="goto page ..." />
        <input type="submit" value="go" />
    </form>




    <div>
        <a href="?page=<?php echo $Pagination->getPageFirst(); ?>">[first]</a>
        <a href="?page=<?php echo $Pagination->getPageJumpBackward(); ?>">[&lt;&lt;]</a>
        <a href="?page=<?php echo $Pagination->getPagePrevious(); ?>">[prev]</a>




        <!-- START nav left buttons/links -->
<?php
foreach($Pagination->getLeft() as $number){
?>
        <a href="?page=<?php echo $number; ?>">[<?php echo $number; ?>]</a>
<?php
} // /foreach
?>
        <!-- END nav left buttons/links -->




        <span><?php echo $Pagination->getMiddle(); ?></span> <!-- current page -->




        <!-- START nav right buttons/links -->
<?php
foreach($Pagination->getRight() as $number){
?>
        <a href="?page=<?php echo $number; ?>">[<?php echo $number; ?>]</a>
<?php
} // /foreach
?>
        <!-- END nav right buttons/links -->




        <a href="?page=<?php echo $Pagination->getPageNext(); ?>">[next]</a>
        <a href="?page=<?php echo $Pagination->getPageJumpForward(); ?>">[&gt;&gt;]</a>
        <a href="?page=<?php echo $Pagination->getPageLast(); ?>">[last]</a>
    </div>




    <br>
    <hr>
    <h3>An example query to get the current requested data from database:</h3>
    <div class="code">SELECT
    ...
FROM
    `db`.`tbl`
WHERE
    ...
LIMIT $Pagination->getQueryOffset(), $Pagination->getQueryLimit()
;</div>
    <h3>for the current page the LIMIT is:</h3>
    <div class="code">LIMIT <?php echo $Pagination->getQueryOffset(); ?>, <?php echo $Pagination->getQueryLimit(); ?></div>




    <br>
    <hr>
    <h2>The complete code:</h2>
    <div class="code"><?php echo htmlspecialchars(file_get_contents(__FILE__)); ?></div>
</body>
</html>

$page_offset_current = isset($_GET['page']) ? $_GET['page'] : 1;
$lines_count_all = ...("SELECT COUNT(*) FROM ... WHERE ...;");
$lines_per_page = 25;
$n = 3;
$Pagination = new Pagination($page_offset_current, $lines_count_all, $lines_per_page, $n);







$offset = $Pagination->getQueryOffset(); // get current page offset for db query
$limit = $Pagination->getQueryLimit(); // get limit for db query
$data_sets = ...("SELECT ... FROM ... WHERE ... LIMIT $offset, $limit;");







$Pagination->getPageCurrent() // the current page number we are looking at
$Pagination->getPagesMaxNum() // the total amount of pages we can view




$Pagination->getLinesPerPage() // the amount of lines (data sets) we are viewing at one page
$Pagination->getLinesLastPage() // the amount of lines (data sets) we are viewing at the last page
$Pagination->getLinesCountAll() // the amount of all lines (data sets)




$Pagination->getPageFirst() // get first page offset
$Pagination->getPageJumpBackward() // get page offset to jump backwards a dynamic amount of pages
$Pagination->getPagePrevious() // get previous page offset




$Pagination->getLeft() // get array of page offsets for left side
$Pagination->getMiddle() // get page offset for the current page (alias ::getPageCurrent())
$Pagination->getRight() // get array of page offsets for right side




$Pagination->getPageNext() // get next page offset
$Pagination->getPageJumpForward() // get page offset to jump forward a dynamic amount of pages
$Pagination->getPageLast() // get last page offset