Pager class for board.

Page.php

<?php
  /** Pager class for php
   *
   * {{{
   *
   * $pager = new Page($all_data_length, $page_per_post_length);
   * $page_html = "<ul>"
   * foreach($pager.getPage($current_page) as $page) {
   *   $page_html = $page_html . "<li class=\"" . $page['flag'] . "\"></li>" . $page['num'] . "</li>"
   * } 
   *
   * $sql = "SELECT * FROM some_post OFFSET " . $pager.getOffset() . " LIMIT " . $pager.getLimit()
   *
   * }}}
   *
   * NUMBER decide how many page surround current.
   *
   * {{{
   * 
   * // if NUMBER is 3 
   *
   * $pager.getPage(40) // will contain, 1 ... 37 38 39 40 41 42 43 ... 70
   * }}}
   *
   */
  class Page {
    private $NUMBER = 3;
    private $page = array();
    private $offset = 0;
    private $page_per_post = 10;
    private $curr = 0;

    /** Constructor for Page
     *
     * @param $data_length length of a data.
     * @param $page_per_post length of a post which show in one page.
     * 
     */
    function __construct($data_length, $page_per_post) {
      $this->page_per_post = $page_per_post;
      $this->last = $data_length / $page_per_post;
    }

    /** Push a array to $this->page with given range.
     * 
     *  @param range range that want to push $this->page
     * 
     */
    private function pushPage($range) {
      foreach($range as $n) {
        if($n == $this->curr) {
          array_push($this->page, array("flag" => "current", "num" => $n));
        } else {
          array_push($this->page, array("flag" => "page", "num" => $n));
        }
      }
    }

    /** Get page
     * 
     *  @param curr current page number
     *  @return page object
     * 
     */
    public function getPage($curr) {
      if($this->curr != $curr) {
        if($curr > $this->last or $curr < 1) throw new Exception('Invalid Page number'); 

        $this->curr = $curr;
        $this->offset = $this->page_per_post * ($this->curr - 1);
        array_push($this->page, array("flag" => "first", "num" => 1));

        if($this->curr < $this->NUMBER + 2) {
          $this->pushPage(range(2, $this->curr + $this->NUMBER, 1));
        } else if($this->curr < $this->last - ($this->NUMBER + 2)) {
          $this->pushPage(range($this->curr - $this->NUMBER, $this->curr + $this->NUMBER, 1));
        } else {
          $this->pushPage(range($this->curr - $this->NUMBER, $this->last - 1, 1));
        }

        array_push($this->page, array("flag" => "last", "num" => $this->last));
      }

      return $this->page;
    }

    /** Get offset for RDB
     * 
     *  @return offset
     * 
     */
    public function getOffset() {
      return $this->offset;
    }

    /** Get limit for RDB
     * 
     *  @return limit
     * 
     */
    public function getLimit() {
      return $this->page_per_post;
    }

    /** Set NUMBER
     *
     * @param num
     *
     */
    public function setNumber($num) {
      $this->NUMBER = $num;
    }
  };

  $pager = new Page(700, 10);
  echo "---------" ;
  echo var_dump($pager->getPage(3));
  echo "---------" ;
  echo var_dump($pager->getPage(20));
  echo "---------" ;
  echo var_dump($pager->getPage(67));
  echo "---------\n" ;
  echo "Offset : " . $pager->getOffset() . "\n";
  echo "Limit : " . $pager->getLimit() . "\n";
?>