<?php
class Paging {
  public static $count = 0;
  public static $size = 0;
  public static $page = 0;
  static function prepare($sql, $pagesize=10) {
    $page = isset($_GET['page']) ? $_GET['page'] : 1;
    $pageon = ($page - 1) * $pagesize;
    $sql = preg_replace('/select\s/i', '$0SQL_CALC_FOUND_ROWS ', $sql) . " limit $pageon, $pagesize";
    $rs = mysql_query($sql);
    $p = mysql_query('SELECT FOUND_ROWS()');
    list(self::$count) = mysql_fetch_row($p);
    self::$size = $pagesize;
    self::$page = $page;
    return $rs;
  }
  static function bar($tpl='') {
    if(!$tpl) $tpl = '<a href=?reset>首页</a> <a href=?prve>上一页</a> <a href=?next>下一页</a> <a href=?end>尾页</a>';
    $count = ceil(self::$count / self::$size);
    $page = self::$page;
    unset($_GET['page']);
    $d = array(
      'reset' => 1,
      'prve' => $page > 1 ? $page - 1 : 1,
      'next' => $page < $count ? $page + 1 : $count,
      'end' => $count,
    );
    foreach($d as $k=>$v) {
      $_GET['page'] = $v;
      $tpl = str_replace($k, http_build_query($_GET), $tpl);
    }
    echo $tpl;
  }
}