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<?php
//
// Pear DB Pager - Retrieve and return information of databases
// result sets
//
// Copyright (C) 2001 Tomas Von Veschler Cox <cox@idecnet.com>
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//
//
// $Id: Pager.php,v 1.3 2002/05/12 13:59:40 cox Exp $
require_once 'PEAR.php';
require_once 'DB.php';
/**
* This class handles all the stuff needed for displaying paginated results
* from a database query of Pear DB, in a very easy way.
* Documentation and examples of use, can be found in:
* http://vulcanonet.com/soft/pager/ (could be outdated)
*
* IMPORTANT!
* Since PEAR DB already support native row limit (more fast and avaible in
* all the drivers), there is no more need to use $pager->build() or
* the $pager->fetch*() methods.
*
* Usage example:
*
*< ?php
* require_once 'DB/Pager.php';
* $db = DB::connect('your DSN string');
* $from = 0; // The row to start to fetch from (you might want to get this
* // param from the $_GET array
* $limit = 10; // The number of results per page
* $maxpages = 10; // The number of pages for displaying in the pager (optional)
* $res = $db->limitQuery($sql, $from, $limit);
* $nrows = 0; // Alternative you could use $res->numRows()
* while ($row = $res->fetchrow()) {
* // XXX code for building the page here
* $nrows++;
* }
* $data = DB_Pager::getData($from, $limit, $nrows, $maxpages);
* // XXX code for building the pager here
* ? >
*
* @version 0.7
* @author Tomas V.V.Cox <cox@idecnet.com>
* @see http://vulcanonet.com/soft/pager/
*/
class DB_Pager extends PEAR
{
/**
* Constructor
*
* @param object $res A DB_result object from Pear_DB
* @param int $from The row to start fetching
* @param int $limit How many results per page
* @param int $numrows Pager will automatically
* find this param if is not given. If your Pear_DB backend extension
* doesn't support numrows(), you can manually calculate it
* and supply later to the constructor
* @deprecated
*/
function DB_Pager (&$res, $from, $limit, $numrows = null)
{
$this->res = $res;
$this->from = $from;
$this->limit = $limit;
$this->numrows = $numrows;
}
/**
* Calculates all the data needed by Pager to work
*
* @return mixed An assoc array with all the data (see getData)
* or DB_Error on error
* @see DB_Pager::getData
* @deprecated
*/
function build()
{
// if there is no numrows given, calculate it
if ($this->numrows === null) {
$this->numrows = $this->res->numrows();
if (DB::isError($this->numrows)) {
return $this->numrows;
}
}
$data = $this->getData($this->from, $this->limit, $this->numrows);
if (DB::isError($data)) {
return $data;
}
$this->current = $this->from - 1;
$this->top = $data['to'];
return $data;
}
/**
* @deprecated
*/
function fetchRow($mode=DB_FETCHMODE_DEFAULT)
{
$this->current++;
if ($this->current >= $this->top) {
return null;
}
return $this->res->fetchRow($mode, $this->current);
}
/**
* @deprecated
*/
function fetchInto(&$arr, $mode=DB_FETCHMODE_DEFAULT)
{
$this->current++;
if ($this->current >= $this->top) {
return null;
}
return $this->res->fetchInto($arr, $mode, $this->current);
}
/*
* Gets all the data needed to paginate results
* This is an associative array with the following
* values filled in:
*
* array(
* 'current' => X, // current page you are
* 'numrows' => X, // total number of results
* 'next' => X, // row number where next page starts
* 'prev' => X, // row number where prev page starts
* 'remain' => X, // number of results remaning *in next page*
* 'numpages'=> X, // total number of pages
* 'from' => X, // the row to start fetching
* 'to' => X, // the row to stop fetching
* 'limit' => X, // how many results per page
* 'maxpages' => X, // how many pages to show (google style)
* 'firstpage' => X, // the row number of the first page
* 'lastpage' => X, // the row number where the last page starts
* 'pages' => array( // assoc with page "number => start row"
* 1 => X,
* 2 => X,
* 3 => X
* )
* );
* @param int $from The row to start fetching
* @param int $limit How many results per page
* @param int $numrows Number of results from query
*
* @return array associative array with data or DB_error on error
*
*/
function &getData($from, $limit, $numrows, $maxpages = false)
{
if (empty($numrows) || ($numrows < 0)) {
return null;
}
$from = (empty($from)) ? 0 : $from;
if ($limit <= 0) {
return PEAR::raiseError (null, 'wrong "limit" param', null,
null, null, 'DB_Error', true);
}
// Total number of pages
$pages = ceil($numrows/$limit);
$data['numpages'] = $pages;
// first & last page
$data['firstpage'] = 1;
$data['lastpage'] = $pages;
// Build pages array
$data['pages'] = array();
for ($i=1; $i <= $pages; $i++) {
$offset = $limit * ($i-1);
$data['pages'][$i] = $offset;
// $from must point to one page
if ($from == $offset) {
// The current page we are
$data['current'] = $i;
}
}
if (!isset($data['current'])) {
return PEAR::raiseError (null, 'wrong "from" param', null,
null, null, 'DB_Error', true);
}
// Limit number of pages (goole algoritm)
if ($maxpages) {
$radio = floor($maxpages/2);
$minpage = $data['current'] - $radio;
if ($minpage < 1) {
$minpage = 1;
}
$maxpage = $data['current'] + $radio - 1;
if ($maxpage > $data['numpages']) {
$maxpage = $data['numpages'];
}
foreach (range($minpage, $maxpage) as $page) {
$tmp[$page] = $data['pages'][$page];
}
$data['pages'] = $tmp;
$data['maxpages'] = $maxpages;
} else {
$data['maxpages'] = null;
}
// Prev link
$prev = $from - $limit;
$data['prev'] = ($prev >= 0) ? $prev : null;
// Next link
$next = $from + $limit;
$data['next'] = ($next < $numrows) ? $next : null;
// Results remaining in next page & Last row to fetch
if ($data['current'] == $pages) {
$data['remain'] = 0;
$data['to'] = $numrows;
} else {
if ($data['current'] == ($pages - 1)) {
$data['remain'] = $numrows - ($limit*($pages-1));
} else {
$data['remain'] = $limit;
}
$data['to'] = $data['current'] * $limit;
}
$data['numrows'] = $numrows;
$data['from'] = $from + 1;
$data['limit'] = $limit;
return $data;
}
}
?>
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