system/libraries/Zip.php - code-igniter-v3-giggi - Gitiles

 <?php
 /**
  * CodeIgniter
  *
  * An open source application development framework for PHP
  *
  * This content is released under the MIT License (MIT)
  *
  * Copyright (c) 2014 - 2018, British Columbia Institute of Technology
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  *
  * @package	CodeIgniter
  * @author	EllisLab Dev Team
  * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
  * @copyright	Copyright (c) 2014 - 2018, British Columbia Institute of Technology (http://bcit.ca/)
  * @license	http://opensource.org/licenses/MIT	MIT License
  * @link	https://codeigniter.com
  * @since	Version 1.0.0
  * @filesource
  */
 defined('BASEPATH') OR exit('No direct script access allowed');

 /**
  * Zip Compression Class
  *
  * This class is based on a library I found at Zend:
  * http://www.zend.com/codex.php?id=696&single=1
  *
  * The original library is a little rough around the edges so I
  * refactored it and added several additional methods -- Rick Ellis
  *
  * @package		CodeIgniter
  * @subpackage	Libraries
  * @category	Encryption
  * @author		EllisLab Dev Team
  * @link		https://codeigniter.com/user_guide/libraries/zip.html
  */
 class CI_Zip {

 	/**
 	 * Zip data in string form
 	 *
 	 * @var string
 	 */
 	public $zipdata = '';

 	/**
 	 * Zip data for a directory in string form
 	 *
 	 * @var string
 	 */
 	public $directory = '';

 	/**
 	 * Number of files/folder in zip file
 	 *
 	 * @var int
 	 */
 	public $entries = 0;

 	/**
 	 * Number of files in zip
 	 *
 	 * @var int
 	 */
 	public $file_num = 0;

 	/**
 	 * relative offset of local header
 	 *
 	 * @var int
 	 */
 	public $offset = 0;

 	/**
 	 * Reference to time at init
 	 *
 	 * @var int
 	 */
 	public $now;

 	/**
 	 * The level of compression
 	 *
 	 * Ranges from 0 to 9, with 9 being the highest level.
 	 *
 	 * @var	int
 	 */
 	public $compression_level = 2;

 	/**
 	 * mbstring.func_overload flag
 	 *
 	 * @var	bool
 	 */
 	protected static $func_overload;

 	/**
 	 * Initialize zip compression class
 	 *
 	 * @return	void
 	 */
 	public function __construct()
 	{
 		isset(self::$func_overload) OR self::$func_overload = (extension_loaded('mbstring') && ini_get('mbstring.func_overload'));

 		$this->now = time();
 		log_message('info', 'Zip Compression Class Initialized');
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Add Directory
 	 *
 	 * Lets you add a virtual directory into which you can place files.
 	 *
 	 * @param	mixed	$directory	the directory name. Can be string or array
 	 * @return	void
 	 */
 	public function add_dir($directory)
 	{
 		foreach ((array) $directory as $dir)
 		{
 			if ( ! preg_match('|.+/$|', $dir))
 			{
 				$dir .= '/';
 			}

 			$dir_time = $this->_get_mod_time($dir);
 			$this->_add_dir($dir, $dir_time['file_mtime'], $dir_time['file_mdate']);
 		}
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Get file/directory modification time
 	 *
 	 * If this is a newly created file/dir, we will set the time to 'now'
 	 *
 	 * @param	string	$dir	path to file
 	 * @return	array	filemtime/filemdate
 	 */
 	protected function _get_mod_time($dir)
 	{
 		// filemtime() may return false, but raises an error for non-existing files
 		$date = file_exists($dir) ? getdate(filemtime($dir)) : getdate($this->now);

 		return array(
 			'file_mtime' => ($date['hours'] << 11) + ($date['minutes'] << 5) + $date['seconds'] / 2,
 			'file_mdate' => (($date['year'] - 1980) << 9) + ($date['mon'] << 5) + $date['mday']
 		);
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Add Directory
 	 *
 	 * @param	string	$dir	the directory name
 	 * @param	int	$file_mtime
 	 * @param	int	$file_mdate
 	 * @return	void
 	 */
 	protected function _add_dir($dir, $file_mtime, $file_mdate)
 	{
 		$dir = str_replace('\\', '/', $dir);

 		$this->zipdata .=
 			"\x50\x4b\x03\x04\x0a\x00\x00\x00\x00\x00"
 			.pack('v', $file_mtime)
 			.pack('v', $file_mdate)
 			.pack('V', 0) // crc32
 			.pack('V', 0) // compressed filesize
 			.pack('V', 0) // uncompressed filesize
 			.pack('v', self::strlen($dir)) // length of pathname
 			.pack('v', 0) // extra field length
 			.$dir
 			// below is "data descriptor" segment
 			.pack('V', 0) // crc32
 			.pack('V', 0) // compressed filesize
 			.pack('V', 0); // uncompressed filesize

 		$this->directory .=
 			"\x50\x4b\x01\x02\x00\x00\x0a\x00\x00\x00\x00\x00"
 			.pack('v', $file_mtime)
 			.pack('v', $file_mdate)
 			.pack('V',0) // crc32
 			.pack('V',0) // compressed filesize
 			.pack('V',0) // uncompressed filesize
 			.pack('v', self::strlen($dir)) // length of pathname
 			.pack('v', 0) // extra field length
 			.pack('v', 0) // file comment length
 			.pack('v', 0) // disk number start
 			.pack('v', 0) // internal file attributes
 			.pack('V', 16) // external file attributes - 'directory' bit set
 			.pack('V', $this->offset) // relative offset of local header
 			.$dir;

 		$this->offset = self::strlen($this->zipdata);
 		$this->entries++;
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Add Data to Zip
 	 *
 	 * Lets you add files to the archive. If the path is included
 	 * in the filename it will be placed within a directory. Make
 	 * sure you use add_dir() first to create the folder.
 	 *
 	 * @param	mixed	$filepath	A single filepath or an array of file => data pairs
 	 * @param	string	$data		Single file contents
 	 * @return	void
 	 */
 	public function add_data($filepath, $data = NULL)
 	{
 		if (is_array($filepath))
 		{
 			foreach ($filepath as $path => $data)
 			{
 				$file_data = $this->_get_mod_time($path);
 				$this->_add_data($path, $data, $file_data['file_mtime'], $file_data['file_mdate']);
 			}
 		}
 		else
 		{
 			$file_data = $this->_get_mod_time($filepath);
 			$this->_add_data($filepath, $data, $file_data['file_mtime'], $file_data['file_mdate']);
 		}
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Add Data to Zip
 	 *
 	 * @param	string	$filepath	the file name/path
 	 * @param	string	$data	the data to be encoded
 	 * @param	int	$file_mtime
 	 * @param	int	$file_mdate
 	 * @return	void
 	 */
 	protected function _add_data($filepath, $data, $file_mtime, $file_mdate)
 	{
 		$filepath = str_replace('\\', '/', $filepath);

 		$uncompressed_size = self::strlen($data);
 		$crc32  = crc32($data);
 		$gzdata = self::substr(gzcompress($data, $this->compression_level), 2, -4);
 		$compressed_size = self::strlen($gzdata);

 		$this->zipdata .=
 			"\x50\x4b\x03\x04\x14\x00\x00\x00\x08\x00"
 			.pack('v', $file_mtime)
 			.pack('v', $file_mdate)
 			.pack('V', $crc32)
 			.pack('V', $compressed_size)
 			.pack('V', $uncompressed_size)
 			.pack('v', self::strlen($filepath)) // length of filename
 			.pack('v', 0) // extra field length
 			.$filepath
 			.$gzdata; // "file data" segment

 		$this->directory .=
 			"\x50\x4b\x01\x02\x00\x00\x14\x00\x00\x00\x08\x00"
 			.pack('v', $file_mtime)
 			.pack('v', $file_mdate)
 			.pack('V', $crc32)
 			.pack('V', $compressed_size)
 			.pack('V', $uncompressed_size)
 			.pack('v', self::strlen($filepath)) // length of filename
 			.pack('v', 0) // extra field length
 			.pack('v', 0) // file comment length
 			.pack('v', 0) // disk number start
 			.pack('v', 0) // internal file attributes
 			.pack('V', 32) // external file attributes - 'archive' bit set
 			.pack('V', $this->offset) // relative offset of local header
 			.$filepath;

 		$this->offset = self::strlen($this->zipdata);
 		$this->entries++;
 		$this->file_num++;
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Read the contents of a file and add it to the zip
 	 *
 	 * @param	string	$path
 	 * @param	bool	$archive_filepath
 	 * @return	bool
 	 */
 	public function read_file($path, $archive_filepath = FALSE)
 	{
 		if (file_exists($path) && FALSE !== ($data = file_get_contents($path)))
 		{
 			if (is_string($archive_filepath))
 			{
 				$name = str_replace('\\', '/', $archive_filepath);
 			}
 			else
 			{
 				$name = str_replace('\\', '/', $path);

 				if ($archive_filepath === FALSE)
 				{
 					$name = preg_replace('|.*/(.+)|', '\\1', $name);
 				}
 			}

 			$this->add_data($name, $data);
 			return TRUE;
 		}

 		return FALSE;
 	}

 	// ------------------------------------------------------------------------

 	/**
 	 * Read a directory and add it to the zip.
 	 *
 	 * This function recursively reads a folder and everything it contains (including
 	 * sub-folders) and creates a zip based on it. Whatever directory structure
 	 * is in the original file path will be recreated in the zip file.
 	 *
 	 * @param	string	$path	path to source directory
 	 * @param	bool	$preserve_filepath
 	 * @param	string	$root_path
 	 * @return	bool
 	 */
 	public function read_dir($path, $preserve_filepath = TRUE, $root_path = NULL)
 	{
 		$path = rtrim($path, '/\\').DIRECTORY_SEPARATOR;
 		if ( ! $fp = @opendir($path))
 		{
 			return FALSE;
 		}

 		// Set the original directory root for child dir's to use as relative
 		if ($root_path === NULL)
 		{
 			$root_path = str_replace(array('\\', '/'), DIRECTORY_SEPARATOR, dirname($path)).DIRECTORY_SEPARATOR;
 		}

 		while (FALSE !== ($file = readdir($fp)))
 		{
 			if ($file[0] === '.')
 			{
 				continue;
 			}

 			if (is_dir($path.$file))
 			{
 				$this->read_dir($path.$file.DIRECTORY_SEPARATOR, $preserve_filepath, $root_path);
 			}
 			elseif (FALSE !== ($data = file_get_contents($path.$file)))
 			{
 				$name = str_replace(array('\\', '/'), DIRECTORY_SEPARATOR, $path);
 				if ($preserve_filepath === FALSE)
 				{
 					$name = str_replace($root_path, '', $name);
 				}

 				$this->add_data($name.$file, $data);
 			}
 		}

 		closedir($fp);
 		return TRUE;
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Get the Zip file
 	 *
 	 * @return	string	(binary encoded)
 	 */
 	public function get_zip()
 	{
 		// Is there any data to return?
 		if ($this->entries === 0)
 		{
 			return FALSE;
 		}

 		return $this->zipdata
 			.$this->directory."\x50\x4b\x05\x06\x00\x00\x00\x00"
 			.pack('v', $this->entries) // total # of entries "on this disk"
 			.pack('v', $this->entries) // total # of entries overall
 			.pack('V', self::strlen($this->directory)) // size of central dir
 			.pack('V', self::strlen($this->zipdata)) // offset to start of central dir
 			."\x00\x00"; // .zip file comment length
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Write File to the specified directory
 	 *
 	 * Lets you write a file
 	 *
 	 * @param	string	$filepath	the file name
 	 * @return	bool
 	 */
 	public function archive($filepath)
 	{
 		if ( ! ($fp = @fopen($filepath, 'w+b')))
 		{
 			return FALSE;
 		}

 		flock($fp, LOCK_EX);

 		for ($result = $written = 0, $data = $this->get_zip(), $length = self::strlen($data); $written < $length; $written += $result)
 		{
 			if (($result = fwrite($fp, self::substr($data, $written))) === FALSE)
 			{
 				break;
 			}
 		}

 		flock($fp, LOCK_UN);
 		fclose($fp);

 		return is_int($result);
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Download
 	 *
 	 * @param	string	$filename	the file name
 	 * @return	void
 	 */
 	public function download($filename = 'backup.zip')
 	{
 		if ( ! preg_match('|.+?\.zip$|', $filename))
 		{
 			$filename .= '.zip';
 		}

 		get_instance()->load->helper('download');
 		$get_zip = $this->get_zip();
 		$zip_content =& $get_zip;

 		force_download($filename, $zip_content);
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Initialize Data
 	 *
 	 * Lets you clear current zip data. Useful if you need to create
 	 * multiple zips with different data.
 	 *
 	 * @return	CI_Zip
 	 */
 	public function clear_data()
 	{
 		$this->zipdata = '';
 		$this->directory = '';
 		$this->entries = 0;
 		$this->file_num = 0;
 		$this->offset = 0;
 		return $this;
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Byte-safe strlen()
 	 *
 	 * @param	string	$str
 	 * @return	int
 	 */
 	protected static function strlen($str)
 	{
 		return (self::$func_overload)
 			? mb_strlen($str, '8bit')
 			: strlen($str);
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Byte-safe substr()
 	 *
 	 * @param	string	$str
 	 * @param	int	$start
 	 * @param	int	$length
 	 * @return	string
 	 */
 	protected static function substr($str, $start, $length = NULL)
 	{
 		if (self::$func_overload)
 		{
 			// mb_substr($str, $start, null, '8bit') returns an empty
 			// string on PHP 5.3
 			isset($length) OR $length = ($start >= 0 ? self::strlen($str) - $start : -$start);
 			return mb_substr($str, $start, $length, '8bit');
 		}

 		return isset($length)
 			? substr($str, $start, $length)
 			: substr($str, $start);
 	}
 }
	<?php
	/**
	* CodeIgniter
	*
	* An open source application development framework for PHP
	*
	* This content is released under the MIT License (MIT)
	*
	* Copyright (c) 2014 - 2018, British Columbia Institute of Technology
	*
	* Permission is hereby granted, free of charge, to any person obtaining a copy
	* of this software and associated documentation files (the "Software"), to deal
	* in the Software without restriction, including without limitation the rights
	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	* copies of the Software, and to permit persons to whom the Software is
	* furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
	* THE SOFTWARE.
	*
	* @package CodeIgniter
	* @author EllisLab Dev Team
	* @copyright Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
	* @copyright Copyright (c) 2014 - 2018, British Columbia Institute of Technology (http://bcit.ca/)
	* @license http://opensource.org/licenses/MIT MIT License
	* @link https://codeigniter.com
	* @since Version 1.0.0
	* @filesource
	*/
	defined('BASEPATH') OR exit('No direct script access allowed');

	/**
	* Zip Compression Class
	*
	* This class is based on a library I found at Zend:
	* http://www.zend.com/codex.php?id=696&single=1
	*
	* The original library is a little rough around the edges so I
	* refactored it and added several additional methods -- Rick Ellis
	*
	* @package CodeIgniter
	* @subpackage Libraries
	* @category Encryption
	* @author EllisLab Dev Team
	* @link https://codeigniter.com/user_guide/libraries/zip.html
	*/
	class CI_Zip {

	/**
	* Zip data in string form
	*
	* @var string
	*/
	public $zipdata = '';

	/**
	* Zip data for a directory in string form
	*
	* @var string
	*/
	public $directory = '';

	/**
	* Number of files/folder in zip file
	*
	* @var int
	*/
	public $entries = 0;

	/**
	* Number of files in zip
	*
	* @var int
	*/
	public $file_num = 0;

	/**
	* relative offset of local header
	*
	* @var int
	*/
	public $offset = 0;

	/**
	* Reference to time at init
	*
	* @var int
	*/
	public $now;

	/**
	* The level of compression
	*
	* Ranges from 0 to 9, with 9 being the highest level.
	*
	* @var int
	*/
	public $compression_level = 2;

	/**
	* mbstring.func_overload flag
	*
	* @var bool
	*/
	protected static $func_overload;

	/**
	* Initialize zip compression class
	*
	* @return void
	*/
	public function __construct()
	{
	isset(self::$func_overload) OR self::$func_overload = (extension_loaded('mbstring') && ini_get('mbstring.func_overload'));

	$this->now = time();
	log_message('info', 'Zip Compression Class Initialized');
	}

	// --------------------------------------------------------------------

	/**
	* Add Directory
	*
	* Lets you add a virtual directory into which you can place files.
	*
	* @param mixed $directory the directory name. Can be string or array
	* @return void
	*/
	public function add_dir($directory)
	{
	foreach ((array) $directory as $dir)
	{
	if ( ! preg_match('\|.+/$\|', $dir))
	{
	$dir .= '/';
	}

	$dir_time = $this->_get_mod_time($dir);
	$this->_add_dir($dir, $dir_time['file_mtime'], $dir_time['file_mdate']);
	}
	}

	// --------------------------------------------------------------------

	/**
	* Get file/directory modification time
	*
	* If this is a newly created file/dir, we will set the time to 'now'
	*
	* @param string $dir path to file
	* @return array filemtime/filemdate
	*/
	protected function _get_mod_time($dir)
	{
	// filemtime() may return false, but raises an error for non-existing files
	$date = file_exists($dir) ? getdate(filemtime($dir)) : getdate($this->now);

	return array(
	'file_mtime' => ($date['hours'] << 11) + ($date['minutes'] << 5) + $date['seconds'] / 2,
	'file_mdate' => (($date['year'] - 1980) << 9) + ($date['mon'] << 5) + $date['mday']
	);
	}

	// --------------------------------------------------------------------

	/**
	* Add Directory
	*
	* @param string $dir the directory name
	* @param int $file_mtime
	* @param int $file_mdate
	* @return void
	*/
	protected function _add_dir($dir, $file_mtime, $file_mdate)
	{
	$dir = str_replace('\\', '/', $dir);

	$this->zipdata .=
	"\x50\x4b\x03\x04\x0a\x00\x00\x00\x00\x00"
	.pack('v', $file_mtime)
	.pack('v', $file_mdate)
	.pack('V', 0) // crc32
	.pack('V', 0) // compressed filesize
	.pack('V', 0) // uncompressed filesize
	.pack('v', self::strlen($dir)) // length of pathname
	.pack('v', 0) // extra field length
	.$dir
	// below is "data descriptor" segment
	.pack('V', 0) // crc32
	.pack('V', 0) // compressed filesize
	.pack('V', 0); // uncompressed filesize

	$this->directory .=
	"\x50\x4b\x01\x02\x00\x00\x0a\x00\x00\x00\x00\x00"
	.pack('v', $file_mtime)
	.pack('v', $file_mdate)
	.pack('V',0) // crc32
	.pack('V',0) // compressed filesize
	.pack('V',0) // uncompressed filesize
	.pack('v', self::strlen($dir)) // length of pathname
	.pack('v', 0) // extra field length
	.pack('v', 0) // file comment length
	.pack('v', 0) // disk number start
	.pack('v', 0) // internal file attributes
	.pack('V', 16) // external file attributes - 'directory' bit set
	.pack('V', $this->offset) // relative offset of local header
	.$dir;

	$this->offset = self::strlen($this->zipdata);
	$this->entries++;
	}

	// --------------------------------------------------------------------

	/**
	* Add Data to Zip
	*
	* Lets you add files to the archive. If the path is included
	* in the filename it will be placed within a directory. Make
	* sure you use add_dir() first to create the folder.
	*
	* @param mixed $filepath A single filepath or an array of file => data pairs
	* @param string $data Single file contents
	* @return void
	*/
	public function add_data($filepath, $data = NULL)
	{
	if (is_array($filepath))
	{
	foreach ($filepath as $path => $data)
	{
	$file_data = $this->_get_mod_time($path);
	$this->_add_data($path, $data, $file_data['file_mtime'], $file_data['file_mdate']);
	}
	}
	else
	{
	$file_data = $this->_get_mod_time($filepath);
	$this->_add_data($filepath, $data, $file_data['file_mtime'], $file_data['file_mdate']);
	}
	}

	// --------------------------------------------------------------------

	/**
	* Add Data to Zip
	*
	* @param string $filepath the file name/path
	* @param string $data the data to be encoded
	* @param int $file_mtime
	* @param int $file_mdate
	* @return void
	*/
	protected function _add_data($filepath, $data, $file_mtime, $file_mdate)
	{
	$filepath = str_replace('\\', '/', $filepath);

	$uncompressed_size = self::strlen($data);
	$crc32 = crc32($data);
	$gzdata = self::substr(gzcompress($data, $this->compression_level), 2, -4);
	$compressed_size = self::strlen($gzdata);

	$this->zipdata .=
	"\x50\x4b\x03\x04\x14\x00\x00\x00\x08\x00"
	.pack('v', $file_mtime)
	.pack('v', $file_mdate)
	.pack('V', $crc32)
	.pack('V', $compressed_size)
	.pack('V', $uncompressed_size)
	.pack('v', self::strlen($filepath)) // length of filename
	.pack('v', 0) // extra field length
	.$filepath
	.$gzdata; // "file data" segment

	$this->directory .=
	"\x50\x4b\x01\x02\x00\x00\x14\x00\x00\x00\x08\x00"
	.pack('v', $file_mtime)
	.pack('v', $file_mdate)
	.pack('V', $crc32)
	.pack('V', $compressed_size)
	.pack('V', $uncompressed_size)
	.pack('v', self::strlen($filepath)) // length of filename
	.pack('v', 0) // extra field length
	.pack('v', 0) // file comment length
	.pack('v', 0) // disk number start
	.pack('v', 0) // internal file attributes
	.pack('V', 32) // external file attributes - 'archive' bit set
	.pack('V', $this->offset) // relative offset of local header
	.$filepath;

	$this->offset = self::strlen($this->zipdata);
	$this->entries++;
	$this->file_num++;
	}

	// --------------------------------------------------------------------

	/**
	* Read the contents of a file and add it to the zip
	*
	* @param string $path
	* @param bool $archive_filepath
	* @return bool
	*/
	public function read_file($path, $archive_filepath = FALSE)
	{
	if (file_exists($path) && FALSE !== ($data = file_get_contents($path)))
	{
	if (is_string($archive_filepath))
	{
	$name = str_replace('\\', '/', $archive_filepath);
	}
	else
	{
	$name = str_replace('\\', '/', $path);

	if ($archive_filepath === FALSE)
	{
	$name = preg_replace('\|.*/(.+)\|', '\\1', $name);
	}
	}

	$this->add_data($name, $data);
	return TRUE;
	}

	return FALSE;
	}

	// ------------------------------------------------------------------------

	/**
	* Read a directory and add it to the zip.
	*
	* This function recursively reads a folder and everything it contains (including
	* sub-folders) and creates a zip based on it. Whatever directory structure
	* is in the original file path will be recreated in the zip file.
	*
	* @param string $path path to source directory
	* @param bool $preserve_filepath
	* @param string $root_path
	* @return bool
	*/
	public function read_dir($path, $preserve_filepath = TRUE, $root_path = NULL)
	{
	$path = rtrim($path, '/\\').DIRECTORY_SEPARATOR;
	if ( ! $fp = @opendir($path))
	{
	return FALSE;
	}

	// Set the original directory root for child dir's to use as relative
	if ($root_path === NULL)
	{
	$root_path = str_replace(array('\\', '/'), DIRECTORY_SEPARATOR, dirname($path)).DIRECTORY_SEPARATOR;
	}

	while (FALSE !== ($file = readdir($fp)))
	{
	if ($file[0] === '.')
	{
	continue;
	}

	if (is_dir($path.$file))
	{
	$this->read_dir($path.$file.DIRECTORY_SEPARATOR, $preserve_filepath, $root_path);
	}
	elseif (FALSE !== ($data = file_get_contents($path.$file)))
	{
	$name = str_replace(array('\\', '/'), DIRECTORY_SEPARATOR, $path);
	if ($preserve_filepath === FALSE)
	{
	$name = str_replace($root_path, '', $name);
	}

	$this->add_data($name.$file, $data);
	}
	}

	closedir($fp);
	return TRUE;
	}

	// --------------------------------------------------------------------

	/**
	* Get the Zip file
	*
	* @return string (binary encoded)
	*/
	public function get_zip()
	{
	// Is there any data to return?
	if ($this->entries === 0)
	{
	return FALSE;
	}

	return $this->zipdata
	.$this->directory."\x50\x4b\x05\x06\x00\x00\x00\x00"
	.pack('v', $this->entries) // total # of entries "on this disk"
	.pack('v', $this->entries) // total # of entries overall
	.pack('V', self::strlen($this->directory)) // size of central dir
	.pack('V', self::strlen($this->zipdata)) // offset to start of central dir
	."\x00\x00"; // .zip file comment length
	}

	// --------------------------------------------------------------------

	/**
	* Write File to the specified directory
	*
	* Lets you write a file
	*
	* @param string $filepath the file name
	* @return bool
	*/
	public function archive($filepath)
	{
	if ( ! ($fp = @fopen($filepath, 'w+b')))
	{
	return FALSE;
	}

	flock($fp, LOCK_EX);

	for ($result = $written = 0, $data = $this->get_zip(), $length = self::strlen($data); $written < $length; $written += $result)
	{
	if (($result = fwrite($fp, self::substr($data, $written))) === FALSE)
	{
	break;
	}
	}

	flock($fp, LOCK_UN);
	fclose($fp);

	return is_int($result);
	}

	// --------------------------------------------------------------------

	/**
	* Download
	*
	* @param string $filename the file name
	* @return void
	*/
	public function download($filename = 'backup.zip')
	{
	if ( ! preg_match('\|.+?\.zip$\|', $filename))
	{
	$filename .= '.zip';
	}

	get_instance()->load->helper('download');
	$get_zip = $this->get_zip();
	$zip_content =& $get_zip;

	force_download($filename, $zip_content);
	}

	// --------------------------------------------------------------------

	/**
	* Initialize Data
	*
	* Lets you clear current zip data. Useful if you need to create
	* multiple zips with different data.
	*
	* @return CI_Zip
	*/
	public function clear_data()
	{
	$this->zipdata = '';
	$this->directory = '';
	$this->entries = 0;
	$this->file_num = 0;
	$this->offset = 0;
	return $this;
	}

	// --------------------------------------------------------------------

	/**
	* Byte-safe strlen()
	*
	* @param string $str
	* @return int
	*/
	protected static function strlen($str)
	{
	return (self::$func_overload)
	? mb_strlen($str, '8bit')
	: strlen($str);
	}

	// --------------------------------------------------------------------

	/**
	* Byte-safe substr()
	*
	* @param string $str
	* @param int $start
	* @param int $length
	* @return string
	*/
	protected static function substr($str, $start, $length = NULL)
	{
	if (self::$func_overload)
	{
	// mb_substr($str, $start, null, '8bit') returns an empty
	// string on PHP 5.3
	isset($length) OR $length = ($start >= 0 ? self::strlen($str) - $start : -$start);
	return mb_substr($str, $start, $length, '8bit');
	}

	return isset($length)
	? substr($str, $start, $length)
	: substr($str, $start);
	}
	}