<?php
/**
 * @package     Joomla.Platform
 * @subpackage  FileSystem
 *
 * @copyright   Copyright (C) 2005 - 2011 Open Source Matters, Inc. All rights reserved.
 * @license     GNU General Public License version 2 or later; see LICENSE
 */

defined('JPATH_PLATFORM') or die;

/**
 * Gzip format adapter for the JArchive class
 *
 * This class is inspired from and draws heavily in code and concept from the Compress package of
 * The Horde Project <http://www.horde.org>
 *
 * @contributor  Michael Slusarz <slusarz@horde.org>
 * @contributor  Michael Cochrane <mike@graftonhall.co.nz>
 *
 * @package     Joomla.Platform
 * @subpackage  FileSystem
 * @since       11.1
 */
class JArchiveGzip extends JObject
{
    /**
     * Gzip file flags.
     * @var array
     */
    var $_flags = array (
        'FTEXT' => 0x01,
        'FHCRC' => 0x02,
        'FEXTRA' => 0x04,
        'FNAME' => 0x08,
        'FCOMMENT' => 0x10
    );

    /**
     * Gzip file data buffer
     * @var string
     */
    var $_data = null;

    /**
    * Extract a Gzip compressed file to a given path
    *
    * @param    string  $archive        Path to ZIP archive to extract
    * @param    string  $destination    Path to extract archive to
    * @param    array   $options        Extraction options [unused]
    *
    * @return   boolean True if successful
    * @since    11.1
    */
    public function extract($archive, $destination, $options = array ())
    {
        // Initialise variables.
        $this->_data = null;

        if (!extension_loaded('zlib')) {
            $this->set('error.message', JText::_('JLIB_FILESYSTEM_GZIP_NOT_SUPPORTED'));

            return JError::raiseWarning(100, $this->get('error.message'));
        }

        // New style! streams!
        $input = JFactory::getStream();
        $input->set('processingmethod', 'gz'); // use gz

        if (!$input->open($archive)) {
            $this->set('error.message', JText::_('JLIB_FILESYSTEM_GZIP_UNABLE_TO_READ'));

            return JError::raiseWarning(100, $this->get('error.message'));
        }

        $output = JFactory::getStream();

        if (!$output->open($destination, 'w')) {
            $this->set('error.message', JText::_('JLIB_FILESYSTEM_GZIP_UNABLE_TO_WRITE'));
            // Close the previous file
            $input->close(); 

            return JError::raiseWarning(100, $this->get('error.message'));
        }

        $written = 0;
        do
        {
            $this->_data = $input->read($input->get('chunksize', 8196));
            if ($this->_data) {
                if (!$output->write($this->_data)) {
                    $this->set('error.message', JText::_('JLIB_FILESYSTEM_GZIP_UNABLE_TO_WRITE_FILE'));

                    return JError::raiseWarning(100, $this->get('error.message'));
                }
            }
        }
        while ($this->_data);

        $output->close();
        $input->close();

        return true;
    }

    /**
     * Get file data offset for archive
     *
     * @return  int     Data position marker for archive
     * @since   11.1
     */
    function _getFilePosition()
    {
        // gzipped file... unpack it first
        $position = 0;
        $info = @ unpack('CCM/CFLG/VTime/CXFL/COS', substr($this->_data, $position +2));

        if (!$info) {
            $this->set('error.message', JText::_('JLIB_FILESYSTEM_GZIP_UNABLE_TO_DECOMPRESS'));
            return false;
        }

        $position += 10;

        if ($info['FLG'] & $this->_flags['FEXTRA']) {
            $XLEN = unpack('vLength', substr($this->_data, $position +0, 2));
            $XLEN = $XLEN['Length'];
            $position += $XLEN +2;
        }

        if ($info['FLG'] & $this->_flags['FNAME']) {
            $filenamePos = strpos($this->_data, "\x0", $position);
            $filename = substr($this->_data, $position, $filenamePos - $position);
            $position = $filenamePos +1;
        }

        if ($info['FLG'] & $this->_flags['FCOMMENT']) {
            $commentPos = strpos($this->_data, "\x0", $position);
            $comment = substr($this->_data, $position, $commentPos - $position);
            $position = $commentPos +1;
        }

        if ($info['FLG'] & $this->_flags['FHCRC']) {
            $hcrc = unpack('vCRC', substr($this->_data, $position +0, 2));
            $hcrc = $hcrc['CRC'];
            $position += 2;
        }

        return $position;
    }
}