gzip.php

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<?php
/**
 * @package     Joomla.Platform
 * @subpackage  Archive
 *
 * @copyright   Copyright (C) 2005 - 2013 Open Source Matters, Inc. All rights reserved.
 * @license     GNU General Public License version 2 or later; see LICENSE
 */

defined('JPATH_PLATFORM') or die;

jimport('joomla.filesystem.file');

/**
 * 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  Archive
 * @since       11.1
 */
class JArchiveGzip implements JArchiveExtractable
{
        /**
         * Gzip file flags.
         *
         * @var    array
         * @since  11.1
         */
        private $_flags = array('FTEXT' => 0x01, 'FHCRC' => 0x02, 'FEXTRA' => 0x04, 'FNAME' => 0x08, 'FCOMMENT' => 0x10);

        /**
         * Gzip file data buffer
         *
         * @var    string
         * @since  11.1
         */
        private $_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   $options      Extraction options [unused]
         *
         * @return  boolean  True if successful
         *
         * @since   11.1
         * @throws  RuntimeException
         */
        public function extract($archive, $destination, array $options = array ())
        {
                $this->_data = null;

                if (!extension_loaded('zlib'))
                {
                        if (class_exists('JError'))
                        {
                                return JError::raiseWarning(100, 'The zlib extension is not available.');
                        }
                        else
                        {
                                throw new RuntimeException('The zlib extension is not available.');
                        }
                }

                if (!isset($options['use_streams']) || $options['use_streams'] == false)
                {
                        $this->_data = file_get_contents($archive);

                        if (!$this->_data)
                        {
                                if (class_exists('JError'))
                                {
                                        return JError::raiseWarning(100, 'Unable to read archive');
                                }
                                else
                                {
                                        throw new RuntimeException('Unable to read archive');
                                }
                        }

                        $position = $this->_getFilePosition();
                        $buffer = gzinflate(substr($this->_data, $position, strlen($this->_data) - $position));

                        if (empty($buffer))
                        {
                                if (class_exists('JError'))
                                {
                                        return JError::raiseWarning(100, 'Unable to decompress data');
                                }
                                else
                                {
                                        throw new RuntimeException('Unable to decompress data');
                                }
                        }

                        if (JFile::write($destination, $buffer) === false)
                        {
                                if (class_exists('JError'))
                                {
                                        return JError::raiseWarning(100, 'Unable to write archive');
                                }
                                else
                                {
                                        throw new RuntimeException('Unable to write archive');
                                }
                        }
                }
                else
                {
                        // New style! streams!
                        $input = JFactory::getStream();

                        // Use gz
                        $input->set('processingmethod', 'gz');

                        if (!$input->open($archive))
                        {
                                if (class_exists('JError'))
                                {
                                        return JError::raiseWarning(100, 'Unable to read archive (gz)');
                                }
                                else
                                {
                                        throw new RuntimeException('Unable to read archive (gz)');
                                }
                        }

                        $output = JFactory::getStream();

                        if (!$output->open($destination, 'w'))
                        {
                                $input->close();

                                if (class_exists('JError'))
                                {
                                        return JError::raiseWarning(100, 'Unable to write archive (gz)');
                                }
                                else
                                {
                                        throw new RuntimeException('Unable to write archive (gz)');
                                }
                        }

                        do
                        {
                                $this->_data = $input->read($input->get('chunksize', 8196));

                                if ($this->_data)
                                {
                                        if (!$output->write($this->_data))
                                        {
                                                $input->close();

                                                if (class_exists('JError'))
                                                {
                                                        return JError::raiseWarning(100, 'Unable to write file (gz)');
                                                }
                                                else
                                                {
                                                        throw new RuntimeException('Unable to write file (gz)');
                                                }
                                        }
                                }
                        }
                        while ($this->_data);

                        $output->close();
                        $input->close();
                }
                return true;
        }

        /**
         * Tests whether this adapter can unpack files on this computer.
         *
         * @return  boolean  True if supported
         *
         * @since   11.3
         */
        public static function isSupported()
        {
                return extension_loaded('zlib');
        }

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

                if (!$info)
                {
                        if (class_exists('JError'))
                        {
                                return JError::raiseWarning(100, 'Unable to decompress data.');
                        }
                        else
                        {
                                throw new RuntimeException('Unable to decompress data.');
                        }
                }

                $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);
                        $position = $filenamePos + 1;
                }

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