ru-se.com

gzdecode.php (8506B)

---

 <?php
 /**
  * SimplePie
  *
  * A PHP-Based RSS and Atom Feed Framework.
  * Takes the hard work out of managing a complete RSS/Atom solution.
  *
  * Copyright (c) 2004-2016, Ryan Parman, Sam Sneddon, Ryan McCue, and contributors
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without modification, are
  * permitted provided that the following conditions are met:
  *
  * 	* Redistributions of source code must retain the above copyright notice, this list of
  * 	  conditions and the following disclaimer.
  *
  * 	* Redistributions in binary form must reproduce the above copyright notice, this list
  * 	  of conditions and the following disclaimer in the documentation and/or other materials
  * 	  provided with the distribution.
  *
  * 	* Neither the name of the SimplePie Team nor the names of its contributors may be used
  * 	  to endorse or promote products derived from this software without specific prior
  * 	  written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS
  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
  * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS
  * AND CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  *
  * @package SimplePie
  * @copyright 2004-2016 Ryan Parman, Sam Sneddon, Ryan McCue
  * @author Ryan Parman
  * @author Sam Sneddon
  * @author Ryan McCue
  * @link http://simplepie.org/ SimplePie
  * @license http://www.opensource.org/licenses/bsd-license.php BSD License
  */
 
 
 /**
  * Decode 'gzip' encoded HTTP data
  *
  * @package SimplePie
  * @subpackage HTTP
  * @link http://www.gzip.org/format.txt
  */
 class SimplePie_gzdecode
 {
 	/**
 	 * Compressed data
 	 *
 	 * @access private
 	 * @var string
 	 * @see gzdecode::$data
 	 */
 	var $compressed_data;
 
 	/**
 	 * Size of compressed data
 	 *
 	 * @access private
 	 * @var int
 	 */
 	var $compressed_size;
 
 	/**
 	 * Minimum size of a valid gzip string
 	 *
 	 * @access private
 	 * @var int
 	 */
 	var $min_compressed_size = 18;
 
 	/**
 	 * Current position of pointer
 	 *
 	 * @access private
 	 * @var int
 	 */
 	var $position = 0;
 
 	/**
 	 * Flags (FLG)
 	 *
 	 * @access private
 	 * @var int
 	 */
 	var $flags;
 
 	/**
 	 * Uncompressed data
 	 *
 	 * @access public
 	 * @see gzdecode::$compressed_data
 	 * @var string
 	 */
 	var $data;
 
 	/**
 	 * Modified time
 	 *
 	 * @access public
 	 * @var int
 	 */
 	var $MTIME;
 
 	/**
 	 * Extra Flags
 	 *
 	 * @access public
 	 * @var int
 	 */
 	var $XFL;
 
 	/**
 	 * Operating System
 	 *
 	 * @access public
 	 * @var int
 	 */
 	var $OS;
 
 	/**
 	 * Subfield ID 1
 	 *
 	 * @access public
 	 * @see gzdecode::$extra_field
 	 * @see gzdecode::$SI2
 	 * @var string
 	 */
 	var $SI1;
 
 	/**
 	 * Subfield ID 2
 	 *
 	 * @access public
 	 * @see gzdecode::$extra_field
 	 * @see gzdecode::$SI1
 	 * @var string
 	 */
 	var $SI2;
 
 	/**
 	 * Extra field content
 	 *
 	 * @access public
 	 * @see gzdecode::$SI1
 	 * @see gzdecode::$SI2
 	 * @var string
 	 */
 	var $extra_field;
 
 	/**
 	 * Original filename
 	 *
 	 * @access public
 	 * @var string
 	 */
 	var $filename;
 
 	/**
 	 * Human readable comment
 	 *
 	 * @access public
 	 * @var string
 	 */
 	var $comment;
 
 	/**
 	 * Don't allow anything to be set
 	 *
 	 * @param string $name
 	 * @param mixed $value
 	 */
 	public function __set($name, $value)
 	{
 		trigger_error("Cannot write property $name", E_USER_ERROR);
 	}
 
 	/**
 	 * Set the compressed string and related properties
 	 *
 	 * @param string $data
 	 */
 	public function __construct($data)
 	{
 		$this->compressed_data = $data;
 		$this->compressed_size = strlen($data);
 	}
 
 	/**
 	 * Decode the GZIP stream
 	 *
 	 * @return bool Successfulness
 	 */
 	public function parse()
 	{
 		if ($this->compressed_size >= $this->min_compressed_size)
 		{
 			// Check ID1, ID2, and CM
 			if (substr($this->compressed_data, 0, 3) !== "\x1F\x8B\x08")
 			{
 				return false;
 			}
 
 			// Get the FLG (FLaGs)
 			$this->flags = ord($this->compressed_data[3]);
 
 			// FLG bits above (1 << 4) are reserved
 			if ($this->flags > 0x1F)
 			{
 				return false;
 			}
 
 			// Advance the pointer after the above
 			$this->position += 4;
 
 			// MTIME
 			$mtime = substr($this->compressed_data, $this->position, 4);
 			// Reverse the string if we're on a big-endian arch because l is the only signed long and is machine endianness
 			if (current(unpack('S', "\x00\x01")) === 1)
 			{
 				$mtime = strrev($mtime);
 			}
 			$this->MTIME = current(unpack('l', $mtime));
 			$this->position += 4;
 
 			// Get the XFL (eXtra FLags)
 			$this->XFL = ord($this->compressed_data[$this->position++]);
 
 			// Get the OS (Operating System)
 			$this->OS = ord($this->compressed_data[$this->position++]);
 
 			// Parse the FEXTRA
 			if ($this->flags & 4)
 			{
 				// Read subfield IDs
 				$this->SI1 = $this->compressed_data[$this->position++];
 				$this->SI2 = $this->compressed_data[$this->position++];
 
 				// SI2 set to zero is reserved for future use
 				if ($this->SI2 === "\x00")
 				{
 					return false;
 				}
 
 				// Get the length of the extra field
 				$len = current(unpack('v', substr($this->compressed_data, $this->position, 2)));
 				$this->position += 2;
 
 				// Check the length of the string is still valid
 				$this->min_compressed_size += $len + 4;
 				if ($this->compressed_size >= $this->min_compressed_size)
 				{
 					// Set the extra field to the given data
 					$this->extra_field = substr($this->compressed_data, $this->position, $len);
 					$this->position += $len;
 				}
 				else
 				{
 					return false;
 				}
 			}
 
 			// Parse the FNAME
 			if ($this->flags & 8)
 			{
 				// Get the length of the filename
 				$len = strcspn($this->compressed_data, "\x00", $this->position);
 
 				// Check the length of the string is still valid
 				$this->min_compressed_size += $len + 1;
 				if ($this->compressed_size >= $this->min_compressed_size)
 				{
 					// Set the original filename to the given string
 					$this->filename = substr($this->compressed_data, $this->position, $len);
 					$this->position += $len + 1;
 				}
 				else
 				{
 					return false;
 				}
 			}
 
 			// Parse the FCOMMENT
 			if ($this->flags & 16)
 			{
 				// Get the length of the comment
 				$len = strcspn($this->compressed_data, "\x00", $this->position);
 
 				// Check the length of the string is still valid
 				$this->min_compressed_size += $len + 1;
 				if ($this->compressed_size >= $this->min_compressed_size)
 				{
 					// Set the original comment to the given string
 					$this->comment = substr($this->compressed_data, $this->position, $len);
 					$this->position += $len + 1;
 				}
 				else
 				{
 					return false;
 				}
 			}
 
 			// Parse the FHCRC
 			if ($this->flags & 2)
 			{
 				// Check the length of the string is still valid
 				$this->min_compressed_size += $len + 2;
 				if ($this->compressed_size >= $this->min_compressed_size)
 				{
 					// Read the CRC
 					$crc = current(unpack('v', substr($this->compressed_data, $this->position, 2)));
 
 					// Check the CRC matches
 					if ((crc32(substr($this->compressed_data, 0, $this->position)) & 0xFFFF) === $crc)
 					{
 						$this->position += 2;
 					}
 					else
 					{
 						return false;
 					}
 				}
 				else
 				{
 					return false;
 				}
 			}
 
 			// Decompress the actual data
 			if (($this->data = gzinflate(substr($this->compressed_data, $this->position, -8))) === false)
 			{
 				return false;
 			}
 
 			$this->position = $this->compressed_size - 8;
 
 			// Check CRC of data
 			$crc = current(unpack('V', substr($this->compressed_data, $this->position, 4)));
 			$this->position += 4;
 			/*if (extension_loaded('hash') && sprintf('%u', current(unpack('V', hash('crc32b', $this->data)))) !== sprintf('%u', $crc))
 			{
 				return false;
 			}*/
 
 			// Check ISIZE of data
 			$isize = current(unpack('V', substr($this->compressed_data, $this->position, 4)));
 			$this->position += 4;
 			if (sprintf('%u', strlen($this->data) & 0xFFFFFFFF) !== sprintf('%u', $isize))
 			{
 				return false;
 			}
 
 			// Wow, against all odds, we've actually got a valid gzip string
 			return true;
 		}
 
 		return false;
 	}
 }