<?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; } }