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Diffstat (limited to 'lib/simplepie/library/SimplePie/gzdecode.php')
| -rw-r--r-- | lib/simplepie/library/SimplePie/gzdecode.php | 366 |
1 files changed, 366 insertions, 0 deletions
diff --git a/lib/simplepie/library/SimplePie/gzdecode.php b/lib/simplepie/library/SimplePie/gzdecode.php new file mode 100644 index 000000000..f4aeafa28 --- /dev/null +++ b/lib/simplepie/library/SimplePie/gzdecode.php @@ -0,0 +1,366 @@ +<?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, Geoffrey 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, Geoffrey Sneddon, Ryan McCue + * @author Ryan Parman + * @author Geoffrey 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; + } +} |