WordPress/wp-includes/SimplePie/gzdecode.php
Andrew Nacin 405a995659 Update to SimplePie 1.3. props rmccue.
Uses individual files for each class. We now conditionally load only the pieces
we need, resulting in less memory usage. Also easier to maintain now that it is
not a single 387KB file.

fixes #21183.



git-svn-id: http://core.svn.wordpress.org/trunk@21644 1a063a9b-81f0-0310-95a4-ce76da25c4cd
2012-08-28 17:24:33 +00:00

372 lines
8.4 KiB
PHP
Executable File

<?php
/**
* SimplePie
*
* A PHP-Based RSS and Atom Feed Framework.
* Takes the hard work out of managing a complete RSS/Atom solution.
*
* Copyright (c) 2004-2012, 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
* @version 1.3
* @copyright 2004-2012 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;
}
else
{
$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;
}
else
{
return false;
}
}
}