Wordpress 3.5
[autoinstalls/wordpress.git] / wp-includes / SimplePie / gzdecode.php
1 <?php
2 /**
3  * SimplePie
4  *
5  * A PHP-Based RSS and Atom Feed Framework.
6  * Takes the hard work out of managing a complete RSS/Atom solution.
7  *
8  * Copyright (c) 2004-2012, Ryan Parman, Geoffrey Sneddon, Ryan McCue, and contributors
9  * All rights reserved.
10  *
11  * Redistribution and use in source and binary forms, with or without modification, are
12  * permitted provided that the following conditions are met:
13  *
14  *      * Redistributions of source code must retain the above copyright notice, this list of
15  *        conditions and the following disclaimer.
16  *
17  *      * Redistributions in binary form must reproduce the above copyright notice, this list
18  *        of conditions and the following disclaimer in the documentation and/or other materials
19  *        provided with the distribution.
20  *
21  *      * Neither the name of the SimplePie Team nor the names of its contributors may be used
22  *        to endorse or promote products derived from this software without specific prior
23  *        written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS
26  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
27  * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS
28  * AND CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
30  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
31  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
32  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
33  * POSSIBILITY OF SUCH DAMAGE.
34  *
35  * @package SimplePie
36  * @version 1.3.1
37  * @copyright 2004-2012 Ryan Parman, Geoffrey Sneddon, Ryan McCue
38  * @author Ryan Parman
39  * @author Geoffrey Sneddon
40  * @author Ryan McCue
41  * @link http://simplepie.org/ SimplePie
42  * @license http://www.opensource.org/licenses/bsd-license.php BSD License
43  */
44
45
46 /**
47  * Decode 'gzip' encoded HTTP data
48  *
49  * @package SimplePie
50  * @subpackage HTTP
51  * @link http://www.gzip.org/format.txt
52  */
53 class SimplePie_gzdecode
54 {
55         /**
56          * Compressed data
57          *
58          * @access private
59          * @var string
60          * @see gzdecode::$data
61          */
62         var $compressed_data;
63
64         /**
65          * Size of compressed data
66          *
67          * @access private
68          * @var int
69          */
70         var $compressed_size;
71
72         /**
73          * Minimum size of a valid gzip string
74          *
75          * @access private
76          * @var int
77          */
78         var $min_compressed_size = 18;
79
80         /**
81          * Current position of pointer
82          *
83          * @access private
84          * @var int
85          */
86         var $position = 0;
87
88         /**
89          * Flags (FLG)
90          *
91          * @access private
92          * @var int
93          */
94         var $flags;
95
96         /**
97          * Uncompressed data
98          *
99          * @access public
100          * @see gzdecode::$compressed_data
101          * @var string
102          */
103         var $data;
104
105         /**
106          * Modified time
107          *
108          * @access public
109          * @var int
110          */
111         var $MTIME;
112
113         /**
114          * Extra Flags
115          *
116          * @access public
117          * @var int
118          */
119         var $XFL;
120
121         /**
122          * Operating System
123          *
124          * @access public
125          * @var int
126          */
127         var $OS;
128
129         /**
130          * Subfield ID 1
131          *
132          * @access public
133          * @see gzdecode::$extra_field
134          * @see gzdecode::$SI2
135          * @var string
136          */
137         var $SI1;
138
139         /**
140          * Subfield ID 2
141          *
142          * @access public
143          * @see gzdecode::$extra_field
144          * @see gzdecode::$SI1
145          * @var string
146          */
147         var $SI2;
148
149         /**
150          * Extra field content
151          *
152          * @access public
153          * @see gzdecode::$SI1
154          * @see gzdecode::$SI2
155          * @var string
156          */
157         var $extra_field;
158
159         /**
160          * Original filename
161          *
162          * @access public
163          * @var string
164          */
165         var $filename;
166
167         /**
168          * Human readable comment
169          *
170          * @access public
171          * @var string
172          */
173         var $comment;
174
175         /**
176          * Don't allow anything to be set
177          *
178          * @param string $name
179          * @param mixed $value
180          */
181         public function __set($name, $value)
182         {
183                 trigger_error("Cannot write property $name", E_USER_ERROR);
184         }
185
186         /**
187          * Set the compressed string and related properties
188          *
189          * @param string $data
190          */
191         public function __construct($data)
192         {
193                 $this->compressed_data = $data;
194                 $this->compressed_size = strlen($data);
195         }
196
197         /**
198          * Decode the GZIP stream
199          *
200          * @return bool Successfulness
201          */
202         public function parse()
203         {
204                 if ($this->compressed_size >= $this->min_compressed_size)
205                 {
206                         // Check ID1, ID2, and CM
207                         if (substr($this->compressed_data, 0, 3) !== "\x1F\x8B\x08")
208                         {
209                                 return false;
210                         }
211
212                         // Get the FLG (FLaGs)
213                         $this->flags = ord($this->compressed_data[3]);
214
215                         // FLG bits above (1 << 4) are reserved
216                         if ($this->flags > 0x1F)
217                         {
218                                 return false;
219                         }
220
221                         // Advance the pointer after the above
222                         $this->position += 4;
223
224                         // MTIME
225                         $mtime = substr($this->compressed_data, $this->position, 4);
226                         // Reverse the string if we're on a big-endian arch because l is the only signed long and is machine endianness
227                         if (current(unpack('S', "\x00\x01")) === 1)
228                         {
229                                 $mtime = strrev($mtime);
230                         }
231                         $this->MTIME = current(unpack('l', $mtime));
232                         $this->position += 4;
233
234                         // Get the XFL (eXtra FLags)
235                         $this->XFL = ord($this->compressed_data[$this->position++]);
236
237                         // Get the OS (Operating System)
238                         $this->OS = ord($this->compressed_data[$this->position++]);
239
240                         // Parse the FEXTRA
241                         if ($this->flags & 4)
242                         {
243                                 // Read subfield IDs
244                                 $this->SI1 = $this->compressed_data[$this->position++];
245                                 $this->SI2 = $this->compressed_data[$this->position++];
246
247                                 // SI2 set to zero is reserved for future use
248                                 if ($this->SI2 === "\x00")
249                                 {
250                                         return false;
251                                 }
252
253                                 // Get the length of the extra field
254                                 $len = current(unpack('v', substr($this->compressed_data, $this->position, 2)));
255                                 $this->position += 2;
256
257                                 // Check the length of the string is still valid
258                                 $this->min_compressed_size += $len + 4;
259                                 if ($this->compressed_size >= $this->min_compressed_size)
260                                 {
261                                         // Set the extra field to the given data
262                                         $this->extra_field = substr($this->compressed_data, $this->position, $len);
263                                         $this->position += $len;
264                                 }
265                                 else
266                                 {
267                                         return false;
268                                 }
269                         }
270
271                         // Parse the FNAME
272                         if ($this->flags & 8)
273                         {
274                                 // Get the length of the filename
275                                 $len = strcspn($this->compressed_data, "\x00", $this->position);
276
277                                 // Check the length of the string is still valid
278                                 $this->min_compressed_size += $len + 1;
279                                 if ($this->compressed_size >= $this->min_compressed_size)
280                                 {
281                                         // Set the original filename to the given string
282                                         $this->filename = substr($this->compressed_data, $this->position, $len);
283                                         $this->position += $len + 1;
284                                 }
285                                 else
286                                 {
287                                         return false;
288                                 }
289                         }
290
291                         // Parse the FCOMMENT
292                         if ($this->flags & 16)
293                         {
294                                 // Get the length of the comment
295                                 $len = strcspn($this->compressed_data, "\x00", $this->position);
296
297                                 // Check the length of the string is still valid
298                                 $this->min_compressed_size += $len + 1;
299                                 if ($this->compressed_size >= $this->min_compressed_size)
300                                 {
301                                         // Set the original comment to the given string
302                                         $this->comment = substr($this->compressed_data, $this->position, $len);
303                                         $this->position += $len + 1;
304                                 }
305                                 else
306                                 {
307                                         return false;
308                                 }
309                         }
310
311                         // Parse the FHCRC
312                         if ($this->flags & 2)
313                         {
314                                 // Check the length of the string is still valid
315                                 $this->min_compressed_size += $len + 2;
316                                 if ($this->compressed_size >= $this->min_compressed_size)
317                                 {
318                                         // Read the CRC
319                                         $crc = current(unpack('v', substr($this->compressed_data, $this->position, 2)));
320
321                                         // Check the CRC matches
322                                         if ((crc32(substr($this->compressed_data, 0, $this->position)) & 0xFFFF) === $crc)
323                                         {
324                                                 $this->position += 2;
325                                         }
326                                         else
327                                         {
328                                                 return false;
329                                         }
330                                 }
331                                 else
332                                 {
333                                         return false;
334                                 }
335                         }
336
337                         // Decompress the actual data
338                         if (($this->data = gzinflate(substr($this->compressed_data, $this->position, -8))) === false)
339                         {
340                                 return false;
341                         }
342                         else
343                         {
344                                 $this->position = $this->compressed_size - 8;
345                         }
346
347                         // Check CRC of data
348                         $crc = current(unpack('V', substr($this->compressed_data, $this->position, 4)));
349                         $this->position += 4;
350                         /*if (extension_loaded('hash') && sprintf('%u', current(unpack('V', hash('crc32b', $this->data)))) !== sprintf('%u', $crc))
351                         {
352                                 return false;
353                         }*/
354
355                         // Check ISIZE of data
356                         $isize = current(unpack('V', substr($this->compressed_data, $this->position, 4)));
357                         $this->position += 4;
358                         if (sprintf('%u', strlen($this->data) & 0xFFFFFFFF) !== sprintf('%u', $isize))
359                         {
360                                 return false;
361                         }
362
363                         // Wow, against all odds, we've actually got a valid gzip string
364                         return true;
365                 }
366                 else
367                 {
368                         return false;
369                 }
370         }
371 }