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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 | * | |
42c80841 | 8 | * Copyright (c) 2004-2012, Ryan Parman, Geoffrey Sneddon, Ryan McCue, and contributors |
ec397236 NL |
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 | |
42c80841 NL |
36 | * @version 1.3.1 |
37 | * @copyright 2004-2012 Ryan Parman, Geoffrey Sneddon, Ryan McCue | |
ec397236 NL |
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 | |
ec397236 NL |
43 | */ |
44 | ||
45 | ||
46 | /** | |
42c80841 | 47 | * Decode 'gzip' encoded HTTP data |
ec397236 NL |
48 | * |
49 | * @package SimplePie | |
42c80841 NL |
50 | * @subpackage HTTP |
51 | * @link http://www.gzip.org/format.txt | |
ec397236 NL |
52 | */ |
53 | class SimplePie_gzdecode | |
54 | { | |
55 | /** | |
56 | * Compressed data | |
57 | * | |
58 | * @access private | |
42c80841 | 59 | * @var string |
ec397236 NL |
60 | * @see gzdecode::$data |
61 | */ | |
62 | var $compressed_data; | |
63 | ||
64 | /** | |
65 | * Size of compressed data | |
66 | * | |
67 | * @access private | |
42c80841 | 68 | * @var int |
ec397236 NL |
69 | */ |
70 | var $compressed_size; | |
71 | ||
72 | /** | |
73 | * Minimum size of a valid gzip string | |
74 | * | |
75 | * @access private | |
42c80841 | 76 | * @var int |
ec397236 NL |
77 | */ |
78 | var $min_compressed_size = 18; | |
79 | ||
80 | /** | |
81 | * Current position of pointer | |
82 | * | |
83 | * @access private | |
42c80841 | 84 | * @var int |
ec397236 NL |
85 | */ |
86 | var $position = 0; | |
87 | ||
88 | /** | |
89 | * Flags (FLG) | |
90 | * | |
91 | * @access private | |
42c80841 | 92 | * @var int |
ec397236 NL |
93 | */ |
94 | var $flags; | |
95 | ||
96 | /** | |
97 | * Uncompressed data | |
98 | * | |
99 | * @access public | |
100 | * @see gzdecode::$compressed_data | |
42c80841 | 101 | * @var string |
ec397236 NL |
102 | */ |
103 | var $data; | |
104 | ||
105 | /** | |
106 | * Modified time | |
107 | * | |
108 | * @access public | |
42c80841 | 109 | * @var int |
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110 | */ |
111 | var $MTIME; | |
112 | ||
113 | /** | |
114 | * Extra Flags | |
115 | * | |
116 | * @access public | |
42c80841 | 117 | * @var int |
ec397236 NL |
118 | */ |
119 | var $XFL; | |
120 | ||
121 | /** | |
122 | * Operating System | |
123 | * | |
124 | * @access public | |
42c80841 | 125 | * @var int |
ec397236 NL |
126 | */ |
127 | var $OS; | |
128 | ||
129 | /** | |
130 | * Subfield ID 1 | |
131 | * | |
132 | * @access public | |
133 | * @see gzdecode::$extra_field | |
134 | * @see gzdecode::$SI2 | |
42c80841 | 135 | * @var string |
ec397236 NL |
136 | */ |
137 | var $SI1; | |
138 | ||
139 | /** | |
140 | * Subfield ID 2 | |
141 | * | |
142 | * @access public | |
143 | * @see gzdecode::$extra_field | |
144 | * @see gzdecode::$SI1 | |
42c80841 | 145 | * @var string |
ec397236 NL |
146 | */ |
147 | var $SI2; | |
148 | ||
149 | /** | |
150 | * Extra field content | |
151 | * | |
152 | * @access public | |
153 | * @see gzdecode::$SI1 | |
154 | * @see gzdecode::$SI2 | |
42c80841 | 155 | * @var string |
ec397236 NL |
156 | */ |
157 | var $extra_field; | |
158 | ||
159 | /** | |
160 | * Original filename | |
161 | * | |
162 | * @access public | |
42c80841 | 163 | * @var string |
ec397236 NL |
164 | */ |
165 | var $filename; | |
166 | ||
167 | /** | |
168 | * Human readable comment | |
169 | * | |
170 | * @access public | |
42c80841 | 171 | * @var string |
ec397236 NL |
172 | */ |
173 | var $comment; | |
174 | ||
175 | /** | |
176 | * Don't allow anything to be set | |
177 | * | |
42c80841 NL |
178 | * @param string $name |
179 | * @param mixed $value | |
ec397236 NL |
180 | */ |
181 | public function __set($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 | * | |
42c80841 | 189 | * @param string $data |
ec397236 NL |
190 | */ |
191 | public function __construct($data) | |
192 | { | |
193 | $this->compressed_data = $data; | |
194 | $this->compressed_size = strlen($data); | |
195 | } | |
196 | ||
197 | /** | |
198 | * Decode the GZIP stream | |
199 | * | |
42c80841 | 200 | * @return bool Successfulness |
ec397236 NL |
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 | } |