SimplePie: PHP-based RSS and Atom feed handling
 
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  • SimplePie
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Classes

  • SimplePie_Content_Type_Sniffer
  • SimplePie_File
  • SimplePie_gzdecode
  • SimplePie_HTTP_Parser
  • SimplePie_IRI
  • SimplePie_Net_IPv6
  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
 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: }
372: 

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SimplePie is © 2004–2012 Ryan Parman, Geoffrey Sneddon, Ryan McCue and contributors. Licensed under the BSD License. Hosted thanks to Matt Mullenweg, API documentation generated by ApiGen 2.6.1. Variation on the Feed Icon by Wolfgang Bartelme.