inc/3rdparty/simplepie/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) 2004-2009, 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-dev
  37  * @copyright 2004-2010 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  * @todo phpDoc comments
  44  */
  45
  46
  47 /**
  48  * gzdecode
  49  *
  50  * @package SimplePie
  51  */
  52 class SimplePie_gzdecode
  53 {
  54         /**
  55          * Compressed data
  56          *
  57          * @access private
  58          * @see gzdecode::$data
  59          */
  60         var $compressed_data;
  61
  62         /**
  63          * Size of compressed data
  64          *
  65          * @access private
  66          */
  67         var $compressed_size;
  68
  69         /**
  70          * Minimum size of a valid gzip string
  71          *
  72          * @access private
  73          */
  74         var $min_compressed_size = 18;
  75
  76         /**
  77          * Current position of pointer
  78          *
  79          * @access private
  80          */
  81         var $position = 0;
  82
  83         /**
  84          * Flags (FLG)
  85          *
  86          * @access private
  87          */
  88         var $flags;
  89
  90         /**
  91          * Uncompressed data
  92          *
  93          * @access public
  94          * @see gzdecode::$compressed_data
  95          */
  96         var $data;
  97
  98         /**
  99          * Modified time
 100          *
 101          * @access public
 102          */
 103         var $MTIME;
 104
 105         /**
 106          * Extra Flags
 107          *
 108          * @access public
 109          */
 110         var $XFL;
 111
 112         /**
 113          * Operating System
 114          *
 115          * @access public
 116          */
 117         var $OS;
 118
 119         /**
 120          * Subfield ID 1
 121          *
 122          * @access public
 123          * @see gzdecode::$extra_field
 124          * @see gzdecode::$SI2
 125          */
 126         var $SI1;
 127
 128         /**
 129          * Subfield ID 2
 130          *
 131          * @access public
 132          * @see gzdecode::$extra_field
 133          * @see gzdecode::$SI1
 134          */
 135         var $SI2;
 136
 137         /**
 138          * Extra field content
 139          *
 140          * @access public
 141          * @see gzdecode::$SI1
 142          * @see gzdecode::$SI2
 143          */
 144         var $extra_field;
 145
 146         /**
 147          * Original filename
 148          *
 149          * @access public
 150          */
 151         var $filename;
 152
 153         /**
 154          * Human readable comment
 155          *
 156          * @access public
 157          */
 158         var $comment;
 159
 160         /**
 161          * Don't allow anything to be set
 162          *
 163          * @access public
 164          */
 165         public function __set($name, $value)
 166         {
 167                 trigger_error("Cannot write property $name", E_USER_ERROR);
 168         }
 169
 170         /**
 171          * Set the compressed string and related properties
 172          *
 173          * @access public
 174          */
 175         public function __construct($data)
 176         {
 177                 $this->compressed_data = $data;
 178                 $this->compressed_size = strlen($data);
 179         }
 180
 181         /**
 182          * Decode the GZIP stream
 183          *
 184          * @access public
 185          */
 186         public function parse()
 187         {
 188                 if ($this->compressed_size >= $this->min_compressed_size)
 189                 {
 190                         // Check ID1, ID2, and CM
 191                         if (substr($this->compressed_data, 0, 3) !== "\x1F\x8B\x08")
 192                         {
 193                                 return false;
 194                         }
 195
 196                         // Get the FLG (FLaGs)
 197                         $this->flags = ord($this->compressed_data[3]);
 198
 199                         // FLG bits above (1 << 4) are reserved
 200                         if ($this->flags > 0x1F)
 201                         {
 202                                 return false;
 203                         }
 204
 205                         // Advance the pointer after the above
 206                         $this->position += 4;
 207
 208                         // MTIME
 209                         $mtime = substr($this->compressed_data, $this->position, 4);
 210                         // Reverse the string if we're on a big-endian arch because l is the only signed long and is machine endianness
 211                         if (current(unpack('S', "\x00\x01")) === 1)
 212                         {
 213                                 $mtime = strrev($mtime);
 214                         }
 215                         $this->MTIME = current(unpack('l', $mtime));
 216                         $this->position += 4;
 217
 218                         // Get the XFL (eXtra FLags)
 219                         $this->XFL = ord($this->compressed_data[$this->position++]);
 220
 221                         // Get the OS (Operating System)
 222                         $this->OS = ord($this->compressed_data[$this->position++]);
 223
 224                         // Parse the FEXTRA
 225                         if ($this->flags & 4)
 226                         {
 227                                 // Read subfield IDs
 228                                 $this->SI1 = $this->compressed_data[$this->position++];
 229                                 $this->SI2 = $this->compressed_data[$this->position++];
 230
 231                                 // SI2 set to zero is reserved for future use
 232                                 if ($this->SI2 === "\x00")
 233                                 {
 234                                         return false;
 235                                 }
 236
 237                                 // Get the length of the extra field
 238                                 $len = current(unpack('v', substr($this->compressed_data, $this->position, 2)));
 239                                 $this->position += 2;
 240
 241                                 // Check the length of the string is still valid
 242                                 $this->min_compressed_size += $len + 4;
 243                                 if ($this->compressed_size >= $this->min_compressed_size)
 244                                 {
 245                                         // Set the extra field to the given data
 246                                         $this->extra_field = substr($this->compressed_data, $this->position, $len);
 247                                         $this->position += $len;
 248                                 }
 249                                 else
 250                                 {
 251                                         return false;
 252                                 }
 253                         }
 254
 255                         // Parse the FNAME
 256                         if ($this->flags & 8)
 257                         {
 258                                 // Get the length of the filename
 259                                 $len = strcspn($this->compressed_data, "\x00", $this->position);
 260
 261                                 // Check the length of the string is still valid
 262                                 $this->min_compressed_size += $len + 1;
 263                                 if ($this->compressed_size >= $this->min_compressed_size)
 264                                 {
 265                                         // Set the original filename to the given string
 266                                         $this->filename = substr($this->compressed_data, $this->position, $len);
 267                                         $this->position += $len + 1;
 268                                 }
 269                                 else
 270                                 {
 271                                         return false;
 272                                 }
 273                         }
 274
 275                         // Parse the FCOMMENT
 276                         if ($this->flags & 16)
 277                         {
 278                                 // Get the length of the comment
 279                                 $len = strcspn($this->compressed_data, "\x00", $this->position);
 280
 281                                 // Check the length of the string is still valid
 282                                 $this->min_compressed_size += $len + 1;
 283                                 if ($this->compressed_size >= $this->min_compressed_size)
 284                                 {
 285                                         // Set the original comment to the given string
 286                                         $this->comment = substr($this->compressed_data, $this->position, $len);
 287                                         $this->position += $len + 1;
 288                                 }
 289                                 else
 290                                 {
 291                                         return false;
 292                                 }
 293                         }
 294
 295                         // Parse the FHCRC
 296                         if ($this->flags & 2)
 297                         {
 298                                 // Check the length of the string is still valid
 299                                 $this->min_compressed_size += $len + 2;
 300                                 if ($this->compressed_size >= $this->min_compressed_size)
 301                                 {
 302                                         // Read the CRC
 303                                         $crc = current(unpack('v', substr($this->compressed_data, $this->position, 2)));
 304
 305                                         // Check the CRC matches
 306                                         if ((crc32(substr($this->compressed_data, 0, $this->position)) & 0xFFFF) === $crc)
 307                                         {
 308                                                 $this->position += 2;
 309                                         }
 310                                         else
 311                                         {
 312                                                 return false;
 313                                         }
 314                                 }
 315                                 else
 316                                 {
 317                                         return false;
 318                                 }
 319                         }
 320
 321                         // Decompress the actual data
 322                         if (($this->data = gzinflate(substr($this->compressed_data, $this->position, -8))) === false)
 323                         {
 324                                 return false;
 325                         }
 326                         else
 327                         {
 328                                 $this->position = $this->compressed_size - 8;
 329                         }
 330
 331                         // Check CRC of data
 332                         $crc = current(unpack('V', substr($this->compressed_data, $this->position, 4)));
 333                         $this->position += 4;
 334                         /*if (extension_loaded('hash') && sprintf('%u', current(unpack('V', hash('crc32b', $this->data)))) !== sprintf('%u', $crc))
 335                         {
 336                                 return false;
 337                         }*/
 338
 339                         // Check ISIZE of data
 340                         $isize = current(unpack('V', substr($this->compressed_data, $this->position, 4)));
 341                         $this->position += 4;
 342                         if (sprintf('%u', strlen($this->data) & 0xFFFFFFFF) !== sprintf('%u', $isize))
 343                         {
 344                                 return false;
 345                         }
 346
 347                         // Wow, against all odds, we've actually got a valid gzip string
 348                         return true;
 349                 }
 350                 else
 351                 {
 352                         return false;
 353                 }
 354         }
 355 }