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Differences Between: [Versions 39 and 311] [Versions 39 and 400] [Versions 39 and 401] [Versions 39 and 402] [Versions 39 and 403]

   1  <?php
   2  /**
   3   * This file is part of FPDI
   4   *
   5   * @package   setasign\Fpdi
   6   * @copyright Copyright (c) 2019 Setasign - Jan Slabon (https://www.setasign.com)
   7   * @license   http://opensource.org/licenses/mit-license The MIT License
   8   */
   9  
  10  namespace setasign\Fpdi\PdfParser\Filter;
  11  
  12  /**
  13   * Class for handling zlib/deflate encoded data
  14   *
  15   * @package setasign\Fpdi\PdfParser\Filter
  16   */
  17  class Flate implements FilterInterface
  18  {
  19      /**
  20       * Checks whether the zlib extension is loaded.
  21       *
  22       * Used for testing purpose.
  23       *
  24       * @return boolean
  25       * @internal
  26       */
  27      protected function extensionLoaded()
  28      {
  29          return \extension_loaded('zlib');
  30      }
  31  
  32      /**
  33       * Decodes a flate compressed string.
  34       *
  35       * @param string $data The input string
  36       * @return string
  37       * @throws FlateException
  38       */
  39      public function decode($data)
  40      {
  41          if ($this->extensionLoaded()) {
  42              $oData = $data;
  43              $data = @((\strlen($data) > 0) ? \gzuncompress($data) : '');
  44              if ($data === false) {
  45                  // Try this fallback
  46                  $tries = 1;
  47                  while ($tries < 10 && ($data === false || \strlen($data) < (\strlen($oData) - $tries - 1))) {
  48                      $data = @(\gzinflate(\substr($oData, $tries)));
  49                      $tries++;
  50                  }
  51  
  52                  if ($data === false) {
  53                      // let's try if the checksum is CRC32
  54                      $fh = fopen('php://temp', 'w+b');
  55                      \fwrite($fh, "\x1f\x8b\x08\x00\x00\x00\x00\x00" . $oData);
  56                      \stream_filter_append($fh, 'zlib.inflate', \STREAM_FILTER_READ, ['window' => 30]);
  57                      \fseek($fh, 0);
  58                      $data = \stream_get_contents($fh);
  59                      \fclose($fh);
  60                  }
  61  
  62                  if (!$data) {
  63                      throw new FlateException(
  64                          'Error while decompressing stream.',
  65                          FlateException::DECOMPRESS_ERROR
  66                      );
  67                  }
  68              }
  69          } else {
  70              throw new FlateException(
  71                  'To handle FlateDecode filter, enable zlib support in PHP.',
  72                  FlateException::NO_ZLIB
  73              );
  74          }
  75  
  76          return $data;
  77      }
  78  }