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   1  <?php
   2  
   3  namespace GuzzleHttp\Psr7;
   4  
   5  use Psr\Http\Message\StreamInterface;
   6  
   7  /**
   8   * Uses PHP's zlib.inflate filter to inflate deflate or gzipped content.
   9   *
  10   * This stream decorator skips the first 10 bytes of the given stream to remove
  11   * the gzip header, converts the provided stream to a PHP stream resource,
  12   * then appends the zlib.inflate filter. The stream is then converted back
  13   * to a Guzzle stream resource to be used as a Guzzle stream.
  14   *
  15   * @link http://tools.ietf.org/html/rfc1952
  16   * @link http://php.net/manual/en/filters.compression.php
  17   */
  18  class InflateStream implements StreamInterface
  19  {
  20      use StreamDecoratorTrait;
  21  
  22      public function __construct(StreamInterface $stream)
  23      {
  24          // read the first 10 bytes, ie. gzip header
  25          $header = $stream->read(10);
  26          $filenameHeaderLength = $this->getLengthOfPossibleFilenameHeader($stream, $header);
  27          // Skip the header, that is 10 + length of filename + 1 (nil) bytes
  28          $stream = new LimitStream($stream, -1, 10 + $filenameHeaderLength);
  29          $resource = StreamWrapper::getResource($stream);
  30          stream_filter_append($resource, 'zlib.inflate', STREAM_FILTER_READ);
  31          $this->stream = $stream->isSeekable() ? new Stream($resource) : new NoSeekStream(new Stream($resource));
  32      }
  33  
  34      /**
  35       * @param StreamInterface $stream
  36       * @param $header
  37       * @return int
  38       */
  39      private function getLengthOfPossibleFilenameHeader(StreamInterface $stream, $header)
  40      {
  41          $filename_header_length = 0;
  42  
  43          if (substr(bin2hex($header), 6, 2) === '08') {
  44              // we have a filename, read until nil
  45              $filename_header_length = 1;
  46              while ($stream->read(1) !== chr(0)) {
  47                  $filename_header_length++;
  48              }
  49          }
  50  
  51          return $filename_header_length;
  52      }
  53  }