title: Decompress file with wrong size
body: <p>I have a method that decompresses *.gz file:</p>
  
  <pre><code>using (FileStream originalFileStream = new FileStream(gztempfilename, FileMode.Open, FileAccess.Read))
  {
    using (FileStream decompressedFileStream = new FileStream(outputtempfilename, FileMode.Create, FileAccess.Write))
    {
      using (GZipStream decompressionStream = new GZipStream(originalFileStream, CompressionMode.Decompress))
      {
        decompressionStream.CopyTo(decompressedFileStream);
      }
    }
  }
  </code></pre>
  
  <p>It worked perfectly, but recently I received pack of files with wrong size:
  When I open them with 7-zip they have <em>Packed Size</em> ~ 1,600,000 and <em>Size</em> = 7 (it should be ~20,000,000).
  <a href="https://i.stack.imgur.com/gJuCl.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/gJuCl.png" alt="enter image description here"></a>
  So when I extract them using this code I get only a part of the file. But when I extract this file using 7-zip I get full file.</p>
  
  <p>How can I handle this situation in my code?</p>