IsZipFile(Stream stream, bool testExtract) { if (stream == null) { ); } bool flag = false; try { if (!stream.CanRead) { return false; } Stream @null = Stream.Null; using (ZipFile file = Read(stream, null, null, null)) { if (testExtract) { foreach (ZipEntry entry in file) { if (!entry.IsDirectory) { entry.Extract(@null); } } } } flag = true; } catch (IOException) { } catch (ZipException) { } return flag; }

private static ZipFile Read(Stream zipStream, TextWriter statusMessageWriter, Encoding encoding, EventHandler<ReadProgressEventArgs> readProgress) { if (zipStream == null) { ); } ZipFile zf = new ZipFile { _StatusMessageTextWriter = statusMessageWriter, _alternateEncoding = encoding ?? DefaultEncoding, _alternateEncodingUsage = ZipOption.Always }; if (readProgress != null) { zf.ReadProgress += readProgress; } zf._readstream = (zipStream.Position == 0L) ? zipStream : new OffsetStream(zipStream); zf._ReadStreamIsOurs = false; if (zf.Verbose) { zf._StatusMessageTextWriter.WriteLine(); } ReadIntoInstance(zf); return zf; }