Crisis.Ionic.Zip.ZipEntry.MaybeApplyCompression C# (CSharp) Method

        private Stream MaybeApplyCompression(Stream s, long streamLength)
        {
            if (_CompressionMethod == 0x08 && CompressionLevel != Crisis.Ionic.Zlib.CompressionLevel.None)
            {
#if !NETCF
                // ParallelDeflateThreshold == 0    means ALWAYS use parallel deflate
                // ParallelDeflateThreshold == -1L  means NEVER use parallel deflate
                // Other values specify the actual threshold.
                if (_container.ParallelDeflateThreshold == 0L ||
                    (streamLength > _container.ParallelDeflateThreshold &&
                     _container.ParallelDeflateThreshold > 0L))
                {
                    // This is sort of hacky.
                    //
                    // It's expensive to create a ParallelDeflateOutputStream, because
                    // of the large memory buffers.  But the class is unlike most Stream
                    // classes in that it can be re-used, so the caller can compress
                    // multiple files with it, one file at a time.  The key is to call
                    // Reset() on it, in between uses.
                    //
                    // The ParallelDeflateOutputStream is attached to the container
                    // itself - there is just one for the entire ZipFile or
                    // ZipOutputStream. So it gets created once, per save, and then
                    // re-used many times.
                    //
                    // This approach will break when we go to a "parallel save"
                    // approach, where multiple entries within the zip file are being
                    // compressed and saved at the same time.  But for now it's ok.
                    //

                    // instantiate the ParallelDeflateOutputStream
                    if (_container.ParallelDeflater == null)
                    {
                        _container.ParallelDeflater =
                            new Crisis.Ionic.Zlib.ParallelDeflateOutputStream(s,
                                                                       CompressionLevel,
                                                                       _container.Strategy,
                                                                       true);
                        // can set the codec buffer size only before the first call to Write().
                        if (_container.CodecBufferSize > 0)
                            _container.ParallelDeflater.BufferSize = _container.CodecBufferSize;
                        if (_container.ParallelDeflateMaxBufferPairs > 0)
                            _container.ParallelDeflater.MaxBufferPairs =
                                _container.ParallelDeflateMaxBufferPairs;
                    }
                    // reset it with the new stream
                    Crisis.Ionic.Zlib.ParallelDeflateOutputStream o1 = _container.ParallelDeflater;
                    o1.Reset(s);
                    return o1;
                }
#endif
                var o = new Crisis.Ionic.Zlib.DeflateStream(s, Crisis.Ionic.Zlib.CompressionMode.Compress,
                                                     CompressionLevel,
                                                     true);
                if (_container.CodecBufferSize > 0)
                    o.BufferSize = _container.CodecBufferSize;
                o.Strategy = _container.Strategy;
                return o;
            }


#if BZIP
            if (_CompressionMethod == 0x0c)
            {
#if !NETCF
                if (_container.ParallelDeflateThreshold == 0L ||
                    (streamLength > _container.ParallelDeflateThreshold &&
                     _container.ParallelDeflateThreshold > 0L))
                {

                    var o1 = new Ionic.BZip2.ParallelBZip2OutputStream(s, true);
                    return o1;
                }
#endif
                var o = new Ionic.BZip2.BZip2OutputStream(s, true);
                return o;
            }
#endif

            return s;
        }