private static void InitCompressionStreamCreators()
        {
            if (ZipEngine.compressionStreamCreators == null)
            {
                ZipEngine.compressionStreamCreators = new
                                                      Dictionary <ZipCompressionMethod, Converter <Stream, Stream> >();
                ZipEngine.decompressionStreamCreators = new
                                                        Dictionary <ZipCompressionMethod, Converter <Stream, Stream> >();

                ZipEngine.RegisterCompressionStreamCreator(
                    ZipCompressionMethod.Store,
                    CompressionMode.Compress,
                    delegate(Stream stream) {
                    return(stream);
                });
                ZipEngine.RegisterCompressionStreamCreator(
                    ZipCompressionMethod.Deflate,
                    CompressionMode.Compress,
                    delegate(Stream stream) {
                    return(new DeflateStream(stream, CompressionMode.Compress, true));
                });
                ZipEngine.RegisterCompressionStreamCreator(
                    ZipCompressionMethod.Store,
                    CompressionMode.Decompress,
                    delegate(Stream stream) {
                    return(stream);
                });
                ZipEngine.RegisterCompressionStreamCreator(
                    ZipCompressionMethod.Deflate,
                    CompressionMode.Decompress,
                    delegate(Stream stream) {
                    return(new DeflateStream(stream, CompressionMode.Decompress, true));
                });
            }
        }
 /// <summary>
 /// Registers a delegate that can create a warpper stream for
 /// compressing or uncompressing the data of a source stream.
 /// </summary>
 /// <param name="compressionMethod">Compression method being registered.</param>
 /// <param name="compressionMode">Indicates registration for ether
 /// compress or decompress mode.</param>
 /// <param name="creator">Delegate being registered.</param>
 /// <remarks>
 /// For compression, the delegate accepts a stream that writes to the archive
 /// and returns a wrapper stream that compresses bytes as they are written.
 /// For decompression, the delegate accepts a stream that reads from the archive
 /// and returns a wrapper stream that decompresses bytes as they are read.
 /// This wrapper stream model follows the design used by
 /// System.IO.Compression.DeflateStream, and indeed that class is used
 /// to implement the Deflate compression method by default.
 /// <para>To unregister a delegate, call this method again and pass
 /// null for the delegate parameter.</para>
 /// </remarks>
 /// <example>
 /// When the ZipEngine class is initialized, the Deflate compression method
 /// is automatically registered like this:
 /// <code>
 ///        ZipEngine.RegisterCompressionStreamCreator(
 ///            ZipCompressionMethod.Deflate,
 ///            CompressionMode.Compress,
 ///            delegate(Stream stream) {
 ///                return new DeflateStream(stream, CompressionMode.Compress, true);
 ///            });
 ///        ZipEngine.RegisterCompressionStreamCreator(
 ///            ZipCompressionMethod.Deflate,
 ///            CompressionMode.Decompress,
 ///            delegate(Stream stream) {
 ///                return new DeflateStream(stream, CompressionMode.Decompress, true);
 ///            });
 /// </code></example>
 public static void RegisterCompressionStreamCreator(
     ZipCompressionMethod compressionMethod,
     CompressionMode compressionMode,
     Converter <Stream, Stream> creator)
 {
     ZipEngine.InitCompressionStreamCreators();
     if (compressionMode == CompressionMode.Compress)
     {
         ZipEngine.compressionStreamCreators[compressionMethod] = creator;
     }
     else
     {
         ZipEngine.decompressionStreamCreators[compressionMethod] = creator;
     }
 }
 /// <summary>
 /// Creates a new instance of the zip engine.
 /// </summary>
 public ZipEngine()
     : base()
 {
     ZipEngine.InitCompressionStreamCreators();
 }
        /// <summary>
        /// Unpacks a single file from an archive or archive chain.
        /// </summary>
        private void UnpackOneFile(
            IUnpackStreamContext streamContext,
            ZipFileHeader header,
            ref Stream archiveStream)
        {
            ZipFileInfo fileInfo   = null;
            Stream      fileStream = null;

            try
            {
                Converter <Stream, Stream> compressionStreamCreator;
                if (!ZipEngine.decompressionStreamCreators.TryGetValue(
                        header.compressionMethod, out compressionStreamCreator))
                {
                    // Silently skip files of an unsupported compression method.
                    return;
                }

                long compressedSize;
                long uncompressedSize;
                long localHeaderOffset;
                int  archiveNumber;
                uint crc;
                header.GetZip64Fields(
                    out compressedSize,
                    out uncompressedSize,
                    out localHeaderOffset,
                    out archiveNumber,
                    out crc);

                if (this.currentArchiveNumber != archiveNumber + 1)
                {
                    if (archiveStream != null)
                    {
                        streamContext.CloseArchiveReadStream(
                            this.currentArchiveNumber,
                            String.Empty,
                            archiveStream);
                        archiveStream = null;

                        this.OnProgress(ArchiveProgressType.FinishArchive);
                        this.currentArchiveName = null;
                    }

                    this.currentArchiveNumber         = (short)(archiveNumber + 1);
                    this.currentArchiveBytesProcessed = 0;
                    this.currentArchiveTotalBytes     = 0;

                    archiveStream = this.OpenArchive(
                        streamContext, this.currentArchiveNumber);

                    FileStream archiveFileStream = archiveStream as FileStream;
                    this.currentArchiveName = (archiveFileStream != null ?
                                               Path.GetFileName(archiveFileStream.Name) : null);

                    this.currentArchiveTotalBytes = archiveStream.Length;
                    this.currentArchiveNumber--;
                    this.OnProgress(ArchiveProgressType.StartArchive);
                    this.currentArchiveNumber++;
                }

                archiveStream.Seek(localHeaderOffset, SeekOrigin.Begin);

                ZipFileHeader localHeader = new ZipFileHeader();
                if (!localHeader.Read(archiveStream, false) ||
                    !ZipEngine.AreFilePathsEqual(localHeader.fileName, header.fileName))
                {
                    string msg = "Could not read file: " + header.fileName;
                    throw new ZipException(msg);
                }

                fileInfo = header.ToZipFileInfo();

                fileStream = streamContext.OpenFileWriteStream(
                    fileInfo.FullName,
                    fileInfo.Length,
                    fileInfo.LastWriteTime);

                if (fileStream != null)
                {
                    this.currentFileName           = header.fileName;
                    this.currentFileBytesProcessed = 0;
                    this.currentFileTotalBytes     = fileInfo.Length;
                    this.currentArchiveNumber--;
                    this.OnProgress(ArchiveProgressType.StartFile);
                    this.currentArchiveNumber++;

                    this.UnpackFileBytes(
                        streamContext,
                        fileInfo.FullName,
                        fileInfo.CompressedLength,
                        fileInfo.Length,
                        header.crc32,
                        fileStream,
                        compressionStreamCreator,
                        ref archiveStream);
                }
            }
            finally
            {
                if (fileStream != null)
                {
                    streamContext.CloseFileWriteStream(
                        fileInfo.FullName,
                        fileStream,
                        fileInfo.Attributes,
                        fileInfo.LastWriteTime);

                    this.currentArchiveNumber--;
                    this.OnProgress(ArchiveProgressType.FinishFile);
                    this.currentArchiveNumber++;
                }
            }
        }