Re: how to compress file!

06-16-2009 11:49 PM |

You need create ZipEntry for each file in zip file.

I wrote a sample to test compress and decompress image, then display.

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            var ofd1 = new OpenFileDialog();
            var result = ofd1.ShowDialog();
            if (result.HasValue && result.Value)
            {
                //read file to byte[]
                Stream fileStream = ofd1.File.OpenRead();
                var filebuffer = new byte[(int)fileStream.Length];
                fileStream.Read(filebuffer, 0, (int)fileStream.Length);
                fileStream.Close();
                fileStream.Dispose();

                //create isolatedstorage file
                var isolatedStorageFile = IsolatedStorageFile.GetUserStoreForApplication();
                var filestream2 = isolatedStorageFile.CreateFile(ofd1.File.Name+".zip");

                //zip
                var zs = new ZipOutputStream(filestream2);
                var entry = new ZipEntry(ofd1.File.Name);
                zs.PutNextEntry(entry);
                zs.Write(filebuffer, 0, filebuffer.Length);
                zs.CloseEntry();
                zs.Close();
                filestream2.Close();
                filestream2.Dispose();

                //get isolatedstorage file
                var filestream3 = isolatedStorageFile.OpenFile(ofd1.File.Name + ".zip", FileMode.Open);
                
                //unzip
                byte[] buff1 = new byte[1024];
                var memstream1 = new MemoryStream();
                var zis = new ZipInputStream(filestream3);
                zis.GetNextEntry();
                int readlength=0;
                while (true)
                {
                    readlength = zis.Read(buff1, 0, buff1.Length);
                    memstream1.Write(buff1, 0, readlength);
                    if (readlength <= 0)
                        break;
                }

                //display
                var bitmap1 = new BitmapImage();
                bitmap1.SetSource(memstream1);
                img1.Source = bitmap1;
            }
        }

Re: how to compress file!

06-17-2009 2:37 AM |

For 1st question, based on my test,  write isolatedstorage file cost up to 90% time, compress and decompress only cost about 7% time, so if you use memorystream instead of isolatedstoragefilestream, the process will speed up 10 times

For second question, try use BackgroundWorker to run compression on other thread.

my code.  

        FileInfo _fileinfo;
        private void Button_Click(object sender, RoutedEventArgs e)
        {
            var ofd1 = new OpenFileDialog();
            var result = ofd1.ShowDialog();
            if (result.HasValue && result.Value)
            {
                tb1.Text = "Compressing...";
                _fileinfo = ofd1.File;

                BackgroundWorker bw = new BackgroundWorker();
                bw.DoWork += new DoWorkEventHandler(bw_DoWork);
                bw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bw_RunWorkerCompleted);
                bw.RunWorkerAsync();
            }
        }

        void bw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            //tb1.Text = "Compression complete.";
        }

        void bw_DoWork(object sender, DoWorkEventArgs e)
        {
            DateTime starttime = DateTime.Now;
            string timestring="";

            //read file to byte[]
            Stream fileStream = _fileinfo.OpenRead();
            var filebuffer = new byte[(int)fileStream.Length];
            fileStream.Read(filebuffer, 0, (int)fileStream.Length);
            fileStream.Close();
            fileStream.Dispose();

            timestring += "read file stream: " + (DateTime.Now - starttime).TotalMilliseconds;
            starttime = DateTime.Now;

            //create isolatedstorage file
            var isolatedStorageFile = IsolatedStorageFile.GetUserStoreForApplication();
            var filestream2 = isolatedStorageFile.CreateFile(_fileinfo.Name + ".zip");

            timestring += "\ncreate isolatedstorage file: " + (DateTime.Now - starttime).TotalMilliseconds;
            starttime = DateTime.Now;

            //zip
            var zs = new ZipOutputStream(filestream2);
            var entry = new ZipEntry(_fileinfo.Name);
            zs.PutNextEntry(entry);
            zs.Write(filebuffer, 0, filebuffer.Length);
            zs.CloseEntry();
            zs.Close();
            filestream2.Close();
            filestream2.Dispose();

            timestring += "\nzip and write isolatedstoreage file: " + (DateTime.Now - starttime).TotalMilliseconds;
            starttime = DateTime.Now;

            //get isolatedstorage file
            var filestream3 = isolatedStorageFile.OpenFile(_fileinfo.Name + ".zip", FileMode.Open);

            //unzip
            byte[] buff1 = new byte[1024];
            var memstream1 = new MemoryStream();
            var zis = new ZipInputStream(filestream3);
            zis.GetNextEntry();
            int readlength = 0;
            while (true)
            {
                readlength = zis.Read(buff1, 0, buff1.Length);
                memstream1.Write(buff1, 0, readlength);
                if (readlength <= 0)
                    break;
            }

            timestring += "\nunzip file: " + (DateTime.Now - starttime).TotalMilliseconds;
            starttime = DateTime.Now;

            //display.
            //use Dispather switch to UI thread.
            Dispatcher.BeginInvoke(delegate
            {
                var bitmap1 = new BitmapImage();
                bitmap1.SetSource(memstream1);
                img1.Source = bitmap1;
                tb1.Text = timestring;
            });
        }  

For 3rd question, you can use MemoryStream.

Re: how to compress file!

06-17-2009 10:29 PM |

my code, compress 6MB wma file spend 2 seconds

    private MemoryStream CompressFile(FileInfo inputfile)
    {
        FileStream inputstream = inputfile.OpenRead();
        MemoryStream stream1 = new MemoryStream();
        ZipOutputStream stream2 = new ZipOutputStream(stream1);

        //read file
        byte[] buffer1 = new byte[(int)inputstream.Length];
        inputstream.Read(buffer1, 0, (int) inputstream.Length);
        inputstream.Close();
        inputstream.Dispose();

        //compress
        ZipEntry entry = new ZipEntry(inputfile.Name);
        stream2.PutNextEntry(entry);
        stream2.Write(buffer1, 0, buffer1.Length);
        stream2.CloseEntry();
        stream1.Flush();
       
        return stream1;
    }

Re: how to compress file!

06-18-2009 8:56 AM |

in above mentioned code if you add following 2 lines, you will not get exception if you trying to unzip file in java