Programming with .NET - General

Re: Re: Re: how to compress file!

SaurabhAgg — Wed, 01 Jul 2009 14:56:15 GMT

I'm not sure if I'm missing on to something, but even this won't allow me to compress a folder with files that can be read using winzip / winrar (saw this in the comments).

Thanks.

Re: Re: how to compress file!

joji777 — Wed, 01 Jul 2009 14:12:08 GMT

ok then try this one, this should help

http://www.eggheadcafe.com/tutorials/aspnet/d566463d-83bd-486a-8633-53aa54f405bf/silverlight-2-beta-2-doi.aspx

Re: Re: how to compress file!

SaurabhAgg — Wed, 01 Jul 2009 14:00:27 GMT

Thanks for the quick reply .. actually what I want to do is that I have some folders & files which I want to be packaged in a zip file. Using SharpZipLib, I guess we can just compress a single file, and that too can't be read using winzip / winrar.

Thanks.

Re: Re: how to compress file!

joji777 — Wed, 01 Jul 2009 13:47:28 GMT

have a look on this thread, hope it will help

http://silverlight.net/forums/t/21392.aspx

Re: Re: how to compress file!

SaurabhAgg — Wed, 01 Jul 2009 13:38:52 GMT

@Mog Liang

I couldn't find any ZipOutputStream class for Silverlight, is this from vjslib.dll ?

If yes, then is there any way we can create a zip of a folder in Silverlight ?

Thanks.

-Saurabh

Re: how to compress file!

joji777 — Thu, 18 Jun 2009 12:56:22 GMT

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

zipEntry.CompressionMethod = CompressionMethod.Deflated;

zipEntry.Size = actualfilebufer.Length;

Regards

Re: how to compress file!

joji777 — Thu, 18 Jun 2009 12:13:29 GMT

one critical issue i am unable to figure out so far is follwoing exception. my requirments are like, I zip a file in silverlight component and later i have to read that file for my java applet. when we try to open file in java following exception occur.

Exception in thread "main" java.util.zip.ZipException: invalid entry size (expected 4294967295 but got 8628524 bytes)

at java.util.zip.ZipInputStream.readEnd(ZipInputStream.java:373)

at java.util.zip.ZipInputStream.read(ZipInputStream.java:141)

at java.util.zip.InflaterInputStream.read(InflaterInputStream.java:105)

why header is incorrect ??

Re: how to compress file!

ksleung — Thu, 18 Jun 2009 02:33:16 GMT

That's way too long to zip. Perhaps you wanna look at ZipForge which is another zip package. I have no issue with it. Perhaps more efficient than SharpZipLib?

Re: how to compress file!

Mog Liang - MSFT — Thu, 18 Jun 2009 02:29:45 GMT

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!

joji777 — Wed, 17 Jun 2009 13:11:52 GMT

many thanks for code samples and guidance, I just tried it with memory stream and it still takes same amount of time to zip. May be i am doing something wrong, can you please update your snippet doing it with memory stream, that will makes me clear if i am suing memory stream in right way or not.

Best regards

Re: how to compress file!

ksleung — Wed, 17 Jun 2009 07:49:40 GMT

Is this code built on SL2 or SL3? A while ago I reported an IsolatedStorage write performance bug, and it was mentioned that this will be fixed in SL3, although I haven't tested it as I dealt with it using the "workaround" already. The zip package may very well exercise the same performance problem.

See this thread http://silverlight.net/forums/p/75315/180892.aspx

Re: how to compress file!

Mog Liang - MSFT — Wed, 17 Jun 2009 06:37:47 GMT

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!

joji777 — Wed, 17 Jun 2009 04:25:58 GMT

Hi Mog Liang,

Thanks for sharing the code, yes it works. However I found following issues, can you please help me out for these issues as well:

1) I used your given code and it took 2 minutes 25 seconds to compress an audio file size 8.22 Mb, only addition in my code was I set zipoutputstream.SetLevel(9) , I wanted to make maximum compressed file.

2) In silvelright after user select a file in open file dilaouge it keep the dilaouge showing while compression routine is running, it shows kind of stuck, how can I update the look and give message to user "compressing...." i tried but as soon compression code starts it stucks until compression is done.

3) is there anyway to get a compressed stream in byte array, wihtout reading it again from stored place ?

Regards

Re: how to compress file!

Mog Liang - MSFT — Wed, 17 Jun 2009 03:49:02 GMT

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!

joji777 — Mon, 15 Jun 2009 13:37:05 GMT

i tried with memory stream and i sitll see the same error. Can anyone please help me to figure out why sharp zip lib raising this error "No open entry.".