Unzip splitted zip file c# (load parts from CD)

Question

I'm trying to unzip a zip file which is splitted to 5 parts. Problem is each part is in a different CD and i need to be able to change disks while unzipping. I have used Ionic.Zip to do that with no luck!

foreach (var entry in zip.Entries)
    {
        var stream = entry.OpenReader();
        var buffer = new byte[readByte];
        int n;
        try
        {
            while ((n = stream.Read(buffer, 0, buffer.Length)) > 0)
            {
               fileStream.Write(buffer, 0, buffer.Length);
            }
        }
        catch (FileNotFoundException ex)
        {
            // stream is closed and you cant continue           
            MessageBox.Show("Change CD");

            while ((n = stream.Read(buffer,0, buffer.Length)) > 0)
            {
                fileStream.Write(buffer, 0, buffer.Length);
            }
        }
    }

I have tried SevenZip, ZipSharp but i just cant implement it! Is there any way to handle this situation?

How is the split implemented? if it is just splitted and no special magic happend, can't you just load all files into one byte array and load it via ZipArchive? — Sebastian L, Mar 15 '17 at 07:52
yes i'm sure. files :: part1.z01 ... part2.z02 ... part3.z03 ........ — Milad Hosseinpanahi, Mar 15 '17 at 08:20
there are many tutorials on this, what is the errormessage you get? — Sebastian L, Mar 15 '17 at 08:54
well i can't find one. if you give me a link or something that would be awesome — Milad Hosseinpanahi, Mar 15 '17 at 09:01
unfortunately your answer does not work in my case. i have upvoted it but your way will not work for me. because there is very big files and i can't use this method and also i'm not able to use encryption and other features . thanks for your time — Milad Hosseinpanahi, Mar 19 '17 at 07:30

Sebastian L · Answer 1 · 2017-03-17T07:51:46.130

To open a splitted ZipArchive no extra Library is needed, but some extra work needs to be done

List<string> files = new List<string> { "zip.001",
                                        "zip.002",
                                        "zip.003",
                                        "zip.004",
                                        };
using (var zipFile = new ZipArchive(new CombinationStream(files.Select(x => new FileStream(x, FileMode.Open) as Stream).ToList()), ZipArchiveMode.Read)) 
{
    // Do whatever you want
}

In this Example i use CombinationStream to open all zipfiles, but you can easily write your own class inheriting Stream for your needs which waits for all CDs to be read.

A startingpoint could be (just pseudocode):

public class MultiDeviceStream : Stream
{
    [...]
    private Queue<Stream> streams;
    private Stream activeStream;

    public byte ReadByte() {
        byte result;
        if (!activeStream.EndOfStream) {
            result = activeStream.ReadByte();
            if (!streams.CanDequeue && activeStream.EndOfStream) {
                // raise some event signaling to change the CD and wait for the new filestream here
                this.EndOfStream = true;
            }
        } else {
            if (streams.CanDequeue) {
                activeStream = streams.Dequeue();
            }
            else
            {
                throw EndOfStreamException();
            }
            return ReadByte();
        }
        return result;
    }
}

Unzip splitted zip file c# (load parts from CD)

1 Answers1

Linked