c# - Compressing / Decompressing Folders & Files


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Does anyone know of a good way to compress or decompress files and folders in C# quickly? Handling large files might be necessary.


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    The .Net 2.0 framework namespace System.IO.Compression supports GZip and Deflate algorithms. Here are two methods that compress and decompress a byte stream which you can get from your file object. You can subsitute GZipStream for DefaultStream in the methods below to use that algorithm. This still leaves the problem of handling files compressed with different algorithms though.

    public static byte[] Compress(byte[] data)
    {
        MemoryStream output = new MemoryStream();
    
        GZipStream gzip = new GZipStream(output, CompressionMode.Compress, true);
        gzip.Write(data, 0, data.Length);
        gzip.Close();
    
        return output.ToArray();
    }
    
    public static byte[] Decompress(byte[] data)
    {
        MemoryStream input = new MemoryStream();
        input.Write(data, 0, data.Length);
        input.Position = 0;
    
        GZipStream gzip = new GZipStream(input, CompressionMode.Decompress, true);
    
        MemoryStream output = new MemoryStream();
    
        byte[] buff = new byte[64];
        int read = -1;
    
        read = gzip.Read(buff, 0, buff.Length);
    
        while (read > 0)
        {
            output.Write(buff, 0, read);
            read = gzip.Read(buff, 0, buff.Length);
        }
    
        gzip.Close();
    
        return output.ToArray();
    }
    

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    I've always used the SharpZip Library.

    Here's a link


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    As of .Net 1.1 the only available method is reaching into the java libraries.
    Using the Zip Classes in the J# Class Libraries to Compress Files and Data with C#
    Not sure if this has changed in recent versions.


  • Fitch Lee
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    You can use a 3rd-party library such as SharpZip as Tom pointed out.

    Another way (without going 3rd-party) is to use the Windows Shell API. You'll need to set a reference to the Microsoft Shell Controls and Automation COM library in your C# project. Gerald Gibson has an example at:

    Internet Archive's copy of the dead page


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    My answer would be close your eyes and opt for DotNetZip. It's been tested by a large community.


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    GZipStream is a really good utility to use.


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    This is very easy to do in java, and as stated above you can reach into the java.util.zip libraries from C#. For references see:

    java.util.zip javadocs
    sample code

    I used this a while ago to do a deep (recursive) zip of a folder structure, but I don't think I ever used the unzipping. If I'm so motivated I may pull that code out and edit it into here later.


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    Another good alternative is also DotNetZip.


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    you can create zip file with this method:

    public async Task<string> CreateZipFile(string sourceDirectoryPath, string name)
        {
            var path = HostingEnvironment.MapPath(TempPath) + name;
            await Task.Run(() =>
            {
                if (File.Exists(path)) File.Delete(path);
                ZipFile.CreateFromDirectory(sourceDirectoryPath, path);
            });
            return path;
        }
    

    and then you can unzip zip file with this methods:
    1- this method work with zip file path

    public async Task ExtractZipFile(string filePath, string destinationDirectoryName)
        {
            await Task.Run(() =>
            {
                var archive = ZipFile.Open(filePath, ZipArchiveMode.Read);
                foreach (var entry in archive.Entries)
                {
                    entry.ExtractToFile(Path.Combine(destinationDirectoryName, entry.FullName), true);
                }
                archive.Dispose();
            });
        }
    

    2- this method work with zip file stream

    public async Task ExtractZipFile(Stream zipFile, string destinationDirectoryName)
        {
            string filePath = HostingEnvironment.MapPath(TempPath) + Utility.GetRandomNumber(1, int.MaxValue);
            using (FileStream output = new FileStream(filePath, FileMode.Create))
            {
                await zipFile.CopyToAsync(output);
            }
            await Task.Run(() => ZipFile.ExtractToDirectory(filePath, destinationDirectoryName));
            await Task.Run(() => File.Delete(filePath));
        }