Use pure C# to extract .tar and .tar.gz files

ExtractTarGz.cs

namespace TarExtractor;

using System.IO.Compression;
using System.Text;

public class Tar
{
    /// <summary>
    /// Extracts a <i>.tar.gz</i> archive to the specified directory.
    /// </summary>
    /// <param name="filename">The <i>.tar.gz</i> to decompress and extract.</param>
    /// <param name="outputDir">Output directory to write the files.</param>
    public static void ExtractTarGz(string filename, string outputDir)
    {
        using var stream = File.OpenRead(filename);
        ExtractTarGz(stream, outputDir);
    }

    /// <summary>
    /// Extracts a <i>.tar.gz</i> archive stream to the specified directory.
    /// </summary>
    /// <param name="stream">The <i>.tar.gz</i> to decompress and extract.</param>
    /// <param name="outputDir">Output directory to write the files.</param>
    public static void ExtractTarGz(Stream stream, string outputDir)
    {
        int read;
        const int chunk = 4096;
        var buffer = new byte[chunk];

        // A GZipStream is not seekable, so copy it first to a MemoryStream
        using var gzip = new GZipStream(stream, CompressionMode.Decompress);
        using var memStr = new MemoryStream();
        
        //For .NET 6+
        while ((read = gzip.Read(buffer, 0, buffer.Length)) > 0)
        {
            memStr.Write(buffer, 0, read);
        }

        //For .NET versions < 6
        /*
        do
        {
            read = gzip.Read(buffer, 0, chunk);
            memStr.Write(buffer, 0, read);
        } while (read == chunk);*/

        gzip.Close();
        memStr.Seek(0, SeekOrigin.Begin);
        ExtractTar(memStr, outputDir);
    }

    /// <summary>
    /// Extracts a <c>tar</c> archive to the specified directory.
    /// </summary>
    /// <param name="filename">The <i>.tar</i> to extract.</param>
    /// <param name="outputDir">Output directory to write the files.</param>
    public static void ExtractTar(string filename, string outputDir)
    {
        using var stream = File.OpenRead(filename);
        ExtractTar(stream, outputDir);
    }

    /// <summary>
    /// Extracts a <c>tar</c> archive to the specified directory.
    /// </summary>
    /// <param name="stream">The <i>.tar</i> to extract.</param>
    /// <param name="outputDir">Output directory to write the files.</param>
    public static void ExtractTar(Stream stream, string outputDir)
    {
        var buffer = new byte[100];
        var longFileName = string.Empty;
        while (true)
        {
            stream.Read(buffer, 0, 100);
            var name = string.IsNullOrEmpty(longFileName) ? Encoding.ASCII.GetString(buffer).Trim('\0') : longFileName; //Use longFileName if we have one read
            if (string.IsNullOrWhiteSpace(name))
                break;
            stream.Seek(24, SeekOrigin.Current);
            stream.Read(buffer, 0, 12);
            var size = Convert.ToInt64(Encoding.UTF8.GetString(buffer, 0, 12).Trim('\0').Trim(), 8);
            stream.Seek(20, SeekOrigin.Current); //Move head to typeTag byte
            var typeTag = stream.ReadByte();
            stream.Seek(355L, SeekOrigin.Current); //Move head to beginning of data (byte 512)

	    if (typeTag == 'L')
            {
                //If Type Tag is 'L' we have a filename that is longer than the 100 bytes reserved for it in the header.
                //We read it here and save it temporarily as it will be the file name of the next block where the actual data is
                var buf = new byte[size];
                stream.Read(buf, 0, buf.Length);
                longFileName = Encoding.ASCII.GetString(buf).Trim('\0');
	    }
            else
            {
                //We have a normal file or directory
                longFileName = string.Empty; //Reset longFileName if current entry is not indicating one
		var output = Path.Combine(outputDir, name);
		if (!Directory.Exists(Path.GetDirectoryName(output)))
			Directory.CreateDirectory(Path.GetDirectoryName(output));

		if (!name.EndsWith("/")) //Directories are zero size and don't need anything written
		{
			using var str = File.Open(output, FileMode.OpenOrCreate, FileAccess.Write);
			var buf = new byte[size];
			stream.Read(buf, 0, buf.Length);
			str.Write(buf, 0, buf.Length);
		}
	    }			

            //Move head to next 512 byte block 
            var pos = stream.Position;
            var offset = 512 - (pos % 512);
            if (offset == 512)
                offset = 0;

            stream.Seek(offset, SeekOrigin.Current);
        }
    }
}


/*
    This software is available under 2 licenses -- choose whichever you prefer.
    ------------------------------------------------------------------------------
    ALTERNATIVE A - MIT License
    Copyright (c) 2017 Sean Barrett
    Permission is hereby granted, free of charge, to any person obtaining a copy of
    this software and associated documentation files (the "Software"), to deal in
    the Software without restriction, including without limitation the rights to
    use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
    of the Software, and to permit persons to whom the Software is furnished to do
    so, subject to the following conditions:
    The above copyright notice and this permission notice shall be included in all
    copies or substantial portions of the Software.
    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
    SOFTWARE.
    ------------------------------------------------------------------------------
    ALTERNATIVE B - Public Domain (www.unlicense.org)
    This is free and unencumbered software released into the public domain.
    Anyone is free to copy, modify, publish, use, compile, sell, or distribute this
    software, either in source code form or as a compiled binary, for any purpose,
    commercial or non-commercial, and by any means.
    In jurisdictions that recognize copyright laws, the author or authors of this
    software dedicate any and all copyright interest in the software to the public
    domain. We make this dedication for the benefit of the public at large and to
    the detriment of our heirs and successors. We intend this dedication to be an
    overt act of relinquishment in perpetuity of all present and future rights to
    this software under copyright law.
    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
    ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
    WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

Hi, this is exactly what i am looking for! Unfortunately it doesn't seem to work on the archive i am trying to extract: steamcmd_linux.tar.gz

It fails with this error:

Unhandled exception. System.IO.InvalidDataException: The archive entry was compressed using an unsupported compression method.
   at System.IO.Compression.Inflater.Inflate(FlushCode flushCode)
   at System.IO.Compression.Inflater.ReadInflateOutput(Byte* bufPtr, Int32 length, FlushCode flushCode, Int32& bytesRead)
   at System.IO.Compression.Inflater.ReadOutput(Byte* bufPtr, Int32 length, Int32& bytesRead)
   at System.IO.Compression.Inflater.InflateVerified(Byte* bufPtr, Int32 length)
   at System.IO.Compression.DeflateStream.ReadCore(Span`1 buffer)
   at System.IO.Compression.DeflateStream.Read(Byte[] buffer, Int32 offset, Int32 count)
   at Tar.ExtractTarGz(Stream stream, String outputDir) in C:\repos\s\HelperClasses\Linux\Tar.cs:line 35
   at Tar.ExtractTarGz(String filename, String outputDir) in C:\repos\s\HelperClasses\Linux\Tar.cs:line 16
   at SteamCMD.<>c.<ExtractAsync>b__3_0() in C:\repos\s\SteamCMD\SteamCMD.cs:line 42
   at System.Threading.Tasks.Task.InnerInvoke()
   at System.Threading.Tasks.Task.<>c.<.cctor>b__272_0(Object obj)
   at System.Threading.ExecutionContext.RunFromThreadPoolDispatchLoop(Thread threadPoolThread, ExecutionContext executionContext, ContextCallback callback, Object state)
--- End of stack trace from previous location ---
   at System.Threading.ExecutionContext.RunFromThreadPoolDispatchLoop(Thread threadPoolThread, ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task& currentTaskSlot, Thread threadPoolThread)
--- End of stack trace from previous location ---
   at SteamCMD.ExtractAsync() in C:\repos\s\SteamCMD\SteamCMD.cs:line 39
   at SteamCMD.ExtractSteamCMDAsync() in C:\repos\s\SteamCMD\SteamCMD.cs:line 85
   at SteamCMD.PromptInstallSteamCMD() in C:\repos\s\SteamCMD\SteamCMD.cs:line 77
   at OxideBootConsole.Boot() in C:\repos\s\OxideBootConsole.cs:line 31
   at Program.<Main>$(String[] args) in C:\repos\s\Program.cs:line 11
   at Program.<Main>(String[] args)
Aborted

I don't have the skillset to resolve this myself but nevertheless, maybe it can help with bug fixing. Cheers.

@Dan-Levi

I don't have the skillset to resolve this myself but nevertheless, maybe it can help with bug fixing. Cheers.

Hi Dan. I took the liberty of testing it out myself using your file and I had no problems what so ever with extracting it using the snippet above.

What version of .NET are you running? Perhaps this issue only occurs on an older .NET version? I am testing on .NET 6

Hi Matheo, thanks for responding to my comment. Actually, sorry to have wasted your time! It turned out that there was nothing wrong with the class at all. The url to the zip archive had a typo in my code, so basically all I did was fetching the 404 page. #embarrassing :-)

@Dan-Levi Ok great :) Happens to the best of us 😅