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

ExtractTarGz.cs

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

namespace TarExample
{

	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)
		{
			// A GZipStream is not seekable, so copy it first to a MemoryStream
			using (var gzip = new GZipStream(stream, CompressionMode.Decompress))
			{
				const int chunk = 4096;
				using (var memStr = new MemoryStream())
				{
					int read;
					var buffer = new byte[chunk];
					do
					{
						read = gzip.Read(buffer, 0, chunk);
						memStr.Write(buffer, 0, read);
					} while (read == chunk);

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

		/// <summary>
		/// Extractes 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>
		/// Extractes 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];
			while (true)
			{
				stream.Read(buffer, 0, 100);
				var name = Encoding.ASCII.GetString(buffer).Trim('\0');
				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(376L, SeekOrigin.Current);

				var output = Path.Combine(outputDir, name);
				if (!Directory.Exists(Path.GetDirectoryName(output)))
					Directory.CreateDirectory(Path.GetDirectoryName(output));
                if (!name.Equals("./", StringComparison.InvariantCulture)) 
                {
                    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);
                    }
                }

				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.
 */

I found an edge case where this code crashes. We encountered a case where the name in the 512 byte header of a file was longer than 100 characters (bytes). These cases were handled for us by the use of a "fake file" called ././@LongLink with a typeTag of 'L'. This fake file's data contains the full filename that is larger than 100 bytes. So we need to read this first and temporarily hold onto it as we are about to read the ACTUAL real file in the next iteration. The real file's name is truncated to 100 characters but we will just skip those and use the full name we just read last iteration instead. This solved our problems. I updated my own forked gist with the fix here: https://gist.github.com/Matheos96/da8990030dfe3e27b0a48722042d9c0b