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 ms = new MemoryStream())
				{
					int read;
					var buffer = new byte[chunk];
					do
					{
						read = gzip.Read(buffer, 0, chunk);
						ms.Write(buffer, 0, read);
					}
					while (read == chunk);

					ms.Seek(0, SeekOrigin.Begin);
					ExtractTar(ms, 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];
			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);

				long size;

				string hex = Encoding.ASCII.GetString(buffer, 0, 12).Trim('\0', ' ');
				try
				{
					size = Convert.ToInt64(hex, 8);
				}
				catch (Exception ex)
				{
					throw new Exception("Could not parse hex: " + hex, ex);
				}

				stream.Seek(376L, SeekOrigin.Current);

				var output = Path.Combine(outputDir, name);

				if (size > 0) // ignores directory entries
				{
					Directory.CreateDirectory(Path.GetDirectoryName(output));

					using (var fs = File.Open(output, FileMode.OpenOrCreate, FileAccess.Write))
					{
						var blob = new byte[size];
						stream.Read(blob, 0, blob.Length);
						fs.Write(blob, 0, blob.Length);
					}
				}

				var pos = stream.Position;

				var offset = 512 - (pos  % 512);
				if (offset == 512)
					offset = 0;

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

You can do it better on line 95

if (size > 0) // ignores directory entries

Insted of ignore 0 size files also, you can only ignore directories using:

if(!name.EndsWith("/"))

Look my forked file.