Merge PR #245, Attempt to read two end blocks when reading tararchive

* Attempt to read another block if EOA block found
* Add test for #213
* Add disposable IO utils
* Fixes #213

Author: piksel

src/ICSharpCode.SharpZipLib/Tar/TarInputStream.cs

@@ -390,10 +390,21 @@ public TarEntry GetNextEntry()
 
 			byte[] headerBuf = tarBuffer.ReadBlock();
 
-			if (headerBuf == null) {
+			if (headerBuf == null)
+			{
+				hasHitEOF = true;
+			}
+			else if (TarBuffer.IsEndOfArchiveBlock(headerBuf))
+			{
 				hasHitEOF = true;
-			} else
-				hasHitEOF |= TarBuffer.IsEndOfArchiveBlock(headerBuf);
+
+				// Read the second zero-filled block
+				tarBuffer.ReadBlock();
+			}
+			else
+			{
+				hasHitEOF = false;
+			}
 
 			if (hasHitEOF) {
 				currentEntry = null;

test/ICSharpCode.SharpZipLib.Tests/Tar/TarTests.cs

@@ -665,6 +665,47 @@ public void InputStreamOwnership()
 			Assert.IsFalse(memStream.IsDisposed, "Should not be disposed after parent owner close");
 		}
 
+		[Test]
+		[Category("Tar")]
+		public void EndBlockHandling()
+		{
+			int dummySize = 70145;
+
+			long outCount, inCount;
+
+			using (var ms = new MemoryStream())
+			{
+				using (var tarOut = TarArchive.CreateOutputTarArchive(ms))
+				using (var dummyFile = Utils.GetDummyFile(dummySize))
+				{
+					tarOut.IsStreamOwner = false;
+					tarOut.WriteEntry(TarEntry.CreateEntryFromFile(dummyFile.Filename), false);
+				}
+
+				outCount = ms.Position;
+				ms.Seek(0, SeekOrigin.Begin);
+
+				using (var tarIn = TarArchive.CreateInputTarArchive(ms))
+				using (var tempDir = new Utils.TempDir())
+				{
+					tarIn.IsStreamOwner = false;
+					tarIn.ExtractContents(tempDir.Fullpath);
+
+					foreach (var file in Directory.GetFiles(tempDir.Fullpath, "*", SearchOption.AllDirectories))
+					{
+						Console.WriteLine($"Extracted \"{file}\"");
+					}
+				}
+
+				inCount = ms.Position;
+
+				Console.WriteLine($"Output count: {outCount}");
+				Console.WriteLine($"Input count: {inCount}");
+
+				Assert.AreEqual(inCount, outCount, "Bytes read and bytes written should be equal");
+			}
+		}
+
 		[Test]
 		[Category("Tar")]
 		[Category("Performance")]

test/ICSharpCode.SharpZipLib.Tests/TestSupport/Utils.cs

@@ -1,4 +1,5 @@
 using System;
+using System.IO;
 using NUnit.Framework;
 
 namespace ICSharpCode.SharpZipLib.Tests.TestSupport
@@ -8,6 +9,7 @@ namespace ICSharpCode.SharpZipLib.Tests.TestSupport
 	/// </summary>
 	public static class Utils
 	{
+		static Random random = new Random();
 
 		static void Compare(byte[] a, byte[] b)
 		{
@@ -25,5 +27,97 @@ static void Compare(byte[] a, byte[] b)
 			}
 		}
 
+		public static TempFile GetDummyFile(int size = -1)
+		{
+			var tempFile = new TempFile();
+			if (size < 0)
+			{
+				File.WriteAllText(tempFile.Filename, DateTime.UtcNow.Ticks.ToString("x16"));
+			}
+			else if (size > 0)
+			{
+				var bytes = Array.CreateInstance(typeof(byte), size) as byte[];
+				random.NextBytes(bytes);
+				File.WriteAllBytes(tempFile.Filename, bytes);
+			}
+			return tempFile;
+		}
+
+		public class TempFile : IDisposable
+		{
+			public string Filename { get; internal set; }
+
+			public TempFile()
+			{
+				Filename = Path.GetTempFileName();
+			}
+
+			#region IDisposable Support
+			private bool disposed = false; // To detect redundant calls
+
+
+			protected virtual void Dispose(bool disposing)
+			{
+				if (!disposed)
+				{
+					if (disposing && File.Exists(Filename))
+					{
+						try
+						{
+							File.Delete(Filename);
+						}
+						catch { }
+					}
+
+					disposed = true;
+				}
+			}
+
+			public void Dispose()
+				=> Dispose(true);
+
+			#endregion
+
+		}
+
+		public class TempDir : IDisposable
+		{
+			public string Fullpath { get; internal set; }
+
+			public TempDir()
+			{
+				Fullpath = Path.Combine(Path.GetTempPath(), Path.GetRandomFileName());
+				Directory.CreateDirectory(Fullpath);
+			}
+
+			#region IDisposable Support
+			private bool disposed = false; // To detect redundant calls
+
+
+			protected virtual void Dispose(bool disposing)
+			{
+				if (!disposed)
+				{
+					if (disposing && Directory.Exists(Fullpath))
+					{
+						try
+						{
+							Directory.Delete(Fullpath, true);
+						}
+						catch { }
+					}
+
+					disposed = true;
+				}
+			}
+
+			public void Dispose()
+				=> Dispose(true);
+
+			#endregion
+
+		}
 	}
+
+	
 }