PR #503: Consider AES overhead when testing encrypted folder entries

* Extend the ZipFile.TestEncryptedDirectoryEntry test to test AES encrypted directories

* Consider AES overhead when testing encrypted folder entries

Author: Numpsy

src/ICSharpCode.SharpZipLib/Zip/ZipFile.cs

@@ -1289,15 +1289,15 @@ private long TestLocalHeader(ZipEntry entry, HeaderTest tests)
 						// If so until details are known we will be strict.
 						if (entry.IsCrypted)
 						{
-							if (compressedSize > ZipConstants.CryptoHeaderSize + 2)
+							if (compressedSize > entry.EncryptionOverheadSize + 2)
 							{
 								throw new ZipException("Directory compressed size invalid");
 							}
 						}
 						else if (compressedSize > 2)
 						{
 							// When not compressed the directory size can validly be 2 bytes
-							// if the true size wasnt known when data was originally being written.
+							// if the true size wasn't known when data was originally being written.
 							// NOTE: Versions of the library 0.85.4 and earlier always added 2 bytes
 							throw new ZipException("Directory compressed size invalid");
 						}

test/ICSharpCode.SharpZipLib.Tests/Zip/ZipFileHandling.cs

@@ -875,13 +875,13 @@ public void TestDirectoryEntry()
 			TestDirectoryEntry(new MemoryStreamWithoutSeek());
 		}
 
-		private void TestEncryptedDirectoryEntry(MemoryStream s)
+		private void TestEncryptedDirectoryEntry(MemoryStream s, int aesKeySize)
 		{
 			var outStream = new ZipOutputStream(s);
 			outStream.Password = "Tonto hand me a beer";
 
 			outStream.IsStreamOwner = false;
-			outStream.PutNextEntry(new ZipEntry("YeUnreadableDirectory/"));
+			outStream.PutNextEntry(new ZipEntry("YeUnreadableDirectory/") { AESKeySize = aesKeySize } );
 			outStream.Close();
 
 			var ms2 = new MemoryStream(s.ToArray());
@@ -893,10 +893,10 @@ private void TestEncryptedDirectoryEntry(MemoryStream s)
 
 		[Test]
 		[Category("Zip")]
-		public void TestEncryptedDirectoryEntry()
+		public void TestEncryptedDirectoryEntry([Values(0, 128, 256)]int aesKeySize)
 		{
-			TestEncryptedDirectoryEntry(new MemoryStream());
-			TestEncryptedDirectoryEntry(new MemoryStreamWithoutSeek());
+			TestEncryptedDirectoryEntry(new MemoryStream(), aesKeySize);
+			TestEncryptedDirectoryEntry(new MemoryStreamWithoutSeek(), aesKeySize);
 		}
 
 		[Test]