PR #355: Wire up BZip2 compression support for Zip files

Author: Numpsy

src/ICSharpCode.SharpZipLib/Zip/ZipConstants.cs

@@ -281,6 +281,11 @@ public static class ZipConstants
 		/// </summary>
 		public const int VersionZip64 = 45;
 
+		/// <summary>
+		/// The version required for BZip2 compression (4.6 or higher)
+		/// </summary>
+		public const int VersionBZip2 = 46;
+
 		#endregion Versions
 
 		#region Header Sizes

src/ICSharpCode.SharpZipLib/Zip/ZipEntry.cs

@@ -585,6 +585,10 @@ public int Version
 					{
 						result = 20;
 					}
+					else if (CompressionMethod.BZip2 == method)
+					{
+						result = ZipConstants.VersionBZip2;
+					}
 					else if (IsDirectory == true)
 					{
 						result = 20;
@@ -616,6 +620,7 @@ public bool CanDecompress
 					(Version == 11) ||
 					(Version == 20) ||
 					(Version == 45) ||
+					(Version == 46) ||
 					(Version == 51)) &&
 					IsCompressionMethodSupported();
 			}
@@ -1290,7 +1295,8 @@ public static bool IsCompressionMethodSupported(CompressionMethod method)
 		{
 			return
 				(method == CompressionMethod.Deflated) ||
-				(method == CompressionMethod.Stored);
+				(method == CompressionMethod.Stored) ||
+				(method == CompressionMethod.BZip2);
 		}
 
 		/// <summary>

src/ICSharpCode.SharpZipLib/Zip/ZipFile.cs

@@ -883,6 +883,10 @@ public Stream GetInputStream(long entryIndex)
 					result = new InflaterInputStream(result, new Inflater(true));
 					break;
 
+				case CompressionMethod.BZip2:
+					result = new BZip2.BZip2InputStream(result);
+					break;
+
 				default:
 					throw new ZipException("Unsupported compression method " + method);
 			}
@@ -1899,7 +1903,7 @@ public void AddDirectory(string directoryName)
 		/// <param name="compressionMethod">The compression method for the new entry.</param>
 		private void CheckSupportedCompressionMethod(CompressionMethod compressionMethod)
 		{
-			if (compressionMethod != CompressionMethod.Deflated && compressionMethod != CompressionMethod.Stored)
+			if (compressionMethod != CompressionMethod.Deflated && compressionMethod != CompressionMethod.Stored && compressionMethod != CompressionMethod.BZip2)
 			{
 				throw new NotImplementedException("Compression method not supported");
 			}
@@ -2636,6 +2640,16 @@ private Stream GetOutputStream(ZipEntry entry)
 					result = dos;
 					break;
 
+				case CompressionMethod.BZip2:
+					var bzos = new BZip2.BZip2OutputStream(result)
+					{
+						// If there is an encryption stream in use, then we want that to be disposed when the BZip2OutputStream stream is disposed
+						// If not, then we don't want it to dispose the base stream
+						IsStreamOwner = entry.IsCrypted
+					};
+					result = bzos;
+					break;
+
 				default:
 					throw new ZipException("Unknown compression method " + entry.CompressionMethod);
 			}

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

@@ -141,7 +141,7 @@ public void UnsupportedCompressionMethod()
 			var ze = new ZipEntry("HumblePie");
 			//ze.CompressionMethod = CompressionMethod.BZip2;
 
-			Assert.That(() => ze.CompressionMethod = CompressionMethod.BZip2,
+			Assert.That(() => ze.CompressionMethod = CompressionMethod.Deflate64,
 				Throws.TypeOf<NotSupportedException>());
 		}
 

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

@@ -1611,5 +1611,149 @@ public void AddFileWithAlternateName()
 				}
 			}
 		}
+
+		/// <summary>
+		/// Test a zip file using BZip2 compression.
+		/// </summary>
+		[TestCase(true)]
+		[TestCase(false)]
+		[Category("Zip")]
+		public void ZipWithBZip2Compression(bool encryptEntries)
+		{
+			string password = "pwd";
+
+			using (var memStream = new MemoryStream())
+			{
+				using (ZipFile f = new ZipFile(memStream, leaveOpen: true))
+				{
+					if (encryptEntries)
+						f.Password = password;
+
+					f.BeginUpdate(new MemoryArchiveStorage());
+
+					var m = new StringMemoryDataSource("BZip2Compressed");
+					f.Add(m, "a.dat", CompressionMethod.BZip2);
+
+					var m2 = new StringMemoryDataSource("DeflateCompressed");
+					f.Add(m2, "b.dat", CompressionMethod.Deflated);
+					f.CommitUpdate();
+					Assert.IsTrue(f.TestArchive(true));
+				}
+
+				memStream.Seek(0, SeekOrigin.Begin);
+
+				using (ZipFile f = new ZipFile(memStream))
+				{
+					if (encryptEntries)
+						f.Password = password;
+
+					{
+						var entry = f.GetEntry("a.dat");
+						Assert.That(entry.CompressionMethod, Is.EqualTo(CompressionMethod.BZip2), "Compression method should be BZip2");
+						Assert.That(entry.Version, Is.EqualTo(ZipConstants.VersionBZip2), "Entry version should be 46");
+						Assert.That(entry.IsCrypted, Is.EqualTo(encryptEntries));
+
+						using (var reader = new StreamReader(f.GetInputStream(entry)))
+						{
+							string contents = reader.ReadToEnd();
+							Assert.That(contents, Is.EqualTo("BZip2Compressed"), "extract string must match original string");
+						}
+					}
+
+					{
+						var entry = f.GetEntry("b.dat");
+						Assert.That(entry.CompressionMethod, Is.EqualTo(CompressionMethod.Deflated), "Compression method should be Deflated");
+						Assert.That(entry.IsCrypted, Is.EqualTo(encryptEntries));
+
+						using (var reader = new StreamReader(f.GetInputStream(entry)))
+						{
+							string contents = reader.ReadToEnd();
+							Assert.That(contents, Is.EqualTo("DeflateCompressed"), "extract string must match original string");
+						}
+					}
+				}
+
+				// @@TODO@@ verify the archive with 7-zip?
+			}
+		}
+
+		/// <summary>
+		/// We should be able to read a bzip2 compressed zip file created by 7-zip.
+		/// </summary>
+		[Test]
+		[Category("Zip")]
+		public void ShouldReadBZip2ZipCreatedBy7Zip()
+		{
+			const string BZip2CompressedZipCreatedBy7Zip =
+			"UEsDBC4AAAAMAIa50U4/rHf5qwAAAK8AAAAJAAAASGVsbG8udHh0QlpoOTFBWSZTWTL8pwYAA" +
+			"BWfgEhlUAAiLUgQP+feMCAAiCKaeiaBobU9JiaAMGmoak9GmRNqPUDQ9T1PQsz/t9B6YvEdvF" +
+			"5dhwXzGE1ooO41A6TtATBEFxFUq6trGtUcSJDyWWWj/S2VwY15fy3IqHi3hHUS+K76zdoDzQa" +
+			"VGE/4YkYZe3JAtv1EsIqIsiTnnktIbBo1R4xY3JZEOm2BvwLuSKcKEgZflODAUEsBAj8ALgAA" +
+			"AAwAhrnRTj+sd/mrAAAArwAAAAkAJAAAAAAAAAAgAAAAAAAAAEhlbGxvLnR4dAoAIAAAAAAAA" +
+			"QAYAO97MLZZJdUB73swtlkl1QEK0UTFWCXVAVBLBQYAAAAAAQABAFsAAADSAAAAAAA=";
+
+			const string OriginalText =
+				"SharpZipLib (#ziplib, formerly NZipLib) is a compression library that supports Zip files using both stored and deflate compression methods, PKZIP 2.0 style and AES encryption.";
+
+			var fileBytes = System.Convert.FromBase64String(BZip2CompressedZipCreatedBy7Zip);
+
+			using (var input = new MemoryStream(fileBytes, false))
+			{
+				using (ZipFile f = new ZipFile(input))
+				{
+					var entry = f.GetEntry("Hello.txt");
+					Assert.That(entry.CompressionMethod, Is.EqualTo(CompressionMethod.BZip2), "Compression method should be BZip2");
+					Assert.That(entry.Version, Is.EqualTo(ZipConstants.VersionBZip2), "Entry version should be 46");
+
+					using (var reader = new StreamReader(f.GetInputStream(entry)))
+					{
+						string contents = reader.ReadToEnd();
+						Assert.That(contents, Is.EqualTo(OriginalText), "extract string must match original string");
+					}
+				}
+			}
+		}
+
+		/// <summary>
+		/// We should be able to read a bzip2 compressed / AES encrypted zip file created by 7-zip.
+		/// </summary>
+		[Test]
+		[Category("Zip")]
+		public void ShouldReadAESBZip2ZipCreatedBy7Zip()
+		{
+			const string BZip2CompressedZipCreatedBy7Zip =
+			 "UEsDBDMAAQBjAIa50U4AAAAAxwAAAK8AAAAJAAsASGVsbG8udHh0AZkHAAIAQUUDDAAYg6jqf" +
+			"kvZClVMOtgmqKT0/8I9fMPgo96myxw9hLQUhKj1Qczi3fT7QIhAnAKU+u03nA8rCKGWmDI5Qz" +
+			"qPREy95boQVDPwmwEsWksv3GAWzMfzZUhmB/TgIJlA34a4yP0f2ucy3/QCQYo8QcHjBtjWX5b" +
+			"dZn0+fwY9Ci7q8JSI8zNSbgQ0Ert/lIJ9MxQ4lzBxMl4LySkd104cDPh/FslTAcPtHoy8Mf1c" +
+			"vnI1uICMgjWVeTqYrvSvt2uuHnqr4AiehArFiXTnUEsBAj8AMwABAGMAhrnRTgAAAADHAAAAr" +
+			"wAAAAkALwAAAAAAAAAgAAAAAAAAAEhlbGxvLnR4dAoAIAAAAAAAAQAYAO97MLZZJdUBYdnjul" +
+			"kl1QEK0UTFWCXVAQGZBwACAEFFAwwAUEsFBgAAAAABAAEAZgAAAPkAAAAAAA==";
+
+			const string OriginalText =
+				"SharpZipLib (#ziplib, formerly NZipLib) is a compression library that supports Zip files using both stored and deflate compression methods, PKZIP 2.0 style and AES encryption.";
+
+			var fileBytes = System.Convert.FromBase64String(BZip2CompressedZipCreatedBy7Zip);
+
+			using (var input = new MemoryStream(fileBytes, false))
+			{
+				using (ZipFile f = new ZipFile(input))
+				{
+					f.Password = "password";
+
+					var entry = f.GetEntry("Hello.txt");
+					Assert.That(entry.CompressionMethod, Is.EqualTo(CompressionMethod.BZip2), "Compression method should be BZip2");
+					Assert.That(entry.Version, Is.EqualTo(ZipConstants.VERSION_AES), "Entry version should be 51");
+					Assert.That(entry.IsCrypted, Is.True, "Entry should be encrypted");
+					Assert.That(entry.AESKeySize, Is.EqualTo(256), "AES Keysize should be 256");
+
+					using (var reader = new StreamReader(f.GetInputStream(entry)))
+					{
+						string contents = reader.ReadToEnd();
+						Assert.That(contents, Is.EqualTo(OriginalText), "extract string must match original string");
+					}
+				}
+			}
+		}
 	}
 }