fix(zip): fully implement async deflate

src/ICSharpCode.SharpZipLib/GZip/GzipInputStream.cs

@@ -334,7 +334,7 @@ private void ReadFooter()
 			int crcval = (footer[0] & 0xff) | ((footer[1] & 0xff) << 8) | ((footer[2] & 0xff) << 16) | (footer[3] << 24);
 			if (crcval != (int)crc.Value)
 			{
-				throw new GZipException("GZIP crc sum mismatch, theirs \"" + crcval + "\" and ours \"" + (int)crc.Value);
+				throw new GZipException($"GZIP crc sum mismatch, theirs \"{crcval:x8}\" and ours \"{(int)crc.Value:x8}\"");
 			}
 
 			// NOTE The total here is the original total modulo 2 ^ 32.

src/ICSharpCode.SharpZipLib/GZip/GzipOutputStream.cs

@@ -138,6 +138,11 @@ public string FileName
 			}
 		}
 
+		/// <summary>
+		/// If defined, will use this time instead of the current for the output header
+		/// </summary>
+		public DateTime? ModifiedTime { get; set; }
+
 		#endregion Public API
 
 		#region Stream overrides
@@ -149,21 +154,47 @@ public string FileName
 		/// <param name="offset">Offset of first byte in buf to write</param>
 		/// <param name="count">Number of bytes to write</param>
 		public override void Write(byte[] buffer, int offset, int count)
+			=> WriteSyncOrAsync(buffer, offset, count, null).GetAwaiter().GetResult();
+
+		private async Task WriteSyncOrAsync(byte[] buffer, int offset, int count, CancellationToken? ct)
 		{
 			if (state_ == OutputState.Header)
 			{
-				WriteHeader();
+				if (ct.HasValue)
+				{
+					await WriteHeaderAsync(ct.Value).ConfigureAwait(false);
+				}
+				else
+				{
+					WriteHeader();
+				}
 			}
 
 			if (state_ != OutputState.Footer)
-			{
 				throw new InvalidOperationException("Write not permitted in current state");
-			}
-
+
 			crc.Update(new ArraySegment<byte>(buffer, offset, count));
-			base.Write(buffer, offset, count);
+
+			if (ct.HasValue)
+			{
+				await base.WriteAsync(buffer, offset, count, ct.Value).ConfigureAwait(false);
+			}
+			else
+			{
+				base.Write(buffer, offset, count);
+			}
 		}
 
+		/// <summary>
+		/// Asynchronously write given buffer to output updating crc
+		/// </summary>
+		/// <param name="buffer">Buffer to write</param>
+		/// <param name="offset">Offset of first byte in buf to write</param>
+		/// <param name="count">Number of bytes to write</param>
+		/// <param name="ct">The token to monitor for cancellation requests</param>
+		public override async Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken ct) 
+			=> await WriteSyncOrAsync(buffer, offset, count, ct).ConfigureAwait(false);
+
 		/// <summary>
 		/// Writes remaining compressed output data to the output stream
 		/// and closes it.
@@ -187,7 +218,7 @@ protected override void Dispose(bool disposing)
 			}
 		}
 
-#if NETSTANDARD2_1_OR_GREATER
+#if NETSTANDARD2_1_OR_GREATER || NETCOREAPP3_1_OR_GREATER
 		/// <inheritdoc cref="DeflaterOutputStream.Dispose"/>
 		public override async ValueTask DisposeAsync()
 		{
@@ -225,6 +256,16 @@ public override void Flush()
 			base.Flush();
 		}
 
+		/// <inheritdoc cref="Flush"/>
+		public override async Task FlushAsync(CancellationToken ct)
+		{
+			if (state_ == OutputState.Header)
+			{
+				await WriteHeaderAsync(ct).ConfigureAwait(false);
+			}
+			await base.FlushAsync(ct).ConfigureAwait(false);
+		}
+
 		#endregion Stream overrides
 
 		#region DeflaterOutputStream overrides
@@ -249,21 +290,13 @@ public override void Finish()
 			}
 		}
 
-		/// <inheritdoc cref="Flush"/>
-		public override async Task FlushAsync(CancellationToken ct)
-		{
-			await WriteHeaderAsync().ConfigureAwait(false);
-			await base.FlushAsync(ct).ConfigureAwait(false);
-		}
-
-
 		/// <inheritdoc cref="Finish"/>
 		public override async Task FinishAsync(CancellationToken ct)
 		{
 			// If no data has been written a header should be added.
 			if (state_ == OutputState.Header)
 			{
-				await WriteHeaderAsync().ConfigureAwait(false);
+				await WriteHeaderAsync(ct).ConfigureAwait(false);
 			}
 
 			if (state_ == OutputState.Footer)
@@ -305,7 +338,8 @@ private byte[] GetFooter()
 
 		private byte[] GetHeader()
 		{
-			var modTime = (int)((DateTime.Now.Ticks - new DateTime(1970, 1, 1).Ticks) / 10000000L);  // Ticks give back 100ns intervals
+			var modifiedUtc = ModifiedTime?.ToUniversalTime() ?? DateTime.UtcNow;
+			var modTime = (int)((modifiedUtc - new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc)).Ticks / 10000000L);  // Ticks give back 100ns intervals
 			byte[] gzipHeader = {
 				// The two magic bytes
 				GZipConstants.ID1, 
@@ -351,12 +385,12 @@ private void WriteHeader()
 			baseOutputStream_.Write(gzipHeader, 0, gzipHeader.Length);
 		}
 
-		private async Task WriteHeaderAsync()
+		private async Task WriteHeaderAsync(CancellationToken ct)
 		{
 			if (state_ != OutputState.Header) return;
 			state_ = OutputState.Footer;
 			var gzipHeader = GetHeader();
-			await baseOutputStream_.WriteAsync(gzipHeader, 0, gzipHeader.Length).ConfigureAwait(false);
+			await baseOutputStream_.WriteAsync(gzipHeader, 0, gzipHeader.Length, ct).ConfigureAwait(false);
 		}
 
 		#endregion Support Routines

src/ICSharpCode.SharpZipLib/Zip/Compression/Streams/DeflaterOutputStream.cs

@@ -240,11 +240,9 @@ protected void EncryptBlock(byte[] buffer, int offset, int length)
 		/// are processed.
 		/// </summary>
 		protected void Deflate()
-		{
-			Deflate(false);
-		}
+			=> DeflateSyncOrAsync(false, null).GetAwaiter().GetResult();
 
-		private void Deflate(bool flushing)
+		private async Task DeflateSyncOrAsync(bool flushing, CancellationToken? ct)
 		{
 			while (flushing || !deflater_.IsNeedingInput)
 			{
@@ -257,7 +255,14 @@ private void Deflate(bool flushing)
 
 				EncryptBlock(buffer_, 0, deflateCount);
 
-				baseOutputStream_.Write(buffer_, 0, deflateCount);
+				if (ct.HasValue)
+				{
+					await baseOutputStream_.WriteAsync(buffer_, 0, deflateCount, ct.Value).ConfigureAwait(false);
+				}
+				else
+				{
+					baseOutputStream_.Write(buffer_, 0, deflateCount);
+				}
 			}
 
 			if (!deflater_.IsNeedingInput)
@@ -383,10 +388,18 @@ public override int Read(byte[] buffer, int offset, int count)
 		public override void Flush()
 		{
 			deflater_.Flush();
-			Deflate(true);
+			DeflateSyncOrAsync(true, null).GetAwaiter().GetResult();
 			baseOutputStream_.Flush();
 		}
 
+		/// <inheritdoc/>
+		public override async Task FlushAsync(CancellationToken cancellationToken)
+		{
+			deflater_.Flush();
+			await DeflateSyncOrAsync(true, cancellationToken).ConfigureAwait(false);
+			await baseOutputStream_.FlushAsync(cancellationToken).ConfigureAwait(false);
+		}
+
 		/// <summary>
 		/// Calls <see cref="Finish"/> and closes the underlying
 		/// stream when <see cref="IsStreamOwner"></see> is true.
@@ -491,6 +504,13 @@ public override void Write(byte[] buffer, int offset, int count)
 			Deflate();
 		}
 
+		/// <inheritdoc />
+		public override async Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken ct)
+		{
+			deflater_.SetInput(buffer, offset, count);
+			await DeflateSyncOrAsync(false, ct).ConfigureAwait(false);
+		}
+
 		#endregion Stream Overrides
 
 		#region Instance Fields

src/ICSharpCode.SharpZipLib/Zip/ZipOutputStream.cs

@@ -552,7 +552,7 @@ await baseOutputStream_.WriteProcToStreamAsync(s =>
 		public void CloseEntry()
 		{
 			// Note: This method will run synchronously
-			FinishCompression(null).Wait();
+			FinishCompressionSyncOrAsync(null).GetAwaiter().GetResult();
 			WriteEntryFooter(baseOutputStream_);
 
 			// Patch the header if possible
@@ -566,7 +566,7 @@ public void CloseEntry()
 			curEntry = null;
 		}
 
-		private async Task FinishCompression(CancellationToken? ct)
+		private async Task FinishCompressionSyncOrAsync(CancellationToken? ct)
 		{
 			// Compression handled externally
 			if (entryIsPassthrough) return;
@@ -600,7 +600,7 @@ private async Task FinishCompression(CancellationToken? ct)
 		/// <inheritdoc cref="CloseEntry"/>
 		public async Task CloseEntryAsync(CancellationToken ct)
 		{
-			await FinishCompression(ct).ConfigureAwait(false);
+			await FinishCompressionSyncOrAsync(ct).ConfigureAwait(false);
 			await baseOutputStream_.WriteProcToStreamAsync(WriteEntryFooter, ct).ConfigureAwait(false);
 
 			// Patch the header if possible
@@ -767,9 +767,7 @@ private byte[] CreateZipCryptoHeader(long crcValue)
 		private void InitializeZipCryptoPassword(string password)
 		{
 			var pkManaged = new PkzipClassicManaged();
-			Console.WriteLine($"Output Encoding: {ZipCryptoEncoding.EncodingName}");
 			byte[] key = PkzipClassic.GenerateKeys(ZipCryptoEncoding.GetBytes(password));
-			Console.WriteLine($"Output Bytes: {string.Join(", ", key.Select(b => $"{b:x2}").ToArray())}");
 			cryptoTransform_ = pkManaged.CreateEncryptor(key, null);
 		}
 
@@ -782,6 +780,13 @@ private void InitializeZipCryptoPassword(string password)
 		/// <exception cref="ZipException">Archive size is invalid</exception>
 		/// <exception cref="System.InvalidOperationException">No entry is active.</exception>
 		public override void Write(byte[] buffer, int offset, int count)
+			=> WriteSyncOrAsync(buffer, offset, count, null).GetAwaiter().GetResult();
+
+		/// <inheritdoc />
+		public override async Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken ct)
+			=> await WriteSyncOrAsync(buffer, offset, count, ct).ConfigureAwait(false);
+
+		private async Task WriteSyncOrAsync(byte[] buffer, int offset, int count, CancellationToken? ct)
 		{
 			if (curEntry == null)
 			{
@@ -816,20 +821,34 @@ public override void Write(byte[] buffer, int offset, int count)
 
 			size += count;
 
-			if(curMethod == CompressionMethod.Stored || entryIsPassthrough)
+			if (curMethod == CompressionMethod.Stored || entryIsPassthrough)
 			{
 				if (Password != null)
 				{
 					CopyAndEncrypt(buffer, offset, count);
 				}
 				else
 				{
-					baseOutputStream_.Write(buffer, offset, count);
+					if (ct.HasValue)
+					{
+						await baseOutputStream_.WriteAsync(buffer, offset, count, ct.Value).ConfigureAwait(false);
+					}
+					else
+					{
+						baseOutputStream_.Write(buffer, offset, count);
+					}
 				}
 			}
 			else
 			{
-				base.Write(buffer, offset, count);
+				if (ct.HasValue)
+				{
+					await base.WriteAsync(buffer, offset, count, ct.Value).ConfigureAwait(false);
+				}
+				else
+				{
+					base.Write(buffer, offset, count);
+				}
 			}
 		}
 

test/ICSharpCode.SharpZipLib.Tests/GZip/GZipAsyncTests.cs

@@ -1,4 +1,5 @@
-using System.IO;
+using System;
+using System.IO;
 using System.Text;
 using System.Threading.Tasks;
 using ICSharpCode.SharpZipLib.GZip;
@@ -7,8 +8,6 @@
 
 namespace ICSharpCode.SharpZipLib.Tests.GZip
 {
-
-
 	[TestFixture]
 	public class GZipAsyncTests
 	{
@@ -140,5 +139,48 @@ public async Task EmptyGZipStreamAsync()
 				Assert.IsEmpty(content);
 			}
 		}
+
+		[Test]
+		[Category("GZip")]
+		[Category("Async")]
+		public async Task WriteGZipStreamToAsyncOnlyStream()
+		{
+#if NETSTANDARD2_1 || NETCOREAPP3_0_OR_GREATER
+			var content = Encoding.ASCII.GetBytes("a");
+			var modTime = DateTime.UtcNow;
+
+            await using (var msAsync = new MemoryStreamWithoutSync())
+			{
+				await using (var outStream = new GZipOutputStream(msAsync) { IsStreamOwner = false })
+				{
+					outStream.ModifiedTime = modTime;
+					await outStream.WriteAsync(content);
+				}
+
+				using var msSync = new MemoryStream();
+                using (var outStream = new GZipOutputStream(msSync) { IsStreamOwner = false })
+                {
+                    outStream.ModifiedTime = modTime;
+                    outStream.Write(content);
+                }
+
+				var syncBytes = string.Join(' ', msSync.ToArray());
+				var asyncBytes = string.Join(' ', msAsync.ToArray());
+
+                Assert.AreEqual(syncBytes, asyncBytes, "Sync and Async compressed streams are not equal");
+
+                // Since GZipInputStream isn't async yet we need to read from it from a regular MemoryStream
+                using (var readStream = new MemoryStream(msAsync.ToArray()))
+				using (var inStream = new GZipInputStream(readStream))
+				using (var reader = new StreamReader(inStream))
+				{
+					Assert.AreEqual(content, await reader.ReadToEndAsync());
+				}
+			}
+#else
+			await Task.CompletedTask;
+			Assert.Ignore("AsyncDispose is not supported");
+#endif
+		}
 	}
 }

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

@@ -124,17 +124,19 @@ public async Task WriteReadOnlyZipStreamAsync ()
 		[Test]
 		[Category("Zip")]
 		[Category("Async")]
-		public async Task WriteZipStreamToAsyncOnlyStream ()
+		[TestCase(12, Description = "Small files")]
+		[TestCase(12000, Description = "Large files")]
+        public async Task WriteZipStreamToAsyncOnlyStream (int fileSize)
 		{
 #if NETSTANDARD2_1 || NETCOREAPP3_0_OR_GREATER
 			await using(var ms = new MemoryStreamWithoutSync()){
 				await using(var outStream = new ZipOutputStream(ms) { IsStreamOwner = false })
 				{
 					await outStream.PutNextEntryAsync(new ZipEntry("FirstFile"));
-					await Utils.WriteDummyDataAsync(outStream, 12);
+					await Utils.WriteDummyDataAsync(outStream, fileSize);
 
 					await outStream.PutNextEntryAsync(new ZipEntry("SecondFile"));
-					await Utils.WriteDummyDataAsync(outStream, 12);
+					await Utils.WriteDummyDataAsync(outStream, fileSize);
 
 					await outStream.FinishAsync(CancellationToken.None);
 					await outStream.DisposeAsync();