Add public Options fields

closes #30

Author: dscheg

README.md

@@ -18,7 +18,7 @@ Zstd
 provides both good compression ratio _and_ speed for your standard compression
 needs. "Standard" translates into everyday situations which neither look for
 highest possible ratio (which LZMA and ZPAQ cover) nor extreme speeds (which
-LZ4 covers). Zstandard is licensed under [BSD 3-Clause License](Native/LICENSE).
+LZ4 covers). Zstandard is licensed under [BSD 3-Clause License](ZstdNet/build/LICENSE).
 
 **Zstd** is initially developed by Yann Collet and the source is available at:
 https://github.com/facebook/zstd
@@ -285,7 +285,7 @@ performance and memory overhead.
 * `TrainFromBuffer` generates a compression dictionary from a collection of samples.
 
   ```c#
-  static byte[] TrainFromBuffer(ICollection<byte[]> samples, int dictCapacity = DefaultDictCapacity);
+  static byte[] TrainFromBuffer(IEnumerable<byte[]> samples, int dictCapacity = DefaultDictCapacity);
   ```
 
   Options:

ZstdNet.Tests/SteamingCompressionTests.cs

@@ -110,6 +110,42 @@ public void StreamingCompressionSimpleWrite(byte[] data, int offset, int count)
 			Assert.AreEqual(dataToCompress, resultStream.ToArray());
 		}
 
+		[Test]
+		public void StreamingCompressionKeepReferenceToDict()
+		{
+			var dict = TrainDict();
+			Span<byte> data = dict;
+
+			var tempStream = new MemoryStream();
+			using(var compressionStream = new CompressionStream(tempStream, new CompressionOptions(dict)))
+			{
+				for(int i = 0; i < data.Length; i++)
+				{
+					compressionStream.Write(data.Slice(i, 1));
+
+					GC.Collect();
+					GC.WaitForPendingFinalizers();
+					GC.Collect();
+				}
+			}
+
+			tempStream.Seek(0, SeekOrigin.Begin);
+
+			using(var decompressionStream = new DecompressionStream(tempStream, new DecompressionOptions(dict)))
+			{
+				for(int i = 0; i < data.Length; i++)
+				{
+					Assert.AreEqual(data[i], decompressionStream.ReadByte());
+
+					GC.Collect();
+					GC.WaitForPendingFinalizers();
+					GC.Collect();
+				}
+
+				Assert.AreEqual(-1, decompressionStream.ReadByte());
+			}
+		}
+
 		[TestCase(1)]
 		[TestCase(2)]
 		[TestCase(3)]

ZstdNet/CompressionStream.cs

@@ -20,6 +20,8 @@ public class CompressionStream : Stream
 		private IntPtr cStream;
 		private UIntPtr pos;
 
+		public readonly CompressionOptions Options;
+
 		public CompressionStream(Stream stream)
 			: this(stream, CompressionOptions.Default)
 		{}
@@ -42,6 +44,7 @@ public CompressionStream(Stream stream, CompressionOptions options, int bufferSi
 			cStream = ZSTD_createCStream().EnsureZstdSuccess();
 			ZSTD_CCtx_reset(cStream, ZSTD_ResetDirective.ZSTD_reset_session_only).EnsureZstdSuccess();
 
+			Options = options;
 			if(options != null)
 			{
 				options.ApplyCompressionParams(cStream);

ZstdNet/DecompressionStream.cs

@@ -21,6 +21,8 @@ public class DecompressionStream : Stream
 		private UIntPtr pos;
 		private UIntPtr size;
 
+		public readonly DecompressionOptions Options;
+
 		public DecompressionStream(Stream stream)
 			: this(stream, null)
 		{}
@@ -43,6 +45,7 @@ public DecompressionStream(Stream stream, DecompressionOptions options, int buff
 			dStream = ZSTD_createDStream().EnsureZstdSuccess();
 			ZSTD_DCtx_reset(dStream, ZSTD_ResetDirective.ZSTD_reset_session_only).EnsureZstdSuccess();
 
+			Options = options;
 			if(options != null)
 			{
 				options.ApplyDecompressionParams(dStream);