Ensure compression buffers do not overlap (#121)

Snappier.Tests/SnappyTests.cs

@@ -205,6 +205,14 @@ public void CompressAndDecompressString(string str)
             Assert.Equal(input, output);
         }
 
+        [Fact]
+        public void Compress_OverlappingBuffers_InvalidOperationException()
+        {
+            var input = new byte[1024];
+
+            Assert.Throws<InvalidOperationException>(() => Snappy.Compress(input, input.AsSpan(input.Length - 1)));
+        }
+
         [Fact]
         public void BadData_InsufficentOutputBuffer_ThrowsArgumentException()
         {

Snappier/Internal/SnappyCompressor.cs

@@ -26,6 +26,10 @@ public bool TryCompress(ReadOnlySpan<byte> input, Span<byte> output, out int byt
             {
                 ThrowHelper.ThrowObjectDisposedException(nameof(SnappyCompressor));
             }
+            if (input.Overlaps(output))
+            {
+                ThrowHelper.ThrowInvalidOperationException("Input and output spans must not overlap.");
+            }
 
             _workingMemory.EnsureCapacity(input.Length);
 

Snappier/Snappier.csproj

@@ -20,7 +20,7 @@
       from the official C++ implementation, with the addition of support for the framed stream format.
 
       By avoiding P/Invoke, Snappier is fully cross-platform and works on both Linux and Windows and against any CPU supported
-      by .NET Core. However, Snappier performs best in .NET Core 3.0 and later on little-endian x86/64 processors with the
+      by .NET. However, Snappier performs best in .NET 6 and later on little-endian x86/64 processors with the
       help of System.Runtime.Instrinsics.
     </Description>
     <PackageLicenseExpression>BSD-3-Clause</PackageLicenseExpression>

Snappier/Snappy.cs

@@ -32,6 +32,7 @@ public static int GetMaxCompressedLength(int inputLength) =>
         /// <param name="output">Buffer to receive the compressed data.</param>
         /// <returns>Number of bytes written to <paramref name="output"/>.</returns>
         /// <exception cref="ArgumentException">Output buffer is too small.</exception>
+        /// <exception cref="InvalidOperationException">Input and output spans must not overlap.</exception>
         /// <remarks>
         /// The output buffer must be large enough to contain the compressed output.
         /// </remarks>
@@ -51,6 +52,7 @@ public static int Compress(ReadOnlySpan<byte> input, Span<byte> output)
         /// <param name="input">Data to compress.</param>
         /// <param name="output">Buffer to receive the compressed data.</param>
         /// <param name="bytesWritten">Number of bytes written to the <paramref name="output"/>.</param>
+        /// <exception cref="InvalidOperationException">Input and output spans must not overlap.</exception>
         /// <returns><c>true</c> if the compression was successful, <c>false</c> if the output buffer is too small.</returns>
         public static bool TryCompress(ReadOnlySpan<byte> input, Span<byte> output, out int bytesWritten)
         {