From 8f0dd2f63598196c09955aba91e2323018d4ad7c Mon Sep 17 00:00:00 2001
From: Brant Burnett <bburnett@centeredgesoftware.com>
Date: Sun, 22 Dec 2024 16:39:26 -0500
Subject: [PATCH] Ensure compression buffers do not overlap

---
 Snappier.Tests/SnappyTests.cs         | 8 ++++++++
 Snappier/Internal/SnappyCompressor.cs | 4 ++++
 Snappier/Snappier.csproj              | 2 +-
 3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/Snappier.Tests/SnappyTests.cs b/Snappier.Tests/SnappyTests.cs
index 8db6a3a..e47bc56 100644
--- a/Snappier.Tests/SnappyTests.cs
+++ b/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()
         {
diff --git a/Snappier/Internal/SnappyCompressor.cs b/Snappier/Internal/SnappyCompressor.cs
index 530493f..87b64e7 100644
--- a/Snappier/Internal/SnappyCompressor.cs
+++ b/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);
 
diff --git a/Snappier/Snappier.csproj b/Snappier/Snappier.csproj
index 1503edb..048d6e9 100644
--- a/Snappier/Snappier.csproj
+++ b/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>