From 160ba0938a23f6ec9462794deb478fd613ea80c5 Mon Sep 17 00:00:00 2001
From: Adam Hathcock <adam@hathcock.uk>
Date: Sat, 13 Jun 2026 10:00:39 +0100
Subject: [PATCH] review fixes

---
 .../Compressors/Xz/XZBlock.Async.cs           | 10 +++++---
 src/SharpCompress/Compressors/Xz/XZBlock.cs   | 23 ++++++++++++-------
 .../Streams/LzmaStreamAsyncTests.cs           |  2 +-
 3 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/src/SharpCompress/Compressors/Xz/XZBlock.Async.cs b/src/SharpCompress/Compressors/Xz/XZBlock.Async.cs
index 0175faaf..cac658a0 100644
--- a/src/SharpCompress/Compressors/Xz/XZBlock.Async.cs
+++ b/src/SharpCompress/Compressors/Xz/XZBlock.Async.cs
@@ -1,3 +1,4 @@
+using System;
 using System.Buffers;
 using System.IO;
 using System.Linq;
@@ -66,9 +67,12 @@ public sealed partial class XZBlock
                 await BaseStream
                     .ReadExactAsync(paddingBytes, 0, size, cancellationToken)
                     .ConfigureAwait(false);
-                if (paddingBytes.Any(b => b != 0))
+                for (var i = 0; i < size; i++)
                 {
-                    throw new InvalidFormatException("Padding bytes were non-null");
+                    if (paddingBytes[i] != 0)
+                    {
+                        throw new InvalidFormatException("Padding bytes were non-null");
+                    }
                 }
             }
             finally
@@ -87,7 +91,7 @@ public sealed partial class XZBlock
             await BaseStream
                 .ReadExactAsync(crc, 0, _checkSize, cancellationToken)
                 .ConfigureAwait(false);
-            VerifyCheck(crc);
+            VerifyCheck(crc.AsSpan().Slice(0, _checkSize));
             _crcChecked = true;
         }
         finally
diff --git a/src/SharpCompress/Compressors/Xz/XZBlock.cs b/src/SharpCompress/Compressors/Xz/XZBlock.cs
index 4221e3c4..bfb5f3b0 100644
--- a/src/SharpCompress/Compressors/Xz/XZBlock.cs
+++ b/src/SharpCompress/Compressors/Xz/XZBlock.cs
@@ -98,10 +98,17 @@ public sealed partial class XZBlock : XZReadOnlyStream
 
     private void CheckCrc()
     {
-        var crc = new byte[_checkSize];
-        BaseStream.ReadExact(crc, 0, _checkSize);
-        VerifyCheck(crc);
-        _crcChecked = true;
+        var crc = ArrayPool<byte>.Shared.Rent(_checkSize);
+        try
+        {
+            BaseStream.ReadExact(crc, 0, _checkSize);
+            VerifyCheck(crc.AsSpan().Slice(0, _checkSize));
+            _crcChecked = true;
+        }
+        finally
+        {
+            ArrayPool<byte>.Shared.Return(crc);
+        }
     }
 
     private void UpdateCheck(byte[] buffer, int offset, int count)
@@ -127,7 +134,7 @@ public sealed partial class XZBlock : XZReadOnlyStream
         }
     }
 
-    private void VerifyCheck(byte[] expected)
+    private void VerifyCheck(ReadOnlySpan<byte> expected)
     {
         switch (_checkType)
         {
@@ -147,7 +154,7 @@ public sealed partial class XZBlock : XZReadOnlyStream
         }
     }
 
-    private static void GetLittleEndianBytes(uint value, byte[] expected)
+    private static void GetLittleEndianBytes(uint value, ReadOnlySpan<byte> expected)
     {
         var bytes = ArrayPool<byte>.Shared.Rent(sizeof(uint));
         try
@@ -164,7 +171,7 @@ public sealed partial class XZBlock : XZReadOnlyStream
         }
     }
 
-    private static void GetLittleEndianBytes(ulong value, byte[] expected)
+    private static void GetLittleEndianBytes(ulong value, ReadOnlySpan<byte> expected)
     {
         var bytes = ArrayPool<byte>.Shared.Rent(sizeof(ulong));
         try
@@ -181,7 +188,7 @@ public sealed partial class XZBlock : XZReadOnlyStream
         }
     }
 
-    private void FinalizeSha256Check(byte[] expected)
+    private void FinalizeSha256Check(ReadOnlySpan<byte> expected)
     {
         _sha256.NotNull().TransformFinalBlock(Array.Empty<byte>(), 0, 0);
         if (!expected.SequenceEqual(_sha256.NotNull().Hash))
diff --git a/tests/SharpCompress.Test/Streams/LzmaStreamAsyncTests.cs b/tests/SharpCompress.Test/Streams/LzmaStreamAsyncTests.cs
index 5dd0348f..5a32b4ee 100644
--- a/tests/SharpCompress.Test/Streams/LzmaStreamAsyncTests.cs
+++ b/tests/SharpCompress.Test/Streams/LzmaStreamAsyncTests.cs
@@ -17,7 +17,7 @@ public class LzmaStreamAsyncTests : TestBase
     {
         using var stream = File.OpenRead(Path.Combine(TEST_ARCHIVES_PATH, "bad-1-lzma2-7.xz"));
 
-        var xz = new XZStream(stream);
+        using var xz = new XZStream(stream);
         await Assert.ThrowsAsync<InvalidFormatException>(async () =>
             await xz.TransferToAsync(Stream.Null, long.MaxValue)
         );