From 29f06b753adf2c438647a7aa40ff094a859263a2 Mon Sep 17 00:00:00 2001
From: Adam Hathcock <adam@hathcock.uk>
Date: Thu, 30 Apr 2026 13:07:34 +0100
Subject: [PATCH] add Crc32Stream write async

---
 src/SharpCompress/Crypto/Crc32Stream.cs | 41 +++++++++++++++++++++++++
 tests/SharpCompress.Test/ADCTest.cs     | 35 +++++++++++++++++++++
 2 files changed, 76 insertions(+)

diff --git a/src/SharpCompress/Crypto/Crc32Stream.cs b/src/SharpCompress/Crypto/Crc32Stream.cs
index 4a65587e..a9ca3b90 100644
--- a/src/SharpCompress/Crypto/Crc32Stream.cs
+++ b/src/SharpCompress/Crypto/Crc32Stream.cs
@@ -1,5 +1,7 @@
 using System;
 using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
 
 namespace SharpCompress.Crypto;
 
@@ -34,9 +36,26 @@ public sealed class Crc32Stream : Stream
 
     public override void Flush() => stream.Flush();
 
+    public override async Task FlushAsync(CancellationToken cancellationToken) =>
+        await stream.FlushAsync(cancellationToken).ConfigureAwait(false);
+
     public override int Read(byte[] buffer, int offset, int count) =>
         throw new NotSupportedException();
 
+    public override Task<int> ReadAsync(
+        byte[] buffer,
+        int offset,
+        int count,
+        CancellationToken cancellationToken
+    ) => throw new NotSupportedException();
+
+#if !LEGACY_DOTNET
+    public override ValueTask<int> ReadAsync(
+        Memory<byte> buffer,
+        CancellationToken cancellationToken = default
+    ) => throw new NotSupportedException();
+#endif
+
     public override long Seek(long offset, SeekOrigin origin) => throw new NotSupportedException();
 
     public override void SetLength(long value) => throw new NotSupportedException();
@@ -57,6 +76,28 @@ public sealed class Crc32Stream : Stream
         seed = CalculateCrc(_table, seed, buffer.AsSpan(offset, count));
     }
 
+    public override async Task WriteAsync(
+        byte[] buffer,
+        int offset,
+        int count,
+        CancellationToken cancellationToken
+    )
+    {
+        await stream.WriteAsync(buffer, offset, count, cancellationToken).ConfigureAwait(false);
+        seed = CalculateCrc(_table, seed, buffer.AsSpan(offset, count));
+    }
+
+#if !LEGACY_DOTNET
+    public override async ValueTask WriteAsync(
+        ReadOnlyMemory<byte> buffer,
+        CancellationToken cancellationToken = default
+    )
+    {
+        await stream.WriteAsync(buffer, cancellationToken).ConfigureAwait(false);
+        seed = CalculateCrc(_table, seed, buffer.Span);
+    }
+#endif
+
     public override void WriteByte(byte value)
     {
         stream.WriteByte(value);
diff --git a/tests/SharpCompress.Test/ADCTest.cs b/tests/SharpCompress.Test/ADCTest.cs
index 8ef40a17..cb2b00a9 100644
--- a/tests/SharpCompress.Test/ADCTest.cs
+++ b/tests/SharpCompress.Test/ADCTest.cs
@@ -23,7 +23,10 @@
 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 // THE SOFTWARE.
+using System;
 using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
 using SharpCompress.Compressors.ADC;
 using SharpCompress.Compressors.Deflate;
 using SharpCompress.Crypto;
@@ -121,4 +124,36 @@ public class AdcTest : TestBase
         Assert.Equal(crc32, crc32A);
         Assert.Equal(crc32, crc32B);
     }
+
+    [Fact]
+    public async Task TestCrc32StreamWriteAsync()
+    {
+        var buffer = File.ReadAllBytes(Path.Combine(TEST_ARCHIVES_PATH, "Tar.tar"));
+        var crc32 = Crc32Stream.Compute(buffer);
+
+        using var memory = new MemoryStream();
+        using var crcStream = new Crc32Stream(memory, 0xEDB88320, 0xFFFFFFFF);
+
+        await crcStream.WriteAsync(buffer, 0, buffer.Length, CancellationToken.None);
+
+        Assert.Equal(buffer, memory.ToArray());
+        Assert.Equal(crc32, crcStream.Crc);
+    }
+
+#if !LEGACY_DOTNET
+    [Fact]
+    public async Task TestCrc32StreamWriteMemoryAsync()
+    {
+        var buffer = File.ReadAllBytes(Path.Combine(TEST_ARCHIVES_PATH, "Tar.tar"));
+        var crc32 = Crc32Stream.Compute(buffer);
+
+        using var memory = new MemoryStream();
+        using var crcStream = new Crc32Stream(memory, 0xEDB88320, 0xFFFFFFFF);
+
+        await crcStream.WriteAsync(buffer.AsMemory(), CancellationToken.None);
+
+        Assert.Equal(buffer, memory.ToArray());
+        Assert.Equal(crc32, crcStream.Crc);
+    }
+#endif
 }